Automatic deflection correction device and method thereof

Abstract

The present invention belongs to the technical field of oil and gas well drilling equipment, and proposes an automatic deflection correction device and method thereof. The liquid column pressure in the drill string acts on the piston on the housing that does not rotate with the drill string, pushing all the pistons toward the well wall. When well deflection occurs, the pendulum in the well deflection direction is close to the inner wall of the pendulum cavity under the action of gravity and remains motionless. At this time, the piston in the well deflection direction continues to push toward the well wall under the action of the liquid column pressure. The pendulum in the opposite direction of the well deflection leaves the inner wall of the pendulum cavity under the action of gravity, driving the slider below the pendulum to move, and closing the passage between the pendulum cavity and the piston cavity. At this time, the piston loses the continuous liquid column pressure, retracts into the piston cavity under the action of the drill string gravity and drill string vibration, and the liquid in the piston cavity flows back into the inner tube of the drill string through the check valve. The deflection correction force of the well deflection direction piston acting on the well wall forces the drill string to deflect in the opposite direction of the well deflection, driving the drill bit to drill in the opposite direction of the well deflection, thereby reducing the well deflection. The drill bit keeps drilling in a vertical direction.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas well drilling devices, and in particular relates to an automatic deflection correction device and a method thereof. Background Art

[0002] During the drilling process of oil and gas wells, it is common to encounter formations with different formation dips and lithologies. When drilling into various formations, the wellbore will deviate in a certain direction due to factors such as formation lithology and formation dips, resulting in well deviation.

[0003] There are many means and methods to prevent well deviation. The commonly used means is to make full use of the role of the drill string stabilizer and adjust the position of the stabilizer and drilling parameters to achieve the purpose of preventing and correcting the deviation. This method often has limited anti-deflection effect, or needs to sacrifice some other parameters to meet the requirements. For example, reducing the drilling pressure can reduce the bending of the drill string, but it affects the drilling speed.

[0004] The existing vertical drilling system is installed on the drill string behind the drill bit. The electronic components are used to measure the well inclination in real time, and the extension and retraction of the corresponding straightening blocks are controlled by the electronic components. This can achieve the verticality of the wellbore during drilling and obtain excellent wellbore quality. The biggest advantage of this system is that it liberates the drilling pressure and can greatly increase the drilling speed. However, this system is only in the hands of a few international suppliers and is currently mainly imported. It consumes a large amount of foreign exchange funds every year and is costly. It is also being researched and developed in China, and it has some effects, but it is not ideal and mature enough. A few key technologies still need to be imported, otherwise the performance will be unstable and the speed and efficiency cannot be increased. At the same time, since the electronic components in the tool are limited by the applicable temperature, they cannot be used for some high-temperature wells.

[0005] Relying on domestic mechanical processing technology, getting rid of the technical bottleneck of relying on foreign countries, developing automatic deflection correction technology, and liberating drilling pressure are of practical and important significance. Summary of the invention

[0006] The present invention aims to solve the problems described in the background technology and provides an automatic deflection correction device.

[0007] To achieve the above object, the present invention adopts the following technical solution: an automatic deflection correction method, comprising the steps of 1, assembling a self-deflection correction device and connecting its mandrel system to a drill string;

[0008] Step 2, the liquid in the drill string is transferred to the piston cavity through the mandrel center hole of the mandrel system and the pendulum cavity, and the piston cavity is extended out to support the well wall;

[0009] Step 3, when well deviation occurs, the center line of the mandrel deviates from the vertical state and deviates in the well deviation direction. The pendulum in the well deviation direction is close to the inner wall of the pendulum cavity under the action of gravity and remains stationary; the pendulum in the opposite direction of the well deviation leaves the inner wall of the pendulum cavity under the action of gravity and moves, driving the slider at the lower end of the pendulum to move, closing the piston hole, and the pendulum cavity and the piston cavity are not connected, and the pressure in the corresponding pendulum cavity cannot be transmitted to the piston cavity;

[0010] After the well deviates, the gravity of the drill string has a gravity component in the vertical direction, which acts on the piston in the opposite direction of the well deviate, so that the pressure in the piston cavity rises, and the higher pressure liquid in the piston cavity flows back to the center hole of the core shaft through the one-way return hole; at the same time, the piston retracts into the piston cavity;

[0011] A new pressure balance is formed in the piston cavity and the center hole of the mandrel. The piston in the well inclination direction extends out to support the well wall, and the piston in the opposite direction of the well inclination retracts into the piston cavity. The center point of the mandrel system shifts to the opposite direction of the well inclination, forcing the drill bit to drill in the opposite direction of the well inclination to achieve deflection correction.

[0012] An automatic deflection correction device comprises an upper mandrel and a lower mandrel, wherein the upper mandrel and the lower mandrel constitute a mandrel system, and the mandrel system is provided with a mandrel center hole for installing a drill string;

[0013] The outer side of the mandrel system is connected with a housing through a bearing, an annulus is left between the housing and the mandrel system, and the center hole of the mandrel is connected with the annulus;

[0014] The shell is provided with a plurality of pendulum cavities, which are connected with the central hole of the core shaft through an annulus, and a pendulum mechanism is arranged in the pendulum cavity;

[0015] The shell is provided with a plurality of piston cavities corresponding to the pendulum cavities one by one. The piston cavity is connected with the central hole of the core shaft through a one-way valve and an annulus. The piston cavity is connected with the pendulum cavity. A piston is arranged in the piston cavity.

[0016] In a preferred embodiment of the present invention, the upper core shaft is provided with a pressure transmission inlet hole communicating with the annulus, and the lower core shaft is provided with a pressure transmission outlet hole communicating with the annulus.

[0017] In a preferred embodiment of the present invention, a pendulum chamber inlet hole communicating with the annulus is provided at the upper portion of the pendulum chamber, and a pendulum chamber outlet hole communicating with the annulus is provided at the lower portion of the pendulum chamber.

[0018] In a preferred embodiment of the present invention, the pendulum mechanism includes a pendulum, which is rotatably connected to the housing, and a slider is fixedly connected to the bottom of the pendulum, and the slider is slidably matched with the bottom wall of the pendulum cavity.

[0019] In a preferred embodiment of the present invention, a piston hole connected to the pendulum chamber is provided at the upper portion of the piston chamber, a one-way reflux hole is provided on the side of the piston chamber close to the annulus, and a one-way valve connected to the annulus is fixedly connected in the one-way reflux hole.

[0020] In a preferred embodiment of the present invention, a plurality of pendulum cavities and a plurality of piston cavities are evenly distributed along the circumference of the housing.

[0021] The principle and beneficial effects of the present invention are as follows: the pressure-in hole on the core shaft system transmits the fluid pressure to the pendulum chamber through the entrance of the pendulum chamber, and further transmits it to the piston chamber through the piston hole, providing continuous hydraulic power for the operation of the entire system. The pendulum's own gravity is used to sense the direction of the well inclination, determine whether the pendulum moves, and drive the corresponding movement of the slider at the bottom of the pendulum structure, thereby determining whether the slider closes the piston hole, whether the pendulum chamber and the piston chamber are connected, and jointly determine the extension or retraction of the piston block under the combined effect of the gravity of the drill string. Under the above combined effect, the drill bit is forced to drill in the opposite direction of the well inclination, thereby reducing the well inclination.

[0022] The system's special structural design is ingenious, with high reliability and active deflection correction, which can fully release drilling pressure and maintain vertical drilling of the wellbore, which is of great significance.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1 This is an overall structural diagram of an automatic deflection correction device of the present invention;

[0026] Figure 2 A cross-sectional top view of an initial position of an automatic deflection correction device of the present invention;

[0027] Figure 3 This is a top view of the cross section of an automatic deflection correction device of the present invention at an inclined position.

[0028] Figure 4 The figure is a schematic diagram of the tilt position of an automatic tilt correction device of the present invention.

