CN113617543B - A Downhole Dynamic Cyclone Separation System of Screw Pump - Google Patents

Abstract

A screw pump downhole dynamic cyclone separation system. The device comprises an outer sleeve, a stator, a screw shaft rotor, a cyclone overflow pipe, a cyclone cavity, a cyclone bottom flow pipe, an inner cone and an overflow oil transportation branch pipe; the screw shaft rotor, the overflow oil delivery branch pipe, the cyclone overflow pipe, the inner cone, the cyclone cavity, the outer cone section and the bottom flow pipe are sequentially and fixedly connected on the same central axis to form an integral rotary structural member, and the integral rotary structural member is integrally rotated under the drive of the screw; the rectangular tangential inlet of the cyclone is opposite to the spiral direction; the stator is connected with the overflow oil transportation branch pipe and the screw rod in a matching way at the upper part of the overflow pipe of the cyclone, and an oil collecting cavity and a spiral oil transportation gap are respectively formed; the outer sleeve is in transitional connection with the cyclone overflow pipe through a first bearing, and the first bearing is adjacent to the stator above and welded on the inner side of the outer sleeve; the outer sleeve is in transitional connection with the cyclone underflow pipe through a second bearing and a second bearing filling ring which are positioned at the joint of the cyclone cone section and the cyclone underflow pipe. The separation system has the advantages of high separation efficiency, low cost, small radial size and convenient operation.

Description

A Downhole Dynamic Cyclone Separation System of Screw Pump

technical field

The invention relates to a two-phase separation treatment device applied in the fields of petroleum, chemical industry, environmental protection and the like.

Background technique

At present, in the production fluid water treatment technology used in the oil production well site, most of the production fluid is pumped to the ground and then subjected to sedimentation, cyclone and other separation treatment of the production fluid. In oil fields, such methods are widely used. The processing method takes too much cost. At present, the oil-water separation and reinjection technology in the same well injection and production wells is becoming more and more mature. This technology can directly process the high water content production fluid through the downhole, avoiding a large amount of invalid water to be transported to the ground, and instead realize the reinjection cycle in the wellbore, which can greatly reduce Lifting energy consumption and operating costs, reducing the lower limit of economically effective production of high water-cut oilfields, prolonging the production life of oil wells, and providing new technologies for economical production of high-water-cut oilfields.

The downhole cyclone separation system is a system in the injection and production process of the same well. It is usually designed as a downhole static cyclone and applied downhole to separate the produced fluid in the wellbore. The problems in the prior art are: due to the structural characteristics and working methods of the static hydrocyclone itself, the static hydrocyclone is subject to various restrictions in further improving the separation efficiency, especially when dealing with high-viscosity media (such as heavy oil) During the separation operation, the viscosity of the working medium is large, the internal friction resistance is large, and the pressure loss increases, which makes it difficult to meet the special production needs of the oilfield site. Some dynamic cyclones are also used in practice, and most of these dynamic cyclones are driven by an external motor to rotate a part of the static cyclone. However, this additional power equipment has brought problems such as high energy consumption, easy damage to rotating parts, unreliable sealing and easy wear and tear.

Contents of the invention

In order to solve the technical problems mentioned in the background technology, the present invention provides a dynamic cyclone separation system for downhole screw pumps. Using this system, the outer cylinder of the cyclone can be driven to rotate through the shaft of the screw pump well in the downhole to make the cyclone The dynamic rotation of the device generates a strong centrifugal force field, and the immiscible two-phase mixed liquid such as oil and water with different densities is subjected to cyclone centrifugal separation. The separated low-density oil phase is lifted to the ground, and the water phase can be reinjected into the underground reinjection layer for recycling. . This separation system has the advantages of high separation strength, high separation efficiency, low separation cost, small radial size, compact structure and convenient operation.

The technical scheme of the present invention is: the downhole dynamic cyclone separation system of this kind of screw pump, including the outer sleeve 4, the stator 2, the cyclone overflow pipe 9, the cyclone chamber 14, the cyclone bottom flow pipe 19 and the cyclone The inner cone 13 is unique in that:

The cyclone separation system also includes a screw shaft rotor 3 , an overflow oil delivery branch pipe 7 , a first bearing 8 , a second bearing 17 and a second bearing filling ring 18 .

