Expanding wellbore junction

BACKGROUND

P-0001[0001] The present invention relates generally to operations performed, and equipment utilized, in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides an expanding wellbore junction method.

P-0002[0002] It is well known in the art to expand a wellbore junction downhole as part of a method of interconnecting multiple intersecting wellbores. However, such prior methods suffer from at least one of several deficiencies. Firstly, it is difficult to seal against an expanded tubular member, since an expanded tubular member rarely, if ever, returns to a uniform cylindrical shape. Secondly, an expanded wellbore junction typically has a somewhat misshapen form, which makes access therethrough, and positioning of various devices therein, very difficult. Thirdly, the positioning, expanding, sealing, etc. steps involved in utilizing an expandable wellbore junction typically require an excessive number of trips into the well, which is time-consuming and expensive.

P-0003[0003] From the foregoing, it can be seen that it would be quite desirable to provide expanding wellbore junction methods, systems and apparatus which solve one or more of the above problems in the art.

SUMMARY

P-0004[0004] In carrying out the principles of the present invention, in accordance with embodiments thereof, expanding wellbore junction methods, systems and apparatus are provided, each of which solves at least one of the above problems in the art.

P-0005[0005] In one aspect of the invention, a method of forming a sealed wellbore intersection in a subterranean well is provided. The method includes the steps of drilling a first wellbore, under-reaming the first wellbore, thereby forming a radially enlarged cavity, positioning an expandable wellbore junction within the cavity, expanding the wellbore junction within the cavity, forcing a drift through at least one of multiple tubular legs of the wellbore junction, cementing the wellbore junction within the cavity, drilling a second wellbore through a first one of the tubular legs of the wellbore junction, and drilling a third wellbore through a second one of the tubular legs of the wellbore junction.

P-0006[0006] In another aspect of the invention, an expandable wellbore junction system is provided. The system includes a wellbore junction assembly. The wellbore junction assembly includes an expandable wellbore junction having multiple intersecting tubular legs, and an orienting latch profile attached to the wellbore junction. The orienting latch profile may be used to radially orient various item of equipment relative to the wellbore junction, such as, a deflection device, a drifting apparatus, a drilling whipstock, etc.

P-0007[0007] In yet another aspect of the invention, a drifting apparatus for use in a wellbore junction installed in a subterranean well is provided. The apparatus includes a drift, a displacement device displacing the drift in the wellbore junction, and a securing device securing the apparatus relative to the wellbore junction. The apparatus may be pressure actuated and may be conveyed into the well, and retrieved from the well, with a deflection device in a single trip into the well.

P-0008[0008] In still another aspect of the invention, a deflection device assembly for use in an expandable wellbore junction is provided. The assembly includes a deflection device. The deflection device includes a laterally inclined deflection surface, a generally tubular neck, and a substantially flexible intermediate section connected between the neck and the deflection surface, the intermediate section flexing when the deflection device is installed in the wellbore junction, thereby permitting relative angular deflection between the deflection surface and the neck. This angular deflection may permit installation of the deflection device in an imperfectly expanded wellbore junction.

P-0009[0009] In a further aspect of the invention, a method of drifting an expandable wellbore junction in a subterranean well is provided. The method includes the steps of conveying a drifting apparatus into the wellbore junction, and displacing a drift of the drifting apparatus in at least one of multiple intersecting tubular legs of the wellbore junction. A pressure actuated knuckle joint or another deflection device may be used if desired to direct the drift into a selected one of the tubular legs.

P-0010[0010] These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

P-0011[0011]FIG. 1 is a cross-sectional perspective view of a method embodying principles of the present invention, wherein initial steps of the method have been performed;

P-0012[0012]FIG. 2 is a cross-sectional perspective view of the method, wherein an expandable junction has been positioned in an under-reamed cavity;

P-0013[0013]FIG. 3 is a cross-sectional perspective view of the method, wherein the junction has been expanded within the under-reamed cavity;

P-0014[0014]FIG. 4 is cross-sectional perspective view of the method, wherein the expanded junction is drifted;

P-0015[0015]FIG. 5 is a partially cross-sectional view of a first drifting apparatus which may be used in the method, the apparatus embodying principles of the invention;

