Mounts for blowout preventer bonnets

Background of Invention

Field of the Invention

The invention relates generally to blowout preventers used in the oil and gas industry. Specifically, the invention relates to a blowout preventer with a novel bonnet securing mechanism.

Background Art

Well control is an important aspect of oil and gas exploration. When drilling a well in, for example, oil and gas exploration applications, device must be put in place to prevent injury to personnel and equipment associated with the drilling activities. One such well control device is known as a blowout preventer (BOP).

Blowout preventers are generally used to seal a wellbore. For example, drilling wells in oil or gas exploration involves penetrating a variety of subsurface geologic structures, or "layers". Each layer generally comprises a specific geologic composition such as, for example, shale, sandstone, limestone, etc. Each layer may contain trapped fluids or gas at different formation pressures, and the formation pressures increase with increasing depth. The pressure in the wellbore is generally adjusted to at least balance the formation pressure by, for example, increasing a density of drilling mud in the wellbore or increasing pump pressure at the surface of the well.

There are occasions during drilling operations when a wellbore may penetrate a layer having a formation pressure substantially higher than the pressure maintained in the wellbore. When this occurs, the well is said to have "taken a kick." The pressure increase associated with the kick is generally produced by an influx of formation fluids (which may be a liquid, a gas, or a combination thereof) into the wellbore. The relatively high pressure kick tends to propagate from a point of entry in the wellbore uphole (from a high pressure region to a low pressure region). If the kick is allowed to reach the surface, drilling fluid, well tools, and other drilling structures may be blown out of the wellbore. These "blowouts" often result in catastrophic destruction of the drilling equipment (including, for example, the drilling rig) and in substantial injury or death of rig personnel.

Because of the risk of blowouts, blowout preventers are typically installed at the surface or on the sea floor in deep water drilling arrangements so that kicks may be adequately controlled and "circulated out" of the system. Blowout preventers may be activated to effectively seal in a wellbore until active measures can be taken to control the kick. There are several types of blowout preventers, the most common of which are annular blowout preventers and ram-type blowout preventers.

Annular blowout preventers typically comprise annular elastomer "packers" that may be activated (e.g., inflated) to encapsulate drillpipe and well tools and completely seal the wellbore. A second type of the blowout preventer is the ram-type blowout preventer. Ram-type preventers typically comprise a body and at least two oppositely disposed bonnets. The bonnets are generally secured to the body about their circumference with, for example, bolts. Alternatively, bonnets may be secured to the body with a hinge and bolts so that the bonnet may be rotated to the side for maintenance access.

Interior of each bonnet is a piston actuated ram. The rams may be either pipe rams (which, when activated, move to engage and surround drillpipe and well tools to seal the wellbore) or shear rams (which, when activated, move to engage and physically shear any drillpipe or well tools in the wellbore). The rams are typically located opposite of each other and, whether pipe rams or shear rams, the rams typically seal against one another proximate a center of the wellbore in order to completely seal the wellbore.

As with any tool used in drilling oil and gas wells, blowout preventers must be regularly maintained. For example, blowout preventers comprise high pressure seals between the bonnets and the body of the BOP. The high pressure seals in many instances are elastomer seals. The elastomer seals must be regularly checked to ensure that the elastomer has not been cut, permanently deformed, or deteriorated by, for example, chemical reaction with the drilling fluid in the wellbore. Moreover, it is often desirable to replace pipe rams with shear rams, or vice versa, to provide different well control options. Therefore, it is important that the blowout preventer includes bonnets that are easily removable so that interior components, such as the rams, may be accessed and maintained.

Developing blowout preventers that are easy to maintain is a difficult task. For example, as previously mentioned, bonnets are typically connected to the BOP body by bolts or a combination of a hinge and bolts. The bolts must be highly torqued in order to maintain a seal between a bonnet door and the BOP body. The seal between the bonnet and the BOP body is generally a face seal, and the seal must be able to withstand the very high pressures present in the wellbore.

As a result, special tools and equipment are necessary to install and remove the bonnet doors and bonnets so that the interior of the BOP body may be accessed. The time required to install and remove the bolts connecting the bonnet doors to the BOP body results in rig downtime, which is both expensive and inefficient. Moreover, substantially large bolts and a nearly complete "bolt circle" around the circumference of the bonnet door are generally required to provide sufficient force to hold the bonnet door against the body of the BOP. The size of the bolts and the bolt circle may increase a "stack height" of the BOP. It is common practice to operate a "stack" of BOPs (where several BOPS are installed in a vertical relationship), and a minimized stack eight is desirable in drilling operations.

Several attempts have been made to reduce stack height and the time required to access the interior of the BOP. <patcit id="pcit0001" dnum="US5655745A"><text>U. S. Patent No. 5,655, 745 issued to Morrill </text></patcit>shows a pressure energized seal carrier that eliminates the face seal between the bonnet door and the BOP body. The BOP shown in the '745 patent enables the use of fewer, smaller bolts in less than a complete bolt circle for securing the bonnet to the body. Moreover, the '745 patent shows that a hinge may be used in place of at least some of the bolts.

<patcit id="pcit0002" dnum="US5897094A"><text>U. S. Patent No. 5,897, 094 issued to Brugman et al.</text></patcit> discloses an improved BOP door connection that includes upper and lower connector bars for securing bonnets to the BOP. The improved BOP door connection of the '094 patent does not use bolts to secure the bonnets to the BOP and disclose a design that seeks to minimize a stack height of the BOP. The present application is an improvement over a previous application of the same applicant, said application has been published as <patcit id="pcit0003" dnum="WO02090709A"><text>WO 02/090709</text></patcit>. Embodiments described in said application will be described later on in relation to <figref idref="f0001 f0002 f0003 f0004 f0005 f0006 f0007 f0008 f0009 f0010 f0011">figures 1-25</figref> of the present application.

Summary of Invention

Various aspects of the invention are defined in the appended claims.

Brief Description of Drawings

<figref idref="f0001">Figure 1</figref> shows a partial section and exploded view of a BOP shown in prior art document <patcit id="pcit0004" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit>.

<figref idref="f0002">Figure 2</figref> shows an enlarged view of a portion of the embodiment shown in <figref idref="f0001">Figure 1</figref>.

<figref idref="f0003">Figure 3</figref> shows an embodiment of a radial lock displacement device shown in prior art document <patcit id="pcit0005" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit>.

<figref idref="f0003">Figure 4</figref> shows another embodiment of a radial lock displacement device shown in prior art document <patcit id="pcit0006" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit>.

<figref idref="f0003">Figure 5</figref> shows and embodiment of the prior art document <patcit id="pcit0007" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> where a radial lock is pinned to a portion of a bonnet.

<figref idref="f0003">Figures 6</figref> shows an embodiment of the prior art document <patcit id="pcit0008" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising two halves.

<figref idref="f0004">Figure 7</figref> shows an embodiment of the prior art document <patcit id="pcit0009" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising four segments.

<figref idref="f0004">Figure 8</figref> shows an embodiment of the prior art document <patcit id="pcit0010" dnum="WO02090709A"><text>WO 02/ 090709 </text></patcit>with a radial lock comprising a plurality of segments.

<figref idref="f0004">Figure 9</figref> shows an embodiment of the prior art document <patcit id="pcit0011" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a notched serpentine radial lock.

<figref idref="f0004">Figure 10</figref> shows an embodiment of the prior art document <patcit id="pcit0012" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a locking mechanism used in an embodiment of the invention.

<figref idref="f0005">Figure 11</figref> shows an embodiment of the prior art document <patcit id="pcit0013" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a locking mechanism used in an embodiment of the invention.

<figref idref="f0005">Figure 12</figref> shows an embodiment of the prior art document <patcit id="pcit0014" dnum="WO02090709A"><text>WO 02/ 090709 </text></patcit>with a locking mechanism used in an embodiment of the invention.

<figref idref="f0005">Figure 13</figref> shows an embodiment of the prior art document <patcit id="pcit0015" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a high pressure seal used in an embodiment of the invention.

<figref idref="f0005">Figure 14</figref> shows an embodiment of the prior art document <patcit id="pcit0016" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a high pressure seal used in an embodiment of the invention.

<figref idref="f0006">Figure 15</figref> shows an embodiment of the prior art document <patcit id="pcit0017" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a high pressure seal used in an embodiment of the invention.

<figref idref="f0006">Figure 16</figref> shows an embodiment of the prior art document <patcit id="pcit0018" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a high pressure seal used in an embodiment of the invention.

<figref idref="f0006">Figure 17</figref> shows an embodiment of the prior art document <patcit id="pcit0019" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a high pressure seal used in an embodiment of the invention.

<figref idref="f0007">Figure 18</figref> shows an embodiment of the prior art document <patcit id="pcit0020" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> wherein a radial lock is disposed in a recess in a side passage of a BOP body.

<figref idref="f0007">Figure 19</figref> shows an embodiment of the prior art document <patcit id="pcit0021" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising two halves.

<figref idref="f0007">Figure 20</figref> shows an embodiment of the prior art document <patcit id="pcit0022" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising four segments.

<figref idref="f0008">Figure 21</figref> shows an embodiment of the prior art document <patcit id="pcit0023" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising a plurality of kerfs.

<figref idref="f0008">Figure 22</figref> shows an embodiment of the prior art document <patcit id="pcit0024" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a radial lock comprising graduated kerfs.

<figref idref="f0009">Figure 23</figref> shows a side perspective view of the prior art document <patcit id="pcit0025" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with an embodiment of a swivel slide mount used in one aspect of the invention.

<figref idref="f0010">Figure 24</figref>, shows a front perspective view of an embodiment of the prior art document <patcit id="pcit0026" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with a swivel slide mount used in one aspect of the invention.

