Patent Application
20140102797
Embodiments described herein generally relate to downhole tools. More particularly, such embodiments relate to underreamers and stabilizers for enlarging the diameter of a wellbore.
In the drilling of oil and gas wells, concentric casing strings are installed and cemented in the wellbore as drilling progresses to increasing depths. Each new casing string is supported within the previously installed casing string, thereby limiting the annular area available outside the uppermost casing strings for the cementing operation. Further, as successively smaller diameter casing strings are suspended, the flow area for the production of oil and gas inside the casing strings decreases as the distance from the surface increases. Therefore, to increase the annular space for the cementing operation, and to increase the production flow area, it is often desirable to enlarge the diameter of the wellbore below the lower end portion of the previous casing string.
Underreamers are used for enlarging the diameter of the wellbore below the lower end portion of the previous casing string and stabilizers are used for controlling the trajectory of the underreamer during the drilling process. An underreamer generally has two states—an inactive or collapsed state where the cutters of the underreamer are stationary and the underreamer maintains a diameter small enough to pass through the existing casing strings, and an active or expanded state where one or more arms having the cutters on the end portions thereof extend radially outward from the underreamer. In the active state, the cutters are adapted to enlarge the diameter of the wellbore. As the underreamer is lowered into deeper and harder formations, however, additional underreamers may need to be deployed.
What is needed, therefore, are improved systems and methods for running multiple underreamers and/or stabilizers downhole.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
A downhole tool for increasing a cross-sectional area of a wellbore is disclosed. The downhole tool may include a first drilling assembly which includes a first reaming tool, a first ball seat, and a first piston. The first reaming tool selectively increases the cross-sectional area of the wellbore. The first ball seat may receive a first ball. At least one of the first ball seat and the first ball may deform to allow the first ball to pass through the first ball seat when a predetermined pressure is applied thereto. The first piston may be coupled to the first ball seat. The first ball seat and the first piston may stroke when the first ball is received within the first ball seat, thereby actuating the first reaming tool between an active state and an inactive state. A second drilling assembly may be axially offset from the first drilling assembly along the downhole tool. The second drilling assembly includes a second reaming tool, a second ball seat, and a second piston. The second reaming tool selectively increases the cross-sectional area of the wellbore. The second ball seat may receive a second ball. At least one of the second ball seat and the second ball may deform to allow the second ball to pass through the second ball seat when a predetermined pressure is applied thereto. The second piston may be coupled to the second ball seat. The second ball seat and the second piston may stroke when the second ball is received within the second ball seat, thereby actuating the second reaming tool between an active state and an inactive state.
In another embodiment, the downhole tool may include a first drilling assembly which includes a first reaming tool, a first ball seat, and a first piston. The first reaming tool selectively increases the cross-sectional area of the wellbore. The first ball seat may receive a ball. At least one of the first ball seat and the ball may deform to allow the ball to pass through the first ball seat when a predetermined pressure is applied thereto. The first piston may be coupled to the first ball seat. The first ball seat and the first piston may stroke when the ball is received within the first ball seat. A first indexing mechanism may be coupled to the first piston. The first indexing mechanism may actuate the first reaming tool between an active state and an inactive state after each stroke of the first piston. A second drilling assembly may be axially offset from the first drilling assembly along the downhole tool. The second drilling assembly includes a second reaming tool, a second ball seat, and a second piston. The second reaming tool selectively increases the cross-sectional area of the wellbore. The second ball seat may receive the ball. At least one of the second ball seat and the ball may deform to allow the ball to pass through the second ball seat when a predetermined pressure is applied thereto. The second piston may be coupled to the second ball seat. The second ball seat and the second piston may stroke when the ball is received within the second ball seat. A second indexing mechanism may be coupled to the second piston. The second indexing mechanism may actuate the second reaming tool between an active state and an inactive state after two strokes of the second piston.
