Intelligent Centralizer for Multi-Stage Diameter Reduction

Description

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Chinese Pat. Appl. No. 202411061597.0, filed Aug. 6, 2024, incorporated herein by reference in its entirety.

TECHNICAL FIELD

The invention relates to the technical field of oil and gas resource drilling tools, in particular to an intelligent centralizer for multi-stage diameter reduction.

BACKGROUND OF THE INVENTION

With the passage of time, developed oil fields enter a stage of high water cut and high production, and the output of main old oil fields decreases. It has been difficult for conventional oil field exploitation to meet social and environmental needs, and the development of unconventional oil exploitation technology has become extremely urgent. In order to solve this problem, improvements are needed in the key technology and management technology in the drilling process and drilling efficiency, so as to improve the efficiency and reduce the cost.

In the production process of oil and gas wells, a centralizer controls and adjusts borehole inclination. A conventional fixed stabilizer (e.g., for use in or with a conventional centralizer) can only be replaced during drilling. However, frequent drilling stops, starts and tool use easily cause scraping and piston withdrawal, which not only increases the soaking time of mud on the wall, but also reduces the drilling efficiency and even causes the complex situation of borehole instability, leading to well collapse and blowout. Therefore, in complex mining processes, a remote control variable diameter centralizer that can effectively avoid the risks of accidents is urgently needed.

SUMMARY OF THE INVENTION

The purpose of the invention is to provide an intelligent centralizer for multi-stage diameter reduction, which can adjust its outer diameter by remote control or underground automatic control. Through this adjustment, the purpose of controlling well inclination can be realized, making the drilling process safer and more stable.

In order to realize the purpose of the invention, the technical scheme adopted by the invention is that the intelligent centralizer for multi-stage diameter reduction comprises a control module, a motion execution module and a connecting module.

The control module may be located in a protective housing on the motor, and the control module comprises a microcontroller unit (MCU), a driver and a battery pack. The MCU may control a driver to rotate the motor (e.g., a DC motor) and turn an electromagnet on and off.

The motion execution module comprises a flow channel control execution unit, a stroke control execution unit and a piston extension execution unit.

The flow channel control execution unit comprises a controller, a shunt, a thrust ball bearing, an end cover, a drive shaft, a magnetic coupler, a motor protection shell (e.g., a lower motor protection shell), the motor, and a motor protection housing (e.g., an upper motor protection shell). The motor protection shell and the motor protection housing include 4 uniformly distributed fan cavities, through which the drilling fluid enters the controller. The motor protection shell and the motor protection housing are connected by a threaded connection. The motor is fixed in or on the motor protection housing by bolts (e.g., in the protective housing). The magnetic coupler and the drive shaft are connected by 4 groups of bolts (which may be circumferentially uniformly distributed around a central axis of the intelligent centralizer), the end cover and the controller are connected by 4 groups of bolts (which may also be circumferentially uniformly distributed around the central axis of the intelligent centralizer), the drive shaft is fixed in the controller, and the drive shaft includes first and second ends with a keyway. The drive shaft, the magnetic coupler and the controller realize circumferential transmission (e.g., are configured to transmit a circumferential force) using a key connection (which may include or involve one or more of the keyway and, optionally, corresponding key). The controller includes a lower shell with 3 radial flow channel holes (e.g., which may be distributed uniformly around a circumference of the controller and/or lower shell, and which may be near an end of the controller), the shunt includes 3 flow channel holes corresponding to the controller or one or more structures therein (such as the radial flow channel holes in the controller lower shell), and the shunt has a flow channel therein from radial to axial. The thrust ball bearing is between the controller and the shunt, and may be configured to reduce or eliminate direct friction between the controller and the shunt and/or reduce a driving torque of the motor. The intelligent centralizer further comprises an upper shell having a shoulder therein configured to position the thrust ball bearing axially.

The stroke control execution unit comprises a stroke controller, a reset spring and an electromagnet. The stroke controller includes three slots (which may be spiral and have a U shape) with different heights or lengths, and at least one of the slots has a circular hole (which may have a depth of 8 mm) at an upper end thereof.

The reset spring is on or at a lower end of the stroke controller, and each of the stroke controller and the lower shell have a shoulder configured to position the reset spring (10) axially.

When the stroke controller moves axially, the reset spring compresses or extends. The intelligent centralizer further comprises a screw push block and a lower shell. The screw push block is connected to the stroke controller by a threaded connection to realize synchronous rotation. The intelligent centralizer may comprise three of the electromagnets. The electromagnet includes a threaded external shell, and the lower shell includes a threaded hole in which the threaded external shell is fixed (e.g., through another threaded connection).

The piston extension execution unit may comprise the screw push block, a piston cover, a fixing bolt, a piston and a check valve. The screw push block includes a cylindrical cavity and an outer spline comprising (i) a first spiral spline section configured to coordinate with a spiral spline in the lower shell to realize spiral motion guidance of the screw push block, and (ii) a second spiral spline section with a variable thickness, in contact with the piston and configured to extend (and optionally retract) the piston. Each of the first spiral spline section and the second spiral spline section may have three circumferentially uniformly distributed sections.

The piston cover is helical and includes three uniformly distributed piston holes and eight counterweight threaded holes. The intelligent centralizer may comprise three piston covers, and the piston cover(s) may be uniformly distributed along the circumference (e.g., of the piston and/or the central axis). The piston has a cylindrical upper part, a cuboid lower part, and an inclined bottom having an inclination consistent with a slope of the outer spline of the screw push block (e.g., the second spiral spline section). The intelligent centralizer may comprise nine of the pistons, and the piston(s) (or the intelligent centralizer) may include a spring between the piston and the piston cover, configured to revert or retract the piston.

The intelligent centralizer may comprise three of the check valves, which may be evenly distributed along the circumference (e.g., of the intelligent centralizer, the screw push block, and/or the central axis). The check valve includes an external shell with a threaded connector, which is fixed in a threaded hole in the upper shell. When the intelligent centralizer includes multiple check valves, they may be evenly distributed along the circumference of the intelligent centralizer and/or the central axis.

The piston cover is fixed on the lower shell by fixing bolts (e.g., 24 fixing bolts).

The connecting module comprises an upper joint, the upper shell and the lower shell. The lower shell includes 3 first spiral grooves. Each first spiral groove includes 3 piston holes. The lower shell includes 3 second spiral grooves. The first and second spiral grooves may be evenly distributed along the circumference of the lower shell, the intelligent centralizer, and/or the central axis.

The intelligent centralizer further comprises an upper joint, connected to the upper shell by a conical threaded connection. The upper shell and the lower shell are connected by another conical threaded connection. Thus, the lower shell may comprise a first conical threaded connector, and the upper joint may comprise a second conical threaded connector.

In a further embodiment, the intelligent centralizer may further comprise sealing rings (e.g., O-rings) on or between the controller and the shunt, configured to prevent drilling fluid from penetrating into the thrust ball bearing, and optionally, affecting the life of the thrust ball bearing.

In a further embodiment, the electromagnet may be retracted or retractable when it is not powered on (i.e., off). When the electromagnet is powered on, the positioning pin may extend and move spirally with the stroke controller. After reaching a predetermined or corresponding position, the positioning pin may enter the round or circular hole in the corresponding slot in the stroke controller to achieve stroke positioning.

In a further embodiment, the motor may comprise a DC motor, and the motor may rotate to drive one or more flow channels in or of the controller and the shunt (e.g., to fluidly communicate the controller flow channel with the shunt flow channel). The drilling fluid (which may be at a high pressure) may enter or pass through the flow channel(s), push the screw push block downward and/or spirally, and extend or push the piston out. When the piston is retracted, the screw push block moves upward, and the drilling fluid in a cavity between the screw push block and the shunt is discharged (e.g., from the intelligent centralizer or a drilling tool including the intelligent centralizer) through the check valve, which may reduce compression and/or pressure of the drilling fluid (e.g., in the screw push block) and/or avoid or eliminate unresettability of the screw push block.

In a further embodiment, the slots in or of the screw push block, the outer spline of the stroke controller, and the spiral groove(s) in the lower shell may have a same or identical angle (e.g., spiral angle).