<figref idref="f0011">Figure 25</figref> shows a top perspective view of the prior art document <patcit id="pcit0027" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> with an embodiment of a swivel slide mount used in one aspect of the invention.

<figref idref="f0012">Figure 26</figref> shows a side perspective view of an example of a bonnet mount

<figref idref="f0013">Figure 27A</figref> shows a top view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0013">Figure 27B</figref> shows a side view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0014">Figure 27C</figref> shows a top view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0015">Figure 28A</figref> shows a top view of a bonnet mount

<figref idref="f0015">Figure 28B</figref> shows a side view of a bonnet mount

<figref idref="f0016">Figure 28C</figref> shows a top view of a bonnet mount

<figref idref="f0016">Figure 28D</figref> shows a side view of a bonnet mount

<figref idref="f0017">Figure 29A</figref> shows a top view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0017">Figure 29B</figref> shows an end view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0018">Figure 29C</figref> shows a side view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0018">Figure 29D</figref> shows a top view of an embodiment of a bonnet mount used in one aspect of the invention.

<figref idref="f0019">Figure 30A</figref> shows a top view of a bonnet mount

<figref idref="f0019">Figure 30B</figref> shows a top view of a bonnet mount

<figref idref="f0020">Figure 30C</figref> shows a top view of a bonnet mount

<figref idref="f0021">Figure 31A</figref> shows a top view of a bonnet mount

<figref idref="f0021">Figure 31B</figref> shows a top view of a bonnet mount

<figref idref="f0022">Figure 32</figref> shows a side view of a bonnet mount

Detailed Description

Embodiments of the prior art document <patcit id="pcit0028" dnum="WO02090709A"><text>WO 02/ 090709</text></patcit> will be described there after in relation to <figref idref="f0001 f0002 f0003 f0004 f0005 f0006 f0007 f0008 f0009 f0010 f0011">figures 1-25</figref>. An embodiment shown in <figref idref="f0001">Figure 1</figref> of a ram-type blowout preventer (BOP) 10 comprises a BOP body 12 and oppositely disposed bonnet assemblies 14. The BOP body 12 further comprises couplings 16 (which may be, for example, flanges) on an upper surface and a lower surface of the BOP body 12 for coupling the BOP 10 to, for example, another BOP or to another well tool. The BOP body 12 comprises an internal bore 18 there through for the passage of drilling fluids, drillpipe, well tools, and the like used to drill, for example, an oil or gas well. The BOP body 12 further comprises a plurality of side passages 20 wherein each of the plurality of side passages 20 is generally adapted to be coupled to a bonnet assembly 14.

The bonnet assemblies 14 are coupled to the BOP body 12, typically in opposing pairs as shown in <figref idref="f0001">Figure 1</figref>. Each bonnet assembly 14 further comprises a plurality of components adapted to seal the bonnet assembly 14 to the BOP body 12 and to activate a ram piston 22 within each bonnet assembly 14. Components of the bonnet assemblies 14 comprise passages there through for movement of the ram piston 22.

Each bonnet assembly 14 generally comprises similar components. While each bonnet assembly 14 is a separate and distinct part of the BOP 10, the operation and structure of each bonnet assembly 14 is similar. Accordingly, in order to simplify the description of the operation of the BOP 10 and of the bonnet assemblies 14, the components and operation of one bonnet assembly 14 will be described in detail. It should be understood that each bonnet assembly 14 operates in a similar manner and that, for example, opposing bonnet assemblies 14 typically operate in a coordinated manner.

Proceeding with the description of the operation of one bonnet assembly 14, the piston 22 is adapted to be coupled to a ram (not shown) that may be, for example, a pipe ram or a shear ram. Each ram piston 22 is coupled to a ram actuator cylinder 24 that is adapted to displace the ram piston 22 axially within the bonnet assembly 14 in a direction generally perpendicular to an axis of the BOP body 12, the axis of the BOP body 12 being generally defined as a vertical axis of the internal bore 18 (which is generally parallel with respect to a wellbore axis). A ram (not shown) is generally coupled to the ram piston 22, and, if the rams (not shown) are shear rams, the axial displacement of the ram piston 22 generally moves the ram (not shown) into the internal bore 18 and into contact with a corresponding ram (not shown) coupled to a ram piston 22 in a bonnet assembly 14 disposed on an opposite side of the BOP 10.

Alternatively, if the rams (not shown) are pipe rams, axial displacement of the ram piston generally moves the ram (not shown) into the internal bore 18 and into contact with a corresponding ram (not shown) and with drillpipe and/or well tools present in the wellbore. Therefore, activation of the ram actuator cylinder 24 displaces the ram piston 22 and moves the ram (not shown) into a position to block a flow of drilling and/or formation fluid through the internal bore 18 of the BOP body 12 and, in doing so, to form a high pressure seal that prevents fluid flow from passing into or out of the wellbore (not shown).

The ram actuator cylinder 24 further comprises an actuator 26 which may be, for example, a hydraulic actuator, However, other types of actuators are known in the art and may be used with the invention. Note that for purposes of the description of the invention, a "fluid" may be defined as a gas, a liquid, or a combination thereof.

For example, if the ram (not shown) is a pipe ram, activation of the ram piston 22 moves the ram (not shown) into position to seal around drillpipe (not shown) or well tools (not shown) passing through the internal bore 18 in the BOP body 12. Further, if the ram (not shown) is a shear ram, activation of the ram piston 22 moves the ram (not shown) into position to shear any drillpipe (not shown) or well tools (not shown) passing through the internal bore 18 of the BOP body 12 and, therefore, seal the internal bore 18.

Radial Lock Mechanism for Coupling Bonnets to BOPs

An important aspect of a BOP 10 is the mechanism by which the bonnet assemblies 14 are sealed to the body 12. <figref idref="f0001">Figure 1</figref> shows a radial lock mechanism 28 that is designed to provide a high pressure radial seal between the bonnet assembly 14 and the BOP body 12. Moreover, the radial lock mechanism 28 is designed to simplify maintenance of the bonnet assembly 14 and the rams (not shown) positioned therein.

In the embodiments shown in the Figures, the side passages 20 and other components of the BOP 10 designed to be engaged therewith and therein are shown as being oval or substantially elliptical in shape. An oval or substantially elliptical shape (e. g. , an oval cross-section) helps reduce the stack height of the BOP, thereby minimizing weight, material used, and cost. Other shapes such as circular shapes, however, are also suitable for use with the invention.

The radial lock mechanism 28 is positioned within the bonnet assembly 14 and within the side passage 20 of the BOP body 12. In this embodiment, the radial lock mechanism 28 comprises a bonnet seal 29 disposed on a bonnet body 30, a radial lock 32, a radial lock displacement device 34, a bonnet door 36, and lock actuators 38. The bonnet seat 29 cooperatively seals the bonnet body 30 to the BOP body 12 proximate the side passage 20. The bonnet seal 29 comprises a high pressure seal that prevents fluids from the internal bore 18 of the BOP body 12 from escaping via the side passage 20. Various embodiments of the bonnet seal 29 will be discussed in detail below.

When the bonnet seal 29 is formed between the bonnet body 30 and the BOP body 12, the bonnet body 30 is in an installed position and is located proximate the BOP body 12 and at least partially within the side passage 20. Because the bonnet seat 29 is a high pressure seal, the radial lock mechanism 28 must be robust and able to withstand very high pressures present in the internal bore 18.

The embodiment shown in <figref idref="f0001">Figure 1</figref> comprises a novel mechanism for locking the bonnet assembly 14 (and, as a result, the bonnet seal 29) in place. Referring to <figref idref="f0002">Figure 2</figref>, the radial lock 32 has an inner diameter adapted to fit over an exterior surface 40 of the bonnet body 30 and slide into a position adjacent a sealing end of the bonnet body 30. The radial lock 32 shown in <figref idref="f0002">Figure 2</figref> comprises two halves separated by a center cut 46. However, the radial lock 32 may comprise additional segments. Additional embodiments of the radial lock 32 will be described in greater detail below.

The radial lock displacement device 34 also has an inner diameter adapted to fit over the exterior surface 40 of the bonnet body 30. Moreover, the radial lock displacement device 34 further comprises a wedge surface 48 on an external diameter that is adapted to fit inside an inner diameter 50 of the radial lock <b>32.</b> The radial lock displacement device <b>34</b> also comprises an inner face <b>56</b> that is adapted to contact an outer surface <b>54</b> of the BOP body <b>12.</b> In an installed position, the bonnet body <b>30,</b> the radial lock <b>32,</b> and the radial lock displacement device <b>34</b> are positioned between the BOP body <b>12</b> and the bonnet door <b>36.</b> An inner surface <b>52</b> of the bonnet door <b>36</b> is adapted to contact the outer surface <b>54</b> of the BOP body <b>12.</b> Note that the engagement between the bonnet door <b>36</b> and the BOP body <b>12</b> is not fixed (<i>e.g</i>., the bonnet door <b>36</b> is not bolted to the BOP body <b>12</b>).

Referring again to <figref idref="f0001">Figure 1</figref>, the bonnet assembly <b>14</b> is adapted to slidably engage at least one rod <b>70</b> through a swivel slide mount <b>74</b> (note that two rods <b>70</b> are shown slidably engaged, through the swivel slide mounts <b>74,</b> with each bonnet assembly <b>14</b> in <figref idref="f0001">Figure 1</figref>). As a result of the slidable engagement, the bonnet assembly <b>14</b> may slide along the rods <b>70.</b> As will be discussed below, the slidable engagement permits the bonnet assembly <b>14</b> to be moved into and out of locking and sealing engagement with the BOP body <b>12.</b>

The lock actuators <b>38</b> are coupled to the bonnet door <b>36</b> with either a fixed or removable coupling comprising bolts, adhesive, welds, threaded connections, or similar means known in the art. The lock actuators <b>38</b> are also cooperatively coupled to the radial lock displacement device <b>34</b> in a similar fashion. Additionally, the coupling between the lock actuators <b>38</b> and the radial lock displacement device <b>34</b> may be a simple contact engagement. Note that the embodiments in <figref idref="f0001">Figure 1</figref> shows two lock actuators <b>38</b> coupled to each bonnet door <b>36.</b> However, a single lock actuator cylinder <b>38</b> or a plurality of lock actuators <b>38</b> may be used with the invention. The lock actuators <b>38</b> shown are generally hydraulic cylinders; however, other types of lock actuators (including, for example, pneumatic actuators, electrically powered motors, and the like) are known in the art and may be used with the invention.

