Patent Application
20140131108
Embodiments described herein generally relate to downhole tools. More particularly, such embodiments relate to underreamers and stabilizers for enlarging the diameter of a wellbore.
After a wellbore is drilled, an underreamer is oftentimes used to enlarge the diameter of the wellbore. The underreamer is run into the wellbore in an inactive state. In the inactive state, cutter blocks on the underreamer are folded inwardly toward the body of the underreamer such that the cutter blocks are positioned radially-inward from the surrounding casing or wellbore wall. Once the underreamer reaches the desired depth in the wellbore, the underreamer is actuated to an active state. In the active state, the cutter blocks move radially-outward and into contact with the wellbore wall. The cutter blocks are then used to increase the diameter of the wellbore.
Conventional underreamers have cutter blocks with a fixed outer diameter when in the active state. As such, conventional underreamers are adapted to create a segment of the wellbore having an increased, but uniform, diameter. It is oftentimes desirable, however, for the wellbore to have varying diameters. For example, cutter blocks become worn down due to excessive vibration in the wellbore. Reducing the diameter of the cutter blocks tends to stabilize the downhole tool, thereby reducing or eliminating wear on the cutter blocks. Currently, this is achieved by pulling the underreamer out of the wellbore to the surface to adjust the outer diameter of the cutter blocks. This delay can lead to lost profits in the field.
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.
An underreamer for increasing a diameter of a wellbore is disclosed. The underreamer includes a body having an axial bore extending at least partially therethrough. A sleeve is arranged and designed to move a first axial distance within the body. A cutter block is movably coupled to the body. The cutter block is arranged and designed to move at least the first axial distance with respect to the body to contact the sleeve in response to hydraulic pressure in the bore. The cutter block moves from a first outer diameter to a second outer diameter as the cutter block moves the first axial distance.
In another embodiment, the underreamer includes a body having an axial bore extending at least partially therethrough. A recess is formed on an outer surface of the body. An actuator is disposed at least partially within the bore. An annular sleeve is coupled to the actuator. The sleeve includes a set of threads formed on an outer surface thereof that are engaged with a set of threads formed in an inner surface of the body. The actuator is adapted to rotate the sleeve with respect to the body, thereby moving the sleeve a first axial distance within the body. A cutter block is at least partially disposed in the recess and movably coupled to the body. The cutter block is arranged and designed to move at least the first axial distance with respect to the body to contact the sleeve in response to hydraulic pressure in the bore. The cutter block moves from a first outer diameter to a second outer diameter as the cutter block moves the first axial distance.
A method for increasing a diameter of a wellbore is also disclosed. The method includes operating an actuator to rotate an annular sleeve coupled to the actuator. The sleeve includes a set of threads formed on an outer surface thereof that is engaged with a set of threads formed in an inner surface of a body. The sleeve moves a first axial distance within the body in response to the rotation of the sleeve. The method further includes applying hydraulic force to move a cutter block coupled to the body at least the first axial distance with respect to the body to contact the sleeve. The cutter block moves radially outward from a first outer diameter to a second outer diameter as the cutter block moves the first axial distance. The cutter block increases the diameter of the wellbore to the second outer diameter.
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 its scope.
In at least one embodiment, an actuator 200 may be disposed within the bore 108 of the body 102. The actuator 200 may be a motor, such as an electric motor (“electromotor”), a hydraulic motor, or any other device adapted to move one or more components axially and/or rotationally within the bore 108 of the body 102. An annular sleeve 300 is disposed within the body 102 and coupled to the actuator 200. The actuator 200 is arranged and designed to move the sleeve 300 axially within the body 102 toward the first end portion 104 of the body 102 and/or toward the second end portion 106 of the body 102. The interaction between the actuator 200 and the sleeve 300 is described in more detail below with respect to
As readily known to those skill in the art, actuator 200 may have a control unit (not shown) coupled thereto or integral therewith. The control unit is adapted to control the movement of the actuator 200 in response to a signal received from the surface. Such signal may be or include a mud pulse signal, an electromagnetic signal, an electric signal, a hard wire magnetic signal, an acoustic signal, a pressure signal, or the like. The actuator 200 may also have a power source, e.g., a battery, coupled thereto to power its operation. Such power source may also couple to the control unit to provide power to receive/transmit signals from/to the surface and/or send operational commands to the actuator 200.
An annular sleeve extension 110 may be disposed within the body 102 and axially adjacent to the sleeve 300. In at least one embodiment, the sleeve extension 110 is coupled to and/or integral with the sleeve 300. The sleeve extension 110 may be a single component, or the sleeve extension 110 may include two or more components. As shown, the sleeve extension 110 includes a first or “outer” sleeve extension 112 coupled to a second or “inner” sleeve extension 114.