P-0016[0016]FIG. 6 is a cross-sectional view of a junction assembly configured for use of the apparatus therein, the junction assembly embodying principles of the invention;

P-0017[0017]FIG. 7 is a partially cross-sectional view of a second drifting apparatus which may be used in the method, the second apparatus embodying principles of the invention;

P-0018[0018]FIG. 8 is a cross-sectional perspective view of the method, wherein the expanded junction is cemented within the cavity;

P-0019[0019]FIG. 9 is a cross-sectional perspective view of the method, wherein a wellbore is drilled through one lower leg of the junction; and

P-0020[0020]FIG. 10 is a cross-sectional perspective view of the method, wherein another wellbore is drilled through another lower leg of the junction.

DETAILED DESCRIPTION

P-0021[0021] Representatively illustrated in FIGS. <b>1</b>-<b>4</b> and <b>8</b>-<b>10</b> is an expanding wellbore junction method <b>10</b> which embodies principles of the present invention. In the following description of the method <b>10</b> and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used only for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention.

P-0022[0022] In the method <b>10</b>, an expandable wellbore junction <b>12</b> is positioned within an under-reamed cavity <b>14</b>, the wellbore junction is expanded outward, a drift <b>16</b> is displaced in each of three intersecting branches or legs <b>18</b>, <b>20</b>, <b>22</b> of the wellbore junction, and the wellbore junction is cemented within the cavity. Additional wellbores <b>24</b>, <b>26</b> may then be drilled through each of the lower legs <b>20</b>, <b>22</b> of the wellbore junction <b>12</b>. The method <b>10</b> provides a stable, sealed and strong wellbore intersection which is efficient and economical to install.

P-0023[0023] Referring specifically now to FIG. 1, initial steps of the method <b>10</b> have been performed. A wellbore <b>28</b> has been drilled in the earth and a tubular string <b>30</b> has been installed in the wellbore. The wellbore <b>28</b> may extend to the earth's surface, to another wellbore, or to any other point of origin.

P-0024[0024] The tubular string <b>30</b> may be a casing string, a liner string, or any other type of tubular string. The tubular string <b>30</b> may be cemented in the wellbore <b>28</b> upon installation, or the cementing may be performed later in the method <b>10</b>.

P-0025[0025] The cavity <b>14</b> is then formed in the wellbore <b>28</b>. As depicted in FIG. 1, the cavity <b>14</b> is formed by under-reaming the wellbore <b>28</b>, so that the cavity is radially enlarged relative to the wellbore <b>28</b> above the cavity. However, it is to be understood that other means of enlarging the wellbore <b>28</b> to accommodate the expanded wellbore junction <b>12</b> may be used in keeping with the principles of the invention. For example, the wellbore <b>28</b> could be extended laterally without under-reaming. Thus, any means of forming the cavity <b>14</b> may be used.

P-0026[0026] Note that the wellbore <b>28</b> may extend below the cavity <b>14</b> any distance, or not at all. If the wellbore <b>28</b> is drilled to its terminal depth prior to installation of the expandable wellbore junction <b>12</b>, then there may be no need to drill the wellbore <b>24</b> through the expanded wellbore junction as depicted in FIG. 9. As described herein, it is assumed that the wellbore <b>28</b> extends somewhat below the cavity <b>14</b>, but the wellbore is further drilled to form the wellbore <b>24</b> below the wellbore junction <b>12</b> after it is installed. However, it should be understood that this is merely one example of the many various ways in which the principles of the invention may be practiced.

P-0027[0027] Referring specifically now to FIG. 2, the wellbore junction <b>12</b> is positioned in the cavity <b>14</b> as a part of an overall wellbore junction assembly <b>32</b>. One preferred example of the wellbore junction assembly <b>32</b> is depicted in FIG. 6 and is described in greater detail below. However, the specific equipment used in the junction assembly <b>32</b> described herein is not required for practicing the principles of the invention, as a variety of changes may be made to the assembly, if desired to suit a particular application.

