Patent Application
20180080283
The present invention relates to apparatuses and methods for directional drilling of boreholes in geological formations.
The prior art includes a variety of apparatuses and methods for directional drilling of vertical or non-vertical boreholes in geological formations for recovery of oil and gas.
Directional drilling may be performed with steerable motor systems, in which a drill string includes a bent tubular section and an internal mud motor that rotates a drill bit. Operation of the system is alternated between a rotary mode and a sliding mode to change the trajectory of the borehole. During the rotary mode, a torque device such as a rotary table or a top drive rotates the entire drill sting (including the drill bit) to advance the borehole in a substantially straight path. During the sliding mode, the mud motor rotates only the drill bit to slide the drill string along a curved trajectory dictated by the bent tubular section of the drill string.
Directional drilling may be performed with “push the bit” rotary steerable systems (RSS), in which a drill string includes a straight rotatable tubular section with a plurality of actuable pads near the drill bit. As the tubular section rotates, the pads radially extend and retract from the tubular section so that they apply a controlled resultant radial force to the borehole wall, and thereby force the axis of drill string in a desired direction. However, such systems require a relatively complex valve mechanism to synchronously control the extension of the pads to achieve the desired effect.
Directional drilling may be performed with “point the bit” rotary steerable systems, in which a drill string includes a straight rotatable outer tubular section with an inner drill bit shaft that is adjustable in orientation with respect to the outer tubular section. However, such systems require a mechanism, such as a servomotor, to adjust the orientation of the inner drill bit shaft with respect to the outer tubular housing.
Directional drilling may be performed with systems in which pads or equivalent parts are actuated to engage the borehole wall to limit rotation of a bent tubular section while rotation of an internal drill string advances the drill bit. For example, U.S. Pat. No. 6,059,661 to Simpson discloses a directional drilling system in which pressurized hydraulic fluid actuates pistons that force grip pads radially outward from a stabilizer to anchor the stabilizer in the wellbore. In one embodiment, a hydraulic pump internal to the system pressurizes the hydraulic fluid from an internal reservoir to an internal gallery to extend the grip pads. A remotely controllable valve may control the flow of hydraulic fluid between the reservoir and gallery. United States Patent Application Publication No. 2001/0052428 to Larronde et al. discloses a downhole steering tool in which guide members move to engage the borehole to hold a steering housing against rotation while a drill string rotates a drill bit. The guide members are actuated by hydraulic passage leading to a hydraulic pump incorporated within the steering housing and driven by an electrical motor supplied with power from a MWD pump. United States Patent Application Publication No. 2016/0138381 to Logan et al. discloses an apparatus for directional drilling that allows an uphole section of a drill string to be rotated while maintaining a desired orientation of a bent section of the drill string with the use of pads that can be urged outwardly to engage walls of the wellbore, but does not disclose how the pads are actuated beyond indicating that they are hydraulically actuated.
There remains a need for improved apparatuses and methods for directional drilling that are reliable and avoid such complexities of the prior art.
In one aspect, the present invention comprises an apparatus for directional drilling of a borehole defined by a borehole wall. The apparatus is locatable between an uphole drill string defining a drill string bore for flow of a drilling fluid and a downhole drill bit defining a drill bit opening for flow of the drilling fluid.
The apparatus comprises a bent tubular housing for imparting a direction to the borehole. When the apparatus is disposed in the borehole, an outer annular space defined between an outer wall of the housing and the borehole wall is in drilling fluid communication with the drill bit opening.
The apparatus further comprises a drive shaft for coupling rotation of the drill string to the drill bit. The drive shaft is disposed within the housing. When the drill string and the drill bit are coupled to the drive shaft, an inner annular space defined between an inner wall of the housing and the drive shaft is in drilling fluid communication with the drill string bore and the drill bit opening.
The apparatus further comprises at least one piston in drilling fluid communication with a piston chamber attached to the housing and in drilling fluid communication with the outer annular space and the inner annular space. The piston is movable relative to the housing to, in use, apply pressure to the borehole wall and thereby limit rotation of the housing within the borehole.
The apparatus further comprises a biasing means. The piston, the piston chamber and the biasing means are arranged such that a drilling fluid pressure in the piston chamber urges the piston in a first direction towards the borehole wall, and the biasing means urges the piston in a second direction away from the borehole wall, or vice versa.
The apparatus further comprises at least one valve for selectively controlling drilling fluid flow between the outer annular space and the piston chamber, relative to drilling fluid flow between the inner annular space and the piston chamber and thereby, in use, controlling the drilling fluid pressure variation in the piston chamber.
The apparatus further comprises a clutch for selectively coupling the housing to the drive shaft for rotation with the drive shaft and for adjusting the tool face of the housing.
In an exemplary embodiment, the valve is actuable between a first state and a second state. In the first state, the valve prevents drilling fluid communication from the inner annular space to the piston chamber, and permits drilling fluid communication from the piston chamber to the outer annular space. In the second state, the valve permits drilling fluid communication from the inner annular space to the piston chamber, and prevents drilling fluid communication from the piston chamber to the outer annular space.
In embodiments of the apparatus, the piston chamber is in drilling fluid communication with the inner annular space via an inlet passage defined by the housing.
In embodiments of the apparatus, the piston chamber is in drilling fluid communication with the outer annular space via an outlet passage defined by the housing.
In embodiments of the apparatus, the drive shaft comprises a tubular uphole portion for drilling fluid communication between the drill string bore and the inner annular space, as well as a tubular downhole portion for drilling fluid communication between the inner annular space and the drill bit opening.
In embodiments of the apparatus, the drive shaft comprises a tubular intermediate portion, and a universal joint coupling the tubular intermediate portion to the tubular downhole portion for permitting rotation of the drive shaft within the housing while accommodating a bend angle of the housing.
In embodiments of the apparatus, the clutch comprises a clutch member attached to the inner wall of the housing, the clutch member being actuable to extend radially inwards to be operably connected or into engagement with the drive shaft.
In embodiments of the apparatus, the valve is selected from a two-way valve, a solenoid valve, or an annular valve member.
In embodiments of the apparatus, the valve, the clutch, or both are remotely controllable from outside of the borehole.
In embodiments of the apparatus, the apparatus comprises one valve or more than one valve.
In embodiments of the apparatus, the apparatus comprises more than one piston.
In embodiments of the apparatus, the apparatus comprises an electronic control module comprising a first processor attached to the housing and a second processor at surface and remotely communicating with the first processor for operating the apparatus.
In another aspect, the present invention comprises a method for directional drilling of a borehole defined by a borehole wall. The method comprises the steps of:
In embodiments, the valve is actuable between a first state and a second state. In the first state, the valve prevents drilling fluid communication from the inner annular space to the piston chamber, and permits drilling fluid communication from the piston chamber to the outer annular space. In the second state, the valve permits drilling fluid communication from the inner annular space to the piston chamber, and prevents drilling fluid communication from the piston chamber to the outer annular space.
In embodiments of the method, the drilling fluid flows between the inner annular space and the piston chamber via an inlet passage defined by the housing.
In embodiments of the method, drilling fluid flows between the outer annular space and the piston chamber via an outlet passage defined by the housing.
In embodiments of the method, the drilling fluid flows from the drill string bore to the inner annular space via a tubular uphole portion of the drive shaft, and flows from the inner annular space to the drill bit opening via a tubular downhole portion of the drive shaft.
In embodiments of the method, the clutch comprises a clutch member attached to the inner wall of the housing, the clutch member being actuable to extend radially inwards to be operably connected or into engagement with the drive shaft.
In embodiments of the method, the valve is selected from a two-way valve, a solenoid valve, or an annular valve member.
In embodiments of the method, actuating the valve, the clutch, or both comprises remotely controlling the valve, the clutch, or both from outside of the borehole.
In embodiments of the method, the apparatus comprises one valve or more than one valve.
In embodiments of the method, the apparatus comprises more than one piston.
In embodiments of the method, the apparatus is electronically controlled by an electronic control module comprising a first processor attached to the housing and a second processor at surface and remotely communicating with the first processor.
