CN109356562B - Underground sand-filtering type gas-liquid separation device - Google Patents

Abstract

The invention provides an underground sand filter type gas-liquid separation device, which is applied to the gas-liquid-solid separation of the liquid produced by oil and gas wells and unconventional gas wells. The downhole gas-liquid separation device is mainly composed of a double-tube axial flow separator, a cyclone separator, an axial flow separator and a straight wire sand filter, and is combined with the downhole oil pump to realize the integrated separation of gas, liquid and solid before the production liquid is fed into the pump. , effectively solve the problems of air lock and sand stuck pump; the straight wire sand filter adopts the sand filter type straight wire tube to realize the solid-liquid separation before the liquid production enters the pump, and the axial flow separator adopts the first-stage axial flow pore tube to realize the production The first-stage preliminary gas-liquid separation after liquid-solid-liquid separation, the cyclone separator adopts the second-stage layered cyclone multi-section tube to realize the second-stage gas-liquid separation of the liquid produced, and the double-tube axial flow device is based on the inner axial flow tube. After the first-stage gas-liquid separation, the buffering of the liquid with small bubbles is realized, and the fine sand liquid after the second-stage gas-liquid separation is transported to the oil pump through the outer axial flow pipe.

Description

Downhole sand filter gas-liquid separation device

technical field

The invention relates to a gas-liquid-solid integrated separation device used in the opening of oil and gas wells and unconventional gas wells, in particular to a downhole gas-liquid separation of sand filter type, first-stage axial flow and second-stage layered cyclone flow device.

Background technique

In the production of oil and gas wells with high gas-liquid ratio and unconventional gas wells, the presence of gas will directly affect the efficiency of the entire pumping system. When the gas content is relatively low, the gas mainly affects the fullness of the pump and reduces the pump efficiency. When the gas content is large, a large amount of gas enters the oil pump, which greatly increases the probability of the gas lock phenomenon. At the same time, due to the existence of solid particles such as sand or coal particles, problems such as sand sticking of the pump will also occur.

At present, there are few special studies on the integrated gas-liquid-solid separation device in the downhole, mainly some downhole gas-liquid separators developed for degassing problems. The structure of the downhole gas-liquid separator is also constantly being improved. Gravity type and spiral type are developed to multi-cup iso-flow. The basic principles of these gas-liquid separators are designed based on gravity and centrifugal action. Among them, conventional gravity separators are natural gravity separators, which use casing perforation. The part below the segment is used as a pocket for gravity separation, and the separator is larger in size; the eccentric design of the eccentric gravity separator changes the shape of the annulus, making the annulus more space for gas-liquid separation, and the gas phase entering the separator is also Relatively lower; the helical separator is additionally designed with a helical blade on the center tube of the gravity separator, which relies on the gravity and flow pressure of the fluid to generate a downward velocity, and at the same time moves slowly under the drainage of the helical blade. The working performance depends on the size of the helical blade, and it is not suitable for handling the liquid-containing gas flow with a large volume flow. At the same time, the processing and manufacturing of the helical blade is also difficult.

To this end, based on the existing feasible technology of gas-liquid separation, according to the numerical simulation and simulation analysis results of gas-liquid two-phase flow and solid-liquid two-phase flow in the oil pump, combined with oil and gas wells in Shengli Oilfield and unconventional Ordos Basin According to the field test results of gas wells, a new gas-liquid-solid integrated separation device has been developed, which is of great significance to solve the problems of on-site gas locks and sand trap pumps and to improve the efficiency of the mechanical production system.

SUMMARY OF THE INVENTION

In order to effectively solve the defects and deficiencies existing in the existing downhole solid-liquid separation technology and gas-liquid separation technology, the purpose of the present invention is to provide a downhole sand filter type gas-liquid integrated gas-liquid-solid separation for oil and gas wells and unconventional gas wells. separation device. The downhole gas-liquid separation device adopts sand filter type straight wire tube, first-stage axial flow pore tube and second-stage layered cyclone multi-section tube, combined with downhole oil pump, which can realize the gas-liquid flow before the production liquid is fed into the pump. Solid integration separation, effectively solve the problems of air lock and sand card pump.

The technical solution adopted by the present invention to solve the technical problem is to provide an underground sand filter type gas-liquid separation device. The underground gas-liquid separation device is designed as a symmetrical tube structure as a whole. It consists of a separator, an axial flow separator and a straight wire sand filter. The downhole gas-liquid separation device is connected to the bottom of the oil pump through the outer axial flow pipe of the double-tube axial flow device. The double-tube axial flow device and the straight wire sand filter are arranged concentrically from top to bottom in turn. Enter the inner axial flow tube of the double-tube axial flow device and the axial flow separator is placed in the lumen of the straight wire sand filter. The cyclone separator and the axial flow separator are arranged concentrically from top to bottom.

The straight wire sand filter adopts a sand filter type straight wire tube to realize the solid-liquid separation before the liquid is fed into the pump. It includes a straight wire tube sleeve and a straight wire buckle. The straight thread buckle adopts a variable section disc body with a thin top and a thick bottom. A slot is formed at the change of the cross section of the straight thread buckle, and the axial positioning of the lower end of the straight thread sleeve is realized, and the difference between the upper and lower section radii of the straight thread buckle is equal to the straight thread. The wall thickness of the sleeve.

