Rotary control valve and associated actuator control system

(54) Title: ACTUATOR CONTROL SYSTEM (30) Unionist Priority: 11/28/2007 us 11 / 946,332 (73) Holder (s): Halliburton energy Services inc (72) Inventor (s): Adam D. Wright, Vincent P. Zeller (57) Abstract: ACTUATOR CONTROL SYSTEM. A rotary control valve and associated actuator control system. An actuator control system comprises a rotary control valve including a generally flat face seal, and an actuator operably connected to the rotary control valve. Another actuator control system comprises a control valve including multiple faces having multiple orifices formed in them. Fluid communication is selectively allowed and prevented between the orifices in response to the relative displacement between the faces. A differential area is configured to apply a pressing force that maintains sealing contact between the faces, and which increases in response to a pressure increase applied to the control valve.

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riüo05065-1

ACTUATOR CONTROL SYSTEM.

Background

The present invention generally relates to control valves and, in a configuration described here, more particularly provides a rotary control valve and control system particularly useful for controlling the operation of well tools.

Space is at a premium in most underground pit tools, due to the fact that flow and access must be accommodated while also allowing the tool's functions to be performed. In the past, most hydraulic control systems used sliding sleeves, tailstocks, etc., with o-ring seals or another elastomer to selectively control fluid communication.

However, some of these earlier control systems require dynamic sealing against the o-rings, which leads to wear and eventual failure of the seals. In addition, previous control systems have been bulky or complex to operate.

Therefore, it will be appreciated that it would be desirable to provide improvements in control systems.

summary

In the present specification, a control valve and associated control system are provided which solve at least one problem in the art. An example is described below in which the control valve includes a metal to metal face seal. Another example is described below in which the control valve is interconnected between the pressure sources and an actuator piston.

In one aspect, an actuator control system is provided. The control system comprises a rotary control valve including a generally flat face seal. An actuator is operatively connected to the rotary control valve.

In another aspect, an actuator control system comprises a control valve including multiple faces having multiple orifices formed in them. Fluid communication is selectively allowed and prevented between the orifices in response to the relative displacement between the faces. A differential area is configured to apply a pressing force that maintains sealing contact between the faces. This pressing force increases in response to an increase in pressure applied to the control valve.

These and other characteristics, advantages, benefits and objectives will become apparent to someone of ordinary experience in the art upon careful consideration of the detailed description of configurations representative of the invention here below and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers.

Brief description of the drawings

Fig. 1 is a schematic partially cross-sectional view of a well system including an actuator control system configuring principles of the present invention;

Fig. 2 is a schematic diagram of the actuator control system in fig. 1;

Fig. 3 is a schematic cross-sectional view on an enlarged scale of a rotary control valve of the control system; and

Figs. 4-6 are views of cross sections of a portion of the control valve, taken along line 4-4 of fig. 3, representing various operating positions of the control valve.

Detailed Description

It is to be understood that the various configurations of the present invention described here can be used in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without deviating from the principles of the present invention. The configurations are described merely as examples of useful applications of the principles of the invention, which are not limited to any specific details of these configurations.

In the following description of representative embodiments of the invention, directional terms, such as above, below, top, bottom, etc., are used for convenience when referring to the accompanying drawings. In general, above, above, above and similar terms refer to a direction towards the earth's surface along an underground well, and below, below, down and similar terms refer to a direction away from the surface of the earth. land along the underground well.

Representatively illustrated in fig. 1 is a well system 10 that shapes principles of the present invention. In the well system 10, a drill rod test is performed using, in part, the well tools 44, 46 to control the flow between an inner flow passage 48 of a tubular column 50, a tubular ring 52 formed between the tubular column and an underground well 54, and a formation 56 intercepted by the underground well.

An actuator control system 12 is interconnected on the tubular column 50. Control system 12 is used to control the operation of actuators for well tools 44, 46 during the drill stem test. Well tool actuators 44, 46 are of conventional design and therefore are not further described here, but a schematic actuator 18 that can be used on well tools 44, 46 is shown in fig.

.

The control system 12 controls the operation of the actuators by selectively applying pressure to the actuator pistons. For this purpose, the tubular column 50 can also include pressure sources 20, 22.

For example, a relatively small pressure source can be an atmospheric chamber or a low pressure side of a pump. A relatively high pressure source can be a pressurized gas chamber, hydrostatic pressure in the well, or a high pressure side of a pump. Any type of pressure source can be used, and it is not necessary for any of the pressure sources to be interconnected in the tubular column 50, to maintain the principles of the invention. For example, if hydrostatic pressure is used as a pressure source, the tubular ring 52 or passage 48 can serve as the pressure source.

