A pumping tool for a horizontal well

Abstract

The application relates to a pumping tool for a horizontal well, in particular to a pumping tool for a horizontal well, which comprises a cable, a centralizer, a magnetic positioner, a flexible connecting joint, a pressure relief valve, a power device and a setting ball which are sequentially connected; the power device comprises a thrust cylinder, one end of the thrust cylinder is provided with a containing groove in the center, a matching setting is arranged in the containing groove, and the other end of the thrust cylinder is provided with a stepped cavity in the center; the centralizer structure of the application is used for keeping the instrument centered and facilitating the working condition of the magnetic positioning assembly; the magnetic positioning assembly is used for providing the position information of the instrument at the well bottom, and the basic principle is to provide power according to the pressure difference formed by the gap flow. The main part of the power device is composed of soluble rubber and soluble metal. The size of the soluble metal is slightly smaller than that of the soluble rubber, so that the instrument can smoothly pass through the well hole under the condition of irregular protrusions.

Description

Technical Field

[0001] This invention relates to a delivery tool for downhole fracturing in oil horizontal wells, and more specifically to a pumping tool for horizontal wells. Background Technology

[0002] In recent years, typical wellbores in unconventional shale oil and gas reservoirs have been constructed by drilling long horizontal sections to a predetermined true vertical depth, followed by casing cementing and connection back to surface facilities along this transverse path. During the well completion phase, connectivity with the reservoir is established, particularly through perforation operations. Production is then enhanced by hydraulic fracturing of the well using fluids or fluid / proppant mixtures pumped from the surface, increasing reservoir contact area and creating pathways to facilitate hydrocarbon inflow into the wellbore. However, during hydraulic fracturing, the bridge plug ball-setting technique used in horizontal wells, due to gravity, cannot achieve a safe and stable setting effect.

[0003] In post-perforation fracturing, mechanical packer technology is now widely used. First, the packer is lowered to the designed position, and pressure is applied from inside the tubing to set the annular fracturing packer. Fracturing is then completed through the annulus. To release the packer, pressure is applied from the tubing to a certain level to shear the release pin, and the well-washing channel is opened simultaneously. After successful well-washing, the fracturing string is retrieved, and the process is repeated to achieve segmented perforation and pressure distribution. Field test results show that annular packer segmented fracturing technology has been successfully applied to shallow reservoirs and is relatively mature. However, further improvement and refinement are needed for its application in deep wells. Dual-packer single-clamp segmented fracturing technology is prone to packer jamming by sand, leading to downhole accidents. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a pumping tool for horizontal wells that features a simple structure, ensures safe and reliable setting, and avoids complex operations such as secondary retrieval.

[0005] The present invention provides a pumping tool for horizontal wells, comprising a cable, a centralizer, a magnetic positioner, a flexible connector, a pressure relief valve, a power unit, and a setting ball connected in sequence.

[0006] The power unit includes a thrust cylinder, a receiving groove is provided at the center of one end of the thrust cylinder, the matching is provided in the receiving groove, and a stepped cavity is provided at the center of the other end of the thrust cylinder. The central axis of the receiving groove and the cavity is on the same straight line as the central axis of the thrust cylinder, and the receiving groove and the cavity are connected by a connecting channel.

[0007] A central shaft is movably connected inside the cavity. One end of the central shaft extends out of the cavity away from the receiving groove, passes through the tailstock, and is threadedly connected to the setting ball. The end of the thrust cylinder away from the receiving groove extends into the tailstock and is threadedly connected to the tailstock.

[0008] A limiting groove is provided on the circumferential surface of the central shaft, and a limiting engaging device is provided on the tailstock. When the setting ball pushes the central shaft toward the receiving groove, and the limiting groove corresponds to the limiting engaging device, the limiting engaging device extends into the limiting groove.

[0009] It also includes a power unit, one end of which is sleeved on the circumferential surface of the thrust cylinder, and the other end of which is sleeved on the tailstock. One end of the power unit abuts against the locking nut threaded onto the thrust cylinder, and the other end abuts against the release switch provided on the tailstock. The release switch extends into the tailstock and is matched and connected to the central shaft. When the central shaft moves toward the end of the thrust cylinder that is provided with a receiving groove, the release switch retracts into the tailstock, releasing the power unit.