Moreover, the lock actuators <b>38</b> may also be manually operated. The lock actuators <b>38</b> shown in the present embodiment are typically controlled by, for example, an external electrical signal, a flow of pressurized hydraulic fluid, etc. As an alternative, the radial lock <b>32</b> may be activated by manual means, such as, for example, a lever, a system of levers, a threaded actuation device, or other similar means known in the art. Further, if, for example, the lock actuators <b>38</b> comprise hydraulic cylinders, the hydraulic cylinders may be activated by a manual pump. Accordingly, manual activation of the radial lock <b>32</b> is within the scope of the invention.

A fully assembled view of the bonnet assembly <b>14</b> including the radial lock mechanism <b>28</b> is shown in <figref idref="f0002">Figure 2</figref>. During operation of the radial lock mechanism <b>28,</b> the bonnet assembly <b>14</b> is first moved into position proximate the BOP body <b>12</b> by sliding the bonnet assembly <b>14</b> toward the BOP body <b>12</b> on the rods <b>70.</b> The lock actuators <b>38</b> are then activated so that they axially displace (wherein an axis of displacement corresponds to an axis of the side passage <b>20)</b> the radial lock displacement device <b>34</b> in a direction toward the BOP body <b>12.</b> As the radial lock displacement device <b>34</b> moves axially toward the BOP body <b>12,</b> the wedge surface <b>48</b> contacts the inner diameter <b>50</b> of the radial lock <b>32,</b> thereby moving the radial lock <b>32</b> in a radially outward direction (<i>e.g</i>., toward an inner radial lock surface <b>58</b> of the side passage <b>20).</b> When the activation of the radial lock mechanism <b>28</b> is complete, an inner nose <b>60</b> of the radial lock displacement device <b>34</b> is proximate a load shoulder <b>44</b> of the bonnet body <b>30,</b> and an outer perimeter <b>62</b> of the radial lock <b>32</b> is lockingly engaged with the inner radial lock surface <b>58.</b> Moreover, as will be described below, both the radial lock <b>32</b> and the inner radial lock surface <b>58</b> typically comprise angled surfaces (refer to, for example, the engagement surfaces described in the discussion of <figref idref="f0004">Figures 10</figref> and <figref idref="f0005">11</figref><i>infra</i>). When the radial lock <b>32</b> engages the inner radial lock surface <b>58,</b> the angled surfaces are designed to provide an axial force that "pulls" the bonnet door <b>36</b> in an axially inward direction and firmly against the exterior of the BOP body <b>12</b> and thereby completes the locking engagement of the radial lock mechanism <b>28.</b>

When the radial lock 32 is secured in place by the activation of the lock actuators 38 and the radial lock displacement device 34, the bonnet body 30 and the bonnet assembly 14 are axially locked in place with respect to the BOP body 12 without the use of, for example, bolts. However, an additional manual locking mechanism (not shown) may also be used in combination with the invention to ensure that the radial lock 32 remains securely in place. Once the radial lock 32 is secured in place by, for example, hydraulic actuation, a manual lock (not shown), such as a pinned or threaded mechanism, may be activated as an additional restraint. The secured radial locking mechanism 28 is designed to hold the bonnet assembly 14 and, accordingly, the high pressure bonnet seal 29 in place. The radial lock 32 and the high pressure bonnet seal 29 can withstand the high forces generated by the high pressures present within the internal bore 18 of the BOP body 12 because of the locking engagement between the radial lock 32 and the inner radial lock surface 58 of the BOP body 12.

The radial lock mechanism 28 may be disengaged by reversing the activation of the lock actuators 38 (e. g. , after the pressure in the internal bore 18 has been relieved). As a result, the embodiment comprises a radial lock mechanism 28 that includes a positive disengagement system (e. g., the lock actuators 38 must be activated in order to disengage the radial lock mechanism 28).

The wedge surface 48 used to radially displace the radial lock 32 may comprise any one of several embodiments. Referring to <figref idref="f0003">Figure 3</figref>, in one embodiment, the wedge surface 48 of the radial lock displacement device 34 may comprise a single actuation step 80. In another embodiment shown in <figref idref="f0003">Figure 4</figref>, the wedge surface 48 may comprise a dual actuation step 82. Note that the single actuation step (80 in <figref idref="f0003">Figure 3</figref>) generally has a shorter actuation stroke than the dual actuation step (82 in <figref idref="f0003">Figure 4</figref>). Further, an actuation step angle (84 in <figref idref="f0003">Figures 3 and 4</figref>) is designed to maximize a radial actuation force and minimize a linear actuation force. In one embodiment, the actuation step angle (84 in <figref idref="f0003">Figures 3 and 4</figref>) is approximately 45 degrees. In another embodiment, the actuation step angle (84 in <figref idref="f0003">Figures 3 and 4</figref>) is less than 45 degrees.

In another embodiment shown in <figref idref="f0003">Figure 5</figref>, the radial lock displacement device 34 further comprises a slot 90 and at least one retention pin 92 designed to retain the radial lock 32 against the load shoulder 44 of the bonnet body 30. in this embodiment, the radial lock 32 is retained in place by the at least one retention pin 92, and the bonnet body 30 and the radial lock 32 are held in a fixed relationship after the radial lock 32 has been actuated and is in locking engagement with the inner radial lock surface (58 in <figref idref="f0002">Figure 2</figref>) of the side passage (20 in <figref idref="f0001">Figure 1</figref>).

The radial lock (32 in <figref idref="f0001">Figure 1</figref>) may also comprise any one of several embodiments. The radial lock 32 shown in the embodiment of <figref idref="f0001">Figure 1</figref> comprises two radial mirrored halves 94,96, as further shown in <figref idref="f0003">Figure 6</figref>. In another embodiment, as shown in <figref idref="f0004">Figure 7</figref>, a radial lock 100 may be formed from at least two substantially linear segments 102 and at least two semicircular end segments 104. In another embodiment, as shown in <figref idref="f0004">Figure 8</figref>, a radial lock 106 may be formed from a plurality of substantially straight dogs 108 and a plurality of curved dogs 110. The embodiments shown in <figref idref="f0004">Figures 7 and 8</figref> essentially comprise radial locks 100, 106 similar to the radial lock (32 in <figref idref="f0001">Figures 1</figref> and <figref idref="f0003">6</figref>) of the first embodiment but divided into a plurality of segments. The radial locks 100,106 could be manufactured by, for example, manufacturing a solid radial lock and sequentially saw cutting the solid radial lock into two or more segments. However, other manufacturing techniques are known in the art and may be used to manufacture the radial lock.

In another embodiment shown in <figref idref="f0004">Figure 9</figref>, a radial lock 112 may be formed from a notched serpentine structure 114 similar to a "serpentine belt." The radial lock 112 is formed, for example, as a single solid piece and then cut <b>117</b> through an inner perimeter <b>114</b> or an outer perimeter <b>116.</b> The cuts <b>117</b> can either completely transect the radial lock <b>112</b> or may include only partial cuts. Further, if the cuts <b>117</b> transect the radial lock <b>112,</b> the individual segments can be attached to a flexible band <b>118</b> so that the radial lock <b>112</b> can be actuated with an actuating ring <b>(34</b> in <figref idref="f0001">Figure 1</figref>). The flexible band <b>118</b> may comprise a material with a relatively low elastic modulus (when compared to, for example, the elastic modulus of the individual segments) so that the flexible band <b>118</b> can radially expand in response to the radial displacement produced by the radial lock displacement device <b>(34</b> in <figref idref="f0001">Figure 1</figref>). Radial expansion of the flexible band <b>118</b> results in a locking engagement between the radial lock <b>112</b> and the inner radial lock surface <b>(58</b> in <figref idref="f0002">Figure 2</figref>) of the BOP body <b>(12</b> in <figref idref="f0001">Figure 1</figref>).

The engagement between the radial lock <b>(32</b> in <figref idref="f0001">Figure 1</figref>) and the inner radial lock surface <b>(58</b> in <figref idref="f0002">Figure 2</figref>) may also comprise different embodiments. In one embodiment, as shown in <figref idref="f0004">Figure 10</figref>, a radial lock <b>120</b> may comprise a single profile engagement including a single radial lock engagement surface <b>122.</b> The single radial lock engagement surface <b>122</b> is designed to lockingly engage a BOP engagement surface <b>(59</b> in <figref idref="f0002">Figure 2</figref>) formed on the inner radial lock surface <b>(58</b> in <figref idref="f0002">Figure 2</figref>) of the side passage <b>(20</b> in <figref idref="f0001">Figure 1</figref>).

In another embodiment, as shown in <figref idref="f0005">Figure 11</figref>, a radial lock <b>124</b> comprises a dual profile engagement including two radial lock engagement surfaces <b>126.</b> Moreover, the radial lock <b>124</b> may also comprise a plurality of radial lock engagement surfaces designed to lockingly engage a corresponding number of BOP engagement surfaces <b>(59</b> in <figref idref="f0002">Figure 2</figref>) formed on the inner radial lock surface <b>(58</b> in <figref idref="f0002">Figure 2</figref>) of the side passage <b>(20</b> in <figref idref="f0001">Figure 1</figref>) of the BOP body <b>(12</b> in <figref idref="f0001">Figure 1</figref>).

