Patent Application
20240410252
In the drilling of oil and gas wells, a downhole drilling motor and a drill bit are attached to the end of a drill string. Most downhole drilling motors include a rotor rotating within a stator. The rotation of the rotor provides a vibration to the adjacent drill bit as it cuts through the subterranean formation to drill the wellbore. The drill string slides through the higher portions of the wellbore as the drill bit at the end of the drill string extends the wellbore deeper into the formation. A friction reduction tool is sometimes attached to the drill string a distance above the drill bit (e.g., 800-1,500 feet above the drill bit). The friction reduction tool provides vibration to the portions of the drill string above the friction reduction tool, thereby facilitating a smoother movement of the drill string through the wellbore.
However, continuous operation of the friction reduction tool may not be desirable, such as when the drill bit is drilling vertically from the surface. To address such problems, a selectively activated friction reduction tool may be introduced into the drill string to provide vibration to the drill string upon activation of the friction reduction tool. Such a tool is disclosed herein.
A friction reduction tool of the present disclosure is configured to be selectively activated downhole in response to a variation in an operating condition of a media flow through the tool. The friction reduction tool may include a valve assembly positioned downstream of a power assembly. The power assembly may rotate a segment of the valve assembly in response to a flow of a media through tool. In a stationary mode, media flow through the valve assembly may generate no significant pressure pulse or water hammer. In a dynamic mode, media flow through the valve assembly may generate a pressure pulse or water hammer in a media flow column that is transmitted to a coiled tubing line or a shock sub of a drill string to which the friction reduction tool is attached.
In some embodiments, the friction reduction tool may include an activation assembly. When the activation assembly is in a first position, the friction reduction tool operates in the stationary mode. When the activation assembly is in a second position, the friction reduction tool operates in the dynamic mode. The activation assembly may transition from the first position to the second position in response to certain media operating condition adjustments or variations, such as an increased media flow rate or an increased media density. In the first position, the activation assembly may provide a bypass flow path around the valve assembly for at least a portion of the media flowing through the tool. The flow of media through the bypass flow path limits or minimizes the pressure pulse generated by the valve assembly when the activation assembly is in the first position, which places the friction reduction tool in the stationary mode. In the second position, the activation assembly may discontinue, prevent, or minimize the flow of media through the bypass flow path, which results in all or substantially all of the media flowing through the tool to flow through the valve assembly, which generates pressure pulses and places the friction reduction tool in the dynamic mode.
In certain embodiments, the activation assembly includes one or more bypass ports that are open in the first position and substantially closed in the second position. For example, an increase in flow rate or density of the media flowing through the tool may cause a sleeve of the activation assembly to slide from a default position to an engaged position, thereby transitioning the activation assembly from the first position to the second position. In some embodiments, the sleeve of the activation assembly may close the one or more bypass ports in the engaged position. The closing of the one or more bypass ports may transition the friction reduction tool from the stationary mode to the dynamic mode.
Power assembly 12 may include any hydraulic motor, or any other motor driven by a media, which is configured to rotate a rotating valve segment of valve assembly 14. In some embodiments, power assembly 12 may include a positive displacement motor, such as a Moineau motor or any progressive cavity positive displacement pump. In other embodiments, power assembly 12 may include a vane motor. In still other embodiments, power assembly 12 may include a turbine. As used herein, “media” means any liquid or gas, or any mixture, solution, or other combination of one or more liquids and/or one or more gases. Non-limiting examples of media include water-based drilling fluids, oil-based drilling fluids, compressible fluids, mists, nitrogen gas, and underbalanced mixtures of nitrogen gas in liquids.
In the illustrated embodiment, power assembly 12 may include a positive displacement motor having rotor 20 and stator 22. Stator 22 may be secured within the inner bore of housing 18. Rotor 20 may have no axial bore or central bore running therethrough. In one embodiment, rotor 20 may be a single lobe rotor and stator 22 may be a dual lobe stator. Media flowing through the inner bore of housing 18 flows through cavity 24 between rotor 20 and stator 22, which causes rotor 20 to rotate within stator 22. In this way, power assembly 12 includes rotor 20 configured to rotate with the media flow through power assembly 12.
Valve assembly 14 may include a rotating valve segment and a stationary valve segment each including at least one passage. The rotating valve segment may be configured to rotate with rotation of rotor 20, while the stationary valve segment remains fixed (i.e., does not rotate in relation to housing 18). In an open position, the passage of the rotating valve segment is aligned with the passage of the stationary valve segment to allow media flow through these passages. In a restricted position, the passage of the rotating valve segment is not aligned with the passage in the stationary valve segment (e.g., at least partially unaligned), thereby temporarily restricting any media flow through valve assembly 14.
In the embodiment illustrated in
The stationary valve segment may include stationary valve disk 32 that engages rotating valve disk 30. Stationary valve disk 32 may include one or more passages 40. Stationary valve disk 32 may be secured directly or indirectly to housing 18 such that stationary valve disk 32 does not rotate in relation to housing 18. In a non-limiting example shown in the illustrated embodiment, stationary valve disk 32 may be secured at least partially within an inner bore of activation body 28, which is secured to housing 18 such that activation body 28 and stationary valve disk 32 are prevented from rotating relative to housing 18. Numerous alternative embodiments in which tool 10 is configured to prevent rotation of stationary valve disk 32 in relation to housing 18 are readily understood by skilled artisans. In this way, a valve flow path may be defined by annular space 36 surrounding adaptor 26, lateral ports 27 in adaptor 26, the inner bore of adaptor 26, passages 34 of rotating valve disk 30, and passages 40 of stationary valve disk 32. In the illustrated embodiment, rotor 20 is operatively positioned upstream of valve assembly 14 in which the rotating valve segment is positioned upstream of the stationary valve segment. In other embodiments, the rotating valve segment may be positioned downstream of the stationary valve segment.
With reference to
With reference to
Activation assembly 16 may further include one or more shear mechanisms 54, one or more stop mechanisms 56, and one or more seals 58. Each shear mechanism 54 may extend from a lateral bore or recess in activation body 28 into a lateral bore or recess in activation sleeve 48. With activation assembly 16 in the first position, the shear mechanisms 54 may be disposed upstream, downstream, or at least one upstream and at least one downstream of the bypass ports in activation sleeve 48 and/or the bypass ports in activation body 28. The shear mechanisms 54 may include shear pins, set screws, O-rings, spring-loaded ball arrangements, or any other mechanisms configured to break or change positions in response to a predefined downstream force in order to allow activation sleeve 48 to slide relative to activation body 28. Each stop mechanism 56 may extend from a lateral bore or recess in the inner bore of activation body 28. The stop mechanism 56 may include a ring, an upset, one or more set screws, or any other mechanism configured to limit downstream movement of activation sleeve 48 relative to activation body 28. The seals 58 may include O-rings or any other seal elements.
Referring again to
Activation assembly 16 may be operatively positioned downstream of rotor 20. In certain embodiments, activation assembly 16 may be operatively positioned downstream of valve assembly 14. In the illustrated embodiment, activation assembly 16 may be operatively positioned downstream of both rotor 20 and valve assembly 14.
With reference to
Activation assembly 16 may be configured to selectively activate friction reduction tool 10 by transitioning friction reduction tool 10 from the stationary mode shown in
With reference to
To selectively activate the friction reduction tool 10, a user may vary an operating condition of the media flowing through friction reduction tool 10 in order to increase the downstream force on shoulders 62 and 64 of activation sleeve 48 above the predetermined maximum downstream force associated with shear mechanisms 54. For example, the downstream force on shoulders 62 and 64 and the differential pressure across activation assembly 16 may be increased by increasing the flow rate of the media, by increasing the media's density, or by increasing both the flow rate of the media and the media's density. Each of these operating condition changes cause an increased downstream force to be applied to shoulders 62 and 64. Once friction reduction tool 10 is activated by breaking shear mechanisms 54, the continued flow of media through tool 10 may apply a continued downstream force on shoulder 62, which slides activation sleeve 48 in a downstream direction within the inner bore of activation body 28 until activation sleeve 48 engages stop mechanism 56 in a second position shown in
Because the bypass flow path is substantially closed or blocked when activation sleeve 48 is in the second position, all or a majority of the media flowing from cavity 24 into annular space 36 may flow through the valve flow path of valve assembly 14. In this position, rotation of rotor 20 in response to media flowing through cavity 24 causes valve assembly 14 to cycle between the open position and the closed position. In the open position, the media is allowed to flow through the valve flow path of the valve assembly 14. However, in the closed position, the unaligned passages 34 and 40 of rotating valve disk 30 and stationary valve disk 32, respectively, temporarily restricts or limits media flow through the valve flow path. As media flows through the valve flow path of valve assembly 14 with activation assembly 16 in the second position, the cycling between the open position and the closed position of valve assembly 14 generates a significant repeated pressure pulse or water hammer in a media flow column (i.e., the column of media formed within friction reduction tool 10 and the drill string or coiled tubing line to which it is attached). In this way, friction reduction tool 10 generates significant pressure pulses when media flows through the tool 10 in the dynamic mode after activation of activation assembly 16. As used herein, “significant” pressure pulses or water hammer are pressure pulses or water hammer of sufficient magnitude to stretch or retract a coiled tubing string, or to activate axial movement of a shock sub or another part of a drill string, to which friction reduction tool 10 is connected. For example, but not by way of limitation, significant pressure pulses may be greater than 200 psi, or greater than 300 psi. Whether a pressure pulse of a certain magnitude is significant may depend on the design and configuration of the specific embodiment of the friction reduction tool and the surrounding portions of a coiled tubing string or drill string, such as a shock sub.
In certain alternate embodiments, the activation sleeve of activation assembly 16 may be disposed around the outer surface of the activation body, with the activation sleeve transitioning from a first position, in which it leaves open the one or more bypass ports of the activation body, to a second position, in which it closes the one or more bypass ports in the activation body.
Accordingly, with activation assembly 16 in either the first position or the second position (i.e., in either the stationary mode or dynamic mode of friction reduction tool 10), media flow through cavity 24 rotates rotor 20 and the rotating valve segment of valve assembly 14. However, the bypass flow path provided by activation assembly 16 in the first position minimizes the amount of, or eliminates, media flow through the valve flow path of valve assembly 14 such that the cycling of valve assembly 14 between the open position and the closed position does not generate any significant pressure pulse in the stationary mode of friction reduction tool 10. The activation of friction reduction tool 10 into the dynamic mode with the transition of activation assembly 16 into the second position completely closes, or at least substantially closes, the bypass flow path such that all, or substantially all, of the media flows through the valve flow path of valve assembly 14, thereby generating significant pressure pulses with the cycling of valve assembly 14 between the open position and the closed position.
Referring now to
Friction reduction tool 10a may be selectively activated from the stationary mode to the dynamic mode by increasing the differential pressure across shoulders 62 and 64 of activation sleeve 48 within friction reduction tool 10a. This selective activation may be accomplished by increasing a flow rate, increasing a density, or increasing both a flow rate and a density of the media flowing through the drill string 66. For example, a user may increase media density by introducing a higher density media in a pill into the drill string 66 for a certain period of time. The increased media flow rate or increased media density, or both, may increase the pressure drop across activation sleeve 48 and apply an increased downstream force on shoulders 62 and 64 of activation sleeve 48 within friction reduction tool 10a. The pressure drop increase and downstream force increase created by a particular media condition adjustment is determined by the cross-sectional area of the nozzle provided by the inner bore of the tool's activation sleeve 48 upstream of shoulder 62 and by the reduced inner bore section 53 of the tool's activation sleeve 48 downstream of shoulder 62. When the increased downstream force exceeds a predefined maximum limit, shear mechanisms 54 within friction reduction tool 10a may break, thereby allowing activation sleeve 48 to move downstream into the second position in which the bypass flow path is blocked or closed. In this way, friction reduction tool 10a may be selectively activated from the stationary mode into the dynamic mode. Once the friction reduction tool 10a is activated and placed in the dynamic mode, all or a majority of the media flowing through friction reduction tool 10a will flow through valve assembly 14, thereby generating a significant pressure pulse or water hammer as valve assembly 14 cycles between the open position and closed position. The generated significant pressure pulse or water hammer may be transmitted to drill string 66 (or a coiled tubing string) to which friction reduction tool 10a is connected. The repeated significant pressure pulse generation may cause axial movement of a portion of shock assembly 68a (or stretching and retracting in a coiled tubing string to which friction reduction tool 10a is connected), thereby facilitating axial vibration and easing the movement of the drill string through wellbore 64. The vibration may reduce friction between an outer surface of the drill string and an inner surface of wellbore 64.
In certain embodiments, shock assembly 68a may be connected to an upstream end of friction reduction tool 10a. When present, the shock assembly 68a may facilitate relative axial movement of drill string 66 above friction reduction tool 10a relative to drill string 66 downstream of friction reduction tool 10a thereby vibrating drill string 66 above friction reduction tool 10a.
In certain embodiments, only friction reduction tool 10a may be deployed within wellbore 64. In other embodiments, two or more friction reduction tools, such as friction reduction tool 10a and friction reduction tool 10b, may be deployed within wellbore 64 as shown in
Alternatively, each of friction reduction tools 10a and 10b may be configured to be activated by a different value of a media operating condition adjustment by designing the nozzle provided by the restricted inner bore section 53 of each tool's activation sleeve 48 to have a different cross-sectional area. For example, downstream friction reduction tool 10a may be configured to be activated before upstream friction reduction tool 10b. In this embodiment, a smaller increase in media flow rate and/or media density will activate friction reduction tool 10a, while a larger increase in media flow rate and/or media density will be required to activate friction reduction tool 10b. This configuration may be achieved by sizing the nozzle provided by restricted inner bore section 53 of friction reduction tool 10a's activation sleeve 48 to be smaller than the nozzle provided by restricted inner bore section 53 of friction reduction tool 10b's activation sleeve 48. In another example, upstream friction reduction tool 10b may be configured to be activated before downstream friction reduction tool 10a. In this embodiment, a smaller increase in media flow rate and/or media density will activate friction reduction tool 10b, while a larger increase in media flow rate and/or media density will be required to activate friction reduction tool 10a. This configuration may be achieved by sizing the nozzle provided within friction reduction tool 10b's activation sleeve 48 to be smaller than the nozzle provided within friction reduction tool 10a's activation sleeve 48. Accordingly, two or more friction reduction tools 10 may be configured to be activated in any order within a drill string or coiled tubing string regardless of each friction reduction tool's position.
In some embodiments, downstream friction reduction tool 10a may be introduced into the wellbore in the dynamic mode while one or more upstream friction reduction tools 10b are introduced into the wellbore in the stationary mode, such that these upstream friction reduction tools 10b may be activated with a single or multiple media operating condition adjustments while disposed in the wellbore. Alternatively, a conventional friction reduction tool that operates only in a dynamic mode to generate significant pressure pulses with media flow therethrough may be placed in the drill string 66 between downhole selectively activated friction reduction tool 10a and the bottom hole assembly 70.
As used herein, “above” and any other indication of a greater height or latitude shall also mean upstream, and “below” and any other indication of a lesser height or latitude shall also mean downstream. As used herein, “downhole string” shall include a series of drill string or pipe segments and a coiled tubing line, along with any components secured thereto, including without limitation shock assemblies or shock subs.
While preferred embodiments have been described, it is to be understood that the embodiments are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalents, many variations and modifications naturally occurring to those skilled in the art from a review hereof.
