Rotary steerable tool with dump valve

A rotary steerable tool for directional drilling includes a tool body including an outer surface and a flowbore therethrough, a pad movably coupled to the tool body and alternately movable between an extended position and a retracted position, and a piston engageable with the pad to move the pad. The tool further includes a pressurized fluid supply flow path to provide fluid pressure to the piston for the piston to controllably move the pad to the extended position, and a dump valve in fluid communication with the pressurized fluid supply flow path to selectively vent fluid pressure to allow the pad to move from the extended position toward the retracted position.

BACKGROUND

This section is intended to provide relevant contextual information to facilitate a better understanding of the various aspects of the described embodiments. Accordingly, it should be understood that these statements are to be read in this light and not as admissions of prior art.

Directional drilling is commonly used to drill any type of well profile where active control of the well bore trajectory is required to achieve the intended well profile. For example, a directional drilling operation may be conducted when the target pay zone is not directly below or otherwise cannot be reached by drilling straight down from a drilling rig above it.

Directional drilling operations involve varying or controlling the direction of a downhole tool (e.g., a drill bit) in a borehole to direct the tool towards the desired target destination. Examples of directional drilling systems include point-the-bit rotary steerable drilling systems and push-the-bit rotary steerable drilling systems. In both systems, the drilling direction is changed by repositioning the bit position or angle with respect to the well bore. Push-the-bit tools use pads on the outside of the tool which press against the well bore thereby causing the bit to press on the opposite side causing a direction change. Point-the-bit technologies cause the direction of the bit to change relative to the rest of the tool.

Dogleg capability is the ability of a drilling system to make precise and sharp turns in forming a directional well. Higher doglegs increase reservoir exposure and allow improved utilization of well bores where there are lease line limitations. Tool face control is a fundamental factor of dogleg capability. Typically, a higher and more precise degree of tool face control increases dogleg capability. In some drilling systems, tool face is controlled by pads or pistons that extend from the drilling tool to push the drill bit in an opposing direction. In such system, a pad or piston is extended as it rolls into the appropriate position and retracted as the pad or piston rolls out of said position. In existing systems, the pads or pistons are generally only extendable or retractable at a fixed rate, thereby providing low resolution tool face control.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present disclosure generally relates to oil and gas exploration and production, and more particularly to systems and methods for directional drilling, such as a rotary steerable system (RSS). The disclosure relates to one or more dump valves included within a rotary steerable tool for increased control of pads that extend from the rotary steerable tool, thereby increasing control over the force vectors applied to the borehole wall by the pads or pistons and more accurately directing a drill bit.

Oil and gas hydrocarbons are naturally occurring in some subterranean formations. A subterranean formation containing oil or gas may be referred to as a reservoir, in which a reservoir may be located under land or off shore. Reservoirs are typically located in the range of a few hundred feet (shallow reservoirs) to a few tens of thousands of feet (ultra-deep reservoirs). To produce oil or gas, a wellbore is drilled into a reservoir or adjacent to a reservoir.

A well can include, without limitation, an oil, gas, or water production well, or an injection well. As used herein, a “well” includes at least one wellbore. A wellbore can include vertical, inclined, and horizontal portions, and it can be straight, curved, or branched. As used herein, the term “wellbore” includes any cased, and any uncased, open-hole portion of the wellbore. A near-wellbore region is the subterranean material and rock of the subterranean formation surrounding the wellbore. As used herein, a “well” also includes the near-wellbore region. The near-wellbore region is generally considered to be the region within approximately 100 feet of the wellbore. As used herein, “into a well” means and includes into any portion of the well, including into the wellbore or into the near-wellbore region via the wellbore.

A portion of a wellbore may be an open-hole or cased-hole. In an open-hole wellbore portion, a tubing string may be placed into the wellbore. The tubing string allows fluids to be introduced into or flowed from a remote portion of the wellbore. In a cased-hole wellbore portion, a casing is placed into the wellbore that can also contain a tubing string. A wellbore can contain an annulus. Examples of an annulus include, but are not limited to: the space between the wellbore and the outside of a tubing string in an open-hole wellbore; the space between the wellbore and the outside of a casing in a cased-hole wellbore; and the space between the inside of a casing and the outside of a tubing string in a cased-hole wellbore.