The radial locks described in the referenced embodiments are designed so that the cross-sectional area of engagement between the radial lock engagement surfaces with the BOP engagement surfaces <b>(59</b> in <figref idref="f0002">Figure 2</figref>) is maximized. Maximizing the cross-sectional areas of engagement ensures that the radial locks positively lock the bonnet assembly <b>(14</b> in <figref idref="f0001">Figure 1</figref>) and, as a result, the bonnet seal <b>(29</b> in <figref idref="f0001">Figure 1</figref>) in place against the high pressures present in the internal bore <b>(18</b> in <figref idref="f0001">Figure 1</figref>) of the BOP <b>(10</b> in <figref idref="f0001">Figure 1</figref>). Moreover, as discussed previously, angles of the engagement surfaces may be designed to produce an axial force that firmly pulls the bonnet door <b>(36</b> in <figref idref="f0001">Figure 1</figref>) against the BOP body <b>(12</b> in <figref idref="f0001">Figure 1</figref>) and that in some embodiments may assist in the activation of the bonnet seal <b>(29</b> in <figref idref="f0001">Figure 1</figref>).

The radial locks and the engagement surfaces described in the foregoing embodiments may be coated with, for example, hardfacing materials and/or friction reducing materials. The coatings may help prevent, for example, galling, and may prevent the radial locks from sticking or "hanging-up" in the engagement surfaces during the activation and/or deactivation of the radial lock mechanism <b>(28</b> in <figref idref="f0001">Figure 1</figref>). The coatings may also increase the life of the radial locks and the engagement surfaces by reducing friction and wear.

Another embodiment of the lock ring is shown at <b>127</b> in <figref idref="f0005">Figure 12</figref>. The radial lock <b>127</b> comprises a plurality of saw cuts <b>128,</b> a plurality of holes <b>129,</b> or a combination thereof. The saw cuts <b>128</b> and/or holes <b>129</b> decrease the weight and area moment of inertia of the radial lock <b>127,</b> thereby reducing the actuation force required to radially displace the radial lock <b>127.</b> In order to permit some elastic deformation of the radial lock <b>127,</b> the radial lock <b>127</b> may be formed from a material having a relatively low modulus of elasticity (when compared to, for example, steel). Such materials comprise titanium, beryllium copper, <i>etc.</i> Moreover, modifications to the radial lock <b>127</b> geometry, in addition to those referenced above, may be made to, for example, further reduce the area moment of inertia of the radial lock <b>127</b> and reduce bending stresses.

The radial locks described above are designed to operate below an elastic limit of the materials from which they are formed. Operation below the elastic limit ensures that the radial locks will not permanently deform and, as a result of the permanent deformation, lose effectiveness. Accordingly, material selection and cross-sectional area of engagement of the engagement surfaces is very important to the design of the radial lock mechanism <b>(28</b> in <figref idref="f0001">Figure 1</figref>).

Referring to <figref idref="f0001">Figure 1</figref>, the bonnet seal <b>29</b> is designed to withstand the high pressures present in the internal bore <b>18</b> of the BOP body <b>12</b> and to thereby prevent fluids and/or gases from passing from the internal bore <b>18</b> to the exterior of the BOP <b>10.</b> The bonnet seal <b>29</b> may comprise several different configurations as shown in the following discussion of <figref idref="f0005 f0006">Figures 13-17</figref>. Moreover, the seals disclosed in the discussion below may be formed from a variety of materials. For example, the seals may be elastomer seals or non-elastomer seals (such as, for example, metal seals, PEEK seals, <i>etc</i>.). Metal seals may further comprise metal-to-metal C-ring seals and/or metal-to-metal lip seals. Further, the sealing arrangements shown below may include a combination of seal types and materials. Accordingly, the type of seal, number of seals, and the material used to form radial and face seals are not intended to limit the bonnet seal <b>29.</b>

The embodiment in <figref idref="f0005">Figure 13</figref> comprises a bonnet seal <b>130</b> formed on a radial perimeter <b>132</b> of a bonnet body <b>133.</b> The radial seal <b>130</b> further comprises two o-rings <b>134</b> disposed in grooves <b>136</b> formed on the radial perimeter <b>132</b> of the bonnet body <b>133.</b> The o-rings <b>134</b> sealingly engage an inner sealing perimeter <b>138</b> of the side passage <b>(20</b> in <figref idref="f0001">Figure 1</figref>) in the BOP body <b>12.</b> The embodiment shown in <figref idref="f0005">Figure 13</figref> comprises two grooves <b>136,</b> but a single groove or a plurality of grooves may be suitable for use with the o-rings <b>134.</b> Moreover, while the embodiment shows two o-rings <b>134,</b> a single o-ring or more than two o-rings may be used in the invention.

In another embodiment shown in <figref idref="f0005">Figure 14</figref>, a bonnet seal <b>140</b> comprises at least two packing seals <b>146</b> (which may be, for example, t-seals, lip seals, or seals sold under the trademark PolyPak, which is a mark of Parker Hannifin, Inc.) disposed in grooves <b>148</b> formed on a radial perimeter <b>142</b> of a bonnet body <b>144.</b> The packing seals <b>146</b> sealingly engage an inner sealing perimeter <b>150</b> of the side passage <b>(20</b> in <figref idref="f0001">Figure 1</figref>) of the BOP body <b>12.</b> The embodiment shown in <figref idref="f0005">Figure 14</figref> comprises two grooves <b>148,</b> but a single groove or a plurality of grooves may be suitable for use with the packing seals <b>146.</b> Moreover, while the embodiment shows two packing seals <b>146,</b> a single seal or more than two seals may be used in the invention.

In another embodiment shown in <figref idref="f0006">Figure 15</figref>, the bonnet seal <b>152</b> comprises a radial seal <b>154</b> disposed in a groove <b>166</b> formed on a radial perimeter <b>160</b> of a bonnet body <b>162.</b> Moreover, the embodiment comprises a face seal <b>156</b> disposed in a groove <b>164</b> formed on a mating face surface <b>168</b> of the bonnet body <b>162.</b> The radial seal <b>154</b> is adapted to sealingly engage an inner sealing perimeter <b>158</b> of the side passage <b>(20</b> in <figref idref="f0001">Figure 1</figref>) of the BOP body <b>12.</b> The face seal <b>156</b> is adapted to sealingly engage an exterior face <b>170</b> of the BOP body <b>12.</b> The radial seal <b>154</b> and face seal <b>156</b> shown in the embodiment are both o-rings and are disposed in single grooves <b>166, 164.</b> However, a different type of seal (such as, for example, a packing seal) and more than one seal (disposed in at least one groove) may be used with the invention.

In another embodiment shown in <figref idref="f0006">Figure 16</figref>, the bonnet seal <b>172</b> comprises a radial seal <b>174</b> disposed in a groove <b>178</b> formed on a seal carrier <b>180.</b> The seal carrier <b>180</b> is disposed in a groove <b>182</b> formed in a bonnet body <b>184</b> and also comprises a face seal <b>176</b> disposed in a groove <b>177</b> formed on the seal carrier <b>180.</b> The face seal <b>176</b> is adapted to sealingly engage mating face surface <b>186</b> of the BOP body <b>12,</b> and the radial seal is adapted to sealingly engage an inner sealing perimeter <b>188</b> formed on the bonnet body <b>184.</b> The bonnet seal <b>172</b> may also comprise an energizing mechanism <b>190</b> that is adapted to displace the seal carrier <b>180</b> in a direction toward the exterior surface <b>186</b> of the BOP body <b>12</b> so as to energize the face seal <b>176.</b> The energizing mechanism <b>190</b> may comprise, for example, a spring, a thrust washer, or a similar structure.

The energizing mechanism <b>190</b> helps ensure that the face seal <b>176</b> maintains positive contact with and, thus, maintains a high pressure seal with the exterior surface <b>186</b> of the BOP body <b>12.</b> However, the energizing mechanism <b>190</b> is not required in all embodiments. For example, the seal carrier <b>180</b> may be designed so that both the radial seal <b>174</b> and the face seal <b>176</b> are pressure activated without the assistance of an energizing mechanism <b>190.</b>

In the embodiment without an energizing mechanism, a diameter and an axial thickness of a seal carrier (such as the seal carrier <b>180</b> shown in <figref idref="f0006">Figure 16</figref>) are selected so that high pressure from the internal bore first moves the seal carrier toward the exterior surface of the BOP body. Once the face seal sealingly engages the exterior surface, the high pressure from the internal bore causes the seal carrier to radially expand until the radial seal sealingly engages the groove in the seal carrier. A similar design is disclosed in <patcit id="pcit0029" dnum="US5255890A"><text>U.S. Patent No. 5,255,890</text></patcit> issued to Morrill and assigned to the assignee of the present invention. The '890 patent clearly describes the geometry required for such a seal carrier.

In the embodiment shown in <figref idref="f0006">Figure 16</figref>, the face seal <b>176</b> and the radial seal <b>174</b> may be, for example, o-rings, packing seals, or any other high pressure seal known in the art. Moreover, <figref idref="f0006">Figure 16</figref> only shows single seals disposed in single grooves. However, more than one seal, more than one groove, or a combination thereof may be used with the invention.

In another embodiment shown in <figref idref="f0006">Figure 17</figref>, the seal carrier <b>192</b> as shown in the previous embodiment is used in combination with a backup seal <b>194</b> disposed in a groove <b>196</b> on an external surface <b>198</b> of a bonnet body <b>200.</b> The backup seal <b>194</b> may be an o-ring, a packing seal, a metal seal, or any other high pressure seal known in the art. The backup seal <b>194</b> further maintains a high pressure seal if, for example, there is leakage from the seals disposed on the seal carrier <b>192.</b> Note that the embodiment shown in <figref idref="f0006">Figure 17</figref> does not include an energizing mechanism.

