Sand and gas prevention and extraction machine with sand setting and its using method

Abstract

The application discloses a sand setting type sand and gas prevention and drainage extraction machine pipe column and a use method thereof, which comprises a drainage extraction pump cylinder and a plunger, the drainage extraction pump cylinder is composed of a long pump cylinder, a sand setting pipe, a center pipe and a liquid inlet valve, the lower end of the long pump cylinder is connected with the sand setting pipe, the lower end of the sand setting pipe is connected with a gas anchor, the center pipe is arranged in the sand setting pipe, the lower end of the center pipe is connected with the inner wall of the lower end of the sand setting pipe, the upper end of the center pipe is provided with the liquid inlet valve, the plunger is sleeved in the long pump cylinder, a lower return spring is arranged in the liquid inlet valve, and the gas anchor is provided with a gas and liquid flow channel. The application solves the problems of gas locking, sand jamming and sand burying and ball valve leakage of the conventional drainage extraction pump in a coal bed gas machine extraction well.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal bed methane well machine sand prevention and gas prevention equipment, in particular to a sand setting type sand and gas prevention and production pumping pipe column and a use method thereof. BACKGROUND

[0002] Coal powder is produced by coal seam instability and damage under the action of drilling, fracturing engineering and production disturbance, and can be divided into drilling residual coal powder, wellbore instability produced coal powder, coal matrix fracture produced coal powder according to the source of coal powder. The existence of coal powder reduces the liquid production of the gas well. The coal powder falling on the fixed valve seat of the production pipe pump will cause the fixed valve to be not tightly closed, resulting in pump leakage. Part of the coal powder buries the fixed valve channel, causing the liquid inlet channel to be blocked. The coal powder adhering to the pump plunger will cause the pump to be stuck.

[0003] Hydraulic fracturing reconstruction technology is an effective method for increasing production of coal bed methane. By driving water flow with quartz sand, ceramic and other proppants, the water flow is squeezed into the original and newly created cracks in the reservoir, widening and extending these cracks, and further producing more secondary cracks in the reservoir, which can produce channels with high conductivity, effectively connecting the wellbore and the reservoir, and improving the single well control area and production of the coal bed methane well. After fracturing is completed, during the drainage and gas production process of the gas well, with the discharge of water in the cracks, especially the rapid reduction of bottom hole flowing pressure, the water containing particle size quartz sand, ceramic and other proppants enters the well barrel and the pump. After the sand enters the pump barrel, the sand falls on the fixed valve seat of the production pipe pump, which will cause the fixed valve to be not tightly closed and leak. The mixture of sand and coal powder in part of the wells will block the fixed valve channel, causing the liquid inlet channel to be blocked.

[0004] The conventional machine pumping pipe column structure has a rod pump bottom connected with a gas anchor, a tail pipe and a plug from top to bottom. The gas and water mixture produced by the formation mixed with sand and coal powder enters the gas anchor, and due to the density difference, the gas is separated back to the oil jacket annulus, and the coal powder and sand are separated out and deposited in the tail pipe under the influence of gravity. When the coal powder and sand in the tail pipe are deposited in the tail pipe, the coal powder and sand are easy to enter the pump barrel, causing the pump to be stuck and the pump inlet to be blocked, resulting in the rod pump not working normally.

[0005] Publication No. CN115788319A discloses a method for downhole sand control and coal dust control in co-seam coalbed methane wells. The method involves installing two sets of drainage devices in the co-seam coalbed methane well. First, a co-seam development coalbed methane well with a two-section wellbore structure is constructed on the surface. The lower structural coal seam and the upper primary structural coal seam are then sequentially fracturing and modified. A packer suspends the lower drainage tubing string at the top of the structural coal seam. This allows the flowback fluid, formation water, and coalbed methane produced by the structural coal seam to enter the lower drainage tubing string through a wire-wound screen. Simultaneously, it prevents the large amounts of proppant and coal dust produced by the structural coal seam from entering the drainage tubing string, causing the proppant and coal dust to sink to the artificial well bottom under gravity. Utilizing the lower drainage tubing string for sand and coal dust control reduces the risk of pump jamming and ensures the continuity of the drainage process in co-seam coalbed methane wells. It is especially suitable for coalbed methane drainage in the middle and lower coal seams where the main coal seam is broken and a large amount of sand and powder is discharged during the combined drainage process.