Exemplary embodiments of the present invention are described with reference to the following drawings. In the drawings, like elements are assigned like reference numerals. The drawings are not necessarily to scale, with the emphasis instead placed upon the principles of the present invention. Additionally, each of the embodiments depicted is but one of a number of possible arrangements utilizing the fundamental concepts of the present invention. The drawings are briefly described as follows:
The present invention relates to directional drilling of boreholes. Any term or expression not expressly defined herein shall have its commonly accepted definition understood by a person skilled in the art. As used herein, the terms “uphole” and “downhole” describe relative positions between two parts along the borehole. A first part that is “uphole” of a second part is more proximal to the surface than the second part along the path defined by the borehole. Conversely, a first part that is “downhole” of a second part is more distal from the surface than the second part along the path defined by the borehole.
The apparatus (10) generally comprises a stationary “outer string” and a rotatable “inner string” which is positioned to rotate within the outer string. The stationary outer string and rotatable inner string are connected by uphole and downhole bearing assemblies (42, 44). As will be further described in detail, the stationary outer string generally comprises a bent tubular housing (20) which includes an upper stationary housing (21), an electronic housing (23) comprising a processor (72), bent housing uphole portion (22), and housing downhole portion (24). The rotatable inner string generally comprises a drive shaft (40) which includes a drive shaft uphole portion (46), drive shaft intermediate portion (48), universal joint (52), and drive shaft downhole portion (50).
In the exemplary embodiment of
The bent tubular housing (20) imparts a direction to the borehole (100). The housing (20) is bent in the sense that it comprises a bent housing uphole portion (22) and a housing downhole portion (24) having respective longitudinal centerlines that form a non-zero angle, θ. In an exemplary embodiment, for example, the angle θ may be between 0 and 4 degrees. When the apparatus (10) is disposed within the borehole (100) as shown in
The drive shaft (40) couples rotation of the drill string (104) to the drill bit (108). The drive shaft (40) is positioned within the housing (20) such that an inner annular space (36) is defined between the drive shaft (40) and an inner wall (28) of the housing (20). In the exemplary embodiment of
The piston chamber (62) is attached to the housing (20) and defines a space in drilling fluid communication with the outer annular space (34) and the inner annular space (36). At least one piston (60) moves within the piston chamber (62) so as to press against the borehole wall (102) and thereby limit rotation of the housing (20) within the borehole (100) by virtue of friction between the interfacing surfaces of the piston (60) and the borehole wall (102). As used herein, “limit rotation” includes limiting a non-zero amount of rotation as well as entirely preventing rotation.
In the exemplary embodiment shown in
The biasing means (74) may comprise any device known in the art that is suitable for urging the piston (60) to move relative to the housing (20). For example, in the exemplary embodiment shown in
The piston (60), the piston chamber (62) and the biasing means (74) are arranged such that drilling fluid pressure in the piston chamber (62) urges the piston (60) in a first direction, and the biasing means (74) urges the piston (60) in a second direction. In the exemplary embodiment shown in
At least one valve (70) selectively controls drilling fluid communication between the outer annular space (34) and the piston chamber (62), and between the inner annular space (36) and the piston chamber (62). In the exemplary embodiment of
The clutch (76) is used to perform dual functions, namely the rotary drilling and adjusting the tool face of the housing (20). The clutch (76) selectively couples the housing (20) to the drive shaft (40) for rotation with drive shaft (40). The clutch (76) may comprise any device known in the art that is suitable for transmitting torque from the drive shaft (40) to the housing (20). For example, in the exemplary embodiment shown in
The clutch (76) may be remotely controllable from outside of the borehole (100) by means of an electronic control module comprising a first processor (72) attached to the housing (20) and a second processor (not shown) at the surface and remotely communicating with the first processor (72).
An exemplary use and operation of the exemplary embodiment of the apparatus (10) shown in
A drilling fluid pressure differential between the inner annular space (36) and the outer annular space (34) is established. For example, the drilling fluid flow rate, the size of the drill bit opening (110) or other flow restriction devices may be selected so that the drilling fluid pressure within the inner annular space (36) is higher than the drilling fluid pressure in the outer annular space (34). The drilling fluid in the outer annular space (34) flows in the uphole direction towards the surface carrying along with it cuttings that are produced by the abrasion of the drill bit (108) with the advancing borehole wall (102). During drilling operations, the first processor (72) and the second processor (not shown) at the surface and remotely communicating with the first processor may be used to monitor the tool face orientation of the drill bit.