Advantageously, some of the seal embodiments reduce an axial force necessary to form the bonnet seal. The bonnet seals shown above greatly reduce the sensitivity of the bonnet seal to door flex by maintaining a constant squeeze regardless of wellbore pressure. The radial seal arrangements also reduce the total area upon which wellbore pressure acts and thus reduces a separation force that acts to push the bonnet door away from the BOP body.

In another embodiment of the radial lock shown in <figref idref="f0007">Figure 18</figref>, the radial lock mechanism <b>220</b> comprises a radial lock <b>222</b> disposed in a recess <b>224</b> formed on an internal surface <b>226</b> of a side passage <b>228</b> of a BOP body <b>230.</b> The operation of the radial lock mechanism <b>220</b> differs from the embodiments described above in that securing a bonnet body <b>232</b> and, accordingly, a bonnet door (not shown) and a bonnet assembly (not shown), in place is accomplished by actuating the radial lock mechanism <b>220</b> in radially <i>inward</i> direction.

The structure of the embodiment shown in <figref idref="f0007">Figure 18</figref> is similar to the structure of the embodiments described above except for the direction of actuation of the radial lock mechanism <b>220.</b> Therefore, the discussion of the present embodiment will include a description of how the alternative radial lock mechanism <b>220</b> differs from those shown above. Common elements of the embodiments (such as, for example, the bonnet door <b>36,</b> the linear rods <b>70,</b><i>etc</i>.) will not be described again in detail. Moreover, it should be noted that the embodiment of <figref idref="f0007">Figure 18</figref> does not require, for example, actuator cylinders or a radial lock displacement device (<i>e.g</i>., the embodiment of <figref idref="f0007">Figure 18</figref> does not require an <i>internal</i> actuation mechanism).

Actuation of the radial lock <b>222</b> is in a radially inward direction. Accordingly, the radial lock <b>222</b> must be coupled to an actuation mechanism that differs from, for example, the radial lock displacement device <b>(34</b> in <figref idref="f0001">Figure 1</figref>) described in the previous embodiments. In one embodiment, the radial lock 222 comprises a structure similar to those shown in <figref idref="f0003">Figures 6</figref> and <figref idref="f0004">7</figref>. As shown in <figref idref="f0007">Figure 19</figref>, separate halves 236,238 of the radial lock 222 may be coupled to radially positioned actuators 240. When the bonnet body 232 is moved into a sealing engagement with the BOP body 230, the actuators 240 are activated to displace the halves 236,238 of the radial lock 222 in a radially inward direction so that the radial lock 222 engages a groove (244 in <figref idref="f0007">Figure 18</figref>) formed on an exterior surface (246 in <figref idref="f0007">Figure 18</figref>) of the bonnet body (232 in <figref idref="f0007">Figure 18</figref>). The radial lock mechanism (220 in <figref idref="f0007">Figure 18</figref>) locks the bonnet body (232 in <figref idref="f0007">Figure 18</figref>) and, therefore, the bonnet door (not shown) and the bonnet assembly (not shown) in place and energizes the high pressure seal (234 in <figref idref="f0007">Figure 18</figref>). Note that the high pressure seal (234 in <figref idref="f0007">Figure 18</figref>) may be formed from any of the embodiments shown above (such as the embodiments described with respect to <figref idref="f0005 f0006">Figures 13-17</figref>). Moreover, the radial lock 222 and the groove 244 may comprise angled surfaces (as disclosed in previous embodiments) that produce an axial force that pulls the bonnet body 232 (and the bonnet assembly (not shown) and bonnet door (not shown)) toward the BOP body 230 and further ensure a positive locking engagement.

Moreover, as shown in <figref idref="f0007">Figure 20</figref>, the radial lock 222 may comprise more than two parts. If a radial lock 250 comprises, for example, four parts 252, 254, 256, 258, an equal number of actuators 240 (e. g., four) may be used to actuate the radial lock 250. Alternatively, fewer actuators 240 (e. g. , less than four in the embodiment shown in <figref idref="f0007">Figure 20</figref>) may be used if an actuator 240 is, for example, coupled to more than one part parts 252, 254, 256, 258 of the radial lock 250. The actuators 240 may be hydraulic actuators or any other type of actuator known in the art. Moreover, the actuators 240 may be disposed within the BOP body (230 in <figref idref="f0007">Figure 18</figref>) or may be positioned external to the BOP body (230 in <figref idref="f0007">Figure 18</figref>). The actuators 240 may be coupled to the radial lock 250 with, for example, mechanical or hydraulic linkages (not shown). On another embodiment, the radial lock 222 comprises a plurality of dies or dogs (not shown) that are coupled to and activated by a plurality of actuators (not shown).

In another embodiment shown in <figref idref="f0008">Figure 21</figref>, a lock 270 may be formed from a single segment 272. The radial lock 270 is actuated by circumferential actuators 274 coupled to the radial lock 270 and disposed proximate ends 276,278 of the segment 272. When activated, the circumferential actuators 274 move the ends 276,278 of the segment 272 cowards each other and in a radially inward direction as shown by the arrows in <figref idref="f0008">Figure 21</figref>. The dashed line in <figref idref="f0008">Figure 21</figref> represents an inner surface 277 of the radial lock 270 after actuation. The radial lock 270, when actuated, engages the bonnet body (232 in <figref idref="f0007">Figure 18</figref>) in a manner similar to that shown in <figref idref="f0007">Figure 18</figref>.

The segment 272 of the radial lock 270 may be produced by forming a plurality of kerfs 284 proximate the end segments 280,282. The kerfs 284 may be designed to ease installation of the radial lock 270 in the recess (224 in <figref idref="f0007">Figure 18</figref>) and to improve flexibility for radial deformation of the radial lock 270. The kerfs may be of any shape known in the art. For example, <figref idref="f0008">Figure 22</figref> shows rectangular kerfs 284. However, the kerfs 284 may preferably be formed in a manner that reduces stress concentrations or stress risers at the edges of the kerfs 284. For example, if the kerfs 284 are formed as rectangular shapes, stress risers may form at the relatively sharp corners. Accordingly, the kerfs 284 may comprise filleted corners (not shown) or, for example, substantially trapezoidal shapes (not shown) to minimize the effects of stress risers.

Moreover, the kerfs 284 may be "graduated, " as shown in <figref idref="f0008">Figure 22</figref>, to produce a substantially smooth transition between relatively stiff straight segments 286 and relatively flexible end segments 280, 282. Graduation of the kerfs <b>284</b> effects a smooth stiffness transition that helps prevent stress risers at the last kerf (<i>e.g</i>., at the last kerf proximate the straight segments <b>286).</b>

The radial lock <b>270</b> may be formed from a single material or from different materials (comprising, for example, steel, titanium, beryllium copper, or combinations and/or alloys thereof). For example, the curved end segments <b>280, 282</b> may be formed from a material that is relatively compliant when compared to a relatively rigid material forming the straight segments <b>286</b> (<i>e.g.,</i> the curved and segments <b>280, 282</b> may be formed from a material with an elastic modulus (E_C) that is substantially lower than an elastic modulus (E_S) of the straight segments <b>286).</b> Regardless of the materials used to form the radial lock <b>270,</b> the radial lock <b>270</b> must be flexible enough to permit installation into and removal from the recess <b>(224</b> in <figref idref="f0007">Figure 18</figref>).

Alternatively, the radial lock <b>270</b> of <figref idref="f0008">Figure 21</figref> may comprise more than one segment (<i>e.g</i>., two halves or a plurality of segments) coupled to and actuated by a plurality of circumferential actuators. The radial lock <b>270</b> may also comprise a plurality of separate dies or dogs coupled by a flexible band. The dies may be separated by gaps, and the distance of separation may be selected to provide a desired flexibility for the radial lock <b>270.</b>

The dies and the flexible banding may comprise different materials. For example, the dies may be formed from a substantially stiff material (<i>e.g</i>., a material with a relatively high modulus of elasticity) comprising, for example, steel or nickel based alloys. The flexible banding, in contrast, may be formed from materials having a relatively lower modulus elasticity and comprising, for example, titanium alloys or pultruded flats or shapes comprising fiberglass, carbon fibers, or composite materials thereof. As described above, the radial locks of the embodiments shown in <figref idref="f0007 f0008">Figures 19-22</figref> may be coated with, for example, hardfacing materials (comprising, for example, tungsten carbide, boron nitride, and similar materials known in the art) or low-friction materials (comprising, for example, polytetrafluoroethylene and similar materials known in the art) to, for example, reduce friction and wear and improve the longevity of the parts. The material composition of the radial lock 270 is not intended to be limiting.

The embodiments shown in <figref idref="f0007 f0008">Figures 19-22</figref> may be advantageous because of a reduced bonnet assembly weight and accordingly, reduced overall weight of the BOP. Moreover, there is a potential to retrofit old BOPs to include the radial lock mechanism.

<u style="single">Swivel Slide Mount for Bonnet Assemblies</u>

Referring again to <figref idref="f0001">Figure 1</figref>, another important aspect is the swivel slide mounts 74 cooperatively attached to the rods 70 and to each of the bonnet assemblies 14. As described previously herein, the bonnet assemblies 14 are coupled to the swivel slide mounts 74, and the swivel slide mounts 74 are slidably engaged with the rods 70. The swivel slide mounts 74 are adapted to allow the bonnet assemblies 14 to rotate proximate their axial centerlines so that the rams (not shown) and the interior components of both the bonnet assemblies 14 and the BOP body 12 may be accessed for maintenance, to change the rams, etc.

An embodiment of the swivel slide mount 74 is shown in <figref idref="f0009">Figures 23</figref> and <figref idref="f0010">24</figref>. The swivel slide mount 74 comprises a swivel slide mounting bar 76 and a swivel plate 78. The swivel slide mounting bar 76 is slidably attached to the rods 70. The slidable attachment between the swivel slide mounting bar 76 and the rods 70 may be made with, for example, linear bearings 87 that are coupled to the swivel slide mounting bar 76. However, other slidable attachments known in the art may be used with the invention to form the slideable attachment. Moreover, bushings (not shown), or a combination of linear bearings 87 and bushings (not shown) may be used with the invention. The swivel plate 78 is rotationally attached to the swivel slide mounting bar 76 and is cooperatively attached to an upper surface 75 of the bonnet assembly 14. The cooperative attachment of the swivel slide mount 74 to the bonnet assembly <b>14</b> is made substantially at an axial centerline of the bonnet assembly <b>14.</b>

The rods <b>70</b> are designed to be of sufficient length to permit the bonnet assembly <b>14</b> to disengage from the BOP body <b>12</b> and slide away from the BOP body <b>12</b> until the ram (not shown) is completely outside the side passage <b>20.</b> Moreover, a point of attachment <b>82</b> where the swivel slide mount <b>74</b> is cooperatively attached to the upper surface <b>75</b> of the bonnet assembly <b>14</b> may be optimized so that the point of attachment <b>82</b> is substantially near a center of mass of the bonnet assembly <b>14.</b> Positioning the point of attachment <b>82</b> substantially near the center of mass reduces the force required to rotate the bonnet assembly <b>14</b> and also reduces the bending stress experienced by the swivel plate <b>78.</b>

The swivel plate <b>78</b> may further include a bearing <b>85.</b> For example, the bearing <b>85</b> may be cooperatively attached to the swivel slide mounting bar <b>76</b> and adapted to withstand both radial and thrust loads generated by the rotation of the bonnet assembly <b>14.</b> The bearing <b>85</b> may comprise, for example, a combination radial bearing and thrust bearing (such as, for example, a tapered roller bearing). Alternatively, the bearing <b>85</b> may comprise, for example, a roller bearing to support radial loads and a thrust washer to support axial loads. However, other types of bearing arrangements are known in the art and may be used with the swivel plate <b>78.</b>

When the ram (not shown) is completely out of the side passage <b>20,</b> the bonnet assembly <b>14</b> can rotate about a rotational axis of the swivel plate <b>78</b> so that the ram (not shown) and the side passage <b>20</b> may be accessed for maintenance, inspection, and the like. In the embodiment shown in <figref idref="f0009">Figures 23</figref> and <figref idref="f0010">24</figref>, the lower bonnet assembly <b>14</b> is shown to be rotated approximately 90 degrees with respect to the BOP body <b>12</b> while the upper bonnet assembly <b>14</b> remains in locking engagement with the BOP body <b>12.</b> A ram block attachment point <b>80</b> is clearly visible.

<figref idref="f0011">Figure 25</figref> shows a top view of the BOP 10 when one of the bonnet assemblies 14 has been disengaged from the BOP body 12 and rotated approximately 90 degrees. As shown, the ram block attachment point 80 is clearly visible and may be vertically accessed. Vertical access is a significant advantage because prior art bonnets that include hinges generally pivot about an edge of the bonnet door. Therefore, if, for example, a lower BOP bonnet was unbolted and pivoted open, the ram could not be vertically accessed because the body of the upper BOP bonnet was in the way. Vertical access to the ram is important because it makes it much easier to maintain or replace rams, thus reducing the time required to maintain the BOP and increasing the level of safety of the personnel performing the maintenance. Further, vertical access enables, for example, maintenance of a lower BOP bonnet while an upper bonnet is locked in position (see, for example, <figref idref="f0009 f0010 f0011">Figures 23-25</figref>).

The bonnet assembly 14 may also be rotated approximately 90 degrees in the other direction with respect to an axis of the side passage (20 in <figref idref="f0001">Figure 1</figref>), thereby permitting approximately 180 degrees of rotation. However, other embodiment may be designed that permit rotation of greater than or less than 180 degrees. The range of rotation of the swivel slide mount 74 is not intended to limit the scope of the embodiment.

The swivel slide mount 74 is advantageous because of the simplicity of the design and attachment to the bonnet assembly 14. For example, prior art hinges are generally complex, difficult to manufacture, and relatively expensive. Further, prior art hinges have to be robust because they carry the full weight of the BOP bonnet about a vertical axis positioned some distance away from the center of mass of the bonnet. The bending moment exerted on the hinge is, as a result, very high and deformation of the hinge can lead to "sagging" of the bonnet.

<figref idref="f0012">Figure 26</figref> shows an example of a BOP bonnet mount 602. A BOP 601 has a BOP body 603 that has four side openings, for example, side opening 650. Four BOP bonnets 611, 612, 613, and 614 may be adapted to be coupled to the side openings. For example, <figref idref="f0012">Figure 26</figref> shows BOP bonnet 612 adapted to be coupled to the BOP body 603 at a side opening 650.

A BOP bonnet mount 602 is also shown in <figref idref="f0012">Figure 26</figref>. The BOP bonnet mount 602 comprises two support members 621, 622 and bonnet mounting member 628. The BOP mount 602 enables the BOP bonnet 612 to be moved away from the BOP body 603 in a direction substantially normal to the face 655 of the BOP body 603, and then swiveled so that the ram (not shown) can be more easily replaced.

The support members 621, 622 shown in <figref idref="f0012">Figure 26</figref> are coupled to the BOP body 603. The support members 621, 622 may also be adapted to allow wheels to roll across the top of the support members 621, 622. The support members 621, 622 extend enough distance from the BOP body 603 so that the BOP bonnet 612 may be moved away from the BOP body 603 so that the ram (not shown) is clear of the BOP body 603 and the side opening 650. In this disclosure, "clear" of the BOP body or the side opening means removed to a sufficient extent to that the bonnet may rotate without causing contact between the ram block and the BOP body.

The bonnet mounting member 628 may comprise two wheel blocks 624, 626, and a swivel plate 630. One wheel block is disposed at each end of the bonnet mounting member 628. Each wheel block 624, 626 includes at least one wheel positioned to roll on top of a support member (621 or 622). In the example shown in <figref idref="f0012">Figure 26</figref>, each wheel block 624, 626 includes two wheels, although different numbers of wheels can be used.

A swivel plate 630 may be rotationally attached to the bonnet mounting member 628 and coupled to the bonnet 612. The swivel plate 630 may be rotationally coupled to the bonnet mounting member 628 near a center of the bonnet mounting member 628. The swivel plate 630 may also be coupled to the bonnet 612 above a center of mass of the bonnet 612. The swivel plate 630 may be fixedly coupled to the bonnet mounting member 628 and rotationally coupled to the bonnet 612.

A bonnet mount 602 according to the example shown in <figref idref="f0012">Figure 26</figref> enables easier inspection and replacement of a ram (not shown) disposed on the end of a ram piston 651. The bonnet 612 is first disengaged from the BOP body 603. The method of engagement and disengagement of the bonnet is not part of the invention and the invention is not limited by such methods. Next, the bonnet 612 is moved away from the BOP body 603 in a direction substantially normal to a face 655 of the BOP body 603. The bonnet 612 is coupled to the bonnet mounting member 628, and wheels on the bonnet mounting member 628 enable the bonnet 612 to move away from the BOP body 603. Once the ram (not shown) is clear of the side opening 650, the bonnet 612 may be swiveled to either side so that the ram (not shown) can be inspected or replaced.

<figref idref="f0012">Figure 26</figref> shows three additional bonnets 611, 613, and 614. The operation of the bonnet mounts associated with these bonnets is similar to the one described above. Accordingly, their operation will not be individually described. Further, the embodiments in <figref idref="f0013 f0014 f0015 f0016 f0017 f0018 f0019 f0020 f0021 f0022">Figures 27A-32</figref> show only one bonnet and the associated bonnet mount. It is understood that each embodiment can be used with any number of bonnets on a BOP. Also, with each aspect of the invention, it is desirable to make any couplings with the bonnet near its center of mass or along a center axis. While it may not be mentioned specifically with certain embodiments of the invention, embodiments may include such a coupling. <figref idref="f0014 f0015 f0016 f0017 f0018 f0019 f0020 f0021">Figures 27-31</figref> show a BOP bonnet mount. In each of the examples, the mount is arranged so that the BOP bonnet can be disengaged from the BOP body and moved away from the BOP body in a direction substantially normal to a face of the BOP body so that the ram is clear of the opening. Once the ram is clear, the bonnet may be pivoted, swiveled, or moved to allow easier access to the ram. "Substantially normal" is used to indicated a direction away from the BOP and the face where the side opening is located. Those having skill in the art will realize that the exact direction will depend on the construction of the BOP, the bonnet, and the side opening, but the direction will generally be normal to a face of the BOP body. Many of the examples described with reference to <figref idref="f0013 f0014 f0015 f0016 f0017 f0018 f0019 f0020 f0021">Figures 27A-31B</figref> include two support members. It is understood that more than two support members may be used.

<figref idref="f0013">Figure 27A</figref> shows a top view of a bonnet mount 701 according to an embodiment of the invention. A bonnet 605 is shown withdrawn from a BOP body 603 so that a ram block 607 is clear of the BOP body 603. The bonnet 605 is coupled to a bonnet mounting member 703 that is moveably coupled to two support members 711, 712. The bonnet mounting member 703 is moveably coupled to the support members 711, 712 by two side blocks 706, 707. The side blocks 706, 707 may comprise linear bearings (as shown in <figref idref="f0009">Figure 23</figref>), wheel blocks (as shown in <figref idref="f0012">Figure 26</figref>), or any other suitable coupling that enables the bonnet 605 and the bonnet mounting member 703 to be moved away from the BOP body 603 in a direction substantially normal to a face of the BOP body 603.