[0029] The figure marks in the drawings of the specification include: upper core shaft 1, bearing 2, housing 3, pendulum 4, slider 5, one-way valve 6, piston 7, core shaft center hole 8, pendulum chamber inlet hole 9, pressure transmission inlet hole 10, pendulum chamber 11, pendulum chamber outlet hole 12, piston hole 13, one-way reflux hole 14, pressure transmission outlet hole 15, piston chamber 16, lower core shaft 17, annulus 18, well wall 19, and centralizer 20. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "vertical", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0032] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0033] The present application provides an automatic deflection correction device, basically as shown in the attached Figure 1 As shown, it includes an upper mandrel 1 and a lower mandrel 17, the upper mandrel 1 is threadedly connected with the lower mandrel 17, and constitutes a mandrel system, the mandrel system is provided with a mandrel center hole 8 for installing a drill string, that is, the drill string is located in the mandrel center hole 8 and the mandrel system is fixed on the drill string, and the mandrel system rotates with the drill string.

[0034] In this embodiment, the outer side of the core shaft system is connected to the housing 3 via the bearing 2. Specifically, the upper core shaft 1 and the lower core shaft 17 are fixedly connected with the bearings 2, and the two bearings 2 are fixedly connected to the upper and lower parts of the housing 3.

[0035] An annulus 18 is formed between the shell 3 and the mandrel system. The shell 3 is provided with a plurality of pendulum cavities 11 arranged along its circumference. The upper part of the pendulum cavity 11 is provided with a pendulum cavity inlet hole 9 connected to the annulus 18. The upper mandrel 1 is provided with a pressure transmission inlet hole 10 connected to the mandrel middle hole 8. The pressure transmission inlet hole 10 is connected to the pendulum cavity inlet hole 9 through the annulus 18. A pendulum 4 mechanism is provided in the pendulum cavity 11. The pendulum 4 mechanism includes a pendulum 4 rotatably connected to the side wall of the pendulum cavity 11. The bottom of the pendulum 4 is fixedly connected to a slider 5. The slider 5 is slidably matched with the bottom of the pendulum cavity 11. A pendulum cavity outlet hole 12 is provided at the lower part of the pendulum cavity 11. The pendulum cavity outlet hole 12 is connected to the annulus 18. A pressure transmission outlet hole 15 is provided on the lower mandrel 17. The pressure transmission outlet hole 15 is connected to the annulus 18. The pressure transmission outlet hole 15 is connected to the pendulum cavity outlet hole 12 through the annulus 18.

[0036] The housing 3 is provided with a plurality of piston chambers 16 arranged along the circumference of the housing 3. The piston chambers 16 correspond to the pendulum chambers 11 one by one. A piston hole 13 is opened on the top wall of the piston chamber 16. The piston hole 13 is connected with the pendulum chamber 11. A one-way reflux hole 14 is provided on the upper side of the piston chamber 16 close to the annulus 18. A one-way valve 6 is installed in the one-way reflux hole 14. A piston 7 is provided in the piston chamber 16.

[0037] The present application provides an automatic skew correction method, comprising the following steps:

[0038] Step 1, assemble the above-mentioned automatic deflection correction device and connect its mandrel system to the drill string;

[0039] Step 2, the liquid in the drill string flows through the mandrel hole 8 of the mandrel system, the drill bit water hole, and enters the annulus 18. A pressure difference is formed between the mandrel hole 8 and the annulus 18; the pressure of the mandrel hole 8 passes through the pressure transmission hole 10, the pendulum chamber inlet hole 9, the pendulum chamber 11, the piston hole 13, and enters the piston chamber 16, pushing the piston 7, and the piston 7 extends and supports on the well wall 19;

[0040] Step 3, when well deviation occurs, the center line of the mandrel deviates from the vertical state and deviates in the well deviation direction. The pendulum 4 in the well deviation direction is close to the inner wall of the pendulum chamber 11 under the action of gravity and remains stationary. At this time, the pendulum chamber 11 is connected with the piston hole 13, and the piston hole 13 is connected with the piston chamber 16. The pressure in the piston chamber 16 continuously acts on the piston 7, and the piston 7 acts on the well wall 19, generating a force on the well wall 19.