[0006] The existing technology does not have a gas anchor. When gas enters the pump chamber from the liquid, it can cause gas lock and other problems to the operation of the pump.

[0007] Publication (Announcement) No.: CN206770187U, discloses a double-acting water pump for coalbed methane drainage, including a fixed valve, a traveling valve, a sealing short section, an "I"-shaped plunger, a hollow connecting rod, a connecting rod side valve, a stepped inner pump barrel, an inner pump barrel side valve, an outer pump barrel, a sand control valve, and an oil pipe. The fixed valve is connected to the outer pump barrel, the traveling valve is connected to the lower plunger, the inner and outer pump barrels are rigidly connected to form an annular space, the sealing short section is connected to the inner pump barrel, the connecting rod one-way side valve is installed in the connecting rod groove, the inner pump barrel one-way side valve is installed on the inner pump barrel, and the oil pipe is connected to the outer pump barrel, dividing the water pump into three chambers: A, B, and C. The rigid connection between the inner and outer pump barrels forms an annular space. The advantages include: a compact structure, safety and reliability, increased drainage capacity, improved pump efficiency, reduced energy consumption and cost, and effective prevention of coal dust deposition and pump burial.

[0008] The existing technology does not have a gas anchor. When gas enters the pump chamber from the liquid, it can cause gas lock and other problems to the operation of the pump.

[0009] The utility model discloses (announcement) No. CN211342891U discloses a steering formula gas anchor, including upper joint, positioning seal plate, separation cylinder, partition board, baffle, lower joint, the upper portion inner thread of separation cylinder is below setting and hangs the shoulder, the upper portion of partition board is fixed on the left side of positioning seal plate, the lower end of partition board is connected in the baffle, the lower portion of partition board sets up sieve hole, and the baffle is at the left side of partition board, and positioning seal plate is at the right side of partition board, and positioning seal plate sits on the upper portion inner thread below of separation cylinder and hangs the shoulder, and partition board inserts separation cylinder, and the lower portion of partition board reaches the lower portion of separation cylinder, and partition board will separation cylinder and divide into separation chamber and liquid chamber, and the upper portion one side of separation cylinder sets up liquid inlet groove, and the liquid inlet groove with separation chamber's upper portion is open and shut, and positioning seal plate blocks the upper end of separation chamber, and the baffle blocks the lower end of liquid chamber, and make the fluid that enters the separation chamber through the liquid inlet groove only flow downward and enter the liquid chamber from sieve hole, and the lower portion of separation cylinder is connected with lower joint.

[0010] When the prior art is used, a large amount of gas moves upward along the pipe wall, moves upward along the baffle and the partition plate, and enters the oil pipe from the partition plate hole.

[0011] In summary, the technical solutions of the above disclosed technologies and the technical problems to be solved and the beneficial effects generated are different from those of the present application. The above disclosed technology documents do not have technical inspiration for more technical features and technical problems to be solved and beneficial effects of the present application. SUMMARY

[0012] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a sand setting type sand and gas prevention displacement machine pipe column and its use method, which effectively solves the problems of gas locking, sand sticking and sand burying and ball valve leakage encountered by conventional displacement pumps in coalbed methane machine production wells.

[0013] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0014] A sand setting type sand and gas prevention displacement machine pipe column, comprising a displacement pump cylinder and a plunger, the displacement pump cylinder is composed of a long pump cylinder, a sand setting pipe, a center pipe and a liquid inlet valve;

[0015] The lower end of the long pump cylinder is connected with the sand setting pipe, and the lower end of the sand setting pipe is connected with the gas anchor;

[0016] The center pipe is arranged in the sand setting pipe, the lower end of the center pipe is connected with the inner wall of the lower end of the sand setting pipe, the upper end of the center pipe is provided with a liquid inlet valve, and the plunger is sleeved in the long pump cylinder; a lower return spring is arranged in the liquid inlet valve;

[0017] The gas anchor is provided with a gas and liquid flow passage.

[0018] The plunger is composed of a pull rod, an upper liquid outlet valve, a short plunger and a lower liquid outlet valve;

[0019] The lower end of the pull rod is connected with the upper end of the short plunger, and the upper end of the pull rod is connected with the sucker rod string.