P-0028[0028] As depicted in FIG. 2, the wellbore junction <b>12</b> is in its collapsed configuration. The junction <b>12</b> is preferably made of interconnected generally tubular metal elements which, after they are connected together, are mechanically collapsed so that the junction may pass through the tubular string <b>30</b>. The junction <b>12</b> is preferably expanded by inflating, that is, by applying pressure to its interior to force the tubular elements to expand outward and assume their prior interconnected shapes, as described below. However, any type of wellbore junction, made of any type of material and expanded by any means, may be used in keeping with the principles of the invention.

P-0029[0029] The junction assembly <b>32</b> is preferably composed substantially of liner <b>34</b> above the wellbore junction <b>12</b>. The liner <b>34</b> is anchored to the tubular string <b>30</b>, for example, using a conventional liner hanger (not shown) of the type well known to those skilled in the art. Other means of securing the junction assembly <b>32</b> to the tubular string <b>30</b>, or other means of anchoring the junction assembly so that the junction <b>12</b> is positioned in the cavity <b>14</b>, may be used in keeping with the principles of the invention.

P-0030[0030] Prior to anchoring the junction assembly <b>32</b>, the leg <b>22</b> is radially oriented so that, when the junction <b>12</b> is expanded and cemented within the cavity <b>14</b>, the expanded leg will face in a desired direction for drilling the wellbore <b>26</b>. For convenience of description, the leg <b>22</b> will be referred to as a “lateral” leg, since in the illustrated embodiment the leg <b>22</b> extends somewhat laterally relative to the remainder of the junction <b>12</b>, but it is to be clearly understood that it is not necessary for the leg <b>22</b> to extend laterally at all.

P-0031[0031] For reasons explained below, it may be desired to orient the lateral leg <b>22</b> toward the high side of the wellbore <b>28</b> when the wellbore is not vertical. Other orientations may be desired to suit other circumstances, and in some instances a particular orientation for either of the legs <b>20</b>, <b>22</b> may not be desired.

P-0032[0032] Referring specifically now to FIG. 3, the junction <b>12</b> has been radially outwardly expanded by applying pressure to the junction assembly <b>32</b>, thereby creating a pressure differential from the interior to the exterior of the junction. In its expanded configuration, the lateral leg <b>22</b> extends outward from the junction assembly <b>32</b> in the cavity <b>14</b>. However, it is not expected that the junction <b>12</b> will perfectly resume its pre-collapsed shape when inflated. Unfortunately, such imperfect expansion can restrict access and flow through the junction <b>12</b>, prevent certain equipment from being properly positioned, oriented, connected, etc. to the junction, and may cause other problems.

P-0033[0033] Referring specifically now to FIG. 4, the method <b>10</b> includes provisions for overcoming the difficulties caused by imperfect inflation of the junction <b>12</b>. The drift <b>16</b> is conveyed into the junction assembly <b>32</b> as part of an overall drifting apparatus <b>36</b>. The drifting apparatus <b>36</b> as depicted in FIG. 4 includes the drift <b>16</b> and a tubular string <b>38</b>, such as segmented drill pipe, for conveying the apparatus <b>36</b> downhole. The apparatus <b>36</b> may include other or different elements in keeping with the principles of the invention.

P-0034[0034] As used herein, the term “drift” is used to indicated a tool which is forced through a passage to thereby reform the interior of the passage, so that it takes on a desired shape. In the representatively illustrated method <b>10</b>, the drift <b>16</b> has a round cross-sectional shape, since it is desired to produce a substantially cylindrical shape in the legs <b>18</b>, <b>20</b>, <b>22</b> of the junction <b>12</b>. However, other shapes may be used in keeping with the principles of the invention. The legs <b>18</b>,<b>20</b>, <b>22</b> may be expanded when the drift <b>16</b> is displaced therethrough.

P-0035[0035] Using the apparatus <b>36</b>, each of the legs <b>18</b>, <b>20</b>, <b>22</b> may be drifted (i.e., physically extended outward to a known desired dimension) by displacing the drift <b>16</b> therein. For example, to drift the upper leg <b>18</b>, the apparatus <b>36</b> is lowered by the tubular string <b>38</b>, so that the drift <b>16</b> passes through the leg, <b>15</b> thereby reforming the inner diameter of the leg so that it assumes a substantially cylindrical shape having substantially the same dimension as the outer diameter of the drift.