The straight wire sleeve is made of straight wire bodies evenly distributed along the circumference of the straight wire buckle. The upper and lower ends of the straight wire sleeve are welded with the axial flow clamp and the straight wire buckle respectively, and all the straight wire bodies are inclined at the same time. Placed, so that the straight wire casing presents a V-shaped structure with a thick upper and a thin lower, so as to reduce the probability of collision between the straight wire sand filter and the casing pipe wall during downhole operations, and to ensure that the straight wire sand filter is filtered. Coarse sand grains settle smoothly into the bottom hole pocket, instead of accumulating outside the straight wire casing. The straight wire body is rolled from stainless steel wire, and its cross section is an isosceles trapezoid, and the wide side of the straight wire body is arranged outward, so that the wire seam formed between the adjacent straight wire bodies is radially narrower outside and wider inside, so that the To avoid the blockage caused by the fine sand particles flowing through the silk seam with the production liquid, the straight wire sleeve has a self-cleaning function.

The solid-liquid separation process before the production liquid is fed into the pump is as follows: the straight wire sand filter goes down the well with the tubing string and the oil pump and hangs at the liquid production layer. The production liquid carries the sand particles and flows through the straight wire casing, and the coarse sand particles larger than the wire gap are filtered. According to the V-shaped structure of the straight wire casing, the fine sand particles smaller than the wire fracture smoothly flow through the wire seam and enter the straight wire casing and the axial flow pore tube according to the self-cleaning effect of the straight wire casing. the annular space.

The axial flow separator adopts the first-stage axial-flow pore tube to realize the first-stage preliminary gas-liquid separation after the separation of liquid and solid, which includes an axial-flow clamp and an axial-flow pore tube.

The axial flow clamp adopts a variable-section thick-walled cylinder, the upper part of the outer ring surface of the axial flow clamp is connected with the outer axial flow pipe through pipe threads, and the section change of the lower part of the outer ring surface of the axial flow clamp forms a clamping groove, and The axial positioning of the upper end of the straight wire sleeve is realized, thereby connecting the straight wire sand filter and the outer axial flow tube into one, and at the same time, the inner wall of the annular cavity of the axial flow clamp connects the axial flow pore tube and the inner axial flow tube through the pipe thread. linked together.

The axial flow pore tube adopts a semi-closed equal-diameter long tube body, the inner wall of the annular cavity of the axial flow pore tube is sequentially set with a conical axial flow surface and a columnar axial flow surface from top to bottom, and the conical axial flow surface of the axial flow pore tube adopts an inverted The conical surface makes the cross-sectional area of the flow channel of the conical axial flow surface continuously expand, and the flow rate of the produced liquid in it gradually decreases. There are deceleration holes arranged in layers at equal intervals along the axial direction on the tube wall at the lower part of the columnar axial flow surface of the axial flow pore tube to ensure that the liquid produced in the annular space of the straight wire sleeve and the axial flow pore tube has a certain amount. The first-stage gas-liquid separation is carried out for sufficient time, and then the produced liquid enters the lumen of the axial flow pore tube, and the deceleration holes between adjacent layers are staggered, and the deceleration holes in each layer are evenly distributed along the circumferential direction. The deceleration holes of the axial flow pore tube are all tapered, and the channels of the deceleration holes are thin and thick in the radial direction, and the deceleration holes are placed obliquely. The liquid flow rate gradually decreases.

The first-stage preliminary gas-liquid separation process is that the produced liquid with large bubbles enters the annular space between the straight wire sleeve and the axial flow pore tube through the wire slit with the outer narrow and the inner width, and the flow pressure of the produced liquid drops to complete the preliminary gas-liquid separation. The separated primary gas migrates upwards and overflows from the wire slit on the upper part of the straight wire casing to enter the annular space of the tubing and casing. At the same time, the liquid produced with small bubbles after separation flows downward and passes through the outer finer and inner coarser gasses. After the deceleration hole is decelerated, it enters the lumen of the axial flow aperture tube, and then continues to flow upward and is decelerated by the conical axial flow surface of the axial flow aperture tube to enter the lumen of the double-tube axial flow device.

The cyclone separator adopts the second-stage layered cyclone multi-section tube to realize the second-stage gas-liquid separation of the produced liquid, which includes a gas conduit, a cyclone, a cyclone and a liquid conduit.

The air guide tube and the liquid guide tube are T-shaped three-way pipes and are composed of an inlet pipe section and an outlet pipe section. The inlet pipe sections of the trachea and the catheter are arranged coaxially with the cyclone and the cyclone, the outlet pipe sections of the trachea and the catheter are arranged horizontally and both ends of the outer ring surface are made of pipe threads. The lower end of the inlet pipe section of the air duct is provided with an inverted conical groove, so that the separated secondary gas can be smoothly introduced into the air duct. There are conical swirl surfaces on both sides of the outlet pipe section of the catheter, so that the cyclone separator is kept in communication with the annular spaces of the inner axial flow pipe and the outer axial flow pipe, and the conical swirl flow of the catheter is The surface adopts a conical surface, so that the cross-sectional area of the flow channel of the conical swirl surface is continuously expanded, and the flow rate of the fine sand liquid in the catheter is gradually reduced.