[0020] The upper end of the inner wall of the short plunger is provided with the upper liquid outlet valve, and the lower end is provided with the lower liquid inlet valve.

[0021] The lower liquid outlet valve is internally provided with an upper return spring.

[0022] The gas anchor comprises a gas anchor outer pipe and a gas anchor baffle.

[0023] The upper end of the gas anchor outer pipe is connected with the sand setting pipe.

[0024] The gas anchor baffle is composed of two bent thin plates embedded in the gas anchor outer pipe.

[0025] The gas anchor outer pipe is provided with gas holes at the top of the rising section of the "Z" shaped liquid flow channel.

[0026] The gas holes are at least two.

[0027] The sand setting pipe and the gas anchor outer pipe are provided with a tubing spool.

[0028] The lower end of the gas anchor outer pipe is connected with a tubing joint.

[0029] The lower part of the tubing joint is connected with a tail pipe or a screen pipe.

[0030] The upper end of the long pump barrel is connected with an upper joint, and the upper end of the upper joint is connected with a tubing.

[0031] The center pipe and the sand setting pipe form an annular sand setting cavity, and the annular sand setting cavity is provided with a supporting ring below the liquid inlet valve.

[0032] A use method of a sand setting type sand and gas prevention and production pumping machine pumping string,

[0033] S1, well operation preparation,

[0034] First, connect the production pump barrel and the gas anchor, connect the tubing with the upper end of the production pump barrel, connect the tail pipe and the screen pipe with the lower end of the gas anchor, and then lower them into the design position of the production well together with the tubing string.

[0035] Then connect the upper end of the plunger with the sucker rod, lower them into the bottom of the tubing together with the sucker rod string, realize the pump collision with the production pump barrel, and put the plunger into the production pump barrel.

[0036] S2, pumping operation, the plunger is driven by the sucker rod string to make up and down reciprocating motion in the long pump cylinder of the drainage pump cylinder;

[0037] During the upstroke, the upper outlet valve and the lower inlet valve are closed under the pressure of the tubing string, the liquid in the upper part of the plunger is lifted to the ground, the volume of the pump cavity in the lower part of the plunger increases, the pressure decreases, the inlet valve is opened under the pressure of the oil jacket annulus, the liquid in the coal seam, the sand particles carried by the liquid, the coal powder and part of the gas flow into the pump cavity along the gas anchor channel; when passing through the rising section of the gas anchor "Z" type liquid flow channel entrance, most of the gas escapes from the liquid and returns to the oil jacket annulus along the gas hole, and the rest continues to flow into the pump cavity along the gas anchor "Z" type channel;

[0038] During the downstroke, the volume of the pump cavity decreases, the pressure increases, the upper outlet valve and the lower inlet valve are opened under the action of the liquid in the pump cavity, the tubing cavity in the upper part of the plunger is communicated with the pump cavity in the lower part, and at the same time, the inlet valve is closed under the action of the oil pressure in the pump cavity, the liquid in the pump cavity is squeezed out into the tubing cavity, at this time, the sand particles, coal powder and a small amount of gas carried by the liquid also enter the tubing cavity;

[0039] S3, when pumping is stopped, the liquid in the pump cavity is in a static state, the sand particles and the coal seam will sink downward due to gravity, a part of the sediment directly falls into the annular sand settling chamber between the sand settling pipe and the central pipe, and a part of the sediment will first fall on the conical surface in the upper part of the inlet valve and slide into the annular sand settling chamber as the accumulation increases;

[0040] At the same time, the coal seam gas in the liquid in the lower part of the gas anchor tail pipe continues to escape upward and escape from the gas hole at the top of the rising section of the "Z" type channel entrance in the gas anchor, and returns to the oil jacket annulus; the sand particles and coal powder carried by a small amount of liquid remaining in the upper tubing nipple of the gas anchor and the lower central pipe of the inlet valve will be deposited and fall into the bottom of the gas anchor baffle due to gravity.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] A large annular sand settling chamber is designed below the inlet valve of the drainage pump cylinder, which ensures sufficient deposition space and avoids leakage due to the inlet valve not being tightly closed;

[0043] The setting of the support ring strengthens the stability of the central pipe, and increases the length of the central pipe;