The well tool 44 is shown in fig. 1 as a circulation valve, and the well tool 46 is represented as a tester valve. However, the actuation of any other type or combination of well tools can be controlled using control system 12. Control system 12 can alternatively be used to control the operation of actuators outside a well environment.

At this point, it must be reiterated that the well system 10 is merely an example of an application of the principles of the invention. It is not necessary for a drill rod test to be performed, for the control system 12 to be unconnected on the tubular column 50, for fluid communication between formation 56, the passage 48 and the tubular ring 52 to be controlled, or for the drilling tools. well 44, 46 to be actuated. The principles of the invention are not limited in any way to the details of the well system 10.

Referring now further to fig. 2, a schematic diagram of the hydraulic circuit of the control system 12 is shown separately from the well system 10. In this view it can be seen that a control valve 14 of the control system 12 is interconnected between the pressure sources 20, 22 and chambers 24, 26 on opposite sides of a piston 28 in actuator 18.

As shown in fig. 2, chambers 24, 26 are in fluid communication with respective opposite surface areas 30, 32 on piston 28. However, in other configurations, chambers 24,26 and surface areas 30, 32 are not required to be on opposite sides of piston 28.

It is also not necessary for piston 28 to have a cylindrical shape 5 as shown in fig. 2. The piston 28 can instead have an annular shape or any other shape.

In this example, pressure source 20 will be described as a source of high pressure, and pressure source 22 will be described as a source of low pressure. In other words, the pressure source 20 provides an increased pressure over the pressure provided by the pressure source 22.

For example, pressure source 20 could provide hydrostatic pressure and pressure source 22 could provide substantially atmospheric pressure. The preferable feature is that a pressure differential between pressure sources 20, 22 is maintained, at least during operation of the actuator 18.

When it is desired to move piston 28 to the right as seen in fig. 2, the control valve 14 is operated to allow fluid communication between the pressure source 20 and the chamber 24, θ to allow fluid communication between the pressure source 22 and the chamber 26. When it is desired to move the piston 28 to the left as seen in fig. 2, the control valve 14 is operated to allow fluid communication between the pressure source 22 and the chamber 24, and to allow fluid communication between the pressure source 20 and the chamber 26.

In another feature of the control system 12, the control valve 14 can be operated to prevent fluid communication between each of the chambers 24, 26 and any of the pressure sources 20, 22. In other words, the piston 28 can be fixed in a certain position preventing fluid communication with each of the chambers 24, 26.

Although only an actuator 18, a piston 28 and two pressure sources 20, 22 are represented in the control system 12 of fig. 2, it will be appreciated that any number or combination of these elements can be provided in a control system incorporating principles of the invention. Referring now further to fig. 3, an enlarged scale cross-sectional view of the control valve 14 is shown illustrated. The control valve 14 is described here as a rotary control valve, since it includes a valve member 58 which is rotated about a axis of rotation 42 to operate the valve.

valve member 58 has a generally flat bottom face 34 formed thereon. Orifices 38 are formed in the valve member 58, and in another valve member 60 that has a generally flat top face 36 formed therein. As described more fully below, the relative rotation between valve members 58, 62 is used to selectively allow and prevent fluid communication between the various orifices in the control valve 14, thereby selectively applying pressure between the pressure sources and the actuator 18 .

In an important feature of the control valve 14, a face seal 16 is formed between the surfaces of the faces 34, 36 on the valve members 58, 60.

Preferably, faces 34, 36 are highly polished, such that when sufficient contact pressure exists between the faces, a seal is formed.

In another important aspect of the control valve 14, the face seal 16 is preferably a metal-to-metal seal, with each face 34, 36 being formed on a metallic portion of the respective one of the valve members 58, 60. This metal face seal with metal 16 is very rough and abrasion resistant, and is very well suited to the environmental extremes (eg, high temperatures and pressures, corrosive fluids, etc.) found in underground wells.

In the example shown in fig. 3, the face seal 16 surrounds a differential area A (see figs. 4-6) that is in fluid communication with the low pressure source 22, or is otherwise at a relatively low pressure (such as a chamber atmospheric).

An inner chamber 62 above the valve member 58 is exposed to the high pressure source 20, or is otherwise at a relatively high pressure.

Thus, a differential pressure exists through valve member 58. The pressure differential acts in the differential area A, resulting in a pressing force that increases the contact pressure between faces 34, 36 as the pressure differential increases.

It will be appreciated that, if the high pressure source 20 corresponds to the hydrostatic pressure, then as the control valve 14 is lowered further down into the well, the pressing force applied between the valve members 58, 60 will also increase, increasing thus the contact pressure between the faces 34, 36. In this way, the face seal 16 can be maintained and even reinforced, as the pressure applied to the control valve 14 increases.