Wherein, the inner wall surface of the outer sleeve 4 has a wall array opening 10; the inner wall surface of the outer sleeve 4, the first bearing 8, the second bearing 17, the second bearing filling ring 18, the cyclone overflow pipe 9 The outer wall, the outer wall of the cyclone cavity 14, the outer cone section 16 of the cyclone and the bottom flow pipe 19 of the cyclone together constitute a liquid inlet chamber;

The cyclone chamber 14 is formed by connecting the cyclone cylindrical section 12, the cyclone inner cone 13 and the cyclone outer cone section 16 in sequence, and a cyclone is arranged on the side wall of the cyclone cylindrical section 12 top. A rectangular tangential inlet 11; the cyclone inner cone 13 is fixed at the top axis of the cyclone cylindrical section 12.

The screw shaft rotor 3, the overflow oil delivery branch pipe 7, the cyclone overflow pipe 9, the cyclone inner cone 13, the swirl chamber 14, the outer cone section 16, and the bottom flow pipe 19 are fixedly connected in sequence on the same central axis, Form an integral rotating structural part, which rotates integrally under the drive of the screw shaft rotor 3; the rectangular tangential inlet 11 of the swirler is opposite to the spiral direction, and is used to ensure that the rotation direction of the fluid entering the swirl chamber 14 is consistent with the screw shaft rotor 3 rotation direction Consistent, forming a swirling centrifugal separation flow field.

The stator 2 cooperates with the overflow oil delivery branch pipe 7 and the screw shaft rotor 3 on the upper part of the cyclone overflow pipe 9 to form the oil collection chamber 6 and the spiral oil delivery gap 5, which is used to make the centrifugal separation flow into the central overflow pipe The oil phase at the inlet 15 flows out, and the centrifuged water phase enters the underflow pipe 19 of the cyclone, and flows into the water collection chamber 21 through the outlet 20 of the underflow circular hole.

The outer sleeve 4 and the cyclone overflow pipe 9 are transitionally connected by the first bearing 8, and the first bearing 8 is close to the upper stator 2 and is tightly connected with the inner side of the outer sleeve 4; the outer sleeve 4 and the cyclone bottom flow The pipe 19 is sealed and connected by the second bearing 17 and the second bearing filling ring 18 located at the junction of the outer cone section 16 of the cyclone and the bottom flow pipe 19 of the cyclone.

The present invention has the following beneficial effects: firstly, the screw shaft rotor, overflow oil delivery branch pipe, cyclone overflow pipe, inner cone, swirl chamber, outer cone section, and bottom flow pipe are all aligned on the same central axis through structural design. Secondary fixed connection forms an integrated rotating structural part, which rotates integrally under the drive of the screw, which can realize the dynamic separation of two phases of oil and water in the downhole; secondly, the power to realize the dynamic rotation of the hydrocyclone comes from the rotation of the shaft of the screw pump, so it can be directly controlled by the ground and Adjust the rotational speed of the downhole dynamic swirler; again, the design of the swirler rectangular tangential inlet and the opposite spiral helix structure can effectively ensure that the rotation direction of the fluid entering the swirl chamber is consistent with the helical direction of the screw, thus forming swirl centrifugal separation In addition, the overall structure is novel, the size of the equipment is small, there is no external driving equipment compared with conventional wellbore, and the reliability is high. Compared with the existing cyclone separation equipment, the separation effect has stronger centrifugal separation strength, so the separation is more pure and has outstanding advantages. , for the application in fields such as oilfield production, has considerable promotion and application prospects.

Description of drawings:

Fig. 1 is a schematic structural diagram of a downhole dynamic cyclone separation system of a screw pump according to the present invention.

Fig. 2 is a schematic diagram of fluid flow and phase separation inside the downhole dynamic cyclone separation system of the screw pump, and the arrows in the figure indicate the flow direction of the fluid entering the system.

Fig. 3 is a schematic diagram of the cross-sectional structure of Fig. 1 A-A.

Fig. 4 is a schematic diagram of the B-B cross-sectional structure in Fig. 1 .

Fig. 5 is a schematic diagram of the cross-sectional structure of C-C in Fig. 1 .

Figure 6 is a schematic diagram of the cross-sectional structure of D-D in Figure 1, and the dotted arrow in the figure indicates the direction of rotation of the screw pump.

Fig. 7 is a schematic diagram of the E-E cross-sectional structure in Fig. 1 .

Fig. 8 is a schematic diagram of the integrated rotation of the downhole dynamic swirler of the screw pump and the screw shaft rotor according to the present invention. In the figure, the dotted arrow indicates the direction of rotation of the screw pump, and the solid arrow indicates the direction in which the fluid enters the tangential inlet.