Turning now to the figures,FIG. 1depicts a schematic view of a drilling operation utilizing a directional drilling system100, in accordance with one or more embodiments. The system of the present disclosure will be specifically described below such that the system is used to direct a drill bit in drilling a borehole, such as a subsea well or a land well. Further, it will be understood that the present disclosure is not limited to only drilling an oil well. The present disclosure also encompasses natural gas boreholes, other hydrocarbon boreholes, or boreholes in general. Further, the present disclosure may be used for the exploration and formation of geothermal boreholes intended to provide a source of heat energy instead of hydrocarbons.

Accordingly,FIG. 1shows a schematic view of a tool string126disposed in a directional borehole116, in accordance with one or more embodiments. The tool string126includes a rotary steerable tool128in accordance with various embodiments. The rotary steerable tool128provides full 3D directional control of the drill bit114. A drilling platform102supports a derrick104having a traveling block106for raising and lowering a drill string108. A kelly110supports the drill string108as the drill string108is lowered through a rotary table112. In one or more embodiments, a topdrive is used to rotate the drill string108in place of the kelly110and the rotary table112. A drill bit114is positioned at the downhole end of the tool string126, and, in one or more embodiments, may be driven by a downhole motor129positioned on the tool string126and/or by rotation of the entire drill string108from the surface.

As the bit114rotates, the bit114creates the borehole116that passes through various formations118. A pump120circulates drilling fluid through a feed pipe122and downhole through the interior of drill string108, through orifices in drill bit114. The drilling fluid then flows back to the surface via the annulus136around drill string108and into a retention pit124. The drilling fluid transports cuttings from the borehole116into the pit124and aids in maintaining the integrity of the borehole116. The drilling fluid may also drive the downhole motor129and other portions of the rotary steerable tool128, such as control pads for the tool128.

The tool string126may include one or more logging while drilling (LWD) or measurement-while-drilling (MWD) tools132that collect measurements relating to various borehole and formation properties as well as the position of the bit114and various other drilling conditions as the bit114extends the borehole108through the formations118. The LWD/MWD tool132may include a device for measuring formation resistivity, a gamma ray device for measuring formation gamma ray intensity, devices for measuring the inclination and azimuth of the tool string126, pressure sensors for measuring drilling fluid pressure, temperature sensors for measuring borehole temperature, etc.

The tool string126may also include a telemetry module135. The telemetry module135receives data provided by the various sensors of the tool string126(e.g., sensors of the LWD/MWD tool132), and transmits the data to a surface unit138. Data may also be provided by the surface unit138, received by the telemetry module135, and transmitted to the tools (e.g., LWD/MWD tool132, rotary steering tool128, etc.) of the tool string126. In one or more embodiments, mud pulse telemetry, wired drill pipe, acoustic telemetry, or other telemetry technologies known in the art may be used to provide communication between the surface control unit138and the telemetry module135. In one or more embodiments, the surface unit138may communicate directly with the LWD/MWD tool132and/or the rotary steering tool128. The surface unit138may be a computer stationed at the well site, a portable electronic device, a remote computer, or distributed between multiple locations and devices. The unit138may also be a control unit that controls functions of the equipment of the tool string126.

The rotary steerable tool128is configured to change the direction of the tool string126and/or the drill bit114, such as based on information indicative of tool128orientation and a desired drilling direction or well profile. In one or more embodiments, the rotary steerable tool128is coupled to the drill bit114and drives rotation of the drill bit114. Specifically, the rotary steerable tool128rotates in tandem with the drill bit114. In one or more embodiments, the rotary steerable tool128is a point-the-bit system or a push-the-bit system.