[0044] The "Z" type flow channel gas anchor changes the traditional tail pipe sand settling and upper inlet, avoids the tail pipe from being full of sediment, increases the sand settling space, improves the gas, liquid, coal powder and sand separation effect, effectively reduces the sand, coal powder and gas into the pump cylinder, reduces the influence of the sand particles, coal powder and coal seam gas in the well fluid on the drainage pump, and improves the drainage efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1is a structural schematic diagram of a sand setting type sand and gas prevention and drainage extraction machine pipe column of the present application;

[0046] Figure 2 is a plunger upstroke schematic diagram of a sand setting type sand and gas prevention and drainage extraction machine pipe column of the present application;

[0047] Figure 3 is a plunger downstroke schematic diagram of a sand setting type sand and gas prevention and drainage extraction machine pipe column of the present application;

[0048] In the figure: 1, upper coupling; 2, long pump cylinder; 3, sand setting pipe; 4, support ring; 5, center pipe; 6, lower return spring; 7, liquid inlet valve; 8, pull rod; 9, upper liquid outlet valve; 10, short plunger; 11, upper return spring; 12, lower liquid inlet valve; 13, oil pipe nipple; 14, gas anchor outer pipe; 15, gas anchor baffle; 16, oil pipe joint; I, oil pipe cavity; II, pump cavity; III, annular sand setting cavity; IV, gas hole. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0050] Please refer to Figure 1 The present application provides a sand setting type sand and gas prevention and drainage extraction machine pipe column and a use method thereof, which comprises a drainage extraction pump cylinder and a plunger. The drainage extraction pump cylinder is composed of a long pump cylinder 2, a sand setting pipe 3, a center pipe 5 and a liquid inlet valve 7. The lower end of the long pump cylinder 2 is connected with the sand setting pipe 3, the lower end of the sand setting pipe 3 is connected with a gas anchor, the center pipe 5 is arranged in the sand setting pipe 3, the lower end of the center pipe 5 is connected with the inner wall of the lower end of the sand setting pipe, the upper end of the center pipe is provided with the liquid inlet valve 7, and the plunger is sleeved in the long pump cylinder 2. The liquid inlet valve 7 is provided with a lower return spring 6, which helps the first valve ball in the liquid inlet valve 7 to return.

[0051] The gas anchor is provided with a gas and liquid flow channel.

[0052] The plunger is composed of a pull rod 8, an upper liquid outlet valve 9, a short plunger 10 and a lower liquid outlet valve 12; the pull rod 8 is connected with the upper end of the short plunger 10, the upper end of the inner wall of the short plunger 10 is provided with the upper liquid outlet valve 9, and the lower end is provided with the lower liquid inlet valve 12; the pull rod 8 is connected with the sucker rod string; the short plunger 10 is provided with an annular sand-carrying groove structure, that is, an annular groove is arranged on the outer wall of the short plunger 10, so that when the short plunger 10 is sealed with the long pump barrel 2, sand particles will not be retained in the matching gap and will not pull the surface of the part, the annular groove is not shown in the drawing, but it is clear to those skilled in the art; the lower liquid outlet valve 12 is provided with an upper return spring 11 in the inside, which helps the second valve ball in the lower liquid outlet valve 12 to reset in time.

[0053] The gas anchor includes a gas anchor outer pipe 14 and a gas anchor baffle 15; the upper end of the gas anchor outer pipe 14 is connected with the sand setting pipe 3; the gas anchor baffle 15 is composed of two bent thin plates embedded in the gas anchor outer pipe 14; the gas anchor baffle 15 is divided into an upper baffle and a lower baffle; the upper baffle and the lower baffle are installed in opposite directions, so that the inside of the gas anchor outer pipe 14 forms a "Z" shaped liquid flow channel; the gas anchor outer pipe 14 is provided with at least two gas holes IV at the top of the ascending section of the "Z" shaped liquid flow channel; based on the gas-liquid separation principle, during the upward flow of the liquid, the gas escapes from the liquid and concentrates near the gas holes IV, and then returns to the oil jacket annulus outside the gas anchor outer pipe 14 from the gas holes IV, thereby reducing the gas lock caused by the gas entering the production pump barrel.

[0054] The oil pipe short joint 13 is arranged between the sand setting pipe 3 and the gas anchor outer pipe 14; the lower end of the gas anchor outer pipe 14 is connected with the oil pipe joint; the lower part of the oil pipe joint 16 is connected with the tail pipe or the screen pipe.

