A liquid accumulation-free production and drainage system for oil and gas wells

Abstract

The present invention relates to an oil and gas well liquid accumulation-free production and drainage system, comprising a casing and a production string which are arranged in the oil and gas well and whose bottom is inserted below the oil and gas liquid level, the production string being arranged in the casing, thereby forming an annular space gap between the production string and the casing; the production string is composed of a plurality of oil and gas pipes, a plurality of anti-slip liquid reservoirs and a plurality of anti-slip gas injectors which are connected end to end in sequence, an anti-slip controller is arranged every several oil and gas pipes, an anti-slip gas injector is arranged every several anti-slip liquid reservoirs, and the lower the position of the production string is, the fewer the number of anti-slip liquid reservoirs spaced between adjacent anti-slip gas injectors is; the anti-slip gas injector comprises technical features such as an anti-slip liquid reservoir or an oil and gas pipe joint, and an anti-slip gas injection hole structure; the present invention improves the recovery rate of oil and gas, and can be applied not only to oil wells with associated oil and gas, but also to gas wells with associated oil and gas, and has a wide range of adaptability.

Description

Technical Field

[0001] The invention belongs to the field of oil and natural gas production equipment, and in particular relates to an oil and gas well liquid accumulation-free production and drainage system. Background Art

[0002] Oil and gas wells are usually provided with casings in the wells, and a production string consisting of several oil and gas pipes (also called oil pipes in this industry) connected end to end is provided in the casings. When in use, the gas-liquid mixture at the bottom of the oil and gas well is usually sprayed upward to the ground through the production string under the action of pressure difference to realize oil and gas production. However, in the process of oil and gas production, as the production time increases, the formation pressure gradually decreases and the water content of crude oil gradually increases, which leads to a decrease in the pressure difference between the liquid column and the formation, making the slippage of the liquid column more and more serious, and finally causing the oil and gas well to stop spraying, which seriously affects the output of the oil and gas well.

[0003] To solve this problem, the commonly used methods are to reduce the density of the gas-liquid mixture by gas lift and bubble drainage, use electric submersible pumps, plunger drainage to lift the liquid column, and use the method of lowering small pipe strings to increase the flow rate of the gas-liquid mixture. However, these methods have great limitations for the exploitation of natural gas. For example, the gas lift technology is used to inject gas into the casing into the oil and gas pipe to reduce the liquid density. When exploiting natural gas, the inside of the oil and gas pipe is mainly gas, and the pressure difference is very small. The opening and closing of the gas lift valve is controlled by the pressure difference, which seriously affects the opening and closing of the gas lift valve. Therefore, the gas lift technology is only applicable to It is suitable for crude oil extraction (the density of crude oil is large, and the pressure difference between the upper and lower parts of the oil and gas pipe is large), but not suitable for natural gas extraction. Secondly, the gas supply hole of the gas lift valve is usually a straight hole. The gas introduced into the oil and gas pipe can only reduce the density of the gas-liquid mixture in the oil and gas pipe, but cannot increase the flow rate of the gas-liquid mixture. Therefore, its effect in preventing slippage is also general. In addition, there are also one-way valves set in the oil and gas pipe to prevent the liquid column from slipping, but the one-way valve of this method occupies the central channel of the production pipe string, making it impossible to install other downhole tools and detect various downhole parameters, such as temperature and pressure.

[0004] Therefore, how to increase the flow rate of the gas-liquid mixture in the oil and gas wells and improve the gas-liquid carrying capacity of the oil and gas wells without occupying the central channel of the production string is crucial to improving the recovery rate of oil and gas wells, especially the natural gas recovery rate of gas wells. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide an oil and gas well liquid accumulation-free production and drainage system, which utilizes an anti-slip liquid accumulator to improve the liquid carrying capacity of the gas, utilizes an anti-slip gas injection hole structure to increase the flow rate of the gas-liquid mixture in the production tubing, reduces the density of the gas-liquid mixture, and greatly improves the oil and gas recovery rate. The system can be used not only in oil wells with associated oil and gas, but also in gas wells with associated oil and gas, and has a wide range of adaptability.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A slip-proof gas injection hole structure includes a gas supply channel arranged on a production pipe string and used to connect the inside and outside of the production pipe string, and a jet hole swirl block arranged in the gas supply channel. A jet hole A is arranged at the center of the jet hole swirl block. The jet hole A includes a short tapered hole, a fine hole and a long tapered hole which are arranged and connected in sequence according to the gas flow direction, and the taper of the short tapered hole is greater than the taper of the long tapered hole.

[0008] As a further technical solution, a limiting boss is provided in the air supply channel, and a steel gasket (a gasket made of steel material) and an annular sealing gasket are provided between the limiting boss and the jet hole rotating block;

[0009] As a further technical solution, in the vertical direction, the gas supply channel is inclined, and the distance between the top end of the gas supply channel and the central axis of the production string is smaller than the distance between the bottom end of the gas supply channel and the central axis of the production string.