FIG. 2depicts a radial cross-sectional schematic view of the rotary steerable tool128, showing the pads202(i.e., extendable members), in accordance with one or more embodiments of the present disclosure. The rotary steerable tool128includes a tool body203and a flowbore201through which drilling fluid flows. As shown, the pads202are close to the tool body203in a retracted position and movable outward into an extended position. In the illustrated example, the pads202are coupled to the tool body203and pivot between the retracted and extended positions, such as via hinges204. The pads202can be extended and pushed outward and into the extended position by the pistons212. In the illustrated embodiment, the tool body203includes recesses206which house the pads202when in the retracted position, thereby allowing the pads202to be flush with the tool body203. Further, a piston212is engageable with each respective pad202.

The pads202can be extended to varying degrees. The extended position can refer to any position in which the pad202is extended outwardly beyond the retracted position and not necessarily fully extended. “Retraction” or “retracting” refers to the act of bringing the pad202inward (e.g., radially inward), or moving the pad202from a more extended position to a less extended position, and does not necessarily refer to moving the pad202into a fully retracted position. Similarly, “extension” or “extending” refers to the act of moving the pad202outward, such as from a less extended position to a more extended position, and does not necessarily refer to moving the pad202into a fully extended position.

As shown, the rotary steerable tool128includes three pads spaced 120 degrees apart around the circumference of the tool128. However, the rotary steerable tool128can have more or less than the three pads202shown. The pad202is just one configuration of an extendable member or mechanism designed to push against the wall of the borehole116to urge the drill bit114in a direction. The rotary steerable tool128may include various other types of extendable members or mechanisms, including but not limited to pistons configured to push against the borehole116directly or pads202configured to be acted on by drilling fluid direction without an intermediate piston.

The pads202, or alternative extendable members or mechanism, may also include a retraction mechanism (e.g., a spring or other biasing mechanism) that moves the pads202back into the closed position. In some other embodiments, the pads202may be configured to fall back into the closed position when pressure applied by the drill fluid at the pads202drops. In some embodiments, the pads202are coupled to the pistons212and, thus, travel with the piston212. In other embodiments, as shown inFIG. 2, the pistons212may engage the pads202to push the pads202outwards from the retracted position towards the extended position, with the pads202relying on engagement with the borehole wall, or a retraction mechanism, to move the pads202from the extended position towards the retracted position. In one or more embodiments, the pads202may also function as centralizers, in which all the pads202remain in the extended position, keeping the rotary steerable tool128centralized in the borehole116.

Referring now toFIG. 3, a cross-sectional schematic view of a rotary steerable tool128in accordance with one or more embodiments of the present disclosure. The rotary steerable tool128includes a tool body203with a flowbore201formed through the tool body203for fluid flow and fluid pressure. A drill bit114is coupled to the tool body203for the tool128to control the orientation of the drill bit114when drilling. One or more pads202(i.e., extendable members) are coupled to the tool body203and alternately movable between an extended position and a retracted position with respect to an outer surface220of the tool body203.

One or more pistons212are positioned within the tool body203and also movable between an extended position and a retracted position with respect to the tool body203. Each of the pistons212is engageable with a respective one of the pads202, such that, as the piston212moves from the retracted position to the extended position, the pad202in engagement with the respective piston212also moves from the retracted position to the extended position. Thus, when the piston212is in the extended position, the pad202is in the extended position. Further, if the piston212is coupled (e.g., connected) to the pad202, when the piston212is in the retracted position, the pad202is in the retracted position.

As shown in this embodiment, a rotary valve222is used to control fluid pressure to move the pistons212and the pads202from the retracted position to the extended position. The rotary valve222includes an upper disk224and a lower disk226and is positioned within the tool body203of the rotary steerable tool128. As the upper disk224rotates with respect to the lower disk226, the rotary valve222selectively routes fluid pressure from the flowbore201to one or more of the pistons212through one or more respective pressurized fluid supply flow paths240to move the piston212and the pad202from the retracted position to the extended position.

To control the rotary valve222, the rotary steerable tool128may include or be operably coupled to a turbine230, a generator232, a motor234, and/or a controller236in this embodiment. For example, as shown, the turbine230, the generator232, the motor234, and/or the controller236may be included within the tool body203of the tool128. Alternatively, one or more of these components may be positioned outside of the tool body203, such as included within another tool, and then operably coupled to the tool128. In this embodiment, the turbine230receives fluid flow through the flowbore201, and is coupled to the generator232for the generator232to produce power from the turbine230. The generator232is then operably coupled to the motor234to provide power to the motor234to a drive shaft238. The drive shaft238extends between the motor234and the controller236(e.g., gear box) for the controller236to control the rotary valve222, such as by selectively moving the upper disk224with respect to the lower disk226.