[0010] Preferably, the power unit includes a front end cover fitted onto the thrust cylinder and a rear end cover fitted onto the tailstock. Multiple rubber rings are fitted onto the thrust cylinder and tailstock between the front end cover and the rear end cover, and an annular partition fitted onto the thrust cylinder or tailstock is provided between adjacent rubber rings.

[0011] Preferably, on the axial section of the power unit, the end of the rubber ferrule is trapezoidal, and the end of the partition is an inverted trapezoid that matches the rubber ferrule.

[0012] Preferably, the limiting engagement device includes a check pin, the tailstock is provided with a check hole facing the central axis, the movable rod of the check pin is disposed in the check hole, one end abuts against the central axis, and the other end is connected to a screw plug through a check spring, the screw plug being threadedly connected to the check hole;

[0013] The central axis of the check hole, the central axis of the limiting groove, and the central axis of the central shaft are all located in the same plane.

[0014] The length of the check pin is greater than the depth of the limiting groove.

[0015] Preferably, two limiting grooves are arranged symmetrically about the central axis, and two check holes are also arranged symmetrically about the central axis.

[0016] Alternatively, preferably, the detachable switch includes a switch slot provided on the tailstock, a switch block is movably disposed in the switch slot, a switch limiting protrusion is provided on the switch block, a buckle plate is fixedly covered on the switch slot, a switch through hole is provided on the buckle plate for the switch limiting protrusion to extend out of the switch through hole, and the switch block is connected to the central shaft through a drive structure that drives the switch limiting protrusion to extend out of the switch through hole or retract into the switch through hole.

[0017] The front cover and the rear cover are located in the area between the locking nut and the switch limiting protrusion; when the switch limiting protrusion extends out of the switch through hole, the switch limiting protrusion abuts against the end of the rear cover away from the front cover.

[0018] Preferably, the drive structure includes a truncated cone on the central shaft, and the switch block is a wedge-shaped block that matches the truncated cone on the central shaft. The wedge block is connected to the buckle plate by a push spring. When the seat ball pushes the central shaft toward the receiving groove, the push spring pushes the switch block toward the center of the central shaft, and the switch limiting protrusion retracts into the switch through hole. When the central shaft moves toward the seat ball, the truncated cone on the central shaft pushes the switch block toward a direction away from the central shaft, and the switch limiting protrusion extends out of the switch through hole.

[0019] Preferably, there are two disconnect switches, which are arranged symmetrically about the central axis.

[0020] Preferably, a ring platform is also provided on the central shaft. The ring platform is located inside the cavity, and the side of the ring platform away from the receiving groove abuts against the end of the tailstock connected to the thrust cylinder. The ring platform is connected to the bottom of the cavity by a buffer spring sleeved on the central shaft.

[0021] The centralizer structure of this invention is designed to keep the instrument centered, facilitating the operation of the magnetic positioning component. The magnetic positioning component is designed to provide the instrument's position information at the bottom of the well. The flexible structure allows the instrument to release torque after encountering resistance downhole. The power unit provides power to the instrument during the downhole process; its basic principle is based on the pressure difference generated by the flow in the gaps. The main body of the power unit is constructed from a combination of soluble rubber and soluble metal. The size of the soluble metal is slightly smaller than that of the soluble rubber, facilitating the instrument's smooth passage through the wellbore even on irregular protrusions.

[0022] The setting ball of this invention is installed at the front end of the tool and can always be in a centered state to ensure the safety and reliability of the setting. After the setting is fracturing, if the power structure cannot be removed as a whole due to the obstruction of the fracturing sand, the power structure can be detached as a whole. Moreover, the power structure is made of soluble material, such as aluminum-magnesium alloy, to avoid complicated operations such as secondary salvage. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention.

[0024] Figure 2 This is a schematic diagram of the power unit structure.