P-0036[0036] If the lower leg <b>20</b> is substantially coaxial with the upper leg <b>18</b>, or possibly in other circumstances, the lower leg may be drifted in the same manner as the <b>20</b> upper leg. Of course, the main body of the junction <b>12</b> between the upper and lower legs <b>18</b>, <b>20</b> may also be drifted in the same manner. However, it should be understood that it is not necessary for the upper and lower legs <b>18</b>, <b>20</b> to be substantially coaxial, or for the main body of the junction <b>12</b> to extend substantially linearly between the upper and lower legs, in keeping with the principles of the invention.

P-0037[0037] Since the lateral leg <b>22</b> of the representatively illustrated junction <b>12</b> is not coaxial with the upper leg <b>18</b>, the drifting apparatus <b>36</b> may include provisions for directing the drift <b>16</b> to enter the lateral leg. As depicted in FIG. 4, the apparatus <b>36</b> includes a conventional knuckle joint <b>40</b> to angularly offset the drift <b>16</b> relative to the tubular string <b>38</b> above the knuckle joint.

P-0038[0038] The knuckle joint <b>40</b> may be any type of knuckle joint, for example, a mechanical or pressure actuated knuckle joint, etc. Preferably, the knuckle joint <b>40</b> is pressure actuated, so that when the drift <b>16</b> has been positioned in the junction <b>12</b>, pressure may be applied to the tubular string <b>38</b> to radially outwardly displace the drift. After the knuckle joint <b>40</b> has been actuated, the drift <b>16</b> is displaced in the lateral leg <b>22</b>, for example, by lowering the tubular string <b>38</b>.

P-0039[0039] Referring specifically now to FIG. 5, an alternate drifting apparatus <b>42</b> is representatively illustrated. The apparatus <b>42</b> may be used in place of the apparatus <b>36</b> in the method <b>10</b>. Other means of drifting the junction <b>12</b> may be used in keeping with the principles of the invention.

P-0040[0040] Instead of using manipulations of the tubular string <b>38</b> to displace the drift <b>16</b> in the legs <b>18</b>, <b>20</b>, <b>22</b> of the junction <b>12</b>, the apparatus <b>42</b> utilizes a pressure actuated displacement device <b>44</b>. As depicted in FIG. 5, the displacement device <b>44</b> is an axial extension device which includes a piston <b>46</b> exposed to pressure in the tubular string <b>38</b>.

P-0041[0041] When pressure in the tubular string <b>38</b> exceeds a predetermined level, shear pins or shear ring <b>48</b> shear, permitting the piston <b>46</b> to displace downward. Other types of shear members, or other types of release mechanisms may be used in place of the shear pins <b>48</b>. The piston <b>46</b> is attached to the drift <b>16</b>, so that as the piston <b>46</b> displaces downward, so does the drift.

P-0042[0042] To anchor the extension device <b>44</b> in place while the drift <b>16</b> is being displaced in the junction <b>12</b>, an anchoring or securing device <b>49</b> is included in the apparatus <b>42</b>. The anchoring device <b>49</b> includes at least one gripping structure <b>50</b>, such as a slip of the type conventionally used on packers, liner hangers, etc.

P-0043[0043] The gripping structure <b>50</b> is radially outwardly extended when a predetermined pressure is applied to the tubular string <b>38</b>. The pressure used to actuate the anchoring device <b>49</b> is preferably less than the pressure used to shear the pins <b>48</b>. Other types of anchoring devices and gripping structures may be used in the apparatus <b>42</b> in keeping with the principles of the invention. For example, the gripping structure <b>50</b> could be outwardly extended by manipulation of the tubular string <b>38</b>, etc.

P-0044[0044] When outwardly extended, the gripping structure <b>50</b> grippingly engages a portion of the junction assembly <b>32</b>, such as in a section of liner <b>34</b>, thereby fixing the axial position of the drifting apparatus <b>42</b> in the junction assembly. Such gripping engagement also preferably fixes the radial orientation of the drifting apparatus <b>42</b> relative to the junction <b>12</b>, for reasons explained below.