With respect to one of the pairs or sets of a piston212and a pad202, the rotary valve222is used to route fluid pressure from the flowbore201, through a pressurized fluid supply flow path240extending between the rotary valve222and the piston212, and to a piston reservoir242housing or fluidly coupled to the piston212. This arrangement enables the rotary valve222to selectively control fluid pressure from the flowbore201to the piston212to move the piston212and the pad202from the retracted position to the extended position.

Referring still toFIG. 3, though optional, one or more choke valves250may be included within the rotary steerable tool128. A choke valve250may be in fluid communication with the pressurized fluid supply flow path240to be fluidly coupled between to the piston212and regulate fluid flow between the piston212and an exterior of the tool body203. For example, when fluid pressure is provided to the piston212from the rotary valve222, the choke valve250may regulate and restrict the fluid flow away from the piston212to the exterior of the tool body203. With the choke valve250included within the tool128, the choke valve250provides resistance to fluid flow, which creates fluid pressure, thereby enabling fluid pressure and fluid flow to accumulate within the piston reservoir242to move the piston212from the retracted position to the extended position. The choke valve250also provides a path for fluid pressure and fluid flow away from the piston reservoir242, such as in the event of damage or failure to the piston212or pad202. This may prevent the piston212or pad202from locking (e.g., hydraulically) for the piston212and pad202to still move from the extended position to the retracted position. As such, the choke valve250is shown as positioned within a choke valve flow path252extending between the piston reservoir242and the exterior of the tool body203.

In accordance with one or more embodiments of the present disclosure, one or more dump valves244is included within the rotary steerable tool128, such as to facilitate or increase the rate by which one or more of the pistons212and the pads202is able to move from the extended position to the retracted position. The dump valve244is in fluid communication with the pressurized fluid supply flow path240to be fluidly coupled to the piston212to control fluid flow between the piston212and an exterior of the tool body203. When it is desired to move the piston212and the pad202from the extended position to the retracted position, the dump valve244opens to enable fluid pressure and fluid flow from the pressurized fluid supply flow path240and the piston reservoir242to the exterior of the tool body203, thereby enabling the piston212and the pad202to move without restriction.

In this embodiment, a dump valve flow path246is formed in the tool body203to extend between the piston reservoir242and the exterior of the tool body203. The dump valve244is positioned within the dump valve flow path246to selectively vent fluid pressure from the pressurized fluid supply flow path240to an exterior of the tool128through the dump valve244. In an open position, the dump valve244enables or allows fluid pressure and fluid flow through the dump valve flow path246, and in a closed position, the dump valve244prevents fluid pressure and fluid flow through the dump valve flow path246. A controller248is operably coupled to the dump valve244to control the dump valve244between the open and closed positions, and an actuator is coupled to the dump valve244to move the dump valve244between the open and closed positions. The actuator to move the dump valve244may, for example, include a hydraulic actuator, an electromagnetic actuator, a piezoelectric actuator, or a mechanical drive actuator.

In one or more embodiments, the dump valve244may control fluid pressure and fluid flow therethrough based upon a position of the rotary valve222. For example, the controller248for the dump valve244may monitor or receive a signal regarding the position of the rotary valve222(such as from the controller236), in which the controller248may initiate an actuator to move the dump valve244to the open position or the closed position based upon the position of the upper disk224with respect to the lower disk226of the rotary valve222. If the flow paths of the upper disk224and the lower disk226of the rotary valve222are aligned to provide fluid flow to a respective piston reservoir242, the controller248may have the dump valve244in the closed position to enable fluid flow and pressure to move the piston212and the pad202to an extended position. If the flow paths of the upper disk224and the lower disk226of the rotary valve222are not aligned to not provide fluid flow to the respective piston reservoir242, the controller248may have the dump valve244in the open position to enable vent fluid pressure and move the piston212and the pad202to a retracted position. The dump valve244in the open position enables fluid pressure to vent and flow out of the pressurized fluid supply flow path240and the piston reservoir242more quickly than, for example, through the choke valve250. This enables the piston212and the pad202to move to the retracted position more quickly for better control of the drill bit114.