The bonnet <b>605</b> may be rigidly fixed to the bonnet mounting member <b>703</b> by a bonnet connector <b>705.</b> Alternately, the bonnet <b>605</b> may be rotationally coupled to the bonnet mounting member <b>703</b> by a swivel plate, as described above with reference to <figref idref="f0009">Figures 23</figref> and <figref idref="f0012">26</figref>.

The support members <b>711, 712</b> may be hingedly coupled to the BOP body <b>603.</b><figref idref="f0013">Figure 27A</figref> shows support member <b>711</b> hingedly coupled to the BOP body <b>603</b> by a hinge <b>708.</b> Likewise, support member <b>712</b> is shown hingedly coupled to the BOP body by hinge <b>709.</b> The hinges <b>708, 709</b> enable the support members <b>711, 712</b> to be pivoted so the bonnet moves in a horizontal direction.

<figref idref="f0013">Figure 27B</figref> shows a side view of a bonnet mount <b>701</b> according to this aspect of the invention. The bonnet <b>605</b> is suspended from the support members <b>711, 712</b> (only support member <b>711</b> is shown in the side view of <figref idref="f0013">Figure 27B</figref>). The bonnet mounting member <b>703</b> is rotationally coupled to each of the side blocks <b>706, 707</b> (only side block <b>707</b> is shown in the side view of <figref idref="f0013">Figure 27B). Figure 27B</figref> shows side block <b>707</b> rotationally coupled to the bonnet support member <b>703</b> at pivot point <b>715.</b> Although it is not shown in <figref idref="f0013">Figure 27B</figref>, it is understood that the bonnet mounting member <b>703</b> is similarly coupled to side block <b>706.</b>

<figref idref="f0014">Figure 27C</figref> shows is a top view of the bonnet mount <b>701</b> with the support members <b>711, 712</b> pivoted to one side so that the ram block <b>607</b> is more accessible for inspection and replacement. The support members <b>711, 712</b> pivot at the points where they are hingedly coupled to the BOP body <b>603.</b> In the embodiment shown in <figref idref="f0014">Figure 27C</figref>, support member <b>711</b> is coupled to the BOP body by a hinge <b>708,</b> and support member <b>712</b> is coupled to the BOP body by a hinge <b>709.</b> The hinged couplings <b>708, 709</b> and the rotational couplings of the side blocks <b>706, 707</b> enable the bonnet <b>605</b> to be horizontally swung away from the BOP body <b>603</b> so that the ram block <b>607</b> is easily accessible.

The embodiment shown in <figref idref="f0013 f0014">Figures 27A-27C</figref> includes a bonnet mount that enables the bonnet to be moved horizontally. In some embodiments (not shown), a bonnet mount may enable the vertical movement of the bonnet. In such an embodiment, the support members could be hingedly coupled to the BOP body so that they pivot in an up or down direction. This would be advantageous, for example, if the ram block could be more easily inspected or replaced from above or below the BOP.

<figref idref="f0015 f0016">Figures 28A-28D</figref> show a bonnet mount <b>801</b> . A bonnet <b>605</b> is coupled to a BOP body <b>603</b> so that the bonnet <b>605</b> can be moved away from the BOP body <b>603</b> substantially normal to a face of the BOP body <b>603.</b> Once the ram block <b>607</b> is clear of the BOP body <b>603,</b> the bonnet <b>605</b> is able to rotate in the vertical plane so that the bonnet <b>603</b> is facing the other direction.

<figref idref="f0015">Figure 28A</figref> shows a top view of a bonnet mount <b>801</b> . The bonnet <b>605</b> may be coupled to the BOP body <b>603</b> by two support members <b>807, 808,</b> two movement blocks <b>803, 805,</b> and two bonnet rotational members <b>810, 811.</b>

The support members <b>807, 808</b> are coupled to the BOP body <b>603</b> by any means known in the art. In some embodiments, the support members <b>807, 808</b> are fixedly coupled to the BOP body <b>603.</b> Movement block <b>803</b> is movably coupled to support member <b>807,</b> and movement block <b>805</b> is moveably coupled to support member <b>808.</b> The movement blocks <b>803, 805</b> are adapted to move along the length of the support members.

In some examples, the support members <b>807, 808</b> comprise support rods, and the movement blocks <b>803, 805</b> comprise linear bearings or bushings that are adapted to slide along the length of the support rods. In another embodiments, the movement blocks <b>803, 805</b> each comprise at least one wheel and the support members <b>807, 808</b> are adapted to have the at least one wheel roll along the top of the support members <b>807, 808.</b>

The bonnet <b>605</b> may be coupled to the movement blocks <b>803, 805</b> by two rotational members <b>810, 811.</b> Rotational member <b>810</b> is coupled to the bonnet <b>605</b> and to movement block <b>803.</b> The second rotational member <b>811</b> is coupled to another side of the bonnet <b>605</b> and to movement block <b>805.</b> The rotational members <b>810, 811</b> are coupled in such a way as to enable the bonnet <b>605</b> to rotate about a horizontal axis. This may be accomplished by fixedly coupling the rotational members <b>810, 811</b> to the bonnet <b>605</b> and rotationally coupling the rotational members <b>810, 811</b> to the movement blocks <b>803, 805.</b> Conversely, the rotational members <b>810, 811</b> could be fixedly coupled to the movement blocks <b>803, 805</b> and rotationally coupled to the bonnet <b>605.</b> Other means of moveably and rotationally coupling a bonnet to support members can be devised. For example, all couplings may be rotational couplings.

<figref idref="f0015">Figure 28B</figref> shows a side view of a bonnet mount <b>801</b> . The support members <b>807, 808</b> (only support member <b>807</b> is shown in the side view of <figref idref="f0015">Figure 28B</figref>) may be aligned with the horizontal axis of the bonnet <b>603.</b> The movement blocks <b>803, 805</b> (only movement block <b>803</b> is shown in the side view of <figref idref="f0015">Figure 28B</figref>) and the rotational members <b>(810</b> and <b>811</b> in <figref idref="f0015">Figure 28A</figref>) may be aligned near the center of mass of the bonnet <b>603.</b>

<figref idref="f0016">Figure 28C</figref> shows a top view of a bonnet mount <b>801</b> . The bonnet <b>605</b> is rotated 180° in the vertical plane so that the ram block <b>607</b> is facing away from the BOP body <b>603.</b> In this position, the ram block <b>607</b> may be accessed for inspection and replacement.

<figref idref="f0016">Figure 28D</figref> shows a side view of the bonnet mount <b>801</b> with the bonnet <b>605</b> rotated so that the ram block <b>607</b> is facing away from the BOP body <b>603.</b> The bonnet may rotate from the initial position (as shown in <figref idref="f0015">Figure 28B</figref>) in either direction. In some examples, the bonnet mount <b>801</b> may comprise a lock mechanism that may lock the bonnet <b>605</b> in position to be coupled with a side opening <b>650</b> in the BOP body <b>603</b> or in a 180° rotated position for inspection and replacement. Also, a bonnet mount <b>801</b> may have a lock mechanism that is adapted to lock the bonnet in a 90° position, <i>i.e</i>., with the ram block <b>607</b> pointing either up or down. Such a position would be desirable, for example, if conditions made inspecting a ram block <b>607</b> from above or below advantageous.

<figref idref="f0017 f0018">Figures 29A-29D</figref> show a bonnet mount <b>901</b> according to an embodiment of the invention. A bonnet <b>605</b> is coupled to a BOP body <b>603</b> by at least three support members <b>911, 912, 913,</b> at least two of which <b>911, 912</b> are hingedly coupled to the BOP body <b>605.</b>

<figref idref="f0017">Figure 29A</figref> shows a top view of a bonnet mount <b>901</b> according to this embodiment of the invention. A bonnet <b>605</b> is shown engaged with a BOP body <b>603,</b> and a ram block <b>607</b> is shown located within the BOP body <b>603.</b> The bonnet <b>605</b> is coupled to the BOP body <b>603</b> by a bonnet mounting member <b>915,</b> a vertical bonnet support member <b>921,</b> and three support members <b>911, 912, 913</b> (support member <b>912</b> is not shown in the top view of <figref idref="f0017">Figure 29A</figref>; see <figref idref="f0017">Figures 29B</figref> and <figref idref="f0018">29C</figref>).

<figref idref="f0017">Figure 29B</figref> shows an end view of a bonnet mounting member <b>901.</b> The bonnet 605 is .coupled to the bonnet mounting member <b>915</b> by a bonnet support plate <b>919.</b> In some embodiments, the bonnet support plate <b>919</b> comprises a fixed coupling, although the bonnet support plate <b>919</b> may comprise a rotational coupling without departing from the scope of the invention.

The bonnet mounting member <b>915,</b> on one side, is coupled to the vertical bonnet support member <b>921.</b> On the other side, the bonnet mounting member <b>915</b> is coupled to the movement block <b>917.</b> The bonnet mounting member <b>915</b> is shown suspended from the movement block <b>917,</b> but other coupling types may be used in embodiments of the invention.