When the sleeve 300 is moved by the actuator 200, the sleeve 300 moves the sleeve extension 110 axially within the body 102 toward the first end portion 104 of the body 102 and/or toward the second end portion 106 of the body 102. The sleeve 300 may also limit the axial movement of the sleeve extension 110 in a direction toward the first end portion 104 of the body 102. In other words, the sleeve extension 110 (i.e., if decoupled from the sleeve 300) may move toward the first end portion 104 of the body 102 until it contacts the sleeve 300, at which point further movement toward the first end portion 104 of the body 102 is prevented.
One or more stoppers (one is shown 120) may be coupled to the sleeve extension 110 and extend radially outward therefrom. The stopper 120 may be a single component, or the stopper 120 may include two or more components that are circumferentially offset from one another. The stopper 120 is adapted to move with the sleeve extension 110. Thus, when the sleeve extension 110 is moved by the sleeve 300, the sleeve extension 110 and the stopper 120 move axially within the body 102 toward the first end portion 104 of the body 102 and/or toward the second end portion 106 of the body 102.
One or more cutter blocks (one is shown 130) is at least partially disposed in a recess in the outer surface of the body 102. The cutter block 130 is movably coupled to the body 102 proximate the stopper 120. Although a single cutter block 130 is seen in
The cutter block 130 shown in
As explained in more detail below, an axial force is exerted on the cutter block 130 to move it toward the first end portion 104 of the body 102. The axial movement of the cutter block 130, however, is limited by contact with the stopper 120. In other words, the cutter block 130 moves axially toward the first end portion 104 of the body 102 until it contacts the stopper 120, at which point further axial movement is prevented.
The cutter block 130 may have a plurality of splines 131 disposed or formed on one or more outer side surfaces thereof. The splines 131 on the cutter block 130 may be or include offset ridges or protrusions adapted to engage and slide within corresponding grooves 133 in the body 102 of the underreamer 100. The splines 131 on the cutter block 130 are oriented at an angle with respect to the longitudinal axis through the body 102 of the underreamer 100. The angle of the splines 131 on the cutter block 130 (and the corresponding grooves 133 in the body 102) may range from a low of about 10°, about 15°, about 20°, or about 25° to a high of about 30°, about 40°, about 50°, about 60°, or more. For example, the angle may be between about 15° and about 25° with respect to the longitudinal axis through the body 102.
When an axial force is exerted on the cutter block 130 in a direction toward the first end portion 104 of the body 102, the engagement of the splines 131 on the cutter block 130 and the grooves 133 in the body 102 causes the cutter block 130 to simultaneously move axially toward the first end portion 104 of the body 102 and radially outward (e.g., between about 15° and about 25° with respect to the longitudinal axis through the body 102). Thus, when the cutter block 130 moves a first axial distance 140 toward the first end portion 104 of the body 102, it moves radially outward from the first diameter 134 (
When the cutter block 130 moves a second axial distance 142 toward the first end portion 104 of the body 102, it moves radially outward from the second diameter 136 (
The first distance 140 may be the same as the second distance 142, or it may be different. Although three axial positions (and three corresponding diameters 134, 136, 138) of the cutter block 130 are shown, it may be appreciated that the diameters are exemplary, and the cutter block 130 may be set at any diameter between a minimum diameter (e.g., the first diameter 134) and a maximum diameter (e.g., the third diameter 138).
One or more pins or rods 220, 230 may extend radially outward from the arm 210. As shown, two rods 220, 230 may be coupled to the arm 210 and extend radially outward therefrom. In another embodiment, a single rod (not shown) may extend through the arm 210 and radially outward in opposing directions. The end portions 222, 232 of the rods 220, 230 distal the arm 210 may be disposed within corresponding axial tracks on or grooves 320, 330 in the inner surface of the sleeve 300.
Returning to
When the arm 210 of the actuator 200 rotates in a second direction, the rods 220, 230 also rotate in the second direction. The interaction between the rods 220, 230 and the grooves 320, 330 causes the sleeve 300 to rotate in the second direction. As the sleeve 300 rotates in the second direction, the interaction between the threads 340 on the sleeve 300 and the threads 160 in the body 102 converts the rotational movement of the sleeve 300 to axial movement in a second direction (e.g., toward the second end portion 106 of the body 102) with respect to the arm 210 and the rods 220, 230 (and body 102). The arm 210 and the rods 220, 230 may remain axially stationary with respect to the body 102.