The whirling pipe is composed of a whirling cone pipe section and a whirling column pipe section. The whirl pipe is welded with the air duct through its whirl cone pipe section, and is welded with the whirl tube through its whirl column pipe section. The inner and outer annulus surfaces of the swirling conical pipe section of the swirling pipe are all tapered surfaces, and the diameter of the small end circular surface of the conical surface where the inner and outer annular surfaces of the swirling conical pipe section are located is equal to the diameter of the outer annulus of the inlet pipe section of the airway. Jet holes are drilled on the pipe wall of the spin column pipe section of the spin pipe. The jet holes of the spin pipe are all circular holes, and the hole wall of the jet hole is tangent to the inner wall of the annular cavity of the spin column pipe section of the spin pipe, and The jet holes are placed obliquely; at the same time, there are two rows of jet holes in the spinning tube, the axis of each row of jet holes is located on the same vertical plane, and the vertical plane where the axis of the jet holes is located passes through the axis of the spinning tube, and the two rows of jets The holes are arranged in a staggered manner, so that the produced liquid carrying small bubbles in the inner axial flow tube is injected into the spinning tube through the jet holes and forms multiple beams of rotating liquid flow.

The swirl tube is composed of an upper tapered tube section, a central column tube section and a lower tapered tube section. The inner and outer annular surfaces of the upper and lower tapered tube sections of the swirl tube are all inverted tapered surfaces, and the inner and outer annular surfaces of the upper tapered tube section are located on the inverted tapered surface. The taper is smaller than the taper of the inverted conical surface where the inner and outer annular surfaces of the lower conical tube section are located, while the cone height of the inverted conical surface where the inner and outer annular surfaces of the upper conical tube section is located is greater than that of the inverted conical surface where the inner and outer annular surfaces of the lower conical tube section are located. The diameter of the small end circular surface of the inverted conical surface where the annulus is located and the diameter of the large end circular surface of the inverted conical surface where the inner annulus of the lower conical pipe section is located are both equal to the inner diameter of the central column pipe section.

The second-stage gas-liquid separation process is as follows: the product liquid with small bubbles in the inner axial flow tube is injected into the spin-generating tube through the jet hole to form multiple streams of rotating liquid, and then the multiple streams of rotating liquid flow on the inner wall of the annular cavity of the tube section of the spin-generating column. The bottom converges and finally forms a stratified cyclone, which enters the upper conical tube section and continues to rotate and separate at a high speed. The separated gas migrates to the center of the cyclone and rises in the opposite direction to form a gas column. At the same time, the separated liquid is gradually produced. It is thrown to the tube wall and flows into the middle column tube section. After staying for a period of time, it swirls into the lower conical tube section. The cross section of the flow channel in the lower conical tube section shrinks rapidly, causing the liquid to be continuously accelerated to rotate and separate, and the remaining bubbles in the produced liquid migrate to the swirl tube. A rising air column is formed in the center, and merges with the air column in the upper cone pipe section to form a secondary gas, which is then exported through the air conduit.

The double-tube axial flow device realizes the buffering of the liquid with small bubbles according to the inner axial flow tube, and transports the fine sand liquid to the oil pump through the outer axial flow tube. It includes an inner axial flow tube, an outer axial flow tube, an exhaust pipe, a End caps for gas tubes and end caps for liquid tubes.

The inner axial flow tube adopts an equal diameter thin tube body, while the outer axial flow tube adopts an equal diameter thick tube body. It carries small bubbles to produce liquid buffer, and an annular space is formed between the inner axial flow tube and the outer axial flow tube, which is used to transport the fine sand liquid after the second-stage gas-liquid separation.

The diameter of the inner wall of the annular cavity of the inner axial flow tube is equal to the diameter of the large end circular surface of the inverted conical surface where the conical axial flow surface of the axial flow pore tube is located, so that the product liquid with small bubbles after the first-stage gas-liquid separation can be smoothly introduced into the inner shaft within the annular lumen of the flow tube. The upper and lower parts of the inner axial flow tube wall are provided with circular bosses arranged in layers. The upper and lower circular bosses of the inner axial flow tube are respectively equipped with end caps for air tubes and end caps for liquid tubes. The outer diameter of the outer axial flow tube is equal to the diameter of the outer ring surface of the axial flow clamp. The top of the outer axial flow tube and the bottom of the inner axial flow tube are respectively machined with outer tube threads, and the bottom of the outer axial flow tube is machined with inner tube threads. The top of the inner axial flow pipe is equipped with a blind end flange for sealing, and the lower part of the outer pipe thread of the outer axial flow pipe is provided with inclined holes arranged symmetrically along the radial direction.

The exhaust pipe adopts elbow, the pipe diameter of the exhaust pipe is equal to the pipe diameter of the outlet pipe section of the air duct, the inner side of the exhaust pipe is connected with the end cap of the trachea through pipe threads, and the outer side of the exhaust pipe is connected to the outside by circumferential welding. The inclined hole of the axial flow pipe, thereby maintaining the communication between the cyclone separator and the annular space of the oil pipe and the casing.

Both the gas pipe end cover and the liquid pipe end cover are made of flanged body, the inner wall of the annular cavity of the gas pipe end cover is machined with pipe threads, the inner wall of the liquid pipe end cover is machined with pipe threads, and the ring cavity of the liquid pipe end cover is machined with pipe threads. The diameter of the inner wall of the cavity is equal to the diameter of the large end circular surface of the conical surface where the conical swirl surface of the catheter is located. The inner side of the tracheal end cap is respectively connected with the outlet pipe section of the air conduit, and the inner side of the liquid pipe end cap is respectively connected with the outlet pipe section of the liquid conduit, thereby realizing the fixation of the cyclone separator in the lumen of the inner axial flow tube.

The technical effect that the present invention can achieve is that the overall design of the downhole gas-liquid separation device is a symmetrical pipe body structure, and combined with the downhole oil pump, the gas-liquid-solid integrated separation before the production liquid is fed into the pump can be realized, and the gas lock and the air lock can be effectively solved. The sand card pump and other problems; the straight wire sand filter adopts the sand filter type straight wire tube to realize the solid-liquid separation before the produced liquid enters the pump, and the axial flow separator adopts the first-stage axial flow pore tube to realize the solid-liquid separation of the produced liquid. The first-stage preliminary gas-liquid separation, the cyclone separator adopts the second-stage layered cyclone multi-section tube to realize the second-stage gas-liquid separation of the liquid produced, and the double-tube axial flow device realizes the first-stage gas-liquid separation according to the inner axial flow tube After separation, it carries small bubbles to produce liquid buffer, and the fine sand liquid after the second-stage gas-liquid separation is transported to the oil pump through the outer axial flow tube.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following examples.

FIG. 1 is a schematic diagram of a typical structure of a downhole sand filter type gas-liquid separation device according to the present invention.

Figure 2 is a schematic diagram of the structure of the straight wire sand filter in the downhole sand filter type gas-liquid separation device.

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2 .

Figure 4 is a schematic diagram of the structure of the axial flow separator in the downhole sand filter type gas-liquid separation device.

Figure 5 is a schematic diagram of the structure of the cyclone separator in the downhole sand filter type gas-liquid separation device.

FIG. 6 is a sectional view taken along line B-B of FIG. 5 .

Fig. 7 is a schematic diagram of the structure of the double-tube axial flow device in the downhole sand filter type gas-liquid separation device.

FIG. 8 is a schematic diagram of the solid-liquid separation process before the liquid production is fed into the pump of the downhole sand-filtering gas-liquid separation device.

FIG. 9 is a schematic diagram of the two-stage gas-liquid separation process before the liquid-producing pump of the downhole sand-filtering gas-liquid separation device.

In the figure 1- double-tube axial flow separator, 2- cyclone separator, 3- axial flow separator, 4- straight wire sand filter, 5- straight wire pipe sleeve, 6- straight screw thread, 7- axial flow card Hoop, 8- Axial Flow Aperture Tube, 9- Airway Tube, 10- Spinning Tube, 11- Swirl Tube, 12- Catheter, 13- Exhaust Tube, 14- Tracheal End Cap, 15- External Axial Flow Tube , 16 - inner axial flow tube, 17 - liquid tube end cap.

Detailed ways

In Figure 1, the downhole sand filter gas-liquid separation device is mainly composed of a double-tube axial flow separator 1, a cyclone separator 2, an axial flow separator 3 and a straight wire sand filter 4. It adopts a sand filter type straight wire tube. , The first-stage axial flow pore tube and the second-stage layered swirl multi-segment tube, combined with the downhole oil pump, can realize the integrated separation of gas, liquid and solid before the production liquid is fed into the pump, and effectively solve the problem of air lock and sand stuck pump. And other issues.

In Figure 1, the downhole sand-filtering gas-liquid separation device is designed as a symmetric tube structure as a whole. The sand filter 4 is arranged concentrically from top to bottom in sequence, the cyclone separator 2 is placed in the inner axial flow tube of the double-tube axial flow device 1 and the axial flow separator 3 is placed in the lumen of the straight wire sand filter 4, The cyclone separator 2 and the axial flow separator 3 are arranged concentrically from top to bottom in sequence.

In Figure 1, before the assembly of the downhole sand filter type gas-liquid separation device, the surface of the outer axial flow tube of the double-tube axial flow device 1 is painted and anti-corrosion treated, while the outer axial flow tube and the inner axial flow tube of the double-tube axial flow device 1 are painted. The inner wall of the annular cavity of the cyclone separator 2, the inner wall of the annular cavity of the cyclone tube and the cyclone tube of the cyclone separator 2, and the inner wall of the annular cavity of the axial flow pore tube of the axial flow separator 3 are respectively chemically plated. The outer annular surface of the cyclone and the cyclone and the outer annulus of the axial flow pore tube of the axial flow separator 3 are spray-welded respectively, and the cyclone and the cyclone of the cyclone 2 and the axial flow are kept separate. Clean the inner wall of the axial flow pore tube of the filter 3, and finally check whether the air guide tube of the cyclone separator 2 and the straight wire tube sleeve of the straight wire sand filter 4 are damaged, and check whether the threaded joints are firm and whether there is rust.

In Figure 1, when the downhole sand filter type gas-liquid separation device is assembled, the cyclone separator 2 is connected to the inner axial flow tube lumen of the double-tube axial flow device 1 through its air conduit and liquid conduit, and the double-tube axial flow The inner axial flow tube of the separator 1 is connected into the lumen of the outer axial flow tube through its exhaust pipe, and then the axial flow clamp of the axial flow separator 3 connects its axial flow pore tube with the double tube axial flow tube 1 through the pipe thread. The outer axial flow tube and the inner axial flow tube are connected into one body, and the straight wire tube sleeve of the straight wire sand filter 4 is connected to the straight wire buckle and the axial flow clamp of the axial flow separator 3 by circumferential welding.

In Figures 2 and 3, the specifications of the straight wire casing 5 in the straight wire sand filter 4 are consistent with the specifications of the pump barrel of the oil well pump. The length of the straight wire casing 5 and the width of the wire slit depend on the formation fluid production, The type selection is based on factors such as the amount of sand carried by the produced fluid and the size of the sand particles.