An initial pressing force is provided by a pressing device 40 (such as a spring or other type of pressing device). The initial pressing force maintains sealing contact between faces 34, 36 when the pressure applied to chamber 62 is relatively low, such as at relatively shallow depths in a well.

A motor 64 is used to rotate an axis 66 connected to the

0 valve member 58. Motor 64 is preferably, but not necessarily, an electric motor designed to apply relatively high torque during a relatively limited angular rotation. In this example, engine 64 rotates shaft 66 and valve member 58 only 22% degrees in each direction, but other amounts of rotation can be used, if desired.

It will be appreciated that, as the differential contact pressure

4-6, three between faces 34, 36 increase, the torque required to rotate valve member 58 will also increase. Therefore, the contact pressure should be no greater than that corresponding to a torque that the engine 64 is capable of delivering, while at the same time being large enough to maintain the face seal 16 between the valve members 58, 60. In the control valve 14, the contact pressure can be adjusted by varying the differential area A and / or by varying the pressure supplied through the differential area.

Referring now further to Figs, different positions of valve member 58 on control valve 14 are represented illustrated in the cross-sectional views taken along line 4-4 of fig. 3.

Eight holes 38a-h in valve member 60 are visible in Figs. 4-6. These orifices 38a-h in this example are connected as follows: the orifices 38a &amp; b are connected to the high pressure source 20, the orifices 38c &amp; d are connected to the low pressure source 22, the orifices 38e &amp; f are connected to the actuator chamber 24, and the orifices 38g &amp; h are connected to the actuator chamber 26. Of course, different numbers, arrangements and combinations of holes 38 can be used, if desired. For example, if multiple actuators 18 are to be controlled, additional orifices 38 can be used.

Note that some of the holes 38 that are connected to the same pressure are equally spaced circumferentially on the geometric axis of rotation

42. That is, the holes 38a &amp; b (which are both connected to the high pressure source 20) are spaced 180 degrees apart, the holes 38c &amp; d (which are both connected to the low pressure source 22) are spaced 180 degrees apart, the holes 38e &amp; f (which are both connected to chamber 24) are spaced 180 degrees apart, and holes 38g &amp; h (which are both connected to chamber 26) are spaced 180 degrees apart. If three of:

holes 38 were connected to the same pressure source, they would preferably be spaced 120 degrees apart, if four of the holes were connected to the same pressure source, they would preferably be spaced 90 degrees apart, etc.

In addition, note that the holes 38 that are connected to the same pressure source are also equally spaced radially in relation to the geometric axis of rotation 42. This circumferential and radial spacing of the holes

38 exposed to the same pressure provides a corresponding balance of forces applied to valve members 58, 60 by pressures, thus helping to prevent faces

34, 36 to be separated from each other due to an imbalance in pressures.

Two of the orifices 38 are connected to each of the pressure source 20, pressure source 22, chamber 24 and chamber 26 to provide this balance of forces, but it will be appreciated that any number of holes (preferably greater than one) can be used, if desired.

Circumferentially extending slits 68a-c are formed in valve member 58 to provide fluid communication between orifices 38a-h. In fig. 4, the valve member 58 is positioned such that each of the slots 68a25 c is only in fluid communication with one of the holes 38a-c, respectively.

The face seal 16 prevents any fluid communication between the holes 38a-h at the interface between the faces 34, 36. In this position, the piston 28 would be prevented from moving, because the chambers 24, 26 would be isolated from both sources of pressure 20, 22.

In fig. 5, valve member 58 has been rotated 22% degrees clockwise from its position in fig. 4 as seen in the drawing. Slit 68a now provides fluid communication between holes 38a &amp; e, slot 68b now provides fluid communication between holes 38b &amp; f, slot 68c now provides fluid communication between holes 38c &amp; g, and slot 68d now provides fluid communication between holes 38d &amp; h.

In this position, the high pressure source 20 is in fluid communication with the chamber 24 and the low pressure source 22 is in fluid communication with the chamber 26. This will work to press the piston 28 of the actuator 18 to the right as seen in fig . 2.

In fig. 6, valve member 58 has been rotated 22% degrees counterclockwise from its position in fig. 4 as seen in the drawing. Slit 68a now provides fluid communication between holes 38a &amp; h, slot 68b now provides fluid communication between holes 38b &amp; g, slot 68c now provides fluid communication between holes 38c &amp; e, and slot 68d now provides fluid communication between holes 38d &amp; f.