In a further embodiment, the reset spring may comprise a steel alloy, and a method of processing (e.g., processing the reset spring) may include a hot coil processing method.

Compared with the prior art, the invention has the following beneficial effects: (1) Compared with the applicable borehole diameter range of other variable diameter centralizers, the innovation of the invention lies in that centralizing and stabilizing functions at or under three different diameters can be realized through the coordination of the stroke controller and the electromagnet, and the application range is wider. (2) Between the screw push rod and the lower shell, a screw drive or similar device may be used to extend or push the piston out, which works stably during operation of intelligent centralizer, and has large carrying capacity. (3) The magnetic coupler realizes transmission between the motor and the controller, which solves the sealing problem of the motor and the control circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of an exemplary intelligent centralizer for multi-stage diameter reduction according to the invention;

FIG. 2 is a cross-sectional profile of the exemplary intelligent centralizer for multi-stage diameter reduction along the line A-A in FIG. 1 according to the invention;

FIG. 3 is a cross-sectional profile of the exemplary intelligent centralizer for multi-stage diameter reduction along the line B-B in FIG. 1 according to the invention;

FIG. 4 is an enlarged view of the exemplary intelligent centralizer for multi-stage diameter reduction in the circle C in FIG. 1 according to the invention;

FIG. 5 is a working principle diagram for the exemplary intelligent centralizer for multi-stage diameter reduction according to the invention;

FIG. 6 is a structural diagram of an exemplary screw push block for the exemplary intelligent centralizer for multi-stage diameter reduction according to the invention;

FIG. 7 is a structural diagram of an exemplary stroke controller for the exemplary intelligent centralizer for multi-stage diameter reduction according to the invention;

FIG. 8 is an expansion diagram of an exemplary CAM part in the exemplary stroke controller for the exemplary intelligent centralizer for multi-stage diameter reduction according to the invention.

FIG. 9 is an exemplary diagram of a circuit for positive and negative motor rotation for the intelligent centralizer for multi-stage diameter reduction.

FIG. 10 is an exemplary diagram of a circuit for controlling an electromagnet for the intelligent centralizer for multi-stage diameter reduction.

In the drawings, the same reference numerals are used for the same components to illustrate the principles of the present invention only, and are not drawn to actual scale.

Part names in the figures: 1. upper joint, 2. upper shell, 3. controller, 4. shunt or diverter, 5. screw push block, 6. lower shell, 7. piston cover, 8. fixing bolt, 9. stroke controller, 10. reset spring, 11. electromagnet, 12. piston, 13. check valve, 14. thrust ball bearing, 15. end cover, 16. drive shaft, 17. magnetic coupler, 18. (lower) motor protection shell, 19. motor, 20. motor protection housing or upper motor protection shell, 21. MCU, 22. battery pack, 1701. outer rotor, 1702. permanent magnet, 1703. inner rotor.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to FIG. 1, the invention provides an intelligent centralizer for multi-stage diameter reduction, which comprises a control module, a motion execution module and a connecting module.

The control module is in the motor protection housing 20. The control module comprises a microcontroller unit (MCU) 21 and a battery pack 22.

The motion execution module comprises a flow channel control execution unit, a stroke control execution unit and a piston extension execution unit.

The flow channel control execution unit comprises a controller 3, a shunt 4, a thrust ball bearing 14, an end cover 15, a drive shaft 16, a magnetic coupler 17, a lower motor protection shell 18, a motor 19, and an upper motor protection shell 20. The lower motor protection shell 18 and the upper motor protection shell 20 include 4 uniformly distributed fan cavities, through which the drilling fluid enters the controller 3. The lower motor protection shell 18 and the upper motor protection shell 20 are connected by a threaded connection (e.g., a screw fitting). The motor 19 is fixed in the motor protection housing 20 by bolts. The magnetic coupler 17 and the drive shaft 16 are connected by 4 first groups of circumferentially uniform bolts, and the end cover 15 and the controller 3 are connected by 4 second groups of circumferentially uniform bolts. The drive shaft 16 is fixed in the controller 3, and includes a keyway (not identified) at each of two opposite ends of the drive shaft 16. Circumferential transmission between the drive shaft 16, the magnetic coupler 17 and the controller 3 is realized through a key connection, which may include the keyway, and optionally, one or more keys (not shown). The controller 3 has a lower shell (not identified) that includes 3 circumferentially uniform radial flow channel holes (not shown) near an end thereof. The shunt 4 includes 3 flow channel holes (not shown) corresponding to the radial flow channel holes of the controller 3. The shunt 4 has a flow channel therein from radial to axial. The thrust ball bearing 14 is between the controller 3 and the shunt 4, and the upper shell 2 includes a shoulder therein (not identified) configured to axially position the thrust ball bearing 14 therein.