In Figure 2 and Figure 3, the straight wire sand filter 4 uses a sand filter type straight wire tube to achieve solid-liquid separation before the liquid is fed into the pump. It includes a straight wire tube sleeve 5 and a straight wire buckle 6. The circumferential direction of the thread buttons 6 is uniformly distributed to form a straight wire sleeve 5, and the straight wire sleeve 5 presents a V-shaped structure with a thick upper and a thin lower, and the wire seam is radially narrow outside and wide inside, so that the straight wire sleeve 5 has self-cleaning properties. Function.

In FIG. 4 , the specification of the axial flow aperture tube 8 in the axial flow separator 3 is consistent with the specification of the straight wire sleeve 5 , and the length of the axial flow aperture tube 8 is adjusted according to the length of the straight wire sleeve 5 . The specific position of the deceleration holes of the pore tube 8 in the middle and lower part of the tube wall is designed according to factors such as the formation liquid production volume and the amount of large bubbles carried in the produced liquid. The design should be carried out according to factors such as the amount of liquid produced with small bubbles after separation.

In FIG. 4 , the axial flow separator 3 adopts the first-stage axial flow pore tube to realize the first-stage preliminary gas-liquid separation after the separation of the solid and liquid produced. It includes an axial flow clamp 7 and an axial flow pore tube 8. The flow clamp 7 connects the straight wire sand filter 4 and the axial flow pore tube 8 with the inner and outer axial flow tubes of the double-tube axial flow device 1, and the deceleration hole of the axial flow pore tube 8 is located in the tube wall. The middle and lower positions are to ensure that the produced liquid entering the annular space of the straight wire sleeve 5 and the axial flow pore tube 8 has enough time to implement the first-stage gas-liquid separation, and at the same time, the produced liquid with large bubbles is separated into first-stage gas and carrier gas. The production of small bubbles.

In Figures 5 and 6, the specifications of the cyclone 10 and the cyclone 11 in the cyclone separator 2 are selected according to factors such as the amount of liquid produced after the first-stage gas-liquid separation and the amount of small bubbles carried in the produced liquid. The number and diameter of the jet holes in the whirling tube 10 are designed according to factors such as the liquid production volume with small bubbles after the first-stage gas-liquid separation, and the diameter of the air guide tube 9 is based on the second-stage gas-liquid separation after the second-stage gas-liquid separation. According to factors such as the flow rate and other factors, the diameter of the catheter 12 is designed according to factors such as the flow rate of the fine sand liquid after the second-stage gas-liquid separation.

In FIGS. 5 and 6 , the cyclone separator 2 adopts the second-stage layered cyclone multi-section pipe to realize the second-stage gas-liquid separation of the produced liquid, which includes a gas conduit 9 , a cyclone 10 , and a cyclone 11 And the liquid conduit 12, the inlet pipe section of the gas conduit 9 is provided with an inverted conical groove, so as to smoothly introduce the separated secondary gas, and the two sides of the outlet pipe section of the liquid conduit 12 are provided with conical swirl surfaces to separate the gas. After the fine sand liquid is decelerated and rectified, it is led out. The product liquid carrying small bubbles in the inner axial flow tube of the double-tube axial flow device 1 is injected into the whirl tube 10 through the jet hole and forms multiple beams of rotating liquid flows. The layered swirling flow in the upper and lower conical tube sections accelerates the rotation and separation, and at the same time separates the produced liquid with small bubbles into secondary gas and fine sand liquid.

In FIG. 7 , the size of the annular space between the outer axial flow tube 15 and the inner axial flow tube 16 in the double-tube axial flow device 1 is based on the amount of liquid produced with small bubbles and the production of small bubbles after the first-stage gas-liquid separation. The size of the annular space between the inner axial flow tube 16 and the swirling tube 10 and the swirling tube 11 is based on the flow rate of the fine sand liquid and the fine sand liquid after the second-stage gas-liquid separation. The design is carried out according to factors such as the flow velocity required for the movement of fine sand, and the diameter of the exhaust pipe 13 is adjusted according to the diameter of the air conduit 9 .

In FIG. 7 , the double-pipe axial flow device 1 includes an exhaust pipe 13, a gas pipe end cover 14, an outer axial flow pipe 15, an inner axial flow pipe 16 and a liquid pipe end cover 17. The double-pipe axial flow device 1 is based on the inner axial flow. The annular space between the tube 16 and the swirling tube 10 and the swirling tube 11 realizes the buffering of the liquid with small bubbles, and the fine sand liquid is transported to the oil pump through the annular space between the outer axial flow tube 15 and the inner axial flow tube 16 , the two sides of the exhaust pipe 13 are respectively connected with the trachea end cover 14 and the outer axial flow pipe 15 to maintain communication between the cyclone separator 2 and the annular space of the oil pipe and the casing, while the liquid pipe end cover 17 is connected to the liquid conduit The tubes 12 are connected to maintain communication between the cyclone separator 2 and the annular spaces of the outer axial flow tube 15 and the inner axial flow tube 16 .

In Fig. 8, in the solid-liquid separation process of the downhole sand filter type gas-liquid separation device before the liquid is fed into the pump, the straight wire sand filter 4 goes down the well with the tubing string and the oil pump and hangs at the liquid producing layer, and the formation output carries The liquid produced by the sand particles first settles fully in the annular space of the tubing and casing, and then the produced liquid carries the sand particles and flows through the straight wire sand filter 4 before entering the pump. And according to the V-shaped structure of the straight wire casing 5, the production liquid in the annular space of the tubing and casing settles smoothly to the bottom hole pocket, and at the same time, the fine sand particles smaller than the wire fracture follow the self-cleaning effect of the straight wire casing 5. The produced liquid flows smoothly through the silk slit and enters the annular space of the straight wire sleeve 5 and the axial flow aperture tube 8 .

In Fig. 9, in the two-stage gas-liquid separation process before the production liquid of the downhole sand filter type gas-liquid separation device is fed into the pump, the production liquid with large bubbles enters the straight wire sleeve 5 and the axial flow through the wire slit with the outer narrow and the inner width. In the annular space of the pore tube 8, the flow pressure of the produced liquid drops to complete the preliminary gas-liquid separation, and the separated primary gas migrates in the opposite direction of the flow of the produced liquid, and overflows from the wire slit on the upper part of the straight wire sleeve 5 to enter the oil pipe and the oil pipe. The annular space of the casing is finally output through the wellhead device and the gas pipeline manifold; at the same time, the separated liquid with small bubbles flows downward in the annular space of the straight wire casing 5 and the axial flow pore tube 8, and passes through the casing. After the deceleration holes on the wall of the axial flow pore tube 8 are decelerated, they enter the lumen of the axial flow pore tube 8, and then the produced liquid carrying small bubbles continues to flow upward in the axial flow pore tube 8, and is transported by the axial flow pore tube 8. After the conical axial flow surface of the flow hole tube 8 is decelerated, it enters the annular space between the inner axial flow tube 16 and the swirling tube 10 and the swirl tube 11, thereby implementing the first-stage preliminary gas-liquid separation after the liquid-producing solid-liquid separation. separation.

In Fig. 9, in the two-stage gas-liquid separation process before the production liquid of the downhole sand filter type gas-liquid separation device is fed into the pump, the produced liquid with small bubbles is fully buffered in the inner axial flow tube 16, and then passes through the spinning tube 10. The jet holes on the wall are injected into the cyclone separator 2, and multiple beams of rotating liquid flows are formed on the inner wall of the annular cavity of the cyclone 10, and then the multiple swirling streams continue to rotate downward along the inner wall of the annular cavity of the cyclone 10 at the same time. flow, and converge at the bottom of the inner wall of the annular cavity of the swirl column pipe section in the swirl pipe 10 to form a layered swirl; The taper of the inverted conical surface where the inner annular surface is located is small, the stratified cyclone continues to rotate at a high speed and starts to separate gas and liquid, and the separated gas moves to the central part of the upper conical pipe section of the cyclone tube 11 and rises in the opposite direction to form a gas column, At the same time, the separated product liquid is gradually thrown to the pipe wall of the upper conical tube section of the cyclone tube 11 and flows into the middle column section of the cyclone tube 11; then, the separated product liquid stays in the middle column section of the cyclone tube 11 After a period of time, it swirls into the lower conical tube section of the swirl tube 11. The inner annular surface of the lower conical tube section of the swirl tube 11 has a larger taper, and the swirling flow channel section of the liquid produced after separation shrinks rapidly, while The produced liquid is continuously accelerated and rotated in the lower conical tube section of the cyclone tube 11 and continues to be separated from gas and liquid, and the remaining bubbles in the produced liquid migrate to the central part of the lower conical tube section of the cyclone tube 11 and form a gas column, and then rise in the opposite direction. And it merges with the gas column in the upper conical pipe section of the swirl pipe 11 to form a secondary gas, which is led out through the gas pipe 9 and transported to the annular space of the oil pipe and the casing by the exhaust pipe 13. At the same time, after the separation The fine sand liquid is decelerated and rectified by the outlet pipe section of the liquid conduit 12 and then exported to the annular space between the outer axial flow pipe 15 and the inner axial flow pipe 16 and transported to the inlet of the oil pump. The second stage of gas-liquid separation.

The above-mentioned embodiments are only used to illustrate the present invention, and the structure and connection mode of each component can be changed to some extent. outside the scope of protection of the invention.

Claims (9)

1. An underground sand filter type gas-liquid separation device, which is designed as a symmetrical tube structure as a whole. The double-tube axial flow device and the straight wire sand filter are arranged concentrically from top to bottom in turn, and the cyclone separator is placed in the double tube. The inner axial flow tube of the tube axial flow device and the axial flow separator are placed in the lumen of the straight wire sand filter, and the cyclone separator and the axial flow separator are arranged concentrically from top to bottom in order, and are characterized in that: Straight wire sand filter; the straight wire sand filter adopts a sand filter type straight wire tube to achieve solid-liquid separation before the liquid is fed into the pump, which includes a straight wire tube sleeve and a straight wire buckle; The straight wire sleeve is evenly distributed along the circumferential direction of the straight wire buckle, and all the straight wire bodies are placed obliquely, so that the straight wire sleeve presents a V-shaped structure with a thick upper and a thin lower. , the wire seam formed between the adjacent straight wire bodies is narrow outside and wide in the radial direction, so the straight wire sleeve has a self-cleaning function; An axial flow separator; the axial flow separator adopts the first-stage axial flow pore tube to realize the first-stage preliminary gas-liquid separation after the separation of the solid and liquid produced, which includes an axial flow clamp and an axial flow pore tube; The flow clamp adopts a thick-walled cylinder with variable cross-section, and a groove is formed at the section change of the lower part of the outer ring surface of the axial flow clamp. The conical axial flow surface and the cylindrical axial flow surface are arranged in sequence from top to bottom. The tube wall at the lower part of the cylindrical axial flow surface of the axial flow pore tube is milled with deceleration holes arranged in layers at equal intervals along the axial direction. The channel of the deceleration hole is thin outside and thick inside along the radial direction; A cyclone separator; the cyclone separator adopts the second-stage layered cyclone multi-section pipe to realize the second-stage gas-liquid separation of the liquid produced, and it includes a gas conduit, a cyclone, a cyclone and a liquid conduit ; The air guide tube and the liquid guide tube are all T-shaped three-way pipes and are composed of an inlet pipe section and an outlet pipe section. The lower end of the inlet pipe section of the air guide pipe is provided with an inverted cone-shaped groove, and the outlet pipe section of the liquid pipe is provided with a conical spiral groove on both sides. The flow surface; the whirling pipe is composed of a whirling cone pipe section and a whirling column pipe section. The pipe wall of the whirling column pipe section of the whirl pipe is drilled with jet holes, and the two rows of jet holes are arranged in a staggered manner; the whirl pipe consists of an upper cone pipe section, a middle It consists of a column pipe section and a lower cone pipe section, and the inner and outer annulus surfaces of the upper cone pipe section and the lower cone pipe section of the swirl tube are all inverted cone surfaces; A double-tube axial flow device; the double-tube axial flow device realizes the buffering of the liquid produced by carrying small bubbles according to the inner axial flow tube, and transports the fine sand liquid to the oil pump through the outer axial flow tube, which includes an inner axial flow tube, an outer axial flow tube, and an outer axial flow tube. Axial flow pipe, exhaust pipe, trachea end cap and liquid pipe end cap; the inner axial flow tube adopts the equal diameter thin tube body, while the outer axial flow tube adopts the equal diameter thick tube body, the inner axial flow tube and the spiral tube and the An annular space is formed between the swirl tubes, and an annular space is formed between the inner axial flow tube and the outer axial flow tube. The upper and lower parts of the inner axial flow tube wall are provided with circular bosses arranged in layers and equipped with tracheal end caps respectively. And the liquid pipe end cover, the lower part of the outer pipe thread of the outer axial flow pipe is provided with inclined holes arranged symmetrically along the radial direction, the exhaust pipe adopts elbow, and the gas pipe end cover and the liquid pipe end cover are flanged bodies. 2. The downhole sand filter type gas-liquid separation device according to claim 1 is characterized in that: the downhole sand filter type gas-liquid separation device is connected to the bottom of the oil pump through the outer axial flow pipe of the double-tube axial flow device; The solid-liquid separation process of the downhole sand filter type gas-liquid separation device before the production liquid is fed into the pump is that the production liquid carries the sand particles and flows through the straight wire sleeve, and the coarse sand particles larger than the wire gap are filtered out and V-shaped according to the straight wire sleeve. The structure settles smoothly to the bottom hole pocket, and the fine sand particles smaller than the silk fracture smoothly flow through the silk fracture with the production fluid according to the self-cleaning effect of the straight wire casing and enter the annular space between the straight wire casing and the axial flow pore tube. 3. The downhole sand filter type gas-liquid separation device according to claim 1 is characterized in that: a slot is formed at the cross-sectional change of the straight wire buckle in the straight wire sand filter, and the lower end of the straight wire sleeve is realized. Axial positioning, and the difference between the radii of the upper and lower sections of the straight thread is equal to the wall thickness of the straight thread sleeve; The upper and lower ends of the straight wire sleeve in the straight wire sand filter are respectively welded with the axial flow clamp and the straight wire buckle. And the broad side of the straight wire body is arranged outward. 4 . The downhole sand filter type gas-liquid separation device according to claim 1 , wherein the upper part of the outer annular surface of the axial flow clamp in the axial flow separator is connected to the outer axial flow pipe through pipe threads, and The groove at the lower part of the outer annular surface of the axial flow clamp realizes the axial positioning of the upper end of the straight wire tube sleeve, thereby connecting the straight wire sand filter and the outer axial flow tube into one, and at the same time, the inner wall of the annular cavity of the axial flow clamp passes through The pipe thread connects the axial flow pore tube and the inner axial flow tube into one; The conical axial flow surface of the axial flow pore tube in the axial flow separator adopts an inverted conical surface, so that the cross-sectional area of the flow channel of the conical axial flow surface is continuously enlarged, and the flow rate of the liquid produced therein gradually decreases; the axial flow pores The deceleration holes between adjacent layers on the pipe wall are staggered, and the deceleration holes in each layer are evenly distributed in the circumferential direction. The deceleration holes of the axial flow pore tube are all tapered, and the deceleration holes are placed obliquely, and the produced liquid flows through the axial flow pore tube. The cross-sectional area of the channel during the deceleration hole continues to expand, and the flow rate of the liquid production decreases gradually. 