Patent Application
20160258219
Drilling systems are employed for drilling a variety of wellbores. A drilling system may comprise a drill string and a drill bit which is rotated to drill a wellbore through a desired subterranean formation. In various drilling applications, a desired borehole trajectory is planned and calculated prior to drilling based on geological data. A number of steering techniques and equipment types may be employed to achieve a planned trajectory. For example, a bottom hole assembly may comprise a rotary steerable tool used to enable directional drilling while rotating the drill string. Rotary steerable drilling systems utilize various components including stabilizers, actuator pads, and other components to control the drilling direction. However, existing systems tend to be complex assemblies with multiple moving parts, and this complexity can lead to service quality issues and downtime. For example, existing push-the-bit rotary steerable systems sometimes incur seal failure, cracking hinge bushes, hinge pin bending, and high wear rates on actuator pads. Existing systems also may have limitations in certain applications due to external moving parts, actuator pads positioned a substantial distance from the drill bit, and limited actuation force.
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. In some embodiments, a system for use in a well includes a drill string including a drill bit and a steering tool for controlling the trajectory of a borehole formed by rotating the drill bit. The steering tool includes a main body and a steering sleeve pivotably mounted to the main body by a joint located to enable pushing contact via the steering sleeve against a surrounding borehole wall at a location between the joint and the drill bit. The steering sleeve is selectively pivoted by a plurality of actuators between the main body and the steering sleeve.
In some embodiments, a method of drilling includes pivotably coupling a steering sleeve, having a sacrificial liner, to a main body to form a steering tool. The sacrificial liner positioned along an interior of the steering sleeve is used. A plurality of actuators are located between the main body and the steering sleeve. The steering tool is coupled to a drill bit. The method further includes rotating the drill bit and controlling the drilling orientation of the drill bit by selectively actuating selected actuators of the plurality of actuators to cause the steering sleeve to pivot against a surrounding borehole wall, thus pushing the drill bit. In some embodiments, a system includes a steering tool operable to control a trajectory of a borehole during drilling of the borehole. The steering tool includes a main body and a steering sleeve pivotably mounted to the main body by a gimbal joint to enable pushing contact via the steering sleeve against a surrounding borehole wall. The steering sleeve is selectively pivoted by a plurality of actuators disposed between the main body and the steering sleeve.
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:
In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The present disclosure generally relates to a system and methodology which facilitate steering during, for example, a borehole drilling operation. For example, the technique facilitates directional drilling applications by providing a steerable drilling system, e.g. a rotary steerable drilling system, with improved performance, greater dependability and lower cost. In an embodiment, the rotary steerable drilling system is constructed with a relatively low number of components arranged to enable improved use of mechanical advantage and to produce higher steering forces while operating at a lower pressure drop, thus reducing the risk of erosion to the rotary steerable drilling system.
According to an embodiment, the rotary steerable drilling system employs a steering tool constructed to provide better wellbore integrity by using a steering sleeve as the push component rather than actuator pads. The construction enables application of higher forces as well as steering forces applied closer to the drill bit. The steering sleeve also may be constructed to provide a greater contact area against the surrounding formation compared to conventional actuator pads. Use of the steering sleeve reduces or eliminates external moving parts and thus there are fewer moving parts to fail or to fall free of the system. The use of fewer mechanical parts also reduces cost and assembly time while providing a more dependable system. The construction minimizes the number of threaded fasteners and enables the steering tool to operate at a lower pressure drop. Use of the lower pressure drop reduces the potential of erosion with respect to the steering tool.
An embodiment of a surface system includes a platform and derrick assembly 28 positioned over the borehole 20. An example of assembly 28 includes a rotary table 30, a kelly 32, a hook 34 and a rotary swivel 36. The drill string 22 is rotated by the rotary table 30, energized by a suitable system (not shown) which engages the kelly 32 at the upper end of the drill string 22. The drill string 22 is suspended from the hook 34, attached to a traveling block (not shown) through the kelly 32 and the rotary swivel 36 which permits rotation of the drill string 22 relative to the hook 34. A top drive system can be used in other embodiments.