When it is desired to advance the borehole (100) in a straight trajectory, the apparatus (10) is configured into a rotary mode. The configuration process may be automated in part or in full with the assistance of processors. The apparatus (10) operates under electronic control, whereby an electronic control module comprises the first processor (72) attached to the housing (20) and the second processor (not shown) at the surface and remotely communicating with the first processor.
In the rotary mode, the clutch (76) couples the housing (20) to the drive shaft (40) for rotation with the drive shaft (40). Further, as shown schematically in
When it is desired to advance the borehole (100) in a deviated trajectory from the existing borehole (100) path, the apparatus (10) is configured into a sliding mode. The configuration process may be automated in part or in full with the assistance of the processor (72). In the sliding mode, the clutch (76) decouples the housing (20) from rotation with the drive shaft (40). Nonetheless, it will be appreciated that rotation of the drive shaft (40) within the housing (20) may induce some rotational tendency in the housing (20) due to phenomena such as seal friction. Therefore, the valve (70) is actuated to a second state where the valve (70) permits drilling fluid communication from the inner annular space (36) to the piston chamber (62) via the inlet passage (30) (as indicated by the unshaded valve member and the arrow lines), and prevents drilling fluid communication from the piston chamber (62) to the outer annular space (34) via the outlet passage (as indicated by the shaded valve member and non-arrow line). Accordingly, the drilling fluid pressure in the piston chamber (62) will tend towards equilibrium with the drilling fluid pressure in the inner annular space (36). The stiffness of the biasing means (74) is pre-selected such that the radially outward resultant force applied to the piston (60) by the expected drilling fluid pressure in the piston chamber (62) during the sliding mode is greater than the radially inward biasing force applied by the biasing means (74) to the piston (60). It will be appreciated that the drilling fluid will tend to flow into the piston chamber (62) without the need for pressurization beyond that provided by the drilling fluid pump (not shown) at the surface if the resultant force of the drilling fluid pressure in the inner annular space (36) is sufficiently high. Accordingly, the piston (60) moves radially outwards towards the borehole wall (102) and applies a pressure to the borehole wall (102) that is sufficient to limit rotation of the housing (20) within the borehole (100) by frictional engagement. While in the sliding mode, the torque device (not shown) such as a top drive, rotary table or Kelly drive rotates the drill string (104), while the pistons (60) limit rotation of the housing (20) within the wellbore. As the drill string (104) rotates the drill bit (108), the borehole (100) will advance along a curved trajectory imparted by the non-rotating housing (20) as it slides along the advancing borehole (100).
It will be appreciated that the apparatus of the present invention may be operated without the need for any pumping devices additional to the drilling fluid pump at the surface to push the pads out. Further, it will be appreciated that a single valve may be used to control the actuation of a plurality of pistons.
The present invention has been described above and shown in the drawings by way of exemplary embodiments and uses, having regard to the accompanying drawings. The exemplary embodiments and uses are intended to be illustrative of the present invention. It is not necessary for a particular feature of a particular embodiment to be used exclusively with that particular exemplary embodiment. Instead, any of the features described above and/or depicted in the drawings can be combined with any of the exemplary embodiments, in addition to or in substitution for any of the other features of those exemplary embodiments. One exemplary embodiment's features are not mutually exclusive to another exemplary embodiment's features. Instead, the scope of this disclosure encompasses any combination of any of the features. Further, it is not necessary for all features of an exemplary embodiment to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used. Accordingly, various changes and modifications can be made to the exemplary embodiments and uses without departing from the scope of the invention as defined in the claims that follow.
This application is a U.S. Non-Provisional patent application which claims priority from U.S. Provisional application for Patent No. 62/395,746 filed Sep. 16, 2016 which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62395746 | Sep 2016 | US |