P-0045[0045] The drifting apparatus <b>42</b> may also, or alternatively, include a securing device or latch <b>52</b> to aid in positioning the drifting apparatus <b>42</b> in the junction assembly <b>32</b>. For example, the latch <b>52</b> may be used to provide an indication to an operator at the surface that the drifting apparatus <b>42</b> is appropriately positioned in the junction assembly <b>32</b>. The latch <b>52</b> may also releasably retain the drifting apparatus <b>42</b> in position in the junction assembly <b>32</b> until the anchoring device <b>49</b> is actuated.

P-0046[0046] The latch <b>52</b> is configured to engage a latch profile <b>54</b> included in the junction assembly <b>32</b> (see FIG. 6). The latch profile <b>54</b> may be positioned anywhere in the junction assembly <b>32</b>, and any number of latch profiles may be used, but preferably at least one latch profile is positioned above the upper leg <b>18</b> of the junction <b>12</b>, and another latch profile <b>56</b> is positioned below the lower leg <b>20</b>, as depicted in FIG. 6.

P-0047[0047] The upper latch profile <b>54</b> permits the drifting apparatus <b>42</b> to be appropriately positioned in the junction assembly <b>32</b> before, during and after drifting the upper leg <b>18</b>. The lower latch profile <b>56</b> permits appropriate positioning of other equipment in the junction assembly <b>32</b> (as described below) after the drifting of at least the upper leg <b>18</b> and the lower leg <b>20</b>.

P-0048[0048] For reasons explained below, the latch <b>52</b> is preferably of the type known to those skilled in the art as an orienting latch, and the profiles <b>54</b>, <b>56</b> are preferably orienting latch profiles. That is, the engagement between the latch <b>52</b> and either of the latch profiles <b>54</b>, <b>56</b> serves to radially orient the latch relative to the latch profile. Thus, when the latch <b>52</b> in the drifting apparatus <b>42</b> is properly engaged with the latch profile <b>54</b>, the drifting apparatus is radially oriented in a particular direction relative to the junction assembly <b>32</b>. A suitable latch and latch profile which may be used for the latch <b>52</b> and profile <b>54</b> is available from Halliburton Energy Services, Inc. as the Sperry-Sun Latch Coupling with Orienting Sub.

P-0049[0049] Note that it is not necessary in the method <b>10</b> for the drifting apparatus <b>42</b> to be radially oriented relative to the junction assembly <b>32</b>. However, when such radial orientation is desired, as explained below, the latch <b>52</b> and profile <b>54</b> are available to perform this function. For example, the latch <b>52</b> may be included in the drifting apparatus <b>36</b> depicted in FIG. 4 to radially orient the apparatus <b>36</b> so that when the knuckle joint <b>40</b> is actuated, the drift <b>16</b> is directed in the appropriate radial direction to displace toward the lateral leg <b>22</b> of the junction <b>12</b>.

P-0050[0050] The drifting apparatus <b>42</b> may be used to drift the upper leg <b>18</b> as follows: Convey the drifting apparatus <b>42</b> on the tubular string <b>38</b> into the junction assembly <b>32</b>. Engage the latch <b>52</b> with the latch profile <b>54</b> and apply a predetermined pressure to the tubular string <b>38</b>, to thereby actuate the anchoring device <b>49</b> and fix the axial and radial position of the apparatus <b>42</b> in the assembly <b>32</b>. Apply an increased predetermined pressure to the tubular string <b>38</b> to thereby actuate the extension device <b>44</b> (i.e., displace the piston <b>46</b>) and thereby displace the drift <b>16</b> in the leg <b>18</b>. When the drifting is completed, pressure in the tubular string <b>38</b> may be relieved to enable the gripping structure <b>50</b> to retract for retrieval of the apparatus <b>42</b> from the well.

P-0051[0051] If the extension device <b>44</b> is suitably configured, and if the junction legs <b>18</b>, <b>20</b> are substantially coaxial, both of the junction legs <b>18</b>, <b>20</b> may be drifted in a single trip into the well by continuing to displace the drift <b>16</b> downward through the main body of the junction <b>12</b> and into the lower leg <b>20</b> after drifting the upper leg <b>18</b>. Alternatively, the legs <b>18</b>, <b>20</b> may be drifted in separate trips into the well.