[0010] As a further technical solution, in the horizontal direction, the gas supply channel is eccentrically arranged with the central axis of the production string as the center.

[0011] An oil and gas well liquid accumulation-free production and drainage system, comprising a casing and a production string which are arranged in the oil and gas well and whose bottom is inserted below the oil and gas liquid level, wherein the production string is arranged in the casing, so as to form an annular space between the production string and the casing; the production string is formed by connecting a plurality of oil and gas pipes, a plurality of anti-slip liquid accumulators and a plurality of anti-slip gas injectors in sequence end to end, wherein an anti-slip liquid accumulator or an anti-slip gas injector is arranged every a plurality of oil and gas pipes, and an anti-slip gas injector is arranged every a plurality of anti-slip liquid accumulators, and the lower the position of the production string is, the fewer the number of anti-slip liquid accumulators spaced between adjacent anti-slip gas injectors is;

[0012] Wherein, the anti-slip gas injector comprises an anti-slip liquid reservoir or an oil and gas pipe joint, and the anti-slip gas injection hole structure arranged on the anti-slip liquid reservoir or the oil and gas pipe joint;

[0013] As a further technical solution, the anti-slip liquid reservoir includes a tube body, a main gas channel arranged in the center of the tube body, an annular groove arranged on the inner wall of the tube body and connected to the main gas channel, a gas branch channel arranged in the annular groove and an annular liquid receiving groove opening upward, and the gas branch channel passes through the annular liquid receiving groove.

[0014] As a further technical solution, an annular guide plate is further provided on the top wall of the annular groove, the inner wall of the annular guide plate is smoothly connected to the inner wall of the upper part of the tube body, and the lower part of the annular guide plate is inserted into the annular liquid receiving groove, thereby forming a bent passage in the annular liquid receiving groove;

[0015] As a further technical solution, an annular cylinder is provided on the inner wall of the tube body, the annular cylinder and the inner wall of the tube body enclose an annular cavity, the main gas channel is provided at the center of the annular cylinder, the annular liquid receiving groove is provided on the annular cylinder, and the annular cylinder is also provided with a plurality of gas inlets connecting the main gas channel and the annular cavity;

[0016] As a further technical solution, the annular cylinder is connected to the top wall gap of the annular groove, so as to form a first channel connecting the annular cavity and the bent passage and an annular gas outlet connecting the bent passage and the main gas passage;

[0017] As a further technical solution, the air inlet, the annular cavity, the first channel, the bent passage, and the annular air outlet are connected in sequence to form the gas branch channel.

[0018] As a further technical solution, the annular tube includes an annular base arranged on the inner wall of the tube body, and an annular liquid receiving groove arranged on the annular base;

[0019] As a further technical solution, the air inlet is arranged on the annular base, and the position of the air inlet is higher than the lowest point of the annular cavity;

[0020] As a further technical solution, the annular liquid receiving groove is surrounded by an inner ring plate and an outer ring plate, and the upper surface of the inner ring plate is lower than the upper surface of the outer ring plate.

[0021] As a further technical solution, the tube body includes an upper tube body and a lower tube body, the outer wall of the upper tube body is provided with an annular groove, and the bottom of the lower tube body is provided with an annular tube adapted to the annular groove, the annular tube is arranged in the annular groove and is bonded, welded or threadedly connected to the annular groove.

[0022] As a further technical solution, when the anti-slip air injection hole structure is arranged on the tube body of the anti-slip liquid reservoir, the two ends of the air supply channel are respectively connected to the annular space gap and the main gas channel or the gas branch channel.

[0023] As a further technical solution, the oil and gas pipe joint includes a joint body, a central gas channel arranged on the joint body, and external threads and internal threads respectively arranged at both ends of the joint body;

[0024] As a further technical solution, the anti-slip and degassing air injection hole structure is arranged on the joint pipe body, and two ends of the air supply channel of the anti-slip and degassing air injection hole structure are respectively connected to the annular space gap and the central gas channel.

[0025] As a further technical solution, a perforation section connecting the oil and gas layer and the interior of the casing is provided at the bottom of the casing, a screen pipe is provided at the bottom of the production tubing, and an oil production tree is also provided after the production tubing extends out of the ground. An air filling port is provided on the annular space, and the air filling port is connected to a high-pressure gas source through an air injection pipeline.

[0026] The oil and gas well liquid accumulation-free production and drainage system is applied in oil wells or gas wells where gas and liquid coexist.