[0041] The pendulum 4 in the opposite direction of the well inclination leaves the inner wall of the pendulum chamber 11 under the action of gravity and moves, driving the slider 5 at the lower end of the pendulum 4 to move, closing the piston hole 13, and the pendulum chamber 11 and the piston chamber 16 are not connected, and the pressure in the corresponding pendulum chamber 11 cannot be transmitted to the piston chamber 16;

[0042] After the well deviates, the gravity of the drill string has a gravity component in the vertical direction, which acts on the piston 7 in the opposite direction of the well deviate, so that the pressure in the piston chamber 16 rises, and the high-pressure liquid in the piston chamber 16 flows back to the core shaft middle hole 8 through the one-way return hole 14. At the same time, the piston 7 retracts into the piston chamber 16;

[0043] A new pressure balance is formed in the piston cavity 16 and the core shaft middle hole 8. The piston 7 in the well inclination direction extends out to support the well wall 19, and the piston 7 in the opposite well inclination direction retracts into the piston cavity 16. The center point of the core shaft system shifts to the opposite well inclination direction, forcing the drill bit to drill in the opposite direction of the well inclination to achieve deflection correction.

[0044] The pendulum 4 in the pendulum chamber 11 moves away from or close to the inner wall of the pendulum 4 as the well inclination changes, so that the piston hole 13 is in a closed or open state. The above actions are repeated to achieve the extension or retraction of the piston 7 in different directions into the piston chamber 16, so that the drill bit always maintains vertical drilling.

[0045] The specific implementation process is as follows:

[0046] During operation, the mandrel system rotates with the drill string, and the piston 7 on the housing 3 is supported on the well wall 19 and does not rotate with the drill string; the drilling fluid flows through the mandrel hole 8, the drill bit, and enters the annulus 18, and returns to the ground. The pressure P 内 and annulus 18 pressure P 外 The pressure difference ΔP is formed between them, ΔP=P 内 -P 外 .

[0047] This example uses four pendulums 4 (uniformly distributed at 90 degrees around the circumference) for explanation, corresponding to four pistons 7. Assume that the wellbore is vertical in the initial state, at which time the pendulum 4 is close to the inner wall of the pendulum chamber 11, and the pendulum chamber 11 is connected to the piston chamber 16 through the piston hole 13. The four pistons 7 are subjected to the pressure difference ΔP, and the four pistons 7 have the same extension degree, and all act on the wellbore wall 19. Figure 2 shown.

[0048] As attached Figure 3 When the wellbore is tilted, assuming the well inclination angle is C, four pistons 7 are numbered 7a, 7b, 7c, and 7d. Assuming the well inclination direction is direction A, piston 7b is in the well inclination direction, and piston 7a is in the opposite direction of the well inclination direction.

[0049] At this time, the pendulum 4 corresponding to the piston 7b is close to the inner wall of the pendulum chamber 11, and the pendulum chamber 11 is connected to the piston chamber 16 through the piston hole 13. Under the action of its own gravity, the pendulum 4 corresponding to the piston 7a leaves the inner wall of the pendulum chamber 11, causing displacement, driving the slider 5 under the pendulum 4 to move, closing the piston hole 13, and at this time, the pendulum chamber 11 and the piston chamber 16 are not connected.

[0050] Assume that the cross-sectional area of ​​the piston 7 near the piston chamber 16 is S 活塞 , then under the pressure difference ΔP, the force F acting on the piston 7 活塞 for:

[0051] F 活塞 =ΔP×S 活塞

[0052] When the wellbore is in a vertical state, the forces acting on the four pistons 7 are equal, all of which are F pistons, and the pressures in the four piston chambers are also P 内 .

[0053] When the well deflection in direction A occurs, connect the drill string gravity G (the weight of all drill strings below the centralizer 20) of this device, such as Figure 4 , there will be a component force G1 of the gravity G, which acts in the opposite direction of direction A, changing the balance of forces acting on different pistons 7. At this time, the gravity separation F acting on piston 7a 7a for:

[0054]

[0055] The force W acting on the piston 7a 7a , the pressure P in the piston chamber corresponding to piston 7a 7a They are:

[0056] W 7a =F 活塞 +F 7a , P 7a =P 内 +F 7a / S 活塞

[0057] The force W acting on piston 7b 7b , the pressure P in the piston chamber corresponding to piston 7b 7b They are:

[0058] W 7b =F 活塞 , P 7b =P 内 ,

[0059] P7a is greater than Pin, under the action of the pressure difference P7a-Pin, the one-way valve 6 opens, and the drilling fluid in the piston chamber 16 corresponding to the piston 7a flows back to the core shaft hole 8 through the one-way return hole 14, which drives the piston 7a to retract the corresponding piston chamber 16, and the center line of the drill string is offset. At this time, the piston hole 13 corresponding to the piston 7b is in an open state, and the pressure in the corresponding piston chamber 16 remains unchanged at Pin. Under the continuous action of the force W7b, the drill bit is forced to drill in the opposite direction of the well deviation, thereby reducing the well deviation.