The stroke control execution unit comprises a stroke controller 9, a reset spring 10 and an electromagnet 11. The stroke controller 9 includes three spiral and/or U-shaped slots (not identified, but shown in FIG. 7) with different lengths or heights (see FIG. 8), and a circular hole which may have a depth of 8 mm is at an end of one or more of the spiral slots. Preferably, the circular hole is at an upper end of each of the spiral slots. The reset spring 10 is at a lower end of the stroke controller 9, and is positioned axially between a lowermost surface or shoulder of the stroke controller 9 and a shoulder or ledge on an inner surface of the lower shell 6. When the stroke controller 9 rotates or moves axially, the reset spring 10 compresses or extends. The screw push block 5 and the stroke controller 9 are connected by a threaded connection to enable synchronous rotation. The intelligent centralizer may include three electromagnets 11. The external shell of the electromagnet 11 is threaded, and is fixed in a corresponding threaded hole in the corresponding lower shell 6 (e.g., through a threaded or screw-type connection).

The piston extension execution unit comprises a screw push block 5, a piston cover 7, a fixing bolt 8, a piston 12 and a check valve 13. The spiral push block 5 has an inner cylindrical cavity (not identified in FIG. 1) and an outer spiral spline that may have two sections (see, e.g., FIG. 6). The first spiral spline section 510 may have 3 circumferentially and/or uniformly distributed teeth 515a-c that can coordinate with a spiral spline (not identified) in the lower shell 6 to realize spiral motion guidance of or from the spiral push block 5. The second spiral spline section 520 may have teeth 525a-c, each having 3 sections of variable thickness. The teeth 525a-c may be circumferentially and/or uniformly distributed, and may be in contact with one or more of the pistons 12 to extend the corresponding piston 12.

The piston covers 7 may be helical, and may comprise three uniformly distributed piston holes and eight counterweight thread holes. The intelligent centralizer may comprise three piston covers 7, and the piston covers 7 may be uniformly distributed along the circumference of the lower shell 6 and/or the intelligent centralizer. The pistons 12 may have a cylindrical section (or upper part) 121, a cuboid section (or lower part) 122, and an inclined surface (e.g., bottom, or lowermost or innermost surface) 123 (FIG. 3). The inclination of the inclined surface may be consistent with a slope of the second spiral spline section 520 (and, more specifically, the variable thickness sections of the teeth 525a-c) of the screw push block 5. Each piston 12 may further include a neck 124 between the cylindrical section 121 and the cuboid section 122. The intelligent centralizer may comprise nine pistons 12 and one or more springs 125 between each of the pistons 12 and the piston cover 7 to retract the pistons 12. Thus, intelligent centralizer may comprise nine or an integer multiple of nine springs 125, evenly distributed among the pistons 12.

The intelligent centralizer may comprise three check valves 13, evenly distributed along the circumference of the intelligent centralizer and/or the upper shell 2, and the check valves 13 may include an external shell with a threaded connector, which is fixed in a corresponding threaded hole in the upper shell 2 (e.g., through a threaded connection).

The piston covers 7 are fixed on the lower shell 6 by a corresponding fixing bolt 8. The intelligent centralizer may comprise 24 fixing bolts 8.

The connecting module comprises an upper joint 1, an upper shell 2 and a lower shell 6. The lower shell 6 may include 3 circumferentially uniform spiral grooves or openings (not identified). Each spiral groove or opening may include from 1 to 3 piston holes. The upper joint 1 and the upper shell 2 are connected through a conical threaded connection, and the upper shell 2 and the lower shell 6 are connected through another conical threaded connection.