As the sleeve 300 moves axially in the first and/or second direction, the rods 220, 230 (axially stationary) slide or transition through the grooves 320, 330 in the sleeve 300. In at least one embodiment, the end portions 222, 232 of the rods 220, 230 may have bearings 224, 234 (
When there is minimal or no axial force acting on the sleeve 300 via the cutter block 130 and/or the sleeve extension 110, the sleeve 300 may be rotated with respect to the body 102. To facilitate rotation of the sleeve 300 within the body 102, at least one of the portions 350, 360, 370 may have a greater cross-sectional width “W” than the remaining portions 350, 360, 370. As shown, the first or “leading” portion 350, which is the portion nearest the first end portion 304 of the sleeve 300, has a greater cross-sectional width W than the remaining portions 360, 370. As a result, when the threads 340 on the sleeve 300 rotate with respect to the threads 160 in the body 102, the portion with the greater width W (e.g., the first portion 350) may be in contact with its corresponding portion of threads 160 in the body 102, while the remaining portions 360, 370 may be spaced apart from their corresponding portions of the threads 160 in the body 102. More particularly, the first and second axial faces 352, 354 of the portion with the greater width W (e.g., the first portion 350) are in contact with their corresponding portions of the threads 160 in the body, while the first and second faces 362, 364 of the second portion 360 are spaced apart from their corresponding portions of the threads 160 in the body 102, and the first and second faces 372, 374 of the third portion 370 are spaced apart from their corresponding portions of the threads 160 in the body 102. Limiting the number of portions 350, 360, 370 in contact with the corresponding portions of threads 160 in the body 102 may reduce the force to rotate the sleeve 300 with respect to the body 102.
The first face 352 and/or the second face 354 of the portion with the greater width W (e.g., the first portion 350) may be curved to reduce the surface area that is in contact with corresponding portions of the threads 160 in the body 102. This may further reduce the force to rotate the sleeve 300 with respect to the body 102.
As such, when an axial force acts on the sleeve 300 via the cutter block 130 and/or the sleeve extension 110, the first portion 350 may deform, thereby allowing the remaining portions 360, 370 to contact their corresponding portions of the threads 160 in the body 102. More particularly, the first face 362 of the second portion 360, and the first face 372 of the third portion 370 may contact their corresponding portions of the threads 160 in the body 102 when an axial force acts on the sleeve 300 via the cutter block 130 and/or the sleeve extension 110 in a direction toward the first end portion 104 of the body 102 (depicted with arrow 380). The remaining portions 360, 370 may be adapted to withstand the axial force applied via the cutter block 130 and/or the sleeve extension 110.
Referring to
To actuate or adjust the cutter block 130 of the underreamer 100 from the first diameter 134, as shown in
Fluid pressure is applied to the bore 108 from the surface, e.g., by pumping mud/drilling fluid downhole to bore 108. Sufficient pressure in the bore 108 causes a chamber 170 disposed between the cutter block 130 and the second end portion 106 of the body 102 to become pressurized (e.g., by opening a port or valve therebetween). The pressurized chamber 170 exerts a hydraulic force on the cutter block 130 in a direction toward the first end portion 104 of the body 102. The force moves the cutter block 130 axially toward the first end portion 104 of the body 102. Through the continued contact between the cutter block 130 and the stopper 120 (e.g., via a spring biasing such continued contact prior to cutter block 130 movement), the movement of the cutter block 130 also moves the stopper 120 and the sleeve extension 110 toward the first end portion 104 of the body 102 the first distance 140. Thus, the cutter block 130, the stopper 120, and the sleeve extension 110 move toward the first end portion 104 of the body 102 the first distance 140 until the sleeve extension 110 contacts the sleeve 300, at which point further axial movement of the cutter block 130, the stopper 120, and the sleeve extension 110 is prevented.
Alternatively, as will be readily understood by those skilled in the art, if the sleeve 300 and the sleeve extension 110 are coupled, then movement of the sleeve 300 via the actuator 200 by the first distance 140 (or any subsequent distance) axially separates the stopper 120 from the cutter block 130. In such embodiment, stopper 120 would not need or necessarily desire a biasing device, e.g., a spring, to maintain contact between stopper 120 and cutter block 130. Subsequent movement of the cutter block 130 toward the first end portion 104 of body 102 continues until contact is reestablished between the stopper 120 and cutter block 130.
The cutter block 130 moves radially outward from the first diameter 134 to the second diameter 136, simultaneously with its axial movement toward the first end portion 104 of the body 102, due to the engagement of the splines 131 and the corresponding grooves 133. When the axial movement is prevented after moving the first distance 140, further radial movement is also prevented, and the cutter block 130 is set at the second diameter 136, as shown in
The axial distance that the sleeve 300, the sleeve extension 110, and the cutter block 130 move with respect to the body 102 may correspond to the number of times that the actuator 200 rotates the sleeve 300. For example, the first distance 140 (and second distance 142) may correspond to five (5) rotations or revolutions of the sleeve 300 but may be any number of rotations or revolutions which equate to the desired first distance 140 (or second distance 142). The radial distance that the cutter block 130 moves with respect to the body 102 (e.g., from the first diameter 134 to the second diameter 136) corresponds to the axial distance (e.g., first distance 140) that the cutter block 130 moves with respect to the body 102. Thus, the cutting diameter of the cutter block 130 may be determined by the number of times the actuator 200 rotates the sleeve 300.