Referring now toFIGS. 4A-4E, multiple arrangements are shown for the dump valve244and the choke valve250with respect to the piston212and the pad202in accordance with one or more embodiments of the present disclosure. In each ofFIGS. 4A-4E, the dump valve244is positioned in the dump valve flow path246and the choke valve250is positioned in the choke valve flow path252. InFIG. 4A, the flow paths246and252partially overlap with each other with the flow paths246and252connected to and in fluid communication with the pressurized fluid supply flow path240extending between the rotary valve and the piston212. InFIG. 4B, the flow paths246and252partially overlap with each other with the flow paths246and252connected to the piston reservoir242. InFIGS. 4C and 4D, the flow paths246and252are independent of each other and are positioned on opposite sides of the piston212with respect to each other.FIG. 4Cshows the opposite arrangement for the flow paths246and252with respect toFIG. 4D. Further, inFIG. 4E, the dump valve flow path246may be formed through the piston212and/or the pad202with the dump valve244positioned therein, enabling fluid to flow from the piston reservoir242, through the piston212, the pad202, the dump valve244, and to the exterior of the rotary steerable tool.

In one or more embodiments, a choke valve250may not be included within a rotary steerable tool128, in which the dump valve244may be solely relied upon to enable fluid pressure and fluid flow away from the piston212to the exterior of the tool128.FIGS. 5A and 5Bshow arrangements in which only a dump valve244, and not a choke valve250, is included with a rotary steerable tool128. InFIG. 5A, the dump valve flow path246connects to and is in fluid communication with the pressurized fluid supply flow path240, and inFIG. 5B, the dump valve flow path246is in fluid communication with the pressurized fluid supply flow path240though the piston reservoir242.

As discussed above, a dump valve244and/or a choke valve250may be used to selectively control fluid pressure from a pressurized fluid supply flow path240and a piston212to an exterior of the tool body203. InFIG. 3, the dump valve flow path246and the choke valve flow path252are formed such that fluid pressure would flow away from the piston212and to the outer surface220of the tool body203. However, the present disclosure is not so limited, as the dump valve flow path246and the choke valve flow path252may be formed such that fluid may flow to the flowbore201formed through the tool body203instead to the outer surface220. For example, inFIG. 6, the dump valve flow path246may extend between the piston212and the flowbore201to control fluid flow therethrough. Similarly, though not shown here, the choke valve flow path252may extend between the piston212and the flowbore201. In such an embodiment, a flow restrictor260or orifice may be positioned or formed within the flowbore201of the tool128. An outlet for the dump valve flow path246is formed within the flowbore201downstream of the flow restrictor260to decrease the fluid pressure at the location of the outlet and enable fluid flow through the dump valve flow path246.

In one or more embodiments, a sensor may be included with the rotary steerable tool128with the dump valve244controlled based upon the output of the sensor. For example,FIGS. 7A and 7Bshow multiple views of a dump valve244included within a dump valve flow path246of a tool body203. A controller248for controlling the dump valve244is positioned within the tool body203, along with a sensor262. In this embodiment, the sensor262may be a pressure sensor with the sensor262fluidly coupled to the dump valve flow path246. The sensor262may measure a characteristic or property of the fluid (e.g., pressure in this example), in which the controller248is operably coupled to the sensor262to receive the measurement from the sensor262. The controller248may compare the measurement from the sensor262with a predetermined value, or based upon a predetermined amount of time, and then move the dump valve244to the open position or the closed position based upon the comparison. For instance, if a pressure measured by the sensor262is above a predetermined amount, or if the dump valve244has been exposed to fluid pressure above a predetermined amount of time, the controller248may open the dump valve244for fluid pressure to flow to the exterior of the tool128and into an annulus within the borehole.