An embodiment of the surface system also includes a drilling fluid 38, e.g., mud, stored in a pit 40 formed at the wellsite. A pump 42 delivers the drilling fluid 38 to the interior of the drill string 22 via one or more ports in the swivel 36, causing the drilling fluid to flow downwardly through the drill string 22 as indicated by directional arrow 44. The drilling fluid exits the drill string 22 via one or more ports in the drill bit 26, and then circulates upwardly through the annulus region between the outside of the drill string 22 and the wall of the borehole, as indicated by directional arrows 46. In this manner, the drilling fluid lubricates the drill bit 26 and carries formation cuttings and particulate matter up to the surface as it is returned to the pit 40 for recirculation.
The illustrated embodiment of bottom hole assembly 24 includes one or more logging-while-drilling (LWD) modules 48/50, one or more measuring-while-drilling (MWD) modules 52, one or more roto-steerable systems and motors (not shown), and the drill bit 26. It will also be understood that more than one LWD module and/or more than one MWD module may be employed in various embodiments, e.g. as represented at 48 and 50.
The LWD module 48/50 is housed in a type of drill collar, and includes capabilities for measuring, processing, and storing information, as well as for communicating with the surface equipment. The LWD module 48/50 also may include a pressure measuring device and one or more logging tools.
The MWD module 52 also is housed in a type of drill collar, and includes one or more devices for measuring characteristics of the drill string 22 and drill bit 26. The MWD module 52 also may include one or more devices for generating electrical power for the downhole system. In an embodiment, the power generating devices include a mud turbine generator (also known as a “mud motor”) powered by the flow of the drilling fluid. In other embodiments, other power and/or battery systems may be employed to generate power.
The MWD module 52 also may include one or more of the following types of measuring devices: a weight-on-bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, and an inclination measuring device.
In an operational example, the wellsite system of
A directional drilling system also may be used in a vertical drilling operation. Often the drill bit will veer off of a planned drilling trajectory because of the unpredictable nature of the formations being penetrated or the varying forces that the drill bit experiences. When such a deviation occurs, a directional drilling system may be used to put the drill bit back on course.
A method of directional drilling utilizes a rotary steerable system (“RSS”) to enable drilling along a desired trajectory. In an embodiment that employs the wellsite system of
In an example of a “point-the-bit” rotary steerable system, the axis of rotation of the drill bit is deviated from the local axis of the bottom hole assembly in the general direction of the new hole. The hole is propagated in accordance with the customary three-point geometry defined by upper and lower stabilizer touch points and the drill bit. The angle of deviation of the drill bit axis coupled with a finite distance between the drill bit and lower stabilizer results in the non-collinear condition which enables a curve to be generated. This may be achieved in a number of different ways, including a fixed bend at a point in the bottom hole assembly close to the lower stabilizer or a flexure of the drill bit drive shaft distributed between the upper and lower stabilizer. In its idealized form, the drill bit does not have to cut sideways because the bit axis is continually rotated in the direction of the curved hole. Examples of “point-the-bit” type rotary steerable systems and their operation are described in U.S. Pat. Nos. 6,394,193; 6,364,034; 6,244,361; 6,158,529; 6,092,610; and 5,113,953; and U.S. Patent Application Publication Nos. 2002/0011359 and 2001/0052428.
In an example of a “push-the-bit” rotary steerable system, there is no specially identified mechanism that deviates the bit axis from the local bottom hole assembly axis. Instead, the requisite non-collinear condition is achieved by causing either or both of the upper or lower stabilizers to apply an eccentric force or displacement in a direction that is orientated with respect to the direction of hole propagation. This may be achieved in a number of different ways, including non-rotating (with respect to the hole) eccentric stabilizers (displacement based approaches) and eccentric actuators that apply force to the drill bit in the desired steering direction. Steering is achieved by creating non co-linearity between the drill bit and at least two other touch points. In its idealized form, the drill bit cuts sideways to generate a curved hole. Examples of “push-the-bit” type rotary steerable systems and their operation are described in U.S. Pat. Nos. 6,089,332; 5,971,085; 5,803,185; 5,778,992; 5,706,905; 5,695,015; 5,685,379; 5,673,763; 5,603,385; 5,582,259; 5,553,679; 5,553,678; 5,520,255; and 5,265,682.