[0027] As a further technical solution, the gas well includes any one of a natural gas well, a shale gas well, and a gas lift gas well; the oil well includes any one of a gas lift oil well, an electric submersible pump oil well, and a screw pump oil well.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention sets a jet hole swirl block in the gas supply channel connecting the inside and outside of the production string. When the gas passes through the jet hole swirl block, a Laval effect can be formed to accelerate the gas flow entering the gas supply channel, so that it is sprayed into the inside of the production string at high speed, thereby forming a negative pressure area near the jet hole A of the production string, thereby increasing the flow rate of the gas-liquid mixture in the production string. Compared with the prior art, it not only uses gas to dilute and atomize the gas-liquid mixture in the production string, thereby reducing its density, but also increases the flow rate of the gas-liquid mixture in the production string, further avoiding its slippage problem.

[0030] 2. The present invention eccentrically arranges the gas supply channel connecting the interior of the production tubing and the annular space, so that the gas can move upward in a spiral when it is sprayed into the production tubing. Compared with the vertical upward movement in the prior art, the Bernoulli principle of the supplied gas can be used to form a lifting force on the original gas-liquid mixture in the production tubing, further preventing it from slipping.

[0031] 3. When natural gas rises in the production string, the gas-liquid mixture is rubbed by the inner wall of the production string, and the speed will gradually decrease. The friction resistance of the production string is transmitted from the periphery of the pipe to the center of the pipe by the viscosity of the gas-liquid mixture. Therefore, the flow rate of the gas-liquid mixture decreases quickly near the inner wall of the production string, while the flow rate of the gas-liquid mixture in the center of the production string decreases slowly. This causes liquid to fall along the inner wall of the pipe body, thereby causing the gas well to be flooded. In order to solve this problem, the present invention adds an anti-skid device at each certain distance. The liquid accumulator is provided with a liquid receiving groove and a guide plate on the inner wall of the pipe body, and a gas branch channel passing through the liquid receiving groove is provided on the inner wall of the pipe body. The liquid falling along the pipe wall is guided into the liquid receiving groove by the guide plate to prevent it from sliding to the bottom of the well. In the process of oil and gas rising along the central gas channel, part of the gas is diverted by the gas branch channel so that the liquid in the liquid receiving groove is taken out in the process of passing through the liquid receiving groove and continues to rise along the production pipe string, thereby avoiding the problem of overflow of the accumulated liquid due to increasing liquid accumulation in the liquid receiving groove and continued sliding after the overflow. In addition, when natural gas is ejected from the gas branch pipeline, the upward airflow can be used to form an upward support force on the liquid on the pipe wall, which can further block the downward movement of the liquid on the pipe wall. In summary, the present invention greatly improves the liquid carrying capacity of natural gas by using the annular liquid receiving groove, the guide plate and the branch gas channel in combination, and avoids the problem of gas well flooding caused by the downward movement of liquid. Compared with the gas lift technology of oil and gas wells, it can be applied not only to oil wells, but also to gas wells, and does not require additional energy. The liquid carrying capacity of natural gas can be improved by using the energy of the production layer itself. It has wider applicability and lower cost.

[0032] In summary, the present invention, on the one hand, utilizes the anti-slip injection hole structure for improvement, so that it can increase the flow rate of the gas-liquid mixture in the production tubing, and on the other hand, adds an anti-slip liquid reservoir on the production tubing, which can make full use of the production layer pressure without occupying the central channel of the production tubing, thereby improving the gas-liquid carrying capacity of the oil and gas wells, achieving the effect of no liquid accumulation, and improving the recovery rate of oil and gas. The present invention can be applied not only to oil wells, but also to gas wells, solving the problem of liquid slippage in the production process of oil and gas wells, as well as the problems of gas well flooding and low natural gas recovery rate caused by the decrease in the liquid carrying capacity of the gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of a valve body A in one embodiment of the present invention;

[0035] Figure 3 This is a schematic structural diagram of an upper tube body in one embodiment of the present invention;

[0036] Figure 4It is a schematic structural diagram of a lower tube body in one embodiment of the present invention;

[0037] Figure 5 A schematic structural diagram of a valve body B in one embodiment of the present invention;

[0038] Figure 6 for Figure 5 A magnified image of point A;

[0039] Figure 7 This is a schematic structural diagram of a valve body B in another embodiment of the present invention;

[0040] Figure 8 for Figure 7 Cross-sectional view along direction BB;

[0041] Fig. 9 This is a schematic structural diagram of a valve body B in another embodiment of the present invention;

[0042] Fig.10 It is a comparison diagram of the first gas lift induced blowout and the second gas lift induced blowout in the effect example of the present invention;

[0043] Fig.11 This is a production diagram 12 days after the well handover of the present invention in the effect example of the present invention.

[0044] In the figure: 1, tube body, 2, main gas channel, 3, annular liquid receiving groove, 4, annular guide plate, 5, bending passage, 6, annular cylinder, 7, