Hollow motor ball screw electric submersible pump and control method

Abstract

The invention belongs to the technical field of oil and gas exploitation and pressurized transportation, and discloses a hollow motor ball screw electric submersible pump and a control method. The electric pump is characterized in that a pump cylinder upper end cover is communicated with an oil pipe through a formed through hole and is connected to the upper part of a motor integrated pump cylinder through a bolt; a through hole is formed in an annular area of the motor integrated pump cylinder to serve as a liquid inlet, a hollow area in the motor integrated pump cylinder serves as a reciprocating motion working cavity of a lead screw end piston, the lower end of the motor integrated pump cylinder serves as a motor mounting base, and a hollow motor composed of a motor rotor and a motor stator is mounted at the lower end of the motor integrated pump cylinder. A lead screw is installed in the motor integrated pump cylinder in a centering mode, and the lead screw and a lead screw nut installed on the lower end cover of the pump cylinder are in threaded meshing transmission to complete linear reciprocating motion. The structure is compact, and the space utilization rate is high; the hollow motor outputs through a hole, so that the operation efficiency is improved, and higher displacement and lift can be provided; and vibration is reduced, so that equipment runs stably.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploitation and pressurized transportation, and in particular relates to a hollow motor ball screw submersible electric pump and a control method thereof. Background Art

[0002] Traditional rod pumping systems use a surface drive to reciprocate the sucker rod, which in turn drives the plunger in the downhole pump barrel to lift the oil. While this technology is mature and widely used, it suffers from significant issues: Because the sucker rod is often several thousand meters long, significant friction and elastic deformation occur during its movement, resulting in low energy transfer efficiency and high energy consumption. In deviated and horizontal wells, or in wells with high sand content or high viscosity, the sucker rod is prone to eccentric wear and sticking, impacting system reliability and service life. The surface drive and sucker rod require significant space, increasing the complexity and cost of surface oilfield facilities. Submersible electric pumps (SEPs) are oil production equipment that integrates a motor with the pump body and is installed directly downhole. They use a motor to drive a centrifugal or multi-stage pump to lift the oil. While existing SEPs address issues such as rod and tubing eccentric wear and low system efficiency compared to SPPs, they often use a centrifugal pump structure. However, existing SEPs are limited in displacement by pump size and number of stages, making them inadequate for high-volume well production. The motor and pump body of a submersible oil pump are typically designed as separate components, resulting in longer downhole equipment and lower space utilization, making them difficult to adapt to operating conditions with limited wellbore space. In wells with high sand content, high viscosity, or high temperatures, the motor and pump body of a submersible oil pump are susceptible to the effects of sand, viscous media, or high temperatures, leading to reduced efficiency and increased failure rates. Summary of the Invention

[0003] To overcome the problems existing in related technologies, the disclosed embodiments of the present invention provide a hollow motor ball screw submersible electric pump and control method. The goal is to achieve oil lift and delivery by rotating the screw nut to drive the piston at the end of the screw, effectively improving transmission efficiency and downhole space utilization.

[0004] The technical solution is as follows: a hollow motor ball screw submersible electric pump, the hollow motor ball screw submersible electric pump is provided with a pump barrel upper end cover;

[0005] The upper end cover of the pump barrel is connected to the oil pipe through a through hole and is connected to the upper part of the motor-integrated pump cylinder by bolts; the annular area of ​​the motor-integrated pump cylinder is provided with a through hole as a liquid inlet, the hollow area inside the motor-integrated pump cylinder serves as a working chamber for the reciprocating motion of the screw end piston, and the lower end of the motor-integrated pump cylinder serves as a motor mounting seat, on which a hollow motor consisting of a motor rotor and a motor stator is installed;

[0006] A lead screw is centrally installed inside the motor-integrated pump cylinder, and is engaged with a lead screw nut installed on the lower end cover of the pump barrel through threaded transmission to complete linear reciprocating motion. The lower end cover of the pump barrel is installed at the bottom of the hollow motor.

[0007] A polished rod is integrally processed on the upper part of the lead screw, and the upper part of the polished rod is connected with a lead screw end piston.

[0008] A plurality of oil inlet valves are symmetrically installed in the annular area of ​​the upper end cover of the pump barrel, and an oil drain valve is installed on the upper part of the through hole opened in the upper end cover of the pump barrel. An oil inlet valve retaining ring and an oil drain valve retaining ring are respectively installed above the oil inlet valve and the oil drain valve.

[0009] The lead screw end piston contacts the motor integrated pump cylinder through the piston seal to form a sealing surface, and the polished rod contacts the polished rod seal located between the polished rod and the lead screw to form a sealing surface during the reciprocating motion of the polished rod.

[0010] The valve cores of the oil inlet valve and the oil discharge valve are both spherical valve balls, and the oil inlet valve retaining ring and the oil discharge valve retaining ring are both annular retaining rings;

[0011] The opening directions of the oil inlet valve and the oil drain valve are both toward the oil pipe.

[0012] The length of the screw is greater than the piston stroke at the end of the screw;

[0013] The motor rotor shaft end is equipped with a magnetic encoder to measure the rotation angle and speed, which are used to control the stroke and stroke frequency of the piston at the end of the screw. The valve seats of the oil inlet valve and the oil discharge valve are equipped with pressure sensors to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve cores of the oil inlet valve and the oil discharge valve;

[0014] The lead screw nut is fixedly connected to the motor stator through a spline and rotates forward and reverse along with the motor stator.

[0015] Another object of the present invention is to provide a method for controlling oil suction and discharge of a hollow motor ball screw submersible electric pump, comprising:

[0016] S1, oil inlet stroke: The hollow motor composed of the motor rotor and motor stator drives the screw nut to rotate. The screw is fixed to the polished rod. The rotation of the screw nut causes the screw to move downward, driving the piston at the end of the screw downward. The volume inside the motor-integrated pump cylinder increases, forming a negative pressure. The oil inlet valve opens under the pressure difference between the inside and outside of the motor-integrated pump cylinder, and oil enters the motor-integrated pump cylinder from the bottom of the well, and the oil discharge valve closes.

[0017] S2, oil discharge stroke: the hollow motor reverses to drive the screw nut to rotate in the opposite direction, driving the screw and the piston at the end of the screw to move upward; the volume of the motor-integrated pump cylinder decreases, the pressure in the motor-integrated pump cylinder increases, the oil inlet valve closes, the oil discharge valve opens, and the oil is pressed into the oil pipe and transported to the ground; the hollow motor continues to rotate forward and reverse, and the piston at the end of the screw reciprocates to complete continuous oil production.

[0018] Furthermore, in step S1, the length of the screw is greater than the piston stroke length of the screw end, and a magnetic encoder is installed at the motor rotor shaft end, and the magnetic encoder is used to measure the rotation angle and speed, L 实际 is the actual displacement of the piston at the end of the screw, θ 编码器 is the encoder angle, P is the lead of the screw, according to the formula The actual displacement of the piston at the end of the screw is calculated.

[0019] In step S1, pressure sensors are installed on the valve seats of the oil inlet valve and the oil discharge valve to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve cores of the oil inlet valve and the oil discharge valve.

[0020] The pressure sensor monitors the pressure difference in real time and provides feedback on the valve core opening and closing status of the oil inlet valve and the oil discharge valve.

[0021] Motor integrated pump cylinder internal volume lead screw end piston;

[0022] The screw end piston aims to minimize the displacement distance cost and matches the displacement demand with the internal volume of the motor-integrated pump cylinder. After determining the optimal internal volume of the motor-integrated pump cylinder, the screw end piston will move the motor-integrated pump cylinder to a distance T. f (i ev ) is fed back to the magnetic encoder; the objective function of the cost model for minimizing the displacement distance of the screw end piston is shown in equations (1)-(2);

[0023]

[0024] T sum (i ev ,i a )=T a (i ev ,i a )+T f (i ev ,i a )+T ch (i ev ,i a )(2)

[0025] Where: Displacement distance cost T sum (i ev ,i a ) including the screw end piston i calculated by the magnetic encoder ev Drive to the motor integrated pump cylinder internal volume i a Running distance T a (i ev ,i a ), the displacement distance T from the piston at the end of the screw to the motor integrated pump cylinder f (i ev ,ia ) and the distance T required for the piston displacement at the end of the screw ch (i ev ,i a );v(i ev ,i a ) is the piston at the end of the screw i ev Pump cylinder volume integrated with motor a The displacement matching logic value of S A The new volume set of the motor-integrated pump cylinder after the magnetic encoder measures the angle and speed scheme is determined by the magnetic encoder.

[0026] The constraints of the screw end piston minimization displacement distance cost model are as follows:

[0027] 1) Constraints on the internal volume of the motor-integrated pump cylinder to be selected

[0028] S A =S E +S C ′ (3)

[0029] S C ′={i c |u(i c )=1}i c ∈S C (4)

[0030] Where: S A The angle and speed of the built motor-integrated pump cylinder point S are measured by the magnetic encoder E And the new motor integrated pump cylinder point S C '; Among them, the new motor integrated pump cylinder point S C ′ is determined by the decision variable u(i c ) The candidate motor-integrated pump-cylinder composition to be built has a value of 1;

[0031] 2) Select the unique constraint of the internal volume of the motor-integrated pump cylinder

[0032]

[0033] Where: When the screw end piston i ev Volume of pump cylinder integrated with motor a When the match is successful, use v(i ev ,i a )=1, when the match fails, use v(i ev ,i a )=0; In fact, each operating node of the screw end piston corresponds to only one motor-integrated pump cylinder displacement, so formula (6) requires that each operating node of the screw end piston can only select at most one motor-integrated pump cylinder internal volume at the same time;

[0034] 3) Maximum screw end piston travel distance constraints:

[0035]

[0036] Where: Piston at the end of the screw i ev The maximum distance that can be run at present; C(i ev ) is the piston diameter of the screw end piston; SOC0(i ev ) is the initial volume state before moving toward the volume of the motor-integrated pump cylinder; ξ(i ev ) is the unit distance change value of the piston at the end of the screw; D(i ev ,i a ) is the piston at the end of the screw i ev To the motor integrated pump cylinder internal volume i a Running distance; when When v(i ev ,i a )=0, that is, no match.

[0037] In combination with all the above technical solutions, the beneficial effects of the present invention are as follows:

[0038] The present invention provides a hollow motor ball screw submersible electric pump, comprising an oil pipe, an oil discharge valve retaining ring, an oil discharge valve, an upper end cover of a pump barrel, an oil inlet valve retaining ring, an oil inlet valve, a piston at the end of a screw, a piston seal, an integrated motor pump cylinder, a polished rod, a polished rod seal, a screw, a screw nut, a lower end cover of a pump barrel, a motor rotor, and a motor stator; the hollow motor drives the screw nut installed inside it to rotate forward and reverse, and the piston at the end of the screw performs a linear reciprocating motion accordingly. The present invention adopts an integrated design, has a compact structure, and has high transmission efficiency. It is suitable for the exploitation of large-displacement, high-viscosity and high-sand content oil wells, and significantly improves the adaptability to downhole environments and the reliability of the equipment.

[0039] The hollow motor ball screw submersible electric pump of the present invention has a hollow motor that drives the screw nut to rotate, and the screw piston moves back and forth accordingly, thereby achieving oil lifting by changing the volume. Compared with traditional rod pumps and split centrifugal pumps, it has many advantages: compact structure and high space utilization; the motor-integrated pump cylinder structure reduces the installation difficulty, reduces the connecting parts and installation distance, and at the same time reduces the maintenance requirements caused by failure of the connecting parts, thereby improving reliability; the hollow motor outputs through the hole, improves the operating efficiency, and can provide higher displacement and head; reduces vibration, so that the equipment runs smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure;

[0041] Figure 1 Schematic diagram of a hollow motor ball screw submersible electric pump provided by an embodiment of the present invention;

[0042] Figure 2 This is an enlarged schematic diagram of the motor portion of the submersible electric pump provided by an embodiment of the present invention;

[0043] In the figure: 1. Oil pipe; 2. Oil drain valve retaining ring; 3. Oil drain valve; 4. Upper end cover of pump barrel; 5. Oil inlet valve retaining ring; 6. Oil inlet valve; 7. Piston at the end of screw; 8. Piston seal; 9. Motor-integrated pump cylinder; 10. Polished rod; 11. Polished rod seal; 12. Screw; 13. Screw nut; 14. Lower end cover of pump barrel; 15. Motor rotor; 16. Motor stator. DETAILED DESCRIPTION

[0044] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] Example 1, as Figure 1-Figure 2 As shown, the hollow motor ball screw submersible electric pump comprises an oil pipe 1, an oil discharge valve retaining ring 2, an oil discharge valve 3, an upper end cover of the pump barrel 4, an oil inlet valve retaining ring 5, an oil inlet valve 6, a piston at the end of the screw 7, a piston seal 8, an integrated motor pump cylinder 9, a polished rod 10, and a polished rod seal 11; a screw 12, a screw nut 13, a lower end cover of the pump barrel 14, a motor rotor 15, and a motor stator 16;

[0046] The pump barrel upper end cover 4 is provided with a through hole communicating with the oil pipe 1 and is bolted to the upper part of the motor-integrated pump cylinder 9; the motor-integrated pump cylinder 9 has a through hole in the annular area as a liquid inlet, the inner hollow area serves as a reciprocating working chamber for the screw end piston 7, and the lower end serves as a motor mounting seat, on which the motor rotor 15 and the motor stator 16 are mounted;

[0047] The screw 12 is centrally mounted inside the motor-integrated pump cylinder 9 and is threadedly engaged with the screw nut 13 to achieve linear reciprocating motion. The screw nut 13 is mounted on the lower end cover 14 of the pump barrel.

[0048] The lead screw 12 and the polished rod 10 are processed as one piece, and the upper part of the polished rod 10 is connected to the lead screw end piston 7.

[0049] For example, a plurality of oil inlet valves 6 are symmetrically installed in the annular area of ​​the upper end cover 4 of the pump barrel, and an oil discharge valve 3 is installed on the through hole opened on the upper part of the upper end cover 4 of the pump barrel. An oil inlet valve retaining ring 5 and an oil discharge valve retaining ring 2 are respectively installed above the oil inlet valve 6 and the oil discharge valve 3 to prevent the valve cores of the feedback oil inlet valve 6 and the oil discharge valve 3 from flying out;

[0050] Exemplarily, the screw end piston 7 contacts the motor-integrated pump cylinder 9 through the piston seal 8 to form a sealing surface, separating the oil area and the transmission area. During the reciprocating motion of the light rod 10, it always contacts the light rod seal 11 located between the light rod 10 and the screw 12 to form a sealing surface, preventing oil leakage and impurities from entering the transmission area of ​​the screw 12.

[0051] The valve cores of the oil inlet valve 6 and the oil discharge valve 3 are both spherical valve balls, and the oil inlet valve retaining ring 5 and the oil discharge valve retaining ring 2 are both annular retaining rings;

[0052] The opening directions of the oil inlet valve 6 and the oil discharge valve 3 are both toward the oil pipe 1 .

[0053] The design length of the lead screw 12 must be greater than the stroke of the lead screw end piston 7, and the design length of the polished rod 10 must ensure that the polished rod contacts the polished rod seal 11 during the reciprocating motion;

[0054] The motor rotor 15 shaft end is equipped with a high-precision magnetic encoder to measure the rotation angle and speed, which is used to control the stroke and stroke frequency of the piston 7 at the end of the screw. Pressure sensors are installed near the valve seats of the oil inlet valve 6 and the oil drain valve 3 to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve ball.

[0055] The lead screw nut 13 is fixedly connected to the motor stator 16 via a spline and rotates forward and reverse therewith.

[0056] The lead screw adopts a ball screw or a threaded lead screw.

[0057] Example 2, as another implementation of the present invention, the upper end cover 4 of the pump barrel is connected to the oil pipe 1 as a discharge outlet, and the annular area of ​​the upper end cover 4 of the pump barrel is provided with an oil inlet valve 6 as a liquid inlet. The screw end piston 7 in the motor-integrated pump cylinder 9 moves back and forth in a straight line under the drive of the hollow motor, thereby realizing the in and out and lifting of the oil.

[0058] For example, in the present invention, the screw nut 13 is fixedly connected to the hollow motor rotor 15 by a spline, and the motor stator 16 drives it to rotate forward and backward, thereby driving the screw 12 threadedly matched with it to perform linear reciprocating motion in the axial direction; the upper part of the screw 12 is a smooth rod 10, and the smooth rod 10 is connected to the screw end piston 7. The up and down reciprocating motion of the screw end piston 7 realizes the periodic change of the internal volume of the motor-integrated pump cylinder 9; when the screw end piston 7 moves upward, the internal volume of the motor-integrated pump cylinder 9 decreases. Under the action of the internal and external pressure difference, the oil inlet valve 6 ball leaves the valve seat, and the oil enters the motor-integrated pump cylinder 9; when the screw end piston 7 moves downward, the internal volume of the motor-integrated pump cylinder 9 increases. Under the action of the internal and external pressure difference, the oil discharge valve 3 ball leaves the valve seat, and the oil enters the oil pipe 1 from the motor-integrated pump cylinder 9. At the same time, a pressure sensor is installed in the motor-integrated pump cylinder 9 for real-time monitoring, and the speed is dynamically adjusted according to the pressure change to stabilize the pressure fluctuation.

[0059] The hollow motor of the present invention is installed at the lower part of the motor-integrated pump cylinder 9. The hollow motor includes a motor rotor 15 and a motor stator 16. The hollow motor and the electric pump are integrated into the same housing, which reduces connecting parts and installation difficulty, making the structure compact.

[0060] A piston seal 8 is provided between the screw end piston 7 and the motor-integrated pump cylinder 9 of the present invention to prevent oil leakage in the motor-integrated pump cylinder 9; a polished rod seal 11 is provided between the polished rod 10 and the motor-integrated pump cylinder 9 to prevent sand-containing impurities from entering the screw transmission area and causing mechanical wear.

[0061] For example, the length of the screw 12 of the present invention is greater than the stroke length of the piston 7 at the end of the screw, and the rotation angle and speed are measured by a high-precision magnetic encoder. 实际 is the actual displacement of the piston (7) at the end of the screw, θ 编码器 is the encoder angle, P is the lead of the screw, according to the formula The actual displacement of the piston 7 at the end of the screw is calculated and limit control is performed to ensure that the polished rod seal 11 is always in contact with the polished rod 10 during the reciprocating motion to form a dynamic sealing surface.

[0062] The lead screw 12 and the polished rod 10 of the present invention are processed as one piece, which ensures coaxiality and concentricity, reduces processing errors, and facilitates installation and matching.

[0063] The valve cores of the oil discharge valve 3 and the oil inlet valve 6 of the present invention are both spherical, and the oil discharge valve retaining ring 2 and the oil inlet valve retaining ring 5 are both annular retaining rings, providing rigid limiting to prevent the valve ball from leaving the valve seat.

[0064] The screw 12 of the present invention may be a ball screw or a threaded screw.

[0065] Working principle.

[0066] The pump barrel upper end cap 4 is connected to the oil pipe 1, and an oil drain valve 3 is installed in the oil discharge channel to control the discharge of oil. An inlet valve 6 is installed in the annular area of ​​the pump barrel upper end cap 4 to control the oil drawn from the oil layer by the electric pump into the motor-integrated pump cylinder 9. The motor stator 15 and electronic rotor 16 are installed in the cylindrical space below the motor-integrated pump cylinder, forming a hollow motor. The lead screw nut 13 is connected to the motor rotor 16 via a spline and can rotate forward and backward with the motor rotor 16 when driven by the motor. Simultaneously, a lead screw 12 is axially mounted in the hollow area formed by the pump barrel upper end cap 4, the motor-integrated pump cylinder 9, and the pump barrel lower end cap 14. This threaded engagement with the lead screw nut 13 allows the lead screw 12 to drive the upper lead screw end piston 7 in linear reciprocating motion when the lead screw nut 13 rotates forward and backward. To prevent the lead screw end piston 7 from rotating, a keyway is provided between the polished rod 10 and the inner wall of the motor-integrated pump cylinder 9. A piston seal 8 is provided between the screw end piston 7 and the motor-integrated pump cylinder 9 to form a dynamic sealing surface to prevent oil leakage in the motor-integrated pump cylinder; a polished rod seal 11 is provided between the polished rod 10 and the motor-integrated pump cylinder 9 to form a dynamic sealing surface to prevent sand-containing impurities from entering the screw transmission area and causing mechanical wear.

[0067] Example 3. This embodiment of the present invention provides a method for controlling the oil suction and discharge of a hollow motor ball screw submersible electric pump. The present invention utilizes a hollow motor to drive the ball screw, which drives the piston to reciprocate, thereby achieving the suction and discharge of oil. Its working process can be divided into the oil inlet stroke (piston downward) and the oil discharge stroke, as follows:

[0068] S1, oil inlet stroke: the hollow motor composed of the motor rotor 15 and the motor stator 16 drives the screw nut 13 to rotate, and the screw 12 is fixed to the polished rod 10. The rotation of the screw nut 13 causes the screw to move downward, driving the piston 7 at the end of the screw to move downward; the piston 7 at the end of the screw moves downward, and the volume of the motor-integrated pump cylinder 9 increases, forming a negative pressure. The oil inlet valve 6 opens under the action of the pressure difference between the inside and outside of the motor-integrated pump cylinder 9, and the oil enters the motor-integrated pump cylinder 9 from the bottom of the well. The oil discharge valve 3 remains closed due to the pressure of the oil pipe 1; the piston seal 8 prevents oil from entering and leaking, and the polished rod seal 11 prevents sand particles from entering the screw transmission area.

[0069] S2, oil discharge stroke: the motor reverses to drive the screw nut 13 to rotate in the opposite direction, driving the screw 12 and the screw end piston 7 upward; the screw end piston 7 moves upward, the volume of the motor-integrated pump cylinder 9 decreases, the pressure in the motor-integrated pump cylinder 9 increases, the oil inlet valve 6 is closed to prevent the oil from flowing back, the oil discharge valve 3 is opened, and the oil is pressed into the oil pipe 1 and transported to the ground; the hollow motor continues to rotate forward and reverse, and the screw end piston 7 reciprocates to achieve continuous oil production.

[0070] For example, in step S1 , the valve seats of the oil inlet valve 6 and the oil discharge valve 3 are installed with pressure sensors to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve cores of the oil inlet valve 6 and the oil discharge valve 3 .

[0071] The pressure sensor monitors the pressure difference in real time and provides feedback on the valve core opening and closing status of the oil inlet valve 6 and the oil discharge valve 3, including:

[0072] The motor-integrated pump cylinder 9 contains a lead screw end piston 7;

[0073] The screw end piston 7 matches the displacement demand with the internal volume of the motor-integrated pump cylinder 9 with the goal of minimizing the displacement distance cost; after determining the optimal internal volume of the motor-integrated pump cylinder 9, the screw end piston 7 moves the internal displacement distance T of the motor-integrated pump cylinder 9. f (i ev ) is fed back to the magnetic encoder; the objective function of the cost model for minimizing the displacement distance of the screw end piston is shown in equations (1)-(2);

[0074]

[0075] T sum (i ev ,i a )=T a (i ev ,i a )+T f (i ev ,i a )+T ch (i ev ,i a )(2)

[0076] Where: Displacement distance cost T sum (i ev ,i a ) including the screw end piston i calculated by the magnetic encoder ev Drive to the motor integrated pump cylinder internal volume i a Running distance T a (i ev ,i a ), the displacement distance T from the end piston of the screw to the motor integrated pump cylinder 9 f (i ev ,i a ) and the required displacement distance T of the screw end piston 7 ch (i ev ,i a );v(i ev ,i a ) is the piston at the end of the screw i ev The internal volume of the motor-integrated pump cylinder 9 is i a The displacement matching logic value of SA The magnetic encoder determines the new internal volume of the motor-integrated pump cylinder 9 after the magnetic encoder measures the angle and speed.

[0077] The constraints of the screw end piston minimization displacement distance cost model are as follows:

[0078] 1) Constraints on the internal volume of the motor-integrated pump cylinder 9 to be selected

[0079] S A =S E +S C ′ (3)

[0080] S C ′={i c |u(i c )=1}i c ∈S C (4)

[0081] Where: S A The angle and speed of the built motor-integrated pump cylinder (9) are measured by the magnetic encoder. E And the new motor integrated pump cylinder 9 o'clock S C ' composition; Among them, the new motor integrated pump cylinder 9 point S C ′ is determined by the decision variable u(i c ) the candidate to be built motor integrated pump cylinder 9 with a value of 1;

[0082] 2) Select the unique constraint of the internal volume of the motor-integrated pump cylinder (9)

[0083]

[0084] Where: When the screw end piston i ev The volume of the pump cylinder 9 integrated with the motor is i a When the match is successful, use v(i ev ,i a )=1, when the match fails, use v(i ev ,i a )=0 means; in fact, each operation node of the screw end piston 7 corresponds to the displacement of only one motor-integrated pump cylinder 9, so formula (6) requires that each operation node of the screw end piston 7 can only select the internal volume of the motor-integrated pump cylinder 9 at most at the same time;

[0085] 3) Maximum running distance constraint of the screw end piston 7:

[0086]

[0087] Where: Piston at the end of the screw i ev The maximum distance that can be run at present; C(i ev) is the piston diameter of the screw end piston 7; SOC0(i ev ) is the initial volume state before moving toward the internal volume of the motor-integrated pump cylinder 9; ξ(i ev ) is the unit distance change value of the screw end piston 7; D(i ev ,i a ) is the piston at the end of the screw i ev To the motor integrated pump cylinder 9 internal volume i a Running distance; when When v(i ev ,i a )=0, that is, no match.

[0088] The piston stroke and speed can be adjusted in real time through sensors (pressure, temperature, vibration), and the valve core opening and closing status of the oil inlet valve 6 and the oil discharge valve 3 can be fed back to adapt to different oil well working conditions.

[0089] It can be seen from the above embodiments that the hollow motor ball screw submersible electric pump proposed by the present invention has a hollow motor that directly drives the screw nut for transmission, which effectively improves the transmission efficiency, can provide higher displacement and head, and is suitable for high-yield wells or deep well mining.

[0090] The hollow motor ball screw submersible electric pump proposed in the present invention integrates the motor and the pump body into a compact unit, thereby reducing the overall length and volume of the equipment, improving the utilization of downhole space and the adaptability to complex well conditions.

[0091] The hollow motor ball screw submersible electric pump proposed in this invention features an integrated motor and pump body, which reduces the number of connecting components, easing installation difficulty and distance, while also reducing maintenance requirements due to component failures. This design improves the operational stability and reliability of the equipment, extending its service life.

[0092] The hollow motor ball screw submersible electric pump proposed in the present invention has an integrated design that facilitates the use of better sealing and cooling technologies, improves the stability of the submersible electric pump performance, and is suitable for high-temperature and high-pressure underground environments.

[0093] The hollow motor ball screw submersible electric pump proposed in the present invention can adopt a modular design for the motor-integrated pump cylinder, and the installation positions of sensors, cables, control modules, etc. can be customized and adjusted, thereby improving the flexibility and adaptability of the equipment.

[0094] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0095] The information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the embodiment of the method of the present invention. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0096] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment.

[0097] An embodiment of the present invention also provides a computer device, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps of any of the above-mentioned method embodiments when executing the computer program.

[0098] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0099] An embodiment of the present invention also provides an information data processing terminal, which is used to provide a user input interface to implement the steps in the above-mentioned method embodiments when executed on an electronic device. The information data processing terminal is not limited to mobile phones, computers, and switches.

[0100] An embodiment of the present invention further provides a server, which is used to provide a user input interface to implement the steps in the above method embodiments when executed on an electronic device.

[0101] An embodiment of the present invention provides a computer program product. When the computer program product is run on an electronic device, the electronic device can implement the steps of the above-mentioned method embodiments when executing the computer program product.

[0102] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium can at least include: any entity or device that can carry the computer program code to the camera / terminal device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk.

[0103] The above description is only a preferred specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A hollow motor ball screw submersible electric pump, characterized in that: The hollow motor ball screw submersible electric pump is provided with a pump barrel upper end cover (4); The pump barrel upper end cover (4) is connected to the oil pipe (1) through a through hole and is connected to the upper part of the motor-integrated pump cylinder (9) by bolts; the annular area of ​​the motor-integrated pump cylinder (9) is used as a liquid inlet by opening a through hole, the hollow area inside the motor-integrated pump cylinder (9) is used as a reciprocating working chamber for the screw end piston (7), and the lower end of the motor-integrated pump cylinder (9) is used as a motor mounting seat, on which a hollow motor consisting of a motor rotor (15) and a motor stator (16) is installed; A lead screw (12) is centrally mounted inside the motor-integrated pump cylinder (9), and is engaged with a lead screw nut (13) mounted on a lower end cover (14) of the pump barrel to complete linear reciprocating motion through threaded engagement. The lower end cover (14) of the pump barrel is mounted on the lower part of the hollow motor. A polished rod (10) is integrally processed on the upper portion of the lead screw (12), and the upper portion of the polished rod (10) is connected with a lead screw end piston (7).

2. The hollow motor ball screw submersible electric pump according to claim 1, characterized in that: A plurality of oil inlet valves (6) are symmetrically mounted in an annular region of the pump barrel upper end cover (4); an oil discharge valve (3) is mounted on the upper portion of the pump barrel upper end cover (4) through a through hole; and an oil inlet valve retaining ring (5) and an oil discharge valve retaining ring (2) are mounted above the oil inlet valve (6) and the oil discharge valve (3), respectively.

3. The hollow motor ball screw submersible electric pump according to claim 1, characterized in that: The screw end piston (7) contacts the motor-integrated pump cylinder (9) through the piston seal (8) to form a sealing surface, and the polished rod (10) contacts the polished rod seal (11) located between the polished rod (10) and the screw (12) to form a sealing surface during the reciprocating motion of the polished rod (10).

4. The hollow motor ball screw submersible electric pump according to claim 1, characterized in that: The valve cores of the oil inlet valve (6) and the oil discharge valve (3) are both spherical valve balls, and the oil inlet valve retaining ring (5) and the oil discharge valve retaining ring (2) are both annular retaining rings; The opening directions of the oil inlet valve (6) and the oil discharge valve (3) are both towards the oil pipe (1).

5. The hollow motor ball screw submersible electric pump according to claim 1, characterized in that: The length of the lead screw (12) is greater than the stroke of the lead screw end piston (7); The shaft end of the motor rotor (15) is equipped with a magnetic encoder to measure the rotation angle and rotation speed, which is used to control the stroke and stroke frequency of the piston (7) at the end of the screw. The valve seats of the oil inlet valve (6) and the oil discharge valve (3) are equipped with pressure sensors to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve cores of the oil inlet valve (6) and the oil discharge valve (3); The lead screw nut (13) is fixedly connected to the motor stator (16) via a spline and rotates forward and reverse along with the motor stator (16).

6. A method for controlling oil suction and discharge of a hollow motor ball screw submersible electric pump, characterized in that: The method for operating the hollow motor ball screw submersible electric pump according to any one of claims 1 to 5 comprises: S1, oil inlet stroke: the hollow motor composed of the motor rotor (15) and the motor stator (16) drives the screw nut (13) to rotate, the screw (12) is fixed to the polished rod (10), and the screw nut (13) rotates to move the screw (12) downward, driving the screw end piston (7) downward; the internal volume of the motor-integrated pump cylinder (9) increases, forming a negative pressure, and the oil inlet valve (6) opens under the action of the pressure difference between the inside and outside of the motor-integrated pump cylinder (9), and the oil enters the motor-integrated pump cylinder (9) from the bottom of the well, and the oil discharge valve (3) is closed; S2, oil discharge stroke: the hollow motor reverses and drives the screw nut (13) to rotate in the opposite direction, driving the screw (12) and the screw end piston (7) upward; the volume of the motor-integrated pump cylinder (9) decreases, the pressure in the motor-integrated pump cylinder (9) increases, the oil inlet valve (6) closes, the oil discharge valve (3) opens, and the oil is pressed into the oil pipe (1) and transported to the ground; the hollow motor continues to rotate forward and reverse, and the screw end piston (7) reciprocates, completing continuous oil production.

7. The oil suction and discharge control method of a hollow motor ball screw submersible electric pump according to claim 6, characterized in that: In step S1, the length of the lead screw (12) is greater than the stroke length of the lead screw end piston (7), and a magnetic encoder is installed at the shaft end of the motor rotor (15). The magnetic encoder measures the rotation angle and the rotation speed. 实际 is the actual displacement of the piston (7) at the end of the screw, θ 编码器 is the encoder angle, P is the lead of the screw (12), according to the formula The actual displacement of the piston (7) at the end of the screw is obtained by calculation.

8. The oil suction and discharge control method of a hollow motor ball screw submersible electric pump according to claim 6, characterized in that: In step S1, the valve seats of the oil inlet valve (6) and the oil discharge valve (3) are equipped with pressure sensors to monitor the pressure difference in real time and provide feedback on the opening and closing status of the valve cores of the oil inlet valve (6) and the oil discharge valve (3).

9. The oil suction and discharge control method of a hollow motor ball screw submersible electric pump according to claim 8, characterized in that: The pressure sensor monitors the pressure difference in real time, and the feedback of the valve core opening and closing status of the oil inlet valve (6) and the oil discharge valve (3) includes: The motor-integrated pump cylinder (9) contains a lead screw end piston (7); The screw end piston (7) matches the displacement demand with the internal volume of the motor-integrated pump cylinder (9) with the goal of minimizing the displacement distance cost; after determining the optimal internal volume of the motor-integrated pump cylinder (9), the screw end piston (7) moves the internal displacement distance T of the motor-integrated pump cylinder (9) f (i ev ) is fed back to the magnetic encoder; the objective function of the cost model for minimizing the displacement distance of the screw end piston is shown in equations (1)-(2); T sum (i ev ,i a )=T a (i ev ,i a )+T f (i ev ,i a )+T ch (i ev ,i a )(2) Where: Displacement distance cost T sum (i ev ,i a ) including the screw end piston (7) calculated by the magnetic encoder ev The internal volume of the motor-integrated pump cylinder (9) is i a Running distance T a (i ev ,i a ), the displacement distance T from the screw end piston (7) to the motor integrated pump cylinder (9) f (i ev ,i a ) and the distance T required for the displacement of the screw end piston (7) ch (i ev ,i a );v(i ev ,i a ) is the piston at the end of the screw (7)i ev The internal volume of the pump cylinder (9) integrated with the motor is i a The displacement matching logic value of S A The magnetic encoder determines the new internal volume of the motor-integrated pump cylinder (9) after the magnetic encoder measures the rotation angle and the rotation speed scheme.

10. The oil suction and discharge control method of a hollow motor ball screw submersible electric pump according to claim 9, characterized in that: The constraints of the screw end piston minimization displacement distance cost model are as follows: 1) Constraints on the internal volume of the selected motor-integrated pump cylinder (9) S A =S E +S C ′ (3) S′ C ={i c |u(i c )=1} i c ∈S C (4) Where: S A The angle and speed of the built motor-integrated pump cylinder (9) are measured by the magnetic encoder. E And the newly built motor integrated pump cylinder (9) point S C ' composition; wherein, a new motor integrated pump cylinder (9) point S C ′ is determined by the decision variable u(i c ) is composed of a candidate motor-integrated pump-cylinder (9) to be built whose value is 1; 2) Select the unique constraint of the internal volume of the motor-integrated pump cylinder (9) Where: When the screw end piston (7)i ev The internal volume of the pump cylinder (9) integrated with the motor is i a When the match is successful, use v(i ev ,i a )=1, when the match fails, use v(i ev ,i a )=0 represents; in fact, each operation node of the screw end piston (7) corresponds to the displacement of only one motor-integrated pump cylinder (9), so formula (6) requires that each operation node of the screw end piston (7) can only select the internal volume of the motor-integrated pump cylinder (9) at most at the same time; 3) Maximum running distance constraint of the screw end piston (7): Where: For the screw end piston (7)i ev The maximum distance that can be run at present; C(i ev ) is the piston diameter of the screw end piston (7); SOC0(i ev ) is the initial volume state before moving toward the internal volume of the motor-integrated pump cylinder (9); ξ(i ev ) is the unit distance change value of the screw end piston (7); D(i ev ,i a ) is the piston at the end of the screw (7)i ev The internal volume of the motor integrated pump cylinder (9) is i a Running distance; when When v(i ev ,i a )=0, that is, no match.

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