P-0052[0052] If, as described above, the junction <b>12</b> is radially oriented in the cavity <b>14</b> so that the lateral leg <b>22</b> faces toward the high side of the wellbore <b>28</b>, then equipment conveyed through the junction from above will enter the lower leg <b>20</b>, due to the force of gravity. This situation is advantageous in that it requires no special equipment or procedures to select the lower leg <b>20</b> for entry. Another benefit is that it enables selection of the lateral leg <b>22</b> for entry by using gravity sensing equipment, such as high side detectors, MWD tools, etc.

P-0053[0053] The upper latch profile <b>54</b> provides yet another method of selecting the lateral leg <b>22</b> for entry. Preferably, before and/or during running the junction assembly <b>32</b> into the well, the latch profile <b>54</b> is oriented so that it has a known radial orientation relative to the lateral leg <b>22</b>. For example, since the distance between the junction <b>12</b> and the position of the latch profile <b>54</b> in the junction assembly <b>32</b> may be too great to conveniently fix the radial orientation of the latch profile relative to the junction prior to running the assembly into the well, a tool, such as a gyroscope, may be used to indicate the relative radial orientation of the lateral leg <b>22</b> after the junction has been run into the well and when the latch profile is connected to the assembly.

P-0054[0054] Of course, other means of radially orienting the latch profile <b>54</b> (or the latch profile <b>56</b>) relative to the lateral leg <b>22</b> may be used in keeping with the principles of the invention. In addition, the latch profile <b>54</b> could be specifically oriented relative to another portion of the junction <b>12</b>, or another portion of the junction assembly <b>32</b>, without departing from the principles of the invention.

P-0055[0055] In the representatively illustrated method <b>10</b>, when it is desired to drift the lateral leg <b>22</b>, a modification is made to the drifting apparatus <b>42</b> to permit the drift <b>16</b> to enter the lateral leg. Referring specifically now to FIG. 7, a deflection device assembly <b>58</b> is added to the drifting apparatus <b>42</b> to deflect the drift <b>16</b> toward the lateral leg <b>22</b>.

P-0056[0056] The deflection device assembly <b>58</b> includes a deflection device <b>6</b>o, a latch <b>62</b>, a releasing device <b>64</b>, an upwardly facing muleshoe <b>66</b> and a generally tubular housing <b>68</b>. The housing <b>68</b> is attached to the displacement device <b>44</b> of the drifting apparatus <b>42</b>, so that the deflection device assembly <b>58</b> is conveyed into the well as part of the drifting apparatus.

P-0057[0057] However, the housing <b>68</b> is releasably attached to the deflection device assembly <b>58</b> using the releasing device <b>64</b>. The releasing device <b>64</b> includes lugs <b>70</b> which retract when a predetermined pressure is applied to the tubular string <b>38</b>, to thereby release the remainder of the deflection device assembly <b>58</b> for axial displacement relative to the rest of the drifting apparatus <b>42</b>. The lugs <b>70</b> also maintain a radial orientation of the deflection device assembly <b>58</b> relative to the latch <b>52</b>, until the lugs are retracted. Other types of releasing devices, such as shear pins, J-slots, etc., may be used in place of, or in addition to, the releasing device <b>64</b>.

P-0058[0058] The deflection device <b>60</b> includes a laterally inclined deflection surface <b>72</b>, an upper generally tubular neck <b>74</b>, and an intermediate section <b>76</b> extending between the neck and the deflection surface. As described above, the junction <b>12</b> is expected to be somewhat imperfectly reformed after it is inflated. Since the deflection device <b>60</b> is configured to extend into both the upper leg <b>18</b> and the lower leg <b>20</b> when installed in the junction <b>12</b>, the intermediate section <b>76</b> is preferably substantially flexible. In this manner, a degree of angular misalignment between the upper and lower legs <b>18</b>, <b>20</b> may be accommodated by flexing in the intermediate section <b>76</b>.