A method for increasing a cross-sectional area of a wellbore is also disclosed. The method includes running a downhole tool into the wellbore. The downhole tool includes first and second drilling assemblies coupled thereto and axially offset from one another. A first ball may be received within a first ball seat of the first drilling assembly. At least one of the first ball seat and the first ball may deform when a predetermined pressure is reached to allow the first ball to pass through the first ball seat. The first ball seat and a first piston coupled thereto move in response to the first ball being received in the first ball seat, thereby actuating a first reaming tool of the first drilling assembly between an active state and an inactive state. The first reaming tool may increase a cross-sectional area of the wellbore in the active state. A second ball may be received within a second ball seat of the second drilling assembly. At least one of the second ball seat and the second ball may deform when the predetermined pressure is reached to allow the second ball to pass through the second ball seat. The second ball seat and a second piston coupled thereto move in response to the second ball being received in the second ball seat, thereby actuating a second reaming tool of the second drilling assembly between the active state and the inactive state. The second reaming tool may increase the cross-sectional area of the wellbore in the active state.
So that the recited features may be understood in detail, a more particular description, briefly summarized above, may be had by reference to one or more embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of scope, for the invention may admit to other equally effective embodiments.
The drilling assemblies 110, 120, 130 each include one or more reaming tools 112, 122, 132, one or more stabilizers (not shown), or a combination thereof. For purposes of simplicity, the foregoing description will refer to reaming tools 112, 122, 132; however, it may be appreciated that any of 112, 122, 132 may also refer to a stabilizer or a reaming tool/stabilizer combination. It may also be appreciated to those skilled in the art that the drilling assemblies of the various embodiments of
Each drilling assembly 110, 120, 130 includes a piston assembly 116, 126, 136 adapted to actuate the corresponding reaming tool 112, 122, 132.
The ball seat 114 and/or the ball 115 may be deformable. For example, the ball seat 114 may be deformable and the ball 115 may be non-deformable. As used herein, the term “deformable” refers to the ability of an element to change shape temporarily and then return to its original shape. When the pressure within the bore reaches a predetermined level, the ball seat 114 and/or the ball 115 may deform to allow the ball 115 to pass through the ball seat 114. Once the ball 115 passes through the ball seat 114, the ball 115 may become retained within a ball catcher 118 disposed downstream from the ball seat 114 (see FIGS. 1 and 2-1). Illustrative ball catchers 118 are shown and described in U.S. Patent Publication No. 2007/027412. Further, once the ball 115 passes through the ball seat 114, the spring 158 may stretch or expand, thereby pushing the shoulder 152 and the cam-piston 117 in the second axial direction.
Each time the cam-piston 117 moves axially within the mandrel 150, a cartridge 160 disposed between the cam-piston 117 and the mandrel 150 may pivot or rotate at least partially around the circumference of the cam-piston 117. The cartridge 160 may have a pin or protrusion 161 extending radially-inward therefrom that is arranged and designed to move through a slot or groove (not shown but see, e.g., 502 of
The axial resting position of the cam-piston 117 relative to the mandrel 150 determines whether one or more ports 162 formed radially through the mandrel 150 are aligned with one or more ports 164 formed radially through the cam-piston 117. When the ports 162, 164 are aligned, pressurized fluid may flow therethrough actuating the reaming tool 112 into an “active” position, and when the ports 162, 164 are axially offset (as shown), the reaming tool 112 is actuated into an “inactive” position. In at least one embodiment, after a single stroke of the cam-piston 117, the ports 162, 164 may be aligned and the reaming tool 112 may actuate into the active state. However, in another embodiment, it may take two (or more) strokes of the cam-piston 117 for the ports 162, 164 to align such that the reaming tool 112 actuates into the active state.
In the inactive state, one or more cutters on the reaming tool 112 may be stationary and folded into the body of the reaming tool 112 allowing the reaming tool 112 to maintain a diameter small enough to pass through the existing casing strings. In the active state, the reaming tool 112 may be in an expanded state where one or more arms with the cutters on the end portions thereof extend radially outward. Further, in the active state, the cutters of the reaming tool 112 may be adapted to cut into the formation and enlarge the diameter of the wellbore.
Referring now to
In operation, the first drilling assembly 110 is actuated by dropping a large ball 115 down the drill string from the surface, and the large ball 115 becomes lodged in the ball seat 114. Pressure is then applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 117 in the piston assembly 116 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 114 (or the large ball 115) deforms and allows the large ball 115 to pass therethrough and become retained within the ball catcher 118. Once the large ball 115 passes through the ball seat 114, the cam-piston 117 moves in the second axial direction due to the expansion of the spring 158, thereby actuating the reaming tool 112 between the inactive state and the active state or vice versa. The first drilling assembly 110 may be actuated between the active and inactive states by dropping subsequent large balls 115 into the tool 100.
The second drilling assembly 120 is actuated by dropping a medium ball 125 down the drill string from the surface, and the medium ball 125 becomes lodged in the ball seat 124. As the medium ball 125 is smaller than the large ball 115, it may pass through the ball seat 114 and the ball catcher 118 without being retained therein. Pressure is then applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 127 of the piston assembly 126 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 124 (or the medium ball 125) deforms and allows the medium ball 125 to pass therethrough and become retained within the ball catcher 128. Once the medium ball passes through the ball seat 124, cam-piston 127 moves in the second axial direction due to the expansion of the spring, thereby actuating the reaming tool 122 between the inactive state and the active state or vice versa. The second drilling assembly 120 may be actuated between the active and inactive states by dropping subsequent medium balls 125 into the tool 100.
The third drilling assembly 130 is actuated by dropping a small ball 135 down the drill string from the surface, and the small ball 135 may become lodged in the ball seat 134. As the small ball 135 is smaller than the large and medium balls 115, 125, it may pass through the ball seats 114, 124 and the ball catchers 118, 128 without becoming retained therein. Pressure is then applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 137 of the piston assembly 136 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 134 (or the small ball 135) deforms and allows the small ball 135 to pass therethrough and become retained within the ball catcher 138. Once the small ball 135 passes through the ball seat 134, the cam-piston 137 moves in the second axial direction due to the expansion of the spring, thereby actuating the reaming tool 132 between the inactive state and the active state or vice versa. The third drilling assembly 130 may be actuated between the active and inactive states by dropping subsequent small balls 135 into the tool 100. The varying sizes of the ball seats 114, 124, 134 and the balls 115, 125, 135 may allow the reaming tools, e.g., 112, to be selectively actuated between the inactive and active states independent of the other reaming tools, e.g., 122, 132.
The drilling assemblies 110, 120, 130 may each have the same cross-sectional length (e.g., diameter) when in the active state. As such, each of the drilling assemblies 110, 120, 130 may be arranged and designed to increase the diameter of the wellbore to a single predetermined diameter. In another embodiment, one or more of the drilling assemblies (e.g., drilling assembly 110) may have a different cross-sectional length (e.g., diameter) than one or more of the other drilling assemblies (e.g., drilling assemblies 120, 130) when in the active state. As such, the drilling assembly 110 may be arranged and designed to increase the diameter of the wellbore to a first diameter, and the drilling assemblies 120, 130 may be arranged and designed to increase the diameter of the wellbore to a second, different diameter.
In operation, a ball 315 is dropped down the drill string from the surface, and the ball 315 becomes lodged in the ball seat 314 of the first drilling assembly 310. Pressure may then be applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 317 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 314 (or ball 315) deforms and allows the ball 315 to pass therethrough. The cam-piston 317 then moves via spring action in the second axial direction, thereby actuating the first reaming tool 312 between the inactive state and the active state or vice versa.
The ball 315 may then flow through the tool 300 and become lodged in the ball seat 324 of the second drilling assembly 320. Pressure may again be applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 327 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 324 (or ball 315) deforms and allows the ball 315 to pass therethrough. The cam-piston 327 then moves via spring action in the second axial direction, thereby actuating the second reaming tool 322 between the inactive state and the active state or vice versa.
The ball 315 may then flow through the tool 300 and become lodged in the ball seat 334 of the third drilling assembly 330. Pressure may again be applied to the drill string from the surface via pump drilling fluid. As the pressure builds, the cam-piston 337 moves in the first axial direction until the pressure reaches a predetermined amount where the ball seat 334 (or ball 315) deforms and allows the ball 315 to pass therethrough. The cam-piston 337 then moves via spring action in the second axial direction, thereby actuating the third reaming tool 332 between the inactive state and the active state or vice versa. When the ball 315 passes through the last drilling assembly, e.g., 330, the ball 315 may become retained within the ball catcher 338. Thus, each drilling assembly 310, 320, 330 may be actuated in sequence by a single ball 315.
The drilling assemblies 410, 420 may be generally similar to the drilling assemblies 310, 320 depicted in
The indexing mechanisms 500, 600 are coupled to and adapted to move with the cam-pistons 417, 427. Although shown as flat in
The cartridge 160 disposed between the cam-piston 417, 427 and the mandrel 150 (see, e.g.,
In at least one embodiment, when the protrusion 161 of the cartridge 160 comes to rest in a long groove 504, 604 of the indexing mechanism 500, 600 after a stroke of the cam-piston 417, 427, the reaming tool 412, 422 is in the inactive state due to the misalignment of the ports 162, 164, and when the protrusion 161 of the cartridge 160 comes to rest in a short groove 506, 606 of the indexing mechanism 500, 600 after a stroke of the cam-piston 417, 427, the reaming tool 412, 422 is in the active state due to the alignment of the ports 162, 164 (see, e.g.,
Accordingly, the first indexing mechanism 500 may require two strokes of the cam-piston 417 to actuate the first reaming tool 412 into the active state while the second indexing mechanism 600 may require one stroke of the cam-piston 427 to actuate the second reaming tool 422 into the active state. In the exemplary embodiment shown in
Thus, in operation, a first ball 415-1 may be dropped down the drill string from the surface. The first ball 415-1 may cause the first and second cam-pistons 417, 427 to stroke a first time. After the first stroke, the first reaming tool 412 remains in the inactive state while the second reaming tool 422 actuates into the active state. A second ball 415-2 may then be dropped down the drill string from the surface. The second ball 415-2 may cause the first and second cam-pistons 417, 427 to stroke a second time. After the second stroke, the first reaming tool 412 actuates into the active state, and the second reaming tool 422 actuates into the inactive state. A third ball 415-3 may then be dropped down the drill string from the surface. The third ball 415-3 may cause the first and second cam-pistons 417, 427 to stroke a third time. After the third stroke, the first reaming tool 412 remains in the active state, and the second reaming tool 422 actuates into the active state. A fourth ball 415-4 may then be dropped down the drill string from the surface. The fourth ball 415-4 may cause the first and second cam-pistons 417, 427 to stroke a fourth time. After the fourth stroke, the first and second reaming tools 412, 422 both actuate into the inactive state, thereby completing the cycle.
Thus, the indexing mechanisms 500, 600 allow the reaming tools 412, 422 to be selectively actuated based upon the number of balls 415 dropped into the tool 400. It may be appreciated that the indexing mechanisms 500, 600 are only exemplary, and other designs are also contemplated herein. It may also be appreciated that this concept may be applied to more than two drilling assemblies 410, 420 coupled to the tool 400. For example, this concept may be applied to a tool having 2, 3, 4, 5, 6, 7, 8, 9, 10, or more drilling assemblies coupled to the tool 400.
Thus, in operation, both reaming tools 812, 822 may begin in the inactive state. A first, small ball 825-1 may be dropped down the drill string from the surface. The first ball 825-1 passes through the first reaming tool 812 and actuates the second reaming tool 822 into the active state. A second, large ball 815-1 may then be dropped down the drill string from the surface. The second ball 815-1 actuates the first reaming tool 812 into the active state and subsequently actuates the second reaming tool 822 into the inactive state. A third, small ball 825-2 may then be dropped down the drill string from the surface. The third ball 825-2 passes through the first reaming tool 812 and actuates the second reaming tool 822 into the active state. A fourth, large ball 815-2 may then be dropped down the drill string from the surface. The fourth ball 815-2 actuates the first and second reaming tools 812, 822 into the inactive state, thereby completing the cycle. It may be appreciated that this sequence is provided for illustrative purposes, and the large and small balls 815-1, 815-2, 825-1, 825-2 may be dropped in any number and any order to selectively actuate the reaming tools 812, 822.
The flow control devices 940, 950, 960 are adapted to selectively actuate a valve 942, 952, 962 disposed within the drilling assembly 910, 920, 930 between an open position and a closed position. When in the open position, fluid may flow through a central flow passage 902 that extends through the tool 900 and each of the drilling assemblies 910, 920, 930. When in the closed position, the valve 942, 952, 962 blocks flow through the central flow passage 902, and the fluid may be directed through a bypass passage 944, 954, 964. The reaming tools 912, 922, 932 are adapted to actuate into the active state when fluid flows therethrough via the central flow passage 902, and into the inactive state when the fluid flows through the bypass passages 944, 954, 964, or vice versa.
In operation, the first reaming tool 912 may be actuated into the active state by opening the first valve 942 with the first flow control device 940 so that fluid may flow through the first reaming tool 912 via the central flow passage 902. The first reaming tool 912 is then actuated into the inactive state by closing the first valve 942 with the first flow control device 940 so that the fluid instead flows through the first bypass passage 944. Similarly, the second reaming tool 922 may be actuated into the active state by opening the second valve 952 with the second flow control device 950 so that fluid may flow through the second reaming tool 922 via the central flow passage 902. The second reaming tool 922 is then actuated into the inactive state by closing the second valve 952 with the second flow control device 950 so that the fluid instead flows through the second bypass passage 954. The third reaming tool 932 may be actuated into the active state by opening the third valve 962 with the third flow control device 960 so that fluid may flow through the third reaming tool 932 via the central flow passage 902. The third reaming tool 932 is then actuated into the inactive state by closing the third valve 962 with the third flow control device 960 so that the fluid instead flows through the third bypass passage 964.
In at least one embodiment, each drilling assembly 910, 920, 930 may include a control unit (not shown) and a valve 942, 952, 962. The control units and/or the valves 942, 952, 962 are adapted to receive signals from the surface. The signals may include an RPM sequence, a flow and/or pressure pulse, a radio signal, communication from a bottom hole assembly (BHA) component, and the like. In at least one embodiment, the signals may be transmitted via wired pipe. Upon receiving the signals, the control units may be adapted to alter the position of the valves 942, 952, 962, and the valves 942, 952, 962 may actuate the reaming tools 912, 922, 932. Thus, the signals may selectively actuate the reaming tools 912, 922, 932 independent of one another.
In another embodiment, the first reaming tool 912 may be actuated by one or more balls (not shown), as described with reference to
The second reaming tool 922 may be actuated by one or more signals as described above. For example, the second reaming tool 922 may be actuated with a flow and/or pressure pulse signal. The third reaming tool 932 may be electromechanically actuated with a control unit. Thus, the reaming tools 912, 922, 932 may each be selectively actuated by different mechanisms.
As used herein, the terms “inner” and “outer,” “up” and “dowry,” “upper” and “lower;” “upward” and “downward;” “above” and “below,” “inward” and “outward;” and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “large,” “medium,” “small,” “long,” “short,” and the like are used herein to refer to relative sizes to one another. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via another element or member.”
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from “Selective Deployment of Underreamers and Stabilizers,” Accordingly, all such modifications are intended to be included within the scope of this disclosure. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
This application claims the benefit of a related U.S. Provisional Patent Application having Ser. No. 61/713,317 filed Oct. 12, 2012, titled “Selective Deployment of Underreamers and Stabilizers,” to Mahajan et al., the disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61713317 | Oct 2012 | US |