[0055] The upper end of the long pump barrel 2 is connected with the upper joint 1; the upper part of the upper joint 1 is connected with the oil pipe.

[0056] The center pipe 5 and the sand setting pipe 3 form an annular sand setting cavity III; due to the longer length of the center pipe 5, a supporting ring 4 is arranged below the inlet valve 7 in the annular sand setting cavity III, which supports the center pipe 5; the supporting ring 4 is provided with through holes or through grooves, which do not block the annular sand setting cavity III.

[0057] The use method is as follows:

[0058] S1, downhole operation preparation, first connect the upper end of the production pump barrel with the oil pipe, the lower end with the tail pipe and the screen pipe, and then lower the oil pipe string into the design position of the production well, then connect the upper end of the plunger pull rod 8 with the sucker rod, and then lower the sucker rod string into the bottom of the oil pipe, so as to realize the bumping of the production pump barrel, and the plunger enters the long pump barrel 2.

[0059] S2, swabbing operation, the plunger reciprocates in the long pump barrel 2 of the production pump barrel under the driving of the sucker rod string.

[0060] When going up, the plunger goes up under the driving of the sucker rod string, the upper liquid valve 9 and the lower liquid valve 12 are closed under the pressure of the tubing string, the liquid in the upper part of the plunger is brought out to the ground, the volume of the pump cavity in the lower part of the plunger increases, the pressure decreases, the liquid valve 7 is opened under the pressure of the oil jacket annulus, the liquid in the coal seam, the sand grains, the coal powder and part of the gas carried by the liquid flow into the pump cavity II along the gas anchor channel, when passing through the rising section of the gas anchor Z-shaped channel entrance, the top of the rising section forms a low pressure area due to the density difference of the oil and gas, most of the gas escapes from the liquid, reenters the oil jacket annulus along the gas hole IV, thereby realizing gas-liquid separation, the remaining part continues to flow into the pump cavity along the gas anchor Z-shaped channel,

[0061] When going down, the plunger goes down under the gravity of the sucker rod string, the volume of the pump cavity II decreases, the pressure increases, the upper liquid valve 9 and the lower liquid valve 12 are opened under the action of the liquid in the pump cavity II, the tubing cavity I in the upper part of the plunger is communicated with the pump cavity II in the lower part, at the same time, the liquid valve 7 is closed under the oil pressure in the pump cavity II, the liquid in the pump cavity II is extruded into the tubing cavity I, at this time, the sand grains, the coal powder and a small amount of gas carried by the liquid also enter the tubing cavity I.

[0062] When stopping pumping, the liquid in the pump cavity II is in a static state, the sand grains and the coal seam will sink downward due to the gravity, part of the sediment directly falls into the annular sand settling cavity III between the sand settling pipe 3 and the central pipe 5, and the other part will first fall on the conical surface in the upper part of the liquid valve and slide into the annular sand settling cavity III as the accumulation increases, since the annular sand settling cavity III is relatively long, enough sand grains or coal powder and other impurities from the tubing can be deposited, thereby reducing the phenomenon of sand burying and sand jamming of the liquid valve; at the same time, the coal seam gas in the liquid in the lower tail pipe of the gas anchor will continue to escape upward due to the density difference of the oil and gas, and escape from the gas hole at the top of the rising section of the entrance of the Z-shaped channel in the gas anchor, reenter the oil jacket annulus; the sand grains and the coal powder carried by the small amount of liquid remaining in the upper tubing nipple 13 of the gas anchor and the lower central pipe 5 of the liquid valve 7 will sink and fall into the bottom of the gas anchor baffle 15 due to the gravity, since the bottom of the baffle is designed to have a large enough sediment space, the sediment does not affect the liquid inlet flow passage in the gas anchor.

[0063] Compared with the conventional drainage and production pipe string structure, the present application has the following advantages:

[0064] (1) The drainage and production pump cylinder lower sand settling pipe 3 and the central pipe 5 of the sand settling type sand prevention and gas prevention drainage and production machine pumping string have a design length of several meters, have a large annular sand settling cavity III, can deposit enough sand grains or coal powder and other impurities from the tubing, no matter when the pump is working normally or when stopping pumping, the liquid valve 7 will not be affected by the sediment such as sand grains, and the design length can be arbitrarily adjusted and the size of the sand settling space can be changed according to the sand content of the well condition, compared with the conventional drainage and production pump, the present application has stronger well condition adaptability, and is especially suitable for the drainage and production wells with more sand grains and coal powder.