5. The downhole sand-filtering gas-liquid separation device according to claim 1, wherein the first-stage preliminary gas-liquid separation process of the downhole sand-filtering gas-liquid separation device is: The wire slit with narrow outer and inner wide enters the annular space of the straight wire sleeve and the axial flow pore tube, and the flow pressure of the produced liquid drops to complete the preliminary gas-liquid separation. At the same time, the product liquid with small bubbles after separation flows downward and is decelerated by the deceleration holes with the outer thin and the inner thick, and then enters the lumen of the axial flow pore tube, and then faces upwards. The flow continues and is decelerated by the conical axial flow surface of the axial flow aperture tube, and then enters the lumen of the double tube axial flow device. 6 . The downhole sand filter type gas-liquid separation device according to claim 1 , wherein the inlet pipe section of the air guide pipe in the cyclone separator is placed in the cyclone and the inlet pipe section of the liquid guide pipe is welded by circumferential welding. 7 . It is connected to the swirl pipe, and the inlet pipe sections of the air guide and the liquid guide are arranged coaxially with the swirl pipe and the swirl pipe. The outlet pipe sections of the air guide and the liquid guide are arranged horizontally. The separated secondary gas is smoothly introduced into the air guide tube, and the conical swirl surface of the liquid guide tube adopts a conical surface, so that the cross-sectional area of the flow channel of the conical swirl surface continues to expand, and the flow rate of the fine sand liquid in the liquid guide tube gradually increases. reduce; The swirling pipe of the cyclone separator is welded with the air guide pipe through its swirling cone pipe section, and is welded with the cyclone pipe through its swirling column pipe section. The inner and outer annular surfaces of the swirling cone pipe section of the cyclone Conical surface is used, and the diameter of the small end circular surface of the conical surface where the inner and outer annular surfaces of the vortexing cone pipe section is located is equal to the diameter of the outer annular surface of the inlet pipe section of the airway; It is kept tangent to the inner wall of the annular cavity of the pipe section of the spinning column of the spinning tube, and the jet holes are placed obliquely. At the same time, the jet holes of the spinning tube have two rows. The axis of each row of jet holes is located on the same vertical plane, and the axis of the jet holes is located The vertical planes pass through the axis of the spiral tube. 7 . The downhole sand filter type gas-liquid separation device according to claim 1 , wherein the taper of the inverted conical surface where the inner and outer annular surfaces of the upper conical tube section of the cyclone tube in the cyclone tube are located is smaller than that of the lower conical tube section. 8 . The taper of the inverted cone where the inner and outer annular surfaces are located, and the cone height of the inverted cone where the inner and outer annular surfaces of the upper conical tube section is located is greater than the cone height of the inverted cone where the inner and outer annular surfaces of the lower conical tube section are located. The diameter of the small end circular surface of the face and the diameter of the large end circular surface of the inverted conical surface where the inner annular surface of the lower tapered pipe section is located are equal to the inner diameter of the middle column pipe section; The second-stage gas-liquid separation process of the downhole sand-filtering gas-liquid separation device is as follows: the liquid produced with small bubbles in the inner axial flow tube is injected into the spinning tube through the jet hole to form multiple beams of rotating liquid flow, and then the multiple beams rotate. The liquid flow converges at the bottom of the inner wall of the annular cavity of the swirling column and finally forms a stratified swirling flow. The stratified swirling flow enters the upper conical tube section and continues to rotate and separate at a high speed. The separated gas migrates to the center of the swirling tube and rises in the opposite direction. A gas column is formed, and at the same time, the separated product liquid is gradually thrown to the pipe wall and flows into the middle column pipe section. After staying for a period of time, it swirls into the lower conical pipe section. The remaining bubbles in the liquid migrate to the center of the cyclone tube to form a rising gas column, and merge with the gas column in the upper conical tube section to form a secondary gas, which is then exported through the air conduit, and the separated fine sand liquid is discharged by the conduit tube. The outlet pipe section is decelerated and rectified and then exported. 8 . The downhole sand filter type gas-liquid separation device according to claim 1 , wherein the diameter of the inner wall of the annular cavity of the inner axial flow tube in the double-tube axial flow device is equal to the conical axial flow of the axial flow pore tube. 9 . The diameter of the large end circular surface of the inverted conical surface where the surface is located, the circular boss of the inner axial flow tube is symmetrically arranged in the radial direction and a circular through hole is drilled in the center of the circular boss, and the outer diameter of the outer axial flow tube is equal to The diameter of the outer ring surface of the axial flow clamp, the top of the outer axial flow tube and the bottom of the inner axial flow tube are respectively machined with outer tube threads, and the bottom of the outer axial flow tube is machined with inner tube threads and the top of the inner axial flow tube is equipped with Blind end flange for closure. 9 . The downhole sand filtering gas-liquid separation device according to claim 1 , wherein the diameter of the exhaust pipe in the double-pipe axial flow device is equal to the pipe diameter of the outlet pipe section of the air guide pipe, and the diameter of the exhaust pipe is equal to the diameter of the exhaust pipe. The inner side is connected with the end cover of the gas pipe by pipe threads, and the outer side of the exhaust pipe is connected to the inclined hole of the outer axial flow pipe by circumferential welding, thereby realizing the communication between the cyclone separator and the annular space of the oil pipe and the casing. ; In the double-tube axial flow device, pipe threads are machined on both sides of the inner wall of the annular cavity of the tracheal end cover, and pipe threads are machined on the inner side of the inner wall of the annular cavity of the liquid pipe end cover, and the diameter of the inner wall of the annular cavity of the liquid pipe end cover is equal to the diameter of the liquid guide. The diameter of the large end circular surface of the conical surface where the conical swirl surface of the pipe is located; the inner side of the tracheal end cap is respectively connected with the outlet pipe section of the trachea, and the inner side of the liquid pipe end cap is respectively connected with the outlet pipe section of the catheter, thus The fixation of the cyclone in the lumen of the inner axial flow tube is achieved.

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