In this position, the high pressure source 20 is in fluid communication with the chamber 26, and the low pressure source 22 is in communication with the chamber 24. This will work to push the piston 28 of the actuator 18 to the left as seen in fig . 2.

Although the above description of the actuator control system 12 uses the control valve 14 to control the actuation of an actuator 18 with a piston 28 separating the two chambers 24, 26, it must be clearly

5 understood that this is simply an example of the wide variety of possible applications for the principles of the present invention. Examples of other applications include, but are not limited to, the use of a modified control valve 14 to control the actuation of multiple actuators 18, the use of the control valve to control fluid communication with multiple areas and / or piston chambers on each side of a piston, the use of the control valve to control the displacement of multiple pistons in an actuator, etc.

It can now be fully appreciated that the above description provides a control system 12 that is well suited to control the performance of one or more actuators 18. The control valve 14 is relatively compact, has few moving parts, has uncomplicated operation and uses a metal face seal with metal 16 to reliably allow and prevent fluid communication between pressure sources 20, 22 and chambers 24, 26 of an actuator 18.

In particular, an actuator control system 12 is described above which comprises a rotary control valve 14 including a generally flat face seal 16. An actuator 18 is operably connected to rotary control valve 14. The face seal 16 can understand a metal to metal seal.

The rotary control valve 14 can selectively allow and prevent fluid communication between at least one pressure source 20, 22 and at least one chamber 24, 26 exposed to a piston 28 of the actuator 18.

The rotary control valve 14 can have a position in which a pressure source 20 is in fluid communication with a surface area 30 of a piston 28 of the actuator 18 and another pressure source 22 is in fluid communication with another area of piston surface 32, and another position in which the first pressure source 20 is in fluid communication with the second surface area 32 and the second pressure source 22 is in fluid communication with the first surface area 30. The rotary control valve 14 can also have another position in which none of the first and second surface areas 30, 32 are in fluid communication with any of the first and second pressure sources, 20, 22, thereby preventing the displacement of the piston 28.

The face seal 16 can include multiple generally flat faces 34, 36 having multiple holes 38 formed therein. Fluid communication can be selectively allowed and prevented between holes 38 in response to the relative displacement between faces 34, 36.

A pressing force can maintain contact between faces 34, 36. The pressing force can increase in response to a pressure increase applied to control valve 14. A pressing device 40 can apply a pressing force that maintains contact between faces 34, 36 .

At least one of the faces 34, 36 can rotate about an axis of rotation 42. The holes 38 that are exposed to an equivalent pressure can be equally spaced circumferentially about the axis of rotation 42. The holes 38 that are exposed to the equivalent pressure they can also be equally radially spaced with respect to the axis of rotation 42. Also described above is an actuator control system 12 that includes a control valve 14 with multiple faces 34, 36 having multiple holes 38 formed therein. Fluid communication is selectively allowed and prevented between holes 38 in response to relative displacement between faces 34, 36. A differential area is configured to apply a pressing force that maintains a sealing contact between the

0 faces 34, 36, and that increases in response to an increase in pressure applied to the control valve 14.

The faces 34, 36 can be part of a generally flat face seal 16. The face seal 16 can comprise a metal to metal seal.

The control valve 14 can selectively allow and prevent fluid communication between at least one pressure source 20, 22 and at least one chamber 24, 26 exposed to a piston 28 of an actuator 18.

The control valve 14 can have a position in which a pressure source 20 is in fluid communication with a surface area 30 of a piston 28 of the actuator 18 and another pressure source 22 is in fluid communication with another surface area. 32 of the piston, and another position in which the first pressure source 20 is in fluid communication with the second surface area 32 and the second pressure source 22 is in fluid communication with the first surface area 30.

The control valve 14 can also have another position in which none of the first and second surface areas 30, 32 are in fluid communication with any of the first and second pressure sources 20,

22, thus preventing displacement of the piston 28.

A pressing device 40 can apply another pressing source that maintains sealing contact between faces 34, 36.

At least one of the faces 34, 36 can rotate about a geometric axis 10 of rotation 42. The holes 38 that are exposed to an equivalent pressure can be equally spaced circumferentially about the geometric axis of rotation 42. The holes 38 that are exposed to the pressure equivalent can also be equally radially spaced in relation to the axis of rotation 42.

At least one of the orifices 38 may be in communication with the pressure applied to the control valve 14.

Of course, a person skilled in the art would, upon careful consideration of the above description of representative configurations of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes can be made to these specific configurations, and such changes are within the scope of the principles of the present invention.

Consequently, the foregoing detailed description must be clearly understood to be given by way of illustration and example only, the spirit and scope of the present invention being limited only by the appended claims and their equivalents.