[0065] (2) The liquid inlet valve 7 of the sand-preventing and gas-preventing drainage pumping machine pipe column is designed with a "Z"-shaped gas separation liquid flow channel, in normal operation, the gas anchor is used as a gas-liquid separation device to perform efficient gas-liquid separation on the gas-containing liquid entering the pump cavity, and the influence of the gas entering the pump cavity on the operation of the drainage pump is reduced, and due to the special baffle design inside the gas anchor, the gas anchor can not only effectively separate gas and liquid, but also not easily cause the accumulation of sand and coal powder in the liquid, causing the flow channel in the gas anchor to be blocked, causing the liquid flow resistance to increase, the drainage pump to be insufficient in liquid supply, and compared with the conventional spiral gas anchor structure, the gas anchor structure can better adapt to the drainage well with more sand and coal powder.

[0066] (3) The "Z"-shaped liquid flow channel of the sand-preventing and gas-preventing drainage pumping machine pipe column structure changes the traditional tail pipe sand and upper liquid inlet, so that the sand and coal powder directly sink to the bottom of the well, avoiding the traditional machine pumping structure tail pipe sand accumulation, and the sand entering the liquid inlet valve leakage.

[0067] (4) The liquid inlet valve 7 and the lower liquid inlet valve 12 of the sand-preventing and gas-preventing drainage pumping machine pipe column are designed with return springs, when the drainage pump is applied in the inclined well, the return spring can help the valve ball in the valve cover to close in time, reduce the ball valve leakage, improve the drainage efficiency, and therefore, the return spring also has strong adaptability to the inclined well.

[0068] (5) The pipe column structure does not need to be washed, has sufficient sand sinking capacity, avoids the sand jamming and sand burying between the pump cylinder and the plunger, and prolongs the service life.

[0069] (6) The pipe column structure is simple, reliable, convenient to operate, and reduces the development cost of the coalbed methane field.

[0070] In summary, the application effectively solves the problems of sand jamming, sand burying, gas locking and ball valve leakage of the conventional drainage pump in the coalbed methane machine pumping well, has long service life, high pump efficiency and wide adaptability.

[0071] In the application, the parts themselves that are not discussed, and the connection methods of the parts in the application are all known technologies in the technical field. Direct application can be used, and no further description is given.

[0072] In the application, the term "a plurality of" refers to two or more, unless otherwise specified. The terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, "connecting" can be fixed connection, or detachable connection, or integral connection; "connecting" can be direct connection, or indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0073] In the description of the application, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", and the like refer to the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the application and simplify the description, and do not indicate or imply that the device or unit referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the application.

[0074] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "a specific embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0075] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A sand-absorbing and gas-proof drainage pumping unit, comprising a drainage pump cylinder and a plunger, characterized in that, The drainage pump cylinder consists of a long pump cylinder, a sand settling pipe, a central pipe, and an inlet valve; The lower end of the long pump cylinder is connected to the sedimentation pipe, and the lower end of the sedimentation pipe is connected to the air anchor. The central tube is installed inside the sedimentation tube, and the lower end of the central tube is connected to the inner wall of the lower end of the sedimentation tube. An inlet valve is installed at the upper end of the central tube, and the plunger is fitted inside the long pump cylinder. A lower return spring is installed inside the inlet valve. The air anchor is equipped with an exhaust liquid flow channel; The air anchor includes an air anchor outer tube and an air anchor baffle; The upper end of the outer pipe of the air anchor is connected to the sand sinking pipe; The air anchor baffle consists of two bent thin plates embedded in the outer tube of the air anchor. The air anchor baffle is divided into an upper baffle and a lower baffle. The upper baffle and the lower baffle are installed in opposite directions, so that the exhaust liquid flow channel inside the outer tube of the air anchor is a "Z" shaped liquid flow channel. The air anchor outer pipe has an air hole at the top of the rising section at the inlet of the "Z"-shaped liquid flow channel.