P-0059[0059] In the method <b>10</b>, the drifting apparatus <b>42</b> including the deflection device assembly <b>58</b> is conveyed into the well after both the upper and lower legs <b>18</b>, <b>20</b> have been drifted as described above. When the latch <b>52</b> engages the latch profile <b>54</b>, the deflection device <b>60</b> is radially oriented so that the deflection surface <b>72</b> faces toward the lateral leg <b>22</b>. The tubular string <b>38</b> is lowered further, thereby causing the latch <b>62</b> on the deflection device assembly <b>58</b> to engage another latch profile <b>78</b> in the junction assembly <b>32</b>.

P-0060[0060] Since, at this point, the deflection device <b>60</b> is already radially oriented relative to the junction <b>12</b>, this engagement between the latch <b>62</b> and the profile <b>78</b> preferably does not radially orient the deflection device, but serves instead to axially and rotationally secure the deflection device assembly <b>58</b> in the junction assembly <b>32</b>. However, engagement between the latch <b>62</b> and the profile <b>78</b> could radially orient the deflection device <b>60</b> if desired, without departing from the principles of the invention. A suitable latch and profile which may be used for the latch <b>62</b> and profile <b>78</b> is available from Halliburton Energy Services, Inc. as the Sperry-Sun Double Collet Latch Coupling.

P-0061[0061] When the latch <b>62</b> engages the profile <b>78</b>, the neck <b>74</b> is preferably positioned in the upper leg <b>18</b> and a bull plug <b>80</b> attached to a lower end of the deflection device <b>60</b> is positioned in the lower leg <b>20</b>. As described above, this positioning of the deflection device <b>60</b> in the junction <b>12</b> may result in flexing of the intermediate section <b>76</b> to accommodate any misalignment between the upper and lower legs <b>18</b>, <b>20</b>.

P-0062[0062] A predetermined pressure is then applied to the tubular string <b>38</b> to retract the lugs <b>70</b> and release the deflection device assembly <b>58</b> for displacement relative to the remainder of the drifting apparatus <b>42</b>. Preferably, the pressure required to retract the lugs <b>70</b> is less than the pressure required to extend the gripping structure <b>50</b>, and is less than the pressure required to shear the shear pins <b>48</b> to thereby permit the piston <b>46</b> of the displacement device <b>44</b> to displace, so that the deflection device assembly <b>58</b> is released prior to anchoring the drifting apparatus <b>42</b> and prior to displacing the drift <b>16</b> using the displacement device.

P-0063[0063] After the deflection device assembly <b>58</b> has been released, the drifting apparatus <b>42</b> is operated as described above, i.e., by applying an increased pressure to the tubular string <b>38</b> to extend the gripping structure <b>50</b>, and then further increasing the pressure to displace the drift <b>16</b> downward. However, when the drift <b>16</b> eventually contacts the deflection surface <b>72</b>, it is deflected laterally, so that it enters the lateral leg <b>22</b>, instead of the lower leg <b>20</b>. Further displacement of the drift <b>16</b> in the lateral leg <b>22</b> acts to drift the lateral leg to a desired inner dimension or geometry.

P-0064[0064] After the lateral leg <b>22</b> has been drifted, pressure on the tubular string <b>38</b> is relieved, thereby permitting the gripping structure <b>50</b> to retract. The tubular string <b>38</b> may then be raised to retrieve the drifting apparatus <b>42</b>, disengaging the latch <b>52</b> from the latch profile <b>54</b>. The deflection device assembly <b>58</b> may be retrieved along with the remainder of the drifting apparatus <b>42</b> by provision of a radially enlarged shoulder <b>82</b> on a mandrel <b>84</b> extending between the displacement device <b>44</b> and the drift <b>16</b>. When the drifting apparatus <b>42</b> is raised, the mandrel <b>84</b> is also raised, causing the shoulder <b>82</b> to contact a no-go shoulder <b>86</b> attached to the deflection device <b>60</b>. This contact between the shoulders <b>82</b>, <b>86</b> permits retrieval of the deflection device assembly <b>58</b> along with the remainder of the drifting apparatus <b>42</b>. Thus, the drifting apparatus <b>42</b> including the deflection device assembly <b>58</b> may be installed in the junction assembly <b>32</b> and retrieved therefrom in a single trip into the well.