To actuate or adjust the cutter block 130 of the underreamer 100 from the second diameter 136, as shown in
Pressure is again applied to the bore 108 from the surface. The pressure in the bore 108 causes the chamber 170 to become pressurized. The pressurized chamber 170 exerts a hydraulic force on the cutter block 130 in a direction toward the first end portion 104 of the body 102. The force moves the cutter block 130 toward the first end portion 104 of the body 102. Through the continued contact between the cutter block 130 and the stopper 120, the movement of the cutter block 130 also moves the stopper 120 and the sleeve extension 110 toward the first end portion 104 of the body 102. The cutter block 130, the stopper 120, and the sleeve extension 110 move toward the first end portion 104 of the body 102 the second distance 142 until the sleeve extension 110 contacts the sleeve 300, at which point further axial movement of the cutter block 130, the stopper 120, and the sleeve extension 110 is prevented. Alternatively, if the sleeve 300 and the sleeve extension 110 are coupled, then as similarly disclosed above with respect to the first distance 140, the cutter block 130 will be permitted to move the second distance 142 into contact with the stopper 120.
The cutter block 130 moves radially outward from the second diameter 136 to the third diameter 138, simultaneously with its axial movement toward the first end portion 104 of the body 102, due to the engagement of the splines 131 and the grooves 133. When the axial movement is prevented after moving the second distance 142, further radial movement is also prevented, and the cutter block 130 is set at the third diameter 138, as shown in
To actuate or adjust the cutter block 130 of the underreamer 100 from the third diameter 138, as shown in
As the sleeve 300 moves toward the second end portion 106 of the body 102, the sleeve 300 may be in contact with the sleeve extension 110 and thus move the sleeve extension 110 toward the second end portion 106 of the body 102 the sum of the first and second distances 140, 142. As the sleeve extension 110 moves toward the second end portion 106 of the body 102, the stopper 120 (which is coupled to the sleeve extension 110) is in contact with the cutter block 130 (e.g., via a biasing device or spring) and thus moves the cutter block 130 toward the second end portion 106 of the body 102 the sum of the first and second distances 140, 142. As the cutter block 130 moves axially toward the second end portion 106 of the body 102 the second distance 142, the cutter block 130 moves radially inward from the third diameter 138 to the second diameter 136, and as the cutter block 130 moves toward the second end portion 106 of the body 102 the first distance 140, the cutter block moves radially inward from the second diameter 136 to the first diameter 134, i.e., into the inactive state. Alternatively, if the sleeve 300 and the sleeve extension 110 are decoupled, the actuator 200 may not need to be rotated in the second direction to retract the cutter block 130 to its inactive state. By reducing pressure in chamber 170, the biasing device, e.g., spring, exerting force on stopper 120 (coupled to the sleeve extension 110) in the second direction may act to move stopper 120 and cutter block 130 into the inactive state. Such operation may be advantageous when it is desired to temporarily return the cutter block 130 to its inactive state while maintaining the desired cutting diameter of cutter block 130 upon the reapplication of sufficient fluid pressure in chamber 170.
An operator may diagnose a blockage or clogging of the cutter block 130 by attempting to move or rotate the actuator 200 while the pressure is being applied to the bore 108 and the chamber 170. For example, if the actuator 200 is able to move or rotate the sleeve 300 while the pressure is being applied to the bore 108 and the chamber 170, either the sleeve extension 110 is not in contact with the sleeve 300, or the cutter block 130 is not in contact with the stopper 120 of the sleeve extension 110. This may indicate or signal that the cutter block 130 is not fully actuated or deployed. However, if the actuator 200 is unable to rotate the sleeve 300 (due to an axial force acting on the sleeve 300) while the pressure is being applied to the bore 108 and the chamber 170, then this may indicate or signal that the cutter block 130 is fully actuated or deployed.
As used herein, the terms “inner” and “outer”; “up” and “down”; “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 “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”
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 “Underreamer for Increasing a Wellbore Diameter.” 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 Application having Ser. No. 61/725,839 filed Nov. 13, 2012, entitled “Underreamer for Increasing a Wellbore Diameter,” to Jianbing Hu, the disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61725839 | Nov 2012 | US |