2. The extraction string of a sand-absorbing and gas-preventing extraction machine according to claim 1, characterized in that, The plunger consists of a pull rod, an upper outlet valve, a short plunger, and a lower outlet valve; The lower end of the pull rod is connected to the upper end of the short plunger, and the upper end of the pull rod is connected to the sucker rod string; The short plunger has an upper liquid outlet valve at the upper end and a lower liquid inlet valve at the lower end on its inner wall. The short plunger has a structure with an annular sand-carrying groove. The lower discharge valve is equipped with an upper return spring.

3. The extraction string of a sand-absorbing and gas-preventing extraction machine according to claim 2, characterized in that, At least two vents are provided.

4. The extraction string of a sand-absorbing and gas-preventing extraction machine according to claim 2, characterized in that, A short oil pipe section is provided between the sand setter pipe and the outer pipe of the air anchor. The lower end of the outer pipe of the air anchor is connected to an oil pipe joint. The lower part of the oil pipe joint is connected to the tail pipe or screen pipe.

5. The extraction string of a sand-absorbing and gas-preventing extraction machine according to claim 1, characterized in that, The upper end of the long pump barrel is connected to an upper coupling, and the upper end of the upper coupling is connected to an oil pipe.

6. The extraction string of a sand-absorbing and gas-preventing extraction machine according to claim 1, characterized in that, The central tube and the sand settling tube form an annular sand settling chamber. A support ring is provided in the annular sand settling chamber below the liquid inlet valve. The support ring is provided with through holes or through grooves.

7. A method for using a suction pipe string in a sedimentation-type sand control and gas extraction machine, characterized in that, The extraction string of a sand-control and gas-controlling extraction machine according to claim 4 includes the following steps: S1. Preparation for well entry operation First, connect the drainage pump barrel and the gas anchor. Connect the oil pipe to the upper end of the drainage pump barrel and the tail pipe and screen pipe to the lower end of the gas anchor. Lower them into the drainage well at the designed position along with the oil pipe string. Then connect the upper end of the plunger to the sucker rod, and lower it into the bottom of the tubing along with the sucker rod, so that it can collide with the drainage pump barrel and the plunger enters the drainage pump barrel; S2. Pumping operation: The plunger, driven by the sucker rod string, moves up and down reciprocally in the long pump barrel of the pumping pump. S3. When pumping stops, the liquid in the pump chamber is in a static state. Sand and coal will settle downwards due to gravity. Some of the sediment will fall directly into the annular sedimentation chamber between the sedimentation pipe and the central pipe. Some of the sediment will first fall onto the cone surface above the inlet valve and slide into the annular sedimentation chamber as the sediment accumulates. Meanwhile, the coalbed methane in the liquid in the lower tailpipe of the gas anchor continues to rise and escapes through the top air hole of the rising section of the "Z"-shaped channel inside the gas anchor, returning to the annulus. The sand and coal dust carried in the small amount of liquid remaining in the upper oil pipe section and the lower central pipe of the inlet valve of the gas anchor will settle and fall to the bottom of the gas anchor baffle due to gravity.

8. The method of using the extraction string of a sedimentation-type sand control and gas extraction machine according to claim 7, characterized in that, When the pumping pump reciprocates up and down in the long pump cylinder: During the upward stroke, the upper outlet valve and the lower inlet valve close under the pressure of the tubing column, and the liquid in the upper part of the plunger is lifted to the ground. The volume of the pump chamber in the lower part of the plunger increases and the pressure drops. The inlet valve opens under the pressure of the annulus. The liquid in the coal seam, along with the sand, coal dust and some gas it carries, flows into the pump chamber along the gas anchor channel. When passing through the inlet section of the gas anchor "Z"-shaped liquid flow channel, most of the gas escapes from the liquid and returns to the annulus along the gas hole. The rest continues to flow into the pump chamber along the gas anchor "Z"-shaped channel. During the downward stroke, the pump chamber volume decreases and the pressure increases. The upper outlet valve and the lower inlet valve open under the action of the liquid in the pump chamber, and the oil pipe chamber above the plunger connects with the lower pump chamber. At the same time, the inlet valve closes under the action of the oil pressure in the pump chamber, and the liquid in the pump chamber is squeezed out into the oil pipe chamber. At this time, the sand particles, coal dust and a small amount of gas carried by the liquid also enter the oil pipe chamber together.

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