[0025] Figure 3 This is a schematic diagram of the power unit structure after the seal is set.

[0026] Figure descriptions: 1-Cable, 2-Center, 3-Magnetic positioner, 4-Flexible connector, 5-Pressure relief valve, 6-Power unit, 7-Thrust cylinder, 8-Locking nut, 9-Front end cover, 10-Rubber sleeve, 11-Blocking plate, 12-Buffer spring, 13-Central shaft, 14-Switch block, 15-Push spring, 16-Snap plate, 17-Plug, 18-Check spring, 19-Check pin, 20-Tail seat, 21-Seating ball. Detailed Implementation

[0027] The present invention provides a pumping tool for horizontal wells, comprising a cable 1, a centralizer 2, a magnetic locator 3, a flexible connector 4, a pressure relief valve 5, a power unit 6, and a setting ball 216 connected in sequence.

[0028] The power unit 6 includes a thrust cylinder 7. A receiving groove is provided at the center of one end of the thrust cylinder 7. The matching is provided in the receiving groove. A stepped cavity is provided at the center of the other end of the thrust cylinder 7. The central axis 13 of the receiving groove and the cavity is on the same straight line as the central axis 13 of the thrust cylinder 7. The receiving groove and the cavity are connected by a connecting channel.

[0029] A central shaft 13 is movably connected inside the cavity. One end of the central shaft 13 extends out of the cavity away from the receiving groove, passes through the tailstock 20, and is threadedly connected to the seat ball 21. The end of the thrust cylinder 7 away from the receiving groove extends into the tailstock 20 and is threadedly connected to the tailstock 20.

[0030] A limiting groove is provided on the circumferential surface of the central shaft 13, and a limiting engaging device is provided on the tailstock 20. When the seat ball 21 pushes the central shaft 13 toward the receiving groove, and the limiting groove corresponds to the limiting engaging device, the limiting engaging device extends into the limiting groove.

[0031] It also includes a power unit 6, one end of which is sleeved on the circumferential surface of the thrust cylinder 7, and the other end of which is sleeved on the tailstock 20. One end of the power unit 6 abuts against the locking nut 8 threaded onto the thrust cylinder 7, and the other end abuts against the release switch provided on the tailstock 20. The release switch extends into the tailstock 20 and is matched and connected to the central shaft 13. When the central shaft 13 moves toward the end of the thrust cylinder 7 that is provided with a receiving groove, the release switch retracts into the tailstock 20, releasing the power unit 6.

[0032] The power unit 6 includes a front end cover 9 fitted onto the thrust cylinder 7 and a rear end cover fitted onto the tailstock 20. Multiple rubber rings 10 are fitted onto the thrust cylinder 7 and the tailstock 20 between the front end cover 9 and the rear end cover. An annular partition 11 fitted onto the thrust cylinder 7 or the tailstock 20 is provided between adjacent rubber rings 10.

[0033] On the axial section of the power unit 6, the end of the rubber ring 10 is trapezoidal, and the end of the partition plate 11 is an inverted trapezoid that matches the rubber ring 10.

[0034] The limiting engagement device includes a check pin 19. The tailstock 20 is provided with a check hole facing the central shaft 13. The movable rod of the check pin 19 is disposed in the check hole, with one end abutting against the central shaft 13 and the other end connected to a screw plug 17 via a check spring 18. The screw plug 17 is threadedly connected to the check hole.

[0035] The center axis 13 line of the check hole, the center axis 13 line of the limiting groove and the center axis 13 line of the center axis 13 are located in the same plane.

[0036] The length of the check pin 19 is greater than the depth of the limiting groove.

[0037] Two limiting grooves are arranged symmetrically about the central axis 13, and two check holes are also arranged symmetrically about the central axis 13.

[0038] The detachable switch includes a switch slot on the tailstock 20, a switch block 14 is movably disposed in the switch slot, a switch limiting protrusion is provided on the switch block 14, a buckle plate 16 is fixedly covered on the switch slot, and a switch through hole is provided on the buckle plate 16 for the switch limiting protrusion to extend out of the switch through hole. The switch block 14 is connected to the central shaft 13 through a drive structure that drives the switch limiting protrusion to extend out of the switch through hole or retract into the switch through hole.

[0039] The front cover 9 and the rear cover are located in the area between the locking nut 8 and the switch limiting protrusion; when the switch limiting protrusion extends out of the switch through hole, the switch limiting protrusion abuts against the end of the rear cover away from the front cover 9.

[0040] The drive structure includes a truncated cone on the central shaft 13. The switch block 14 is a wedge-shaped block that matches the truncated cone on the central shaft 13. The wedge block is connected to the buckle plate 16 by a push spring 15. When the seat ball 21 pushes the central shaft 13 toward the receiving groove, the push spring 15 pushes the switch block 14 toward the center of the central shaft 13, and the switch limiting protrusion retracts into the switch through hole. When the central shaft 13 moves toward the seat ball 21, the truncated cone on the central shaft 13 pushes the switch block 14 toward a direction away from the central shaft 13, and the switch limiting protrusion extends out of the switch through hole.

[0041] Two disconnect switches are provided, and the two disconnect switches are arranged symmetrically about the central axis 13.

[0042] A ring platform is also provided on the central shaft 13. The ring platform is located in the cavity, and the side of the ring platform away from the receiving groove abuts against the end of the tailstock 20 connected to the thrust cylinder 7. The ring platform is connected to the bottom of the cavity by a buffer spring 12 sleeved on the central shaft 13.

[0043] In use, cable 1 is connected to the invention via the retrieval head. The retrieval head prevents the instrument from falling into the well when cable 1 breaks. The centralizer 2 ensures that the front half of the tool is centered. The magnetic locator 3 can determine the position of the tool in real time. The flexible connection structure can prevent the torque generated by the power unit 6 encountering resistance from damaging the invention. The pressure relief valve 5 protects the structure of the invention by timely pressure relief when the surface pumping pressure increases suddenly. The power unit 6 is the component of the invention that generates power from the surface pumping fluid. The power structure is made of soluble materials, such as aluminum-magnesium alloy, to avoid complex operations such as secondary retrieval. The setting ball 21 is a soluble metal part for setting, such as aluminum-magnesium alloy.

[0044] When liquid is pumped from the ground, a gap exists between the rubber sleeve 10 and the sleeve, causing gap flow and generating power. When the invention reaches the bridge plug position, the front bridge plug obstructs the flow, causing the central shaft 13 and the setting ball 21 to overcome the elastic force of the buffer spring 12 and retract, as... Figure 2 As shown, due to the retraction of the central shaft 13, the switch block 14 is pushed by the elastic force of the spring 15 and retracts towards the center of the central shaft 13. At the same time, the spring force of the check pin 19, which prevents the return spring, falls into the limiting groove of the central shaft 13, thereby preventing the central shaft 13 from rebounding and ensuring that the switch block 14 will not pop out. After the downhole fracturing operation is completed, if there are objects such as sand on the power unit 6 that obstruct the lifting of the tool, the rubber sleeve 10 and other components will be stuck at the setting ball 21. If the obstruction is severe, the tension of the cable 1 can break the central shaft 13, and the rubber sleeve 10, setting ball 21 and other components will fall to the bottom of the well. The main body of the invention will then be lifted to the surface, completing the operation.

Claims

1. A pumping tool for a horizontal well, comprising a cable, a centralizer, a magnetic positioner, a flexible connector, a pressure relief valve, a power unit, and a setting ball connected in sequence; Its features are, The power unit includes a thrust cylinder, a receiving groove is provided at the center of one end of the thrust cylinder, the pressure relief valve is matched and installed in the receiving groove, and a stepped cavity is provided at the center of the other end of the thrust cylinder. The central axis of the receiving groove and the stepped cavity is on the same straight line as the central axis of the thrust cylinder. The receiving groove and the stepped cavity are connected by a connecting channel. A central shaft is movably connected inside the stepped cavity. One end of the central shaft extends from the end of the stepped cavity away from the receiving groove, passes through the tailstock, and is threadedly connected to the setting ball. The end of the thrust cylinder away from the receiving groove extends into the tailstock and is threadedly connected to the tailstock. A limiting groove is provided on the circumferential surface of the central shaft, and a limiting engaging device is provided on the tailstock. When the setting ball pushes the central shaft toward the receiving groove, and the limiting groove corresponds to the limiting engaging device, the limiting engaging device extends into the limiting groove. One end of the power unit is sleeved on the circumference of the thrust cylinder, and the other end of the power unit is sleeved on the tailstock. One end of the power unit abuts against the locking nut threaded onto the thrust cylinder, and the other end abuts against the release switch set on the tailstock. The release switch extends into the tailstock and is matched and connected to the central shaft. When the central shaft moves toward the end of the thrust cylinder with the receiving groove, the release switch retracts into the tailstock and releases the power unit.

2. The pumping tool for horizontal wells as described in claim 1, characterized in that, The power unit includes a front end cover fitted onto the thrust cylinder and a rear end cover fitted onto the tailstock. Multiple rubber rings are fitted onto the thrust cylinder and tailstock between the front end cover and the rear end cover. An annular partition plate fitted onto the thrust cylinder or tailstock is provided between adjacent rubber rings.

3. The pumping tool for horizontal wells as described in claim 2, characterized in that, On the axial section of the power unit, the end of the rubber ferrule is trapezoidal, and the end of the partition plate is an inverted trapezoid that matches the rubber ferrule.

4. A pumping tool for horizontal wells as described in claim 2, characterized in that, The limiting engagement device includes a check pin, and the tailstock is provided with a check hole facing the central axis. The movable rod of the check pin is disposed in the check hole, with one end abutting against the central axis and the other end connected to a screw plug through a check spring. The screw plug is threadedly connected to the check hole. The central axis of the check hole, the central axis of the limiting groove, and the central axis of the central shaft are all located in the same plane. The length of the check pin is greater than the depth of the limiting groove.

5. A pumping tool for horizontal wells as described in claim 4, characterized in that, Two limiting grooves are arranged symmetrically about the central axis, and two check holes are also arranged symmetrically about the central axis.

6. A pumping tool for horizontal wells as described in any one of claims 1-5, characterized in that, The detachment switch includes a switch slot on the tailstock, a switch block is movably disposed in the switch slot, a switch limiting protrusion is provided on the switch block, a buckle plate is fixedly covered on the switch slot, and a switch through hole is provided on the buckle plate for the switch limiting protrusion to extend out of the switch through hole. The switch block is connected to the central shaft through a drive structure that drives the switch limiting protrusion to extend out of the switch through hole or retract into the switch through hole. The front cover and the rear cover are located in the area between the locking nut and the switch limiting protrusion; when the switch limiting protrusion extends out of the switch through hole, the switch limiting protrusion abuts against the end of the rear cover away from the front cover.

7. A pumping tool for horizontal wells as described in claim 6, characterized in that, The drive structure includes a truncated cone on the central shaft, and the switch block is a wedge-shaped block that matches the truncated cone on the central shaft. The wedge block is connected to the buckle plate by a push spring. When the seat ball pushes the central shaft toward the receiving groove, the push spring pushes the switch block toward the center of the central shaft, and the switch limiting protrusion retracts into the switch through hole. When the central shaft moves toward the seat ball, the truncated cone on the central shaft pushes the switch block toward a direction away from the central shaft, and the switch limiting protrusion extends out of the switch through hole.

8. A pumping tool for horizontal wells as described in claim 7, characterized in that, The disconnect switch is configured as two switches, which are arranged symmetrically about the central axis.

9. A pumping tool for horizontal wells as described in claim 8, characterized in that, A ring platform is also provided on the central shaft. The ring platform is located in the stepped cavity, and the side of the ring platform away from the receiving groove abuts against the end of the tailstock connected to the thrust cylinder. The ring platform is connected to the bottom of the stepped cavity by a buffer spring sleeved on the central shaft.

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