In the embodiment shown in FIG. 1, the control module is located inside a motor protection housing 20, which has a good seal. The MCU 21 in the control module controls a driver (not identified) to rotate the motor 19 (which may be a DC motor) and turn the electromagnet on and off.

In the embodiment shown in FIG. 1, the motion execution module is a core module of the intelligent centralizer for multi-stage diameter reduction, and includes the flow channel control execution unit, the stroke control execution unit, and the piston extension execution unit. One function of the flow channel control execution unit is to engage the flow channel of the controller 3 and the shunt 4. During this function, the drilling fluid (which may be at a relatively high pressure) enters through the flow channel of the shunt 4, and pushes the spiral pushing block 5 to extend the piston 12 outward. One function of the stroke control execution unit is to control the extension of the positioning pin, which may slide into a round hole in a slot or spiral groove (e.g., in the screw push block 5 or the stroke controller 9). Different positioning pins may vary the angle and/or distance that the stroke controller 9 moves, and enable functionality of the centralizer at different diameters (e.g., of the centralizer, the lower shell 6 or a section thereof, etc.). One function of the piston extension execution unit is to control the extension of the piston 12. When the piston 12 retracts, the drilling fluid remains in the cavity in and along the shunt 4, the screw push block 5 and the lower shell 6. During this function, the drilling fluid can flow out through the check valve 13 to reduce the drilling fluid pressure (e.g., avoid the phenomenon of holding pressure) and allow the piston 12 to retract normally.

In the embodiment shown in FIG. 1, one function of the connecting module is to connect the whole tool (e.g., the centralizer) together within an outer shell, so that the functions of the control module and the motion execution module can be fully and accurately realized.

In the embodiment shown in FIG. 1, the reset spring 10 is configured to reset the screw push block 5. When openings (not identified) in the controller 3 and shunt 4 (e.g., for passage or flow of the drilling fluid) are staggered, the upper end of the screw push block 5 is not subjected to high pressure from the drilling fluid, and the screw push block 5 can be reset by the reset spring 10.

In the embodiment shown in FIG. 1, each piston cover 7 may include 8 sets of threaded holes, and the piston cover 7 is fixed to the lower shell 6 by screws or bolts 8, so that the piston 12 cannot be directly driven out of the lower housing 6 when an outward force is applied to the piston 12.

As shown in FIG. 3, one or more springs 125 are between the piston 12 and the piston cover 7. After the screw push block 5 is reset, the piston 12 will retract due to a force of the spring on the cuboid section 122 of the piston 12.

FIG. 5 shows a working principle of the intelligent centralizer for multi-stage diameter reduction. The selection of the centralizer may require diameter reduction. In the invention, the electronically controlled diameter reduction centralizer may be controlled remotely (e.g., on the surface of the ground). When electrified and/or activated, the electromagnet 11 is energized and may undergo a change (e.g., a reduction) in size. One such change in the size of the electromagnet 11 causes the motor 19 to drive the controller 3 to rotate 60° clockwise, which connects the flow channel(s) of the controller 3 and the shunt 4. The drilling fluid then enters the chamber (e.g., the inner cavity of the centralizer) and exerts pressure on the screw push block 5. The screw push block 5 moves helically, and the positioning pin (not identified) slides along the spiral slot or opening in the screw push block 5. When the positioning pin reaches the round hole at the end of the slot or opening (e.g., to achieve stroke control), the piston 12 extends to achieve diameter reduction (e.g., of the screw push block 5).

When operation of the electronically controlled diameter centralizer ends, first of all, the electromagnet 11 is powered off. The motor 19 then drives the controller 3 to rotate 60° counterclockwise, staggering the flow channels in the controller 3 and the shunt 4. During this operation, the screw push block 5 is no longer under a high pressure from the drilling fluid, so the screw push block 5 is reset by the reset spring 10. The positioning pin is also reset accordingly, and the pistons 12 are also reset by the spring(s) 125.