Segmented submersible screw pump device

Abstract

The utility model discloses a segmented submersible screw pump device, and relates to the technical field of submersible screw pumps, a fixing unit comprises a fixing cylinder and a submersible motor assembly, the fixing cylinder is installed in a sleeve at the bottom of a well, the upper end of the fixing cylinder is connected with a wellhead Christmas tree through an oil string, and a plurality of radial protrusions are evenly distributed on the inner wall of the fixing cylinder; the submersible motor assembly is fixedly connected with the lower end of the fixed cylinder, and an output shaft of the submersible motor assembly extends upwards into the fixed cylinder; the throwing-fishing unit comprises an inserting pipe, a flexible shaft, a screw pump and a packer, a plurality of radial grooves matched with the radial protrusions are evenly distributed in the lower end of the outer wall of the inserting pipe, a middle shaft is rotationally installed at the bottom of the inserting pipe, and a spline housing is arranged at the lower end of the middle shaft; the lower end of the flexible shaft is connected with the upper end of the intermediate shaft; the lower end of a rotor of the screw pump is fixedly connected with the upper end of a flexible shaft; under the condition that the submersible motor assembly works normally, maintenance and replacement can be achieved only by pulling out the stator and the rotor of the screw pump, and the workload is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of submersible screw pumps, and in particular to a segmented submersible screw pump device. Background Art

[0002] As a new type of rodless pump oil production technology, the submersible screw pump integrates the technical advantages of low power consumption, high pump efficiency, and convenient management. It is suitable for wells with complex working conditions such as cluster wells, heavy oil wells, and oil accumulation wells in the well cluster field platform, and can effectively reduce the operating costs of oil wells. With the continuous development of submersible screw pump oil production technology, the application scope of submersible electric pumps has been continuously expanded. The submersible motor and screw pump of the traditional submersible screw pump are fixedly connected to the bottom of the oil pipe, and the submersible cable is installed on the outside of the oil pipe string through the cable clamp.

[0003] However, for oil wells with high gas content and low permeability, the continuous suction of the screw pump can easily cause the centrifugal pump to be submerged too low and the pumping to stop, resulting in the screw pump failing to pump static liquid and causing the submersible motor to shut down due to underload. At the same time, the effective service life of the submersible screw pump stator and screw pump rotor is short and they need to be replaced regularly. The submersible motor components and submersible cables that have no problems need to be lifted out of the oil well together with the screw pump stator and rotor, which can easily cause damage during operation and result in a large workload.

[0004] When the screw pump fails, the submersible motor and screw pump need to be removed for repair and replacement. Since the single-section connected oil pipes need to be disassembled one by one, the submersible cable needs to be coiled, and the cable clips need to be removed, the workload of pump installation and pump lifting and maintenance of the submersible electric pump unit is large and the work speed is slow. The workers' work intensity is high and there are safety hazards. Taking a 3,000-meter submersible screw pump oil well as an example, the pump installation operation requires a 5-person team to work for 6 days to complete, and it is necessary to configure workover rigs, winches, hydraulic pipe clamps and other operating equipment.

[0005] In addition, the submersible cable is easily damaged during the process of being fixed and removed by cable clips outside the oil pipe, and the cable is scratched by the wellhead during the lowering of the oil pipe. The entire cable may be scrapped at one time, resulting in a loss of tens of thousands of yuan.

[0006] Therefore, there are currently problems such as the effective service life of the screw pump stator and screw pump rotor of the submersible screw pump device is short and needs to be replaced regularly, the submersible motor assembly and submersible cable need to be lifted out of the oil well together with the screw pump stator and rotor, which can easily cause damage during operation and the workload is large. Summary of the invention

[0007] The purpose of the present invention is to provide a segmented submersible screw pump device to address the defects of the prior art.

[0008] The technical solution of the present invention is: a segmented submersible screw pump device, comprising a fixing unit fixed in a casing and a catching unit that can be scooped from a wellhead;

[0009] The fixing unit comprises a fixing barrel and a submersible motor assembly. The fixing barrel is installed in the casing at the bottom of the well through an anchoring slip, and its upper end is connected to the wellhead Christmas tree through an oil pipe string, and a plurality of radial protrusions are evenly distributed on its inner wall in a circumferential manner; the submersible motor assembly is fixedly connected to the lower end of the fixing barrel, and its output shaft extends upward into the fixing barrel, and the upper end of the submersible cable electrically connected to the submersible motor assembly passes through the wellhead Christmas tree and is connected to the ground power supply;

[0010] The salvaging unit includes a plug-in tube, a flexible shaft, a screw pump and a packer. The lower end of the outer wall of the plug-in tube is circumferentially evenly distributed with a plurality of radial grooves adapted to the radial protrusions. The radial grooves are plug-fitted with the radial protrusions of the fixed tube so that the plug-in tube is circumferentially fixed relative to the fixed tube. An axially fixed and freely rotatable intermediate shaft is provided at the center of the bottom of the plug-in tube. The intermediate shaft passes through the plug-in tube, and a spline sleeve for connecting the output shaft of the submersible motor assembly is provided at the lower end of the intermediate shaft; the flexible shaft is located in the plug-in tube, and the lower end of the intermediate shaft is fixedly connected to the upper end of the intermediate shaft; the lower end of the screw pump stator is fixedly connected to the upper end of the plug-in tube, and the lower end of the screw pump rotor is fixedly connected to the upper end of the flexible shaft; the packer is installed on the outside of the screw pump stator to seal the annulus between the stator and the oil pipe string.

[0011] Preferably, a plurality of radial through holes are provided on the wall of the fixed cylinder, the radial protrusion is an inner support plate, and a bevel is provided on the upper end of the inner support plate.

[0012] Preferably, a plurality of radial through holes are provided on the wall of the plug-in tube, and an inner bevel adapted to the bevel of the inner support plate is provided at the inner lower end of the radial groove.

[0013] Preferably, the submersible motor assembly comprises a plurality of detachable plug-in motor sections, an electrical plug female head is provided at the bottom of the adjacent upper motor sections, and an electrical plug sub-head which is plugged into and cooperates with the electrical plug female head is provided at the top of the lower motor section; the submersible cable is connected to the lowermost motor section, and the motor shafts of the motor sections are connected by plug-in splines.

[0014] Preferably, the submersible motor assembly includes a submersible motor and a reducer, the input shaft of the reducer is connected to the motor shaft of the submersible motor, the output shaft of the reducer extends into the fixed cylinder and is connected to the spline sleeve of the intermediate shaft; the lower end of the spline sleeve is provided with a trumpet-shaped guide opening.

[0015] Preferably, the submersible motor assembly includes a submersible motor and a protector, the input shaft of the protector is connected to the motor shaft of the submersible motor, and the output shaft of the protector extends into the fixed cylinder and is connected to the spline sleeve of the intermediate shaft.

[0016] Preferably, the upper end of the screw pump stator is connected to a discharge pipe connected to the screw pump, the wall of the discharge pipe is provided with radial through holes, the upper end of the discharge pipe is sealed and connected to a salvaging operation rope; the upper end of the salvaging operation rope extends to the outside of the wellhead Christmas tree and is fixed.

[0017] Preferably, a detachable flange plate is provided above the wellhead Christmas tree, and the salvaging operation steel rope is fixed to the flange plate by a rope clamp.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The submersible motor assembly of the device is fixedly installed at the lower end of the oil pipe string by a fixing barrel, while the screw pump stator and the screw pump rotor are detachably installed in the oil pipe, and the screw pump stator and the rotor can be timely pulled out for maintenance and replacement by casting and fishing operation steel ropes; by arranging a plug-in component at the front end of the screw pump rotor, a quick and stable connection between the screw pump rotor and the output shaft of the submersible motor assembly is achieved, and by arranging a plug-in structure of the fixing barrel and the plug-in tube, the circumferential fixation of the screw pump stator can be achieved, and by arranging a packer, the annulus between the screw pump stator and the oil pipe string can be sealed; when the submersible motor assembly is in normal working condition, only the screw pump stator and the rotor need to be pulled out for maintenance and replacement, which reduces the workload, saves the unnecessary lifting of the submersible motor assembly and the submersible cable out of the oil well, and avoids the damage of the submersible motor assembly and the submersible cable due to the lifting of the oil well. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of the overall structure of the present invention;

[0021] Figure 2 is a structural schematic diagram of a fixed unit;

[0022] Figure 3 It is a structural schematic diagram of a fixed cylinder;

[0023] Figure 4 It is a structural schematic diagram of the casting and catching unit;

[0024] Figure 5 It is a schematic diagram of the structure of the plug-in tube and the flexible shaft.

[0025] In the figure: 1, wellhead Christmas tree, 2, tubing string, 3, casing, 4, fixing tube, 5, inner support plate, 501, bevel, 6, submersible motor assembly, 7, submersible cable, 8, plug-in tube, 801, radial groove, 802, inner bevel, 9, flexible shaft, 10, intermediate shaft, 11, spline sleeve, 1101, guide opening, 12, stator, 13, rotor, 14, packer, 15, discharge pipe, 16, salvage operation rope, 17, flange plate, 18, rope clamp. DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to the accompanying drawings and embodiments. Embodiment 1

[0027] Reference Figure 1-5 As shown, a segmented submersible screw pump device includes a fixing unit fixed in a casing 3 and a fishing unit that can be fished out from a wellhead;

[0028] The fixing unit includes a fixing barrel 4 and a submersible motor assembly 6. The fixing barrel 4 is installed in the casing 3 at the bottom of the well through an anchoring slip, and its upper end is connected to the wellhead oil production tree 1 through the oil pipe string 2, and a plurality of radial protrusions are evenly distributed on its inner wall in a circumferential manner; the submersible motor assembly 6 is fixedly connected to the lower end of the fixing barrel 4, and its output shaft extends upward into the fixing barrel 4. The upper end of the submersible cable 7 electrically connected to the submersible motor assembly 6 passes through the wellhead oil production tree 1 and is connected to the ground power supply.

[0029] The salvaging unit includes a plug-in tube 8, a flexible shaft 9, a screw pump and a packer 14. The lower end of the outer wall of the plug-in tube 8 is circumferentially evenly distributed with a plurality of radial grooves 801 adapted to the radial protrusions. The radial grooves 801 are plugged into and matched with the radial protrusions of the fixed tube 4 so that the plug-in tube 8 is circumferentially fixed relative to the fixed tube 4. An axially fixed and freely rotatable intermediate shaft 10 is provided at the bottom center of the plug-in tube 8. The intermediate shaft 10 passes through the plug-in tube 8, and a spline sleeve 11 for connecting the output shaft of the submersible motor assembly 6 is provided at its lower end; the flexible shaft 9 is located in the plug-in tube 8, and its lower end is fixedly connected to the upper end of the intermediate shaft 10; the lower end of the screw pump stator 12 is fixedly connected to the upper end of the plug-in tube 8, and the lower end of the screw pump rotor 13 is fixedly connected to the upper end of the flexible shaft 9; the packer 14 is installed on the outside of the screw pump stator 12, and is used to seal the annulus between the stator 12 and the oil pipe string 2.

[0030] In more detail, the wall of the fixed tube 4 is provided with a plurality of radial through holes, the radial protrusion is the inner support plate 5, and the upper end of the inner support plate 5 is provided with a bevel 501. The wall of the plug-in tube 8 is provided with a plurality of radial through holes, and the inner lower end of the radial groove 801 is provided with an inner bevel 802 adapted to the bevel 501 of the inner support plate 5.

[0031] In addition, the upper end of the screw pump stator 12 is connected to a discharge pipe 15 connected to the screw pump. The wall of the discharge pipe 15 is provided with radial through holes. The upper end of the discharge pipe 15 is sealed and connected to a salvage operation rope 16. The upper end of the salvage operation rope 16 extends to the outside of the wellhead Christmas tree 1 and is fixed. A detachable flange plate 17 is provided above the wellhead Christmas tree 1, and the salvage operation rope 16 is fixed to the flange plate 17 through a rope clamp 18.

[0032] The downhole operation method of the device comprises the following steps:

[0033] S1. Connect the fixed tube 4 and the submersible motor assembly 6 to the lower end of the tubing string 2 and lower it into the well. After it is in place, the fixed tube 4 is installed in the casing 3 at the bottom of the well by anchoring the slips.

[0034] S2. Assemble the salvage unit: install the screw pump rotor 13 in the stator 12, connect the screw pump rotor 13 to the flexible shaft 9, connect the discharge pipe 15, the screw pump stator 12 and the plug pipe 8 in sequence from top to bottom, and install the packer 14 on the outside of the screw pump stator 12;

[0035] S3. Connect the salvage operation wire rope 16 to the upper end of the discharge pipe 15, and lower the salvage unit through the salvage operation wire rope 16, so that the radial groove 801 at the lower end of the plug tube 8 is plugged with the radial protrusion of the fixed tube 4 to achieve circumferential fixation of the screw pump stator 12, and at the same time, the spline sleeve 11 of the intermediate shaft 10 is plugged with the output shaft of the submersible motor assembly 6;

[0036] S4. Start the packer 14 so that the packer 14 is set to seal the annulus between the oil string 2 and the screw pump stator 12, and finally connect the submersible cable 7 to the ground power supply.

[0037] The submersible motor assembly 6 of the device is fixedly installed at the lower end of the oil pipe string 2 through the fixing tube 4, while the screw pump stator 12 and the screw pump rotor 13 are detachably installed in the oil pipe, and the screw pump stator 12 and the rotor 13 can be timely brought out for maintenance and replacement by throwing and fishing the steel rope 16; by arranging a plug-in component at the front end of the screw pump rotor 13, the screw pump rotor 13 can be quickly and stably connected with the output shaft of the submersible motor assembly 6, the circumferential fixation of the screw pump stator 12 can be achieved by setting the plug-in structure of the fixing tube 4 and the plug-in tube 8, and the annulus between the screw pump stator 12 and the oil pipe string 2 can be sealed by setting the packer 14; when the submersible motor assembly 6 is in normal working condition, it is only necessary to pull out the screw pump stator 12 and the rotor 13 to achieve maintenance and replacement, which reduces the workload, saves the unnecessary lifting of the submersible motor assembly 6 and the submersible cable 7 from the oil well, and avoids the damage of the submersible motor assembly 6 and the submersible cable 7 caused by the lifting of the oil well. Embodiment 2

[0038] The submersible motor assembly 6 of the present embodiment includes a plurality of detachable plug-in motor sections, an electrical plug female head is provided at the bottom of the adjacent upper motor sections, and an electrical plug sub-head which is plugged into and cooperates with the electrical plug female head is provided at the top of the lower motor section; the submersible cable 7 is connected to the lowermost motor section, and the lowermost motor section is installed in the casing 3 at the bottom of the well by means of its own anchoring cava; the motor shafts of the motor sections are connected by plug-in splines, and the motor sections can be lowered, increased or reduced as required without having to pull out the submersible cable 7, which is not only convenient for adjustment but also beneficial for the protection of the submersible cable 7. Embodiment 3

[0039] The submersible motor assembly 6 of the present embodiment includes a submersible motor and a reducer, the input shaft of the reducer is connected to the motor shaft of the submersible motor, the output shaft of the reducer extends into the fixed cylinder 4 and is connected to the spline sleeve 11 of the intermediate shaft 10; in order to facilitate docking with the output shaft of the reducer, a trumpet-shaped guide opening 1101 is provided at the lower end of the spline sleeve 11. Embodiment 4

[0040] The submersible motor assembly 6 of the present embodiment includes a submersible motor and a protector, the input shaft of the protector is connected to the motor shaft of the submersible motor, and the output shaft of the protector extends into the fixed tube 4 and is connected to the spline sleeve 11 of the intermediate shaft 10.

[0041] The present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention. The changed contents still fall within the protection scope of the present invention.

Claims

1. A segmented submersible screw pump device, characterized in that: It includes a fixing unit fixed in the casing and a fishing unit that can be fished out from the wellhead; The fixing unit comprises a fixing barrel and a submersible motor assembly. The fixing barrel is installed in the casing at the bottom of the well through an anchoring slip, and its upper end is connected to the wellhead Christmas tree through an oil pipe string, and a plurality of radial protrusions are evenly distributed on its inner wall in a circumferential manner; the submersible motor assembly is fixedly connected to the lower end of the fixing barrel, and its output shaft extends upward into the fixing barrel, and the upper end of the submersible cable electrically connected to the submersible motor assembly passes through the wellhead Christmas tree and is connected to the ground power supply; The salvaging unit includes a plug-in tube, a flexible shaft, a screw pump and a packer. The lower end of the outer wall of the plug-in tube is circumferentially evenly distributed with a plurality of radial grooves adapted to the radial protrusions. The radial grooves are plug-fitted with the radial protrusions of the fixed tube so that the plug-in tube is circumferentially fixed relative to the fixed tube. An axially fixed and freely rotatable intermediate shaft is provided at the center of the bottom of the plug-in tube. The intermediate shaft passes through the plug-in tube, and a spline sleeve for connecting the output shaft of the submersible motor assembly is provided at the lower end of the intermediate shaft; the flexible shaft is located in the plug-in tube, and the lower end of the intermediate shaft is fixedly connected to the upper end of the intermediate shaft; the lower end of the screw pump stator is fixedly connected to the upper end of the plug-in tube, and the lower end of the screw pump rotor is fixedly connected to the upper end of the flexible shaft; the packer is installed on the outside of the screw pump stator to seal the annulus between the stator and the oil pipe string.

2. A segmented submersible screw pump device according to claim 1, characterized in that: The wall of the fixed cylinder is provided with a plurality of radial through holes, the radial protrusion is an inner support plate, and the upper end of the inner support plate is provided with a bevel.

3. A segmented submersible screw pump device according to claim 2, characterized in that: A plurality of radial through holes are arranged on the wall of the plug-in tube, and an inner bevel which matches the bevel of the inner support plate is arranged at the inner lower end of the inner side of the radial groove.

4. A segmented submersible screw pump device according to claim 1, characterized in that: The submersible motor assembly includes a plurality of detachable plug-in motor sections, wherein an electrical plug female head is arranged at the bottom of the adjacent upper motor sections, and an electrical plug sub-head which is plugged into and cooperates with the electrical plug female head is arranged at the top of the lower motor section; the submersible cable is connected to the lowermost motor section, and the motor shafts of the motor sections are connected by plug-in splines.

5. A segmented submersible screw pump device according to claim 1, characterized in that: The submersible motor assembly includes a submersible motor and a reducer, wherein the input shaft of the reducer is connected to the motor shaft of the submersible motor, and the output shaft of the reducer extends into a fixed cylinder and is connected to the spline sleeve of the intermediate shaft; a bell-shaped guide opening is provided at the lower end of the spline sleeve.

6. A segmented submersible screw pump device according to claim 1, characterized in that: The submersible motor assembly comprises a submersible motor and a protector, wherein the input shaft of the protector is connected to the motor shaft of the submersible motor, and the output shaft of the protector extends into a fixed cylinder and is connected to the spline sleeve of the intermediate shaft.

7. A segmented submersible screw pump device according to claim 1, characterized in that: The upper end of the screw pump stator is connected to a discharge pipe connected to the screw pump. The pipe wall of the discharge pipe is provided with radial through holes. The upper end of the discharge pipe is sealed and connected to a salvaging operation rope. The upper end of the salvaging operation rope extends to the outside of the wellhead Christmas tree and is fixed.

8. A segmented submersible screw pump device according to claim 7, characterized in that: A detachable flange plate is arranged above the wellhead Christmas tree, and the salvaging operation steel rope is fixed on the flange plate through a rope clamp.

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