Referring generally to
The steering sleeve 58 and the gimbal joint 62 may be oriented such that the steering sleeve 58 applies a steering force against a surrounding wall of borehole 20 at an axial position between the gimbal joint 62 and the drill bit 26. In other words, the pivot joint 60, e.g. gimbal joint 62, may be located uphole of the point at which steering force is applied against the surrounding wall, thus facilitating application of high steering forces and high steerability. When actuators 64 are in the form of hydraulic actuators, the high steering forces can be achieved with a relatively low pressure drop across the actuators 64.
The actuators 64 are positioned to move radially outward against an inside surface of the steering sleeve 58 so as to cause the steering sleeve 58 to push against a surrounding wellbore wall. When the steering sleeve 58 pushes against the surrounding wellbore wall, the drill bit 26 is forced in an opposite direction thus steering the drill bit 26 and steering tool 54. In the embodiment illustrated, the actuators 64 are hydraulic actuators selectively actuated to control the direction of steering via hydraulic fluid, e.g. drilling mud, supplied to the actuators 64 under pressure via hydraulic passages 66 formed in main body 56. By way of example, the hydraulic actuators 64 may be in the form of ball actuators 68 or other suitable actuators, e.g. hydraulic piston actuators or electro-mechanical actuators, selectively operable to pivot steering sleeve 58 about pivot joint 60 so as to push against the surrounding wellbore wall.
Referring also to
Referring generally to
During a steering operation, the actuators 64 are selectively energized to push against an inside of the steering sleeve 58, e.g. against an interior of the sacrificial liner 74 or against other interior surfaces of steering sleeve 58. The steering sleeve 58 is pivoted by the actuators 64 in a desired direction so that the steering sleeve 58 pushes against the surrounding wellbore wall. Pushing the sleeve 58 against the surrounding wall in a given direction forces the drill bit 26 in an opposite direction, thus steering the drill bit 26 and steering tool 54 along a desired trajectory. In some applications, the steering sleeve blades 80 may be positioned at an end of the steering sleeve 58 closest to drill bit 26 to enable higher dogleg severity.
In some embodiments, the steering force applied can be increased by extending the length of the steering sleeve 58 or by moving the pivot point established by pivot joint 60 farther up along the main body 56. The increase in steering force can thus be achieved while utilizing a relatively lower pressure drop (compared to a conventional RSS) to actuate the actuators 64, at least when actuators 64 are in the form of hydraulic actuators utilizing an actuating fluid, e.g. drilling mud. The length of steering sleeve 58 and the position of actuators 64 also may be selected to obtain a desired, improved mechanical advantage useful for a given drilling operation. Such increases in sleeve length and/or other changes also may enable a greater number of actuators 64 to be added within the steering sleeve 58, thus enabling application of still greater force.
Depending on the parameters of a given application, the steering tool 54 may utilize a variety of structures and techniques to control the orientation of drill bit 26. For example, various types of joints, actuators, steering sleeves, and other components may be used to enable steering of the drill bit 26 along a desired trajectory. Similarly, the size and length of the steering sleeve 58 as well as the number and placement of actuators 64 may be selected according to the parameters of a given application. In many applications, the actuators 64 are hydraulic actuators, but electro-mechanical actuators and other suitable actuators may be utilized to provide controlled pivoting of steering sleeve 58.
Additionally, the steering tool 54 may be employed in a wide variety of drilling systems and drilling applications. The unique arrangement of tool body, pivot joint, steering sleeve, and actuators provides a dependable, highly steerable tool 54. Because of the relatively low number of components and the arrangement of components, the steering tool 54 also can be constructed at a relatively low cost. Consequently, embodiments described herein may be used to provide a deviated drilling system utilizing a high force, low pressure drop, rotary steerable bias unit.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not just 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 means-plus-function 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 and priority to U.S. Provisional Application Ser. No.: 62/128,451, filed Mar. 4, 2015, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62128451 | Mar 2015 | US |