[0060] This is a dynamic process. The pendulum 4 in the pendulum chamber 11 changes with the well inclination direction under the action of gravity, and the position state of the piston 7 at different positions changes (extends or retracts). Repeat the above operation principle (the specific calculation formula will be different depending on the position of the piston 7), and the piston 7 at different positions can be extended or retracted, so that the drill bit can always maintain vertical drilling.

[0061] In the description of this specification, the description with reference to the terms "preferred embodiment", "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0062] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An automatic deflection correction method, characterized in that: The steps include: Step 1, assemble the self-deflection correction device and connect its mandrel system to the drill string; the automatic deflection correction device includes an upper mandrel and a lower mandrel, the upper mandrel and the lower mandrel constitute the mandrel system, and the mandrel system is provided with a mandrel center hole for installing the drill string; The outer side of the mandrel system is connected with a housing through a bearing, an annulus is left between the housing and the mandrel system, and the center hole of the mandrel is connected with the annulus; The shell is provided with a plurality of pendulum cavities, which are connected with the central hole of the core shaft through an annulus, and a pendulum mechanism is arranged in the pendulum cavity; The shell is provided with a plurality of piston cavities corresponding to the pendulum cavities one by one, the piston cavity is connected with the central hole of the core shaft through a one-way valve and an annulus, the piston cavity is connected with the pendulum cavity, and a piston is arranged in the piston cavity; the upper core shaft is provided with a pressure transmission inlet hole connected with the annulus, and the lower core shaft is provided with a pressure transmission outlet hole connected with the annulus; the upper part of the pendulum cavity is provided with a pendulum cavity inlet hole connected with the annulus, and the lower part of the pendulum cavity is provided with a pendulum cavity outlet hole connected with the annulus; the pendulum mechanism includes a pendulum, which is rotatably connected to the shell, and a slider is fixedly connected to the bottom of the pendulum, and the slider is slidably matched with the bottom wall of the pendulum cavity; the upper part of the piston cavity is provided with a piston hole connected with the pendulum cavity, and a one-way reflux hole is provided on the side of the piston cavity close to the annulus, and a one-way valve connected with the annulus is fixedly connected in the one-way reflux hole; Step 2, the liquid in the drill string is transferred to the piston cavity through the mandrel center hole of the mandrel system and the pendulum cavity, and the piston cavity is extended out to support the well wall; Step 3, when well deviation occurs, the center line of the mandrel deviates from the vertical state and deviates in the well deviation direction. The pendulum in the well deviation direction is close to the inner wall of the pendulum cavity under the action of gravity and remains stationary; the pendulum in the opposite direction of the well deviation leaves the inner wall of the pendulum cavity under the action of gravity and moves, driving the slider at the lower end of the pendulum to move, closing the piston hole, and the pendulum cavity and the piston cavity are not connected, and the pressure in the corresponding pendulum cavity cannot be transmitted to the piston cavity; After the well deviates, the gravity of the drill string has a gravity component in the vertical direction, which acts on the piston in the opposite direction of the well deviate, so that the pressure in the piston cavity rises, and the higher pressure liquid in the piston cavity flows back to the center hole of the core shaft through the one-way return hole; at the same time, the piston retracts into the piston cavity; A new pressure balance is formed in the piston cavity and the center hole of the core shaft. The piston in the direction of the well inclination extends out to support the well wall, and the piston in the opposite direction of the well inclination retracts into the piston cavity. The center point of the core shaft system shifts to the opposite direction of the well inclination, forcing the drill bit to drill in the opposite direction of the well inclination to achieve deflection correction.

2. The automatic deflection correction method according to claim 1, characterized in that: A plurality of pendulum cavities and a plurality of piston cavities are evenly distributed along the circumference of the shell.

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