A dump valve in accordance with one or more embodiments of the present disclosure may include one or more different types of valves. For example, a dump valve244may include an on/off valve, such as shown inFIG. 8A, may include a variable valve, such as shown inFIG. 8B, or may include a three-way valve, such as shown inFIG. 8C. If the dump valve244is a three-way valve, the dump valve244may be fluidly coupled between pressurized fluid supply flow path240, the piston reservoir242, and the dump valve flow path246. In a first position, the dump valve244may route fluid pressure to the piston212and the pad202to move to the extended position. In a second position, the dump valve244may route fluid flow away from the piston212and the pad202to move to the retracted position. In a third position, the dump valve244may be used to hydraulically lock the piston212and the pad202in place, thereby preventing movement of the piston212and the pad202. In one or more embodiments, a dump valve in accordance with the present disclosure may include a poppet valve, a rotating disk shear valve, a sliding plate shear valve, a spool valve, a gate valve, a ball valve, a diaphragm valve, or a butterfly valve.

Referring now toFIG. 9, a graph in accordance with one or more embodiments of the present disclosure is shown. InFIG. 9, the x-axis represents the angle of rotation of a rotary steerable tool within a borehole, and the y-axis represents the amount of force a pad exerts against the wall of a borehole for directional steering or drilling. Further, three profiles are shown, an upper profile901, a middle profile903, and a lower profile905. The upper profile901shows a desired force profile for three pads used on a rotary steerable tool. As shown in the upper profile901, it is desired for a pad to move from the retracted position to the extended position without any delay (e.g., vertical force profile), and move from the extended position to the retracted position without any delay (e.g., vertical force profile901A). This enables more control when moving the pads for steering the rotary steerable tool within a borehole.

The middle profile903shows the force profile for three pads in a rotary steerable tool that only includes a choke valve and no dump valve. In such an embodiment, a pad is able to move from the retracted position to the extended position without much delay (e.g., almost vertical force profile), but the choke valve prevents the pad from being able to move from the extended position to the retracted position without undue delay (e.g., a slanted profile force profile903A is shown). This slower movement of the pad from the extended position to the retracted position prevents full control for steering a rotary steerable tool, particularly if the tool is rotating at a faster speed within the borehole.

The lower profile905shows the force profile for three pads in a rotary steerable tool that only includes a dump valve, such as shown and discussed above. In such an embodiment, a pad is able to move from the retracted position to the extended position without much delay (e.g., almost vertical force profile), and is also able to move from the extended position to the retracted position without much delay (e.g., almost vertical force profile905A). This quicker movement of the pad from the extended position to the retracted position enables better control for steering a rotary steerable tool, such as with respect to the middle profile903, particularly when used at higher rotational speeds. Thus, a rotary steerable tool in accordance with the present disclosure may reduce the flow restriction and decrease the time duration needed when moving a piston and a pad from the extended position to the retracted position. This may reduce the erosion resistance that may otherwise damage components within the rotary steerable tool and may increase the speed at which the rotary steerable tool may operate.

In addition to the embodiments described above, many examples of specific combinations are within the scope of the disclosure, some of which are detailed below:

Embodiment 1. A rotary steerable tool for directional drilling, comprising:

a tool body including an outer surface and a flowbore therethrough;a pad movably coupled to the tool body and alternately movable between an extended position and a retracted position;a piston engageable with the pad to move the pad;a pressurized fluid supply flow path to provide fluid pressure to the piston for the piston to controllably move the pad to the extended position; anda dump valve in fluid communication with the pressurized fluid supply flow path to selectively vent fluid pressure to allow the pad to move from the extended position toward the retracted position.
Embodiment 2. The tool of Embodiment 1, wherein the piston is coupled to the pad such that the piston moves with the pad from the extended position to the retracted position.
Embodiment 3. The tool of Embodiment 1, wherein the dump valve selectively vents fluid pressure from the pressurized fluid supply flow path to out of the tool body.
Embodiment 4. The tool of Embodiment 3, wherein the dump valve selectively vents fluid pressure to the outer surface of the tool body.
Embodiment 5. The tool of Embodiment 3, wherein the dump valve selectively vents fluid pressure to the flowbore.
Embodiment 6. The tool of Embodiment 1, further comprising a rotary valve in fluid communication with the pressurized fluid supply flow path to selectively control fluid pressure from the flowbore of the tool body to the piston for controllably moving the pad to the extended position.
Embodiment 7. The tool of Embodiment 6, wherein the dump valve selectively vents fluid pressure based upon a position of the rotary valve.
Embodiment 8. The tool of Embodiment 1, further comprising a sensor operably coupled to the dump valve, wherein the dump valve selectively vents fluid pressure based upon a measurement of the sensor.
Embodiment 9. The tool of Embodiment 1, further comprising a choke valve in fluid communication with the pressurized fluid supply flow path to regulate fluid pressure from the pressurized fluid supply flow path to out of the tool body.
Embodiment 10. The tool of Embodiment 1, further comprising a drill bit coupled to the tool body such that an orientation of the drill bit is controlled by the pad.
Embodiment 11. The tool of Embodiment 1, further comprising more than one pad and more than one piston, wherein each piston is engageable with a respective pad for moving the respective pad.
Embodiment 12. The tool of Embodiment 11, further comprising more than one dump valve, each dump valve corresponding to a pad and each being in fluid communication with the pressurized fluid supply flow path to selectively vent fluid pressure to allow the respective pad to move from the extended position toward the retracted position.
Embodiment 13. A method of directionally drilling a borehole, comprising:rotating a tool within the borehole, the tool comprising a pad, a piston engageable with the pad, and a dump valve fluidly coupled to the piston;moving the pad from a retracted position to an extended position by providing fluid pressure to the piston through a pressurized fluid supply flow path, thereby selectively applying a force against the borehole with the pad to push the tool in a direction; andcontrolling the dump valve to vent the fluid pressure from the pressurized fluid supply flow path to allow the pad to move from the extended position to the retracted position.
Embodiment 14. The method of Embodiment 13, wherein the moving the pad from the retracted position to the extended position comprises controlling fluid pressure through the pressurized fluid supply flow path with a rotary valve positioned in a flowbore of the tool to the piston.
Embodiment 15. The method of Embodiment 14, wherein the moving the pad from the retracted position to the extended position comprises controlling the dump valve based upon a position of the rotary valve.
Embodiment 16. The method of Embodiment 13, further comprising regulating fluid pressure flow from the pressurized fluid supply flow path to out of the tool with a choke valve.
Embodiment 17. The method of Embodiment 13, wherein the dump valve vents fluid pressure to an outer surface of the tool or a flowbore of the tool.
Embodiment 18. The method of Embodiment 13, further comprising drilling the borehole in the direction with a drill bit coupled to the tool.
Embodiment 19. A rotary steerable system for directional drilling, comprising:a tool body including an outer surface and a flowbore therethrough;a pad movably coupled to the tool body and alternately movable between an extended position and a retracted position;a piston engageable with the pad to move the pad;a pressurized fluid supply flow path to provide fluid pressure to the piston for the piston to controllably move the pad to the extended position;a rotary valve in fluid communication with the pressurized fluid supply flow path to selectively control fluid pressure flow from the flowbore of the tool body to the piston for controllably moving the piston to the extended position;a dump valve in fluid communication with the pressurized fluid supply flow path to selectively vent fluid pressure based upon a position of the rotary valve to allow the pad to move from the extended position toward the retracted position;a choke valve in fluid communication with the pressurized fluid supply flow path to regulate fluid pressure from the pressurized fluid supply flow path to out of the tool body; anda drill bit coupled to the tool body such that an orientation of the drill bit is controllable by the pad.
Embodiment 20. The system of Embodiment 19, wherein:the piston is coupled to the pad such that the piston moves with the pad from the extended position to the retracted position; andthe dump valve selectively vents fluid pressure from the pressurized fluid supply flow path to the outer surface or the flowbore.

Reference throughout this specification to “one embodiment,” “an embodiment,” “an embodiment,” “embodiments,” “some embodiments,” “certain embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, these phrases or similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.