In the figure 1-oil phase spiral outlet; 2-stator; 3-screw shaft rotor; 4-outer sleeve; 5-helical oil delivery gap formed by stator and screw shaft rotor; 6-oil collection chamber; 7-overflow Oil delivery branch pipe; 8-first bearing; 9-cyclone overflow pipe; 10-oil casing array opening; 11-rectangular tangential inlet of cyclone; 12-cylindrical section of cyclone; 13-swirl Inner cone of the device; 14-swirl cavity; 15-inlet of the center overflow pipe; 16-outer cone section of the cyclone; 17-second bearing; 18-filling ring of the second bearing; 19-bottom flow pipe of the cyclone; 20 -underflow round hole outlet; 21-water collecting cavity.

Detailed ways:

The present invention will be further described below in conjunction with accompanying drawing:

Firstly, the purpose of the invention is introduced as follows: make full use of the downhole rotation condition of the screw pump, innovatively design and realize the dynamic cyclone separation of the downhole oil-water two-phase (take the oil-water two-phase as an example, not limited to the oil-water two-phase), solve the existing downhole separation In the technology, the problems of low separation efficiency such as small oil-water density difference, small oil droplet particles in the dispersed phase, and high viscosity of the continuous phase are realized to achieve efficient separation of two phases.

The downhole dynamic cyclone separation system of the screw pump has a slender cylindrical shape as a whole, and can be connected with the oil production wellbore. As shown in Figure 1, its structure mainly includes: stator 2, screw shaft rotor 3, outer sleeve 4, overflow oil delivery branch pipe 7, first bearing 8, cyclone overflow pipe 9, oil casing array opening Hole 10, cyclone rectangular tangential inlet 11, cyclone cylindrical section 12, cyclone inner cone 13, cyclone outer cone section 16, second bearing 17, second bearing filling ring 18, cyclone underflow Tube 19 and underflow round hole outlet 20.

As shown in Figure 2, it is a schematic diagram of fluid flow and two-phase separation. The arrows in the figure indicate the flow direction of the fluid entering the system. The chamber consists of the inner wall surface of the outer sleeve 4 with the wall array opening 10, the first bearing 8, the second bearing 17, the second bearing filling ring 18, the outer wall of the cyclone overflow pipe 9, the outer wall of the cyclone chamber 14, and the cyclone The outer cone section 16 and the swirler bottom flow pipe 19 are jointly enclosed. The pressure of the oil-water mixture in the liquid inlet chamber is higher than the pressure in the cyclone. At this time, the designed rectangular tangential inlet 11 cooperates with the rotation of the cyclone to generate suction at the rectangular tangential inlet 11 and inside the swirl (centrifugal motion center The region is a low-pressure region), so under the double action of pressure drive and centrifugal suction, the oil-water mixture in the liquid inlet chamber enters the cyclone inner swirl chamber 14 along the rectangular tangential inlet 11. In order to ensure that the streamline movement of the fluid entering the cyclone is consistent with the direction of rotation of the cyclone, the opening direction of the designed rectangular tangential inlet 11 is opposite to the direction of rotation of the cyclone, as shown in Figure 8, the dotted arrow in the figure indicates the screw Pump rotation, solid arrows indicate flow into tangential inlet direction. The swirl chamber 14 is formed by connecting the cylindrical section 12 of the cyclone, the inner cone 13 of the cyclone, and the outer cone section 16 of the cyclone respectively. The swirl chamber 14 is the area where two-phase centrifugal separation occurs. Under the diversion effect of the rectangular tangential inlet 11, the oil-water mixture entering the swirl chamber 14 will make a circular motion in the swirl chamber in the form of a high-speed jet. Due to the different densities of the two phases of oil and water, the light phase and the oil phase will be affected The centrifugal force is small, and it will move to the central area of the cyclone with the rotation, while the heavy phase water phase will be subject to greater centrifugal force, and gradually migrate to the side wall of the cyclone. Among them, the conical structure design of the wall surface of the inner cone 13 of the swirl cavity component can stabilize the flow field of the incoming liquid and the coalescence and collection of the light phase migration to its side wall.

After the cyclone centrifugation process in the cyclone chamber 14, the separated light phase oil phase collected in the center enters the overflow pipe 9, the oil collection chamber 6, the overflow oil delivery branch pipe 7 and the stator and the screw shaft rotor to form The spiral oil delivery gap 5, finally flows out from the oil phase spiral outlet 1; the separated water phase enters the bottom flow pipe 19 of the cyclone along the side wall of the outer cone section 16 of the cyclone, and flows into the water collection through the bottom flow hole outlet 20 Cavity 21.