P-0065[0065] Note that many other means of positioning the deflection device <b>60</b> in the junction assembly <b>32</b> may be used in keeping with the principles of the invention. For example, the deflection device <b>60</b> could be radially oriented relative to the junction <b>12</b> by attaching a latch, such as the latch <b>52</b>, between the bull plug <b>80</b> and the deflection device. This latch would engage the latch profile <b>56</b> below the lower leg <b>20</b>, thereby radially orienting and axially securing the deflection device <b>60</b> relative to the junction <b>12</b>.

P-0066[0066] Referring specifically now to FIG. 8, the junction <b>12</b> is cemented in the cavity <b>14</b> after the drifting operations are completed. As used herein, the terms “cement” and “cementing” are used broadly to encompass the use of any hardenable liquid or slurry to secure and seal equipment in a wellbore, although, technically speaking, the hardenable liquid or slurry may not actually contain a cementitious material. For example, the use of an epoxy or other polymer-containing hardenable liquid may be considered “cementing”, and the hardenable fluid or slurry may be referred to as “cement”. As used herein, the terms “harden” and “hardenable” are used broadly to indicate increased rigidity and strength, and such terms encompass the use of materials such as gels which, although they may not solidify, become more rigid and have increased strength.

P-0067[0067] To cement the junction <b>12</b> in the cavity <b>14</b>, another tubular string <b>88</b> is conveyed into the junction assembly <b>32</b>. A sealing device or stinger go attached to a lower end of the tubular string <b>88</b> is stung into a seal bore <b>92</b> of a cementing device <b>94</b> attached to a lower end of the lower leg <b>20</b>. The cementing device <b>94</b> includes at least one valve <b>96</b> selectively permitting and preventing flow through the cementing device.

P-0068[0068] The valve <b>96</b> is closed when pressure is applied to the interior of the junction <b>12</b> to inflate it. The valve <b>96</b> is opened when it is desired to flow cement <b>98</b> from the tubular string <b>88</b> through the cementing device <b>94</b>, and outward into the cavity <b>14</b> surrounding the junction <b>12</b>. The tubular string <b>88</b> is retrieved from the well along with the stinger go when the cementing operation is completed.

P-0069[0069] Referring specifically now to FIG. 9, after the cement <b>98</b> has hardened, the cementing device <b>94</b> may be drilled through by conveying a cutting device, such as one or more mill or drill <b>100</b> into the junction assembly <b>32</b>. The drill <b>100</b> may also be used to form the wellbore <b>24</b> extending outwardly from the lower leg <b>20</b>. As described above, the wellbore <b>28</b> may extend below the cavity <b>14</b> prior to the junction <b>12</b> being positioned therein, in which case the drill <b>100</b> may be used to further extend the wellbore <b>28</b>.

P-0070[0070] Referring specifically now to FIG. 10, The wellbore <b>26</b> may be formed extending outwardly from the lateral leg <b>22</b> using the drill <b>100</b> by first positioning a deflection device, such as a drilling whipstock <b>102</b>, in the junction <b>12</b>. Note that the whipstock <b>102</b> has an orienting latch <b>104</b> attached to a lower end thereof for engagement with the latch profile <b>56</b> below the lower leg <b>20</b>. In this manner, the whipstock <b>102</b> is radially oriented and axially secured relative to the junction <b>12</b> when the latch <b>104</b> is engaged with the profile <b>56</b>.

P-0071[0071] Alternatively, the same deflection device <b>60</b> used to drift the lateral leg <b>22</b> may be used as the drilling whipstock <b>102</b>.

P-0072[0072] After the wellbores <b>24</b>, <b>26</b> have been drilled, or either of them has been drilled, tubular strings, such as liners, screens, etc. may be positioned in the wellbores and cemented therein, or the wellbores may be completed open hole if desired. If tubular strings are used, these tubular strings may be conveniently attached and sealed to the legs <b>20</b>, <b>22</b> using conventional techniques, such as by using liner hangers, packers, etc., since the legs have been previously drifted and, thus, are well suited for sealing engagement and/or attachment thereto. Note that the method <b>10</b> thus provides a sealed wellbore intersection that is convenient and economical in installation, while permitting unhindered access to each wellbore and pressure isolation between the interior of the junction <b>12</b> and a formation surrounding the junction.

P-0073[0073] Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.