Still referring to <figref idref="f0017">Figure 29B</figref>, support members <b>911</b> and <b>912</b> are coupled to the BOP body <b>603</b> on one side of the side opening <b>650,</b> and support member <b>913</b> is coupled to the BOP body <b>603</b> on the opposing side of the side opening <b>650.</b> The vertical bonnet support member <b>921</b> is movably coupled to support member <b>911</b> near the top of the vertical bonnet support member <b>921,</b> and the vertical bonnet support member <b>921</b> is moveably coupled to support member <b>912</b> near the bottom of the vertical bonnet support member <b>921.</b> The movement block <b>917</b> is moveably coupled to support member <b>913.</b>

As can be seen in <figref idref="f0017">Figures 29A</figref> and <figref idref="f0018">29D</figref>, the support members may be of different lengths. Support members <b>911</b> and <b>912</b> have sufficient length so that the bonnet <b>605</b> can be moved substantially normal to a face of the BOP body <b>603</b> so that the ram block <b>607</b> is clear of the BOP body <b>603.</b> Side support member <b>913,</b> on the other hand, may have a length selected so that as the bonnet <b>605</b> is moved away from the BOP body <b>603,</b> the movement block <b>917</b> moves past the end of support member <b>913.</b> In doing so, the movement block <b>917</b> becomes decoupled from side support <b>member 913.</b>

Support members <b>911, 912</b> may be hingedly coupled to the BOP body <b>603.</b> As shown in <figref idref="f0017">Figures 29A</figref> and <figref idref="f0018">29D</figref>, support member <b>911</b> is hingedly coupled to the BOP body <b>603.</b> The hinged coupling may comprise a hinge <b>923.</b> Likewise, support member <b>912,</b> as seen in <figref idref="f0018">Figure 29C</figref>, is hingedly coupled to the BOP body <b>603.</b> The coupling may comprise a hinge <b>924.</b>

Once the movement block <b>917</b> becomes decoupled from support member <b>913,</b> as can be seen in <figref idref="f0018">Figure 29D</figref>, the remaining support members <b>911, 912</b> and the bonnet <b>605</b> are free to pivot away from the BOP body 6<b>03.</b> In some embodiments, the bonnet mount <b>901</b> includes stops (not shown) that prevent the support members <b>911</b> and <b>912</b> and the bonnet <b>605</b> from rotating past a selected position. By pivoting about the hinged couplings of support members <b>911</b> and <b>912,</b> the ram block <b>607</b> becomes more accessible for inspection and replacement.

To replace the bonnet to the engaged position, as shown in <figref idref="f0017">Figure 29A</figref>, the bonnet <b>605</b> may be pivoted back toward the BOP body <b>603.</b> In some embodiments, the bonnet mount <b>901</b> includes stops that prevent the support members <b>911</b> and <b>912</b> and the bonnet from pivoting past the aligned position. The movement block <b>917</b> may then be recoupled with support member <b>913,</b> and the bonnet <b>605</b> may be moved toward the BOP body <b>603</b> substantially parallel to the axis of the side opening <b>650.</b>

It is noted that the bonnet mount <b>901</b> according to this embodiment of the invention may not include a third support member <b>913.</b> In that case, the bonnet mounting member <b>915</b> would not be coupled with any support member. The bonnet <b>605</b> could be moved away from the BOP body <b>603</b> and then pivoted once the ram block <b>607</b> was clear of the BOP body <b>603.</b>

<figref idref="f0019 f0020">Figure 30A-30C</figref> show a three-pivot hinge bonnet mount <b>1001</b>. A three-pivot hinge bonnet mount <b>1001</b> enables the bonnet <b>605</b> to be moved away from a BOP body <b>603</b> in a direction substantially normal to a face of the BOP body <b>603</b> so that a ram block <b>607</b> is clear of the BOP body <b>603.</b>

<figref idref="f0019">Figure 30A</figref> shows a top view of a bonnet <b>605</b> engaged with a BOP body <b>603.</b> The ram block <b>607</b> is disposed within the BOP body <b>603.</b> The bonnet <b>605</b> is also coupled to the BOP body <b>603</b> by a three-pivot hinge bonnet mount <b>1001.</b> A three-pivot hinge bonnet mount <b>1001</b> according to this embodiment of the invention may include two hinge members <b>1015, 1017</b> and three pivot points <b>1021, 1022, 1023.</b>

A first hinge member <b>1015</b> may be hingedly coupled to the bonnet <b>605</b> at a bonnet hinge connector <b>1013.</b> The bonnet coupling may comprise a hinge <b>1023.</b> A second hinge member may be hingedly coupled to BOP body <b>603</b> at a BOP hinge connector <b>1011.</b> The BOP hinge coupling may comprise a hinge <b>1021.</b> The first hinge member <b>1015</b> and the second hinge member <b>1017</b> may be hingedly coupled to each other, each at an opposite end from their coupling to the bonnet <b>605</b> and the BOP body <b>603,</b> respectively. The coupling between the first hinge member <b>1015</b> and the second hinge member <b>1017</b> hinge members may also be a hinge <b>1022.</b>

As shown in <figref idref="f0019">Figure 30A</figref>, when the bonnet <b>605</b> is engaged with the BOP body <b>603,</b> the hinge members <b>1015, 1017</b> form an angle. This enables the bonnet <b>605</b> to be moved away from the BOP body <b>602</b> substantially normal to a face of the BOP body <b>603.</b><figref idref="f0019">Figure 30B</figref> shows the bonnet <b>605</b> moved away from the BOP body <b>603</b> so that the ram block <b>607</b> is clear of the BOP body <b>603.</b> When the bonnet is moved away from the BOP body <b>603,</b> the hinge members <b>1015, 1017</b> may form a straight line between hinges <b>1021</b> and <b>1023.</b> With the ram block <b>607</b> clear of the BOP body <b>603,</b> the bonnet <b>605</b> can be pivoted away from the BOP body <b>603</b> at any of the hinges <b>1021, 1022, 1023.</b><figref idref="f0020">Figure 30C</figref> shows a top view of a bonnet <b>605</b> pivoted away from a BOP body <b>603</b> by pivoting about hinge <b>1021.</b>

In one or more examples (not shown), the hinge bonnet mount may comprise a single member hingedly coupled to a BOP body and to a bonnet. The single member may be linearly extendable so that the bonnet can be moved away from the BOP body along an axis of a side opening. Once moved away, the bonnet could be pivoted away from the BOP body at either of the hinged couplings.

<figref idref="f0021">Figure 31A and 31B</figref> show a bonnet mount <b>1101</b> . In the example shown, support members <b>1109, 1111</b> are moveably coupled to the BOP body <b>603</b> and may be fixedly coupled to the bonnet <b>605.</b>

<figref idref="f0021">Figure 31A</figref> shows a top view of an example of a bonnet mount <b>1101</b> . The bonnet <b>605</b> may be coupled to a bonnet mounting member <b>1103</b> at a connection point <b>1117.</b> In some examples, the bonnet 605 is rotationally coupled to the bonnet mounting member <b>1103.</b> In one example, the connection point <b>1117</b> comprises a swivel plate.

The bonnet mounting member <b>1103</b> may be coupled to support members <b>1109, 1111</b> at opposite ends of the bonnet mounting member <b>1103.</b> An end block <b>1107</b> may be included at one end of the bonnet mounting member <b>1103.</b> The end block <b>1107</b> may be coupled to support member <b>1109.</b> A second end block <b>1105</b> may be included at a second end of the bonnet mounting member <b>1103.</b> The second end block <b>1105</b> may be coupled to support member <b>1111.</b> In some embodiments, the bonnet mounting member <b>1103</b> may be fixedly coupled to the support members <b>1109, 1111.</b>

The support members <b>1109, 1111</b> may be moveably coupled to the BOP body <b>603.</b> The BOP body <b>603</b> may include support blocks <b>1113, 1115,</b> which may be moveably coupled to the support members <b>1109, 1111.</b> In one embodiment, the support blocks <b>1113, 1115</b> include linear bearings and adapted to allow the support members <b>1109, 1111</b> to slide in and out of the support blocks <b>1113, 1115.</b>

<figref idref="f0021">Figure 31B</figref> shows a bonnet mount <b>1101</b> with the bonnet <b>605</b> moved away from the BOP body and the ram block <b>607</b> clear of the BOP body <b>603.</b> The support members <b>1109, 1111</b> have been moved along with the bonnet <b>605,</b> in relation to the BOP body <b>603.</b> In some examples, the bonnet <b>605</b> is rotationally coupled to the bonnet mounting member <b>1103</b> and may be swiveled once the ram block <b>607</b> is clear of the BOP body <b>603.</b>

Advantageously, a bonnet mount need not have support members that extend past the bonnet, even when the bonnet is engaged with the BOP body. A mount according to this example requires less space when the bonnet is engaged with the BOP body because the support members do not extend past the bonnet.

<figref idref="f0022">Figure 32</figref> shows a side view of an example of a bonnet mount <b>1201</b> . In this example, the support members are not coupled to the BOP body <b>603.</b> Those skilled in the art will appreciate that other examples described herein may be applicable is situations where the support members are not coupled to the BOP body <b>603.</b>

A bonnet <b>605</b> is shown moved away from a BOP body <b>603</b> so that a ram block <b>607</b> is clear of the BOP body <b>603.</b> The bonnet <b>605</b> may be coupled to a vertical support member <b>1207.</b> In some examples, the vertical support member <b>1207</b> is rotationally coupled to the bonnet <b>605</b> at a rotation point <b>1209.</b> Rotating the bonnet <b>605</b> enables easier access to the ram <b>607.</b> In other embodiments, the vertical support member <b>1207</b> is releasably coupled to the bonnet <b>605.</b> When the vertical support member <b>1207</b> is releasably coupled to the bonnet <b>605,</b> the vertical support member <b>1207</b> may be decoupled from the bonnet <b>605</b> and may be used in connection with another bonnet (not shown).

A support member <b>1203</b> may be positioned near the bonnet <b>605</b> so that the vertical support member <b>1207</b> can be coupled to the support member <b>1203.</b> In some examples, the vertical support member <b>1207</b> includes at least one wheel <b>1205</b> that is adapted to roll along the support member <b>1203.</b> In some examples, the support member <b>1203</b> is a rail.

The support member <b>1203</b> may be supported by any means known in the art. The means of support for the support member <b>1203</b> is not intended to limit the invention. As an example, <figref idref="f0022">Figure 32</figref> shows the support member <b>1203</b> connected to a support brace <b>1213</b> and a BOP stack frame <b>1215.</b>

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.