In order to divert the oil phase collected into the overflow pipe 9 to the oil collection chamber 6, a transitional connection part, the overflow oil delivery branch pipe 7, is designed, which is obliquely inserted into the oil accumulation chamber 6 from the center of the bottom by four inclined pipe holes , so that the oil phase of the central overflow pipe 9 can be easily drained into the oil accumulation chamber 6; the oil phase entering the oil collection chamber 6, driven by the rotation of the screw shaft rotor, enters the spiral oil delivery gap 5 to be pressurized and transported to other manifolds or ground.

In addition, the overall rotational movement of the outer wall of the cyclone will also cause the two phases of oil and water in the liquid inlet chamber 14 to follow the circular motion. At this time, the light phase oil phase will migrate to the outer wall of the central cyclone, so there will be a certain degree of coalescence Compared with static cyclone or sedimentation separation device, it has better separation effect.

This system relies on the rotating shaft core of the screw pump well to drive the outer cylinder of the cyclone to rotate, so that the cyclone dynamically rotates to generate a strong centrifugal force field, and performs cyclone centrifugal separation of immiscible two-phase mixtures such as oil and water with different densities. The system simplifies the power structure by driving the rotation of the screw, and at the same time uses the helical cavity of the screw sleeve to transmit the oil phase to reduce the volume of the equipment, realize the dynamic swirling separation of oil and water two phases downhole, and improve the overall separation efficiency of the two phases. It is suitable for working conditions where the two immiscible phases are difficult to separate, such as small density difference, small oil droplet particles in the dispersed phase, and high viscosity of the continuous phase.

The invention provides a new idea for the design of two-phase separation equipment, promotes the development of separation technology, and at the same time, the invention will improve the downhole cyclone separation and same well reinjection technology to a new level. The equipment can also be applied to centrifugal separation treatment of immiscible two-phase media in petroleum, chemical, municipal environmental protection and other industries, such as sewage deoiling, sewage degassing, underground coal washing sewage liquid-solid separation, etc.

Claims (1)

1. A downhole dynamic cyclone separation system of a screw pump, including an outer sleeve (4), a stator (2), a cyclone overflow pipe (9), a cyclone chamber (14), a cyclone underflow pipe (19 ) and the inner cone of the cyclone (13), characterized in that: The cyclone separation system further includes a screw shaft rotor (3), an overflow oil delivery branch pipe (7), a first bearing (8), a second bearing (17) and a second bearing filling ring (18); Among them, the inner wall surface of the outer sleeve (4) is provided with wall array openings (10); the inner wall surface of the outer sleeve (4), the first bearing (8), the second bearing (17), and the second bearing are filled with The ring (18), the outer wall of the cyclone overflow pipe (9), the outer wall of the cyclone chamber (14), the outer cone section of the cyclone (16) and the bottom flow pipe of the cyclone (19) together constitute the liquid inlet chamber; The liquid inlet chamber confluences the oil-water mixture entering through the wall array openings (10); The cyclone cavity (14) is formed by connecting the cyclone cylindrical section (12), the cyclone inner cone (13) and the cyclone outer cone section (16) in sequence, and the cyclone cylindrical section ( 12) The side wall of the top is provided with a cyclone rectangular tangential inlet (11); the cyclone inner cone (13) is fixed at the top axis of the cyclone cylindrical section (12); Screw shaft rotor (3), overflow oil delivery branch pipe (7), cyclone overflow pipe (9), cyclone inner cone (13), swirl cavity (14), outer cone section (16), bottom flow The tubes (19) are fixedly connected sequentially on the same central axis to form an integral rotating structure, which rotates integrally under the drive of the screw shaft rotor (3); To ensure that the rotation direction of the fluid entering the swirl chamber (14) is consistent with the rotation direction of the screw shaft rotor (3), forming a swirl centrifugal separation flow field; The stator (2) cooperates with the overflow oil delivery branch pipe (7) and the screw shaft rotor (3) on the upper part of the cyclone overflow pipe (9) to form the oil collection chamber (6) and the spiral oil delivery gap (5) , used to make the oil phase flowing into the inlet of the central overflow pipe (15) flow out after centrifugation, and the water phase separated by centrifugation enters the underflow pipe (19) of the cyclone, and flows into the water collection chamber through the outlet of the underflow round hole (20) ( twenty one); The outer sleeve (4) and the cyclone overflow pipe (9) are transitionally connected by the first bearing (8). Sealed connection; the outer sleeve (4) and the cyclone bottom flow pipe (19) are connected by the second bearing (17) and the second The bearing filler ring (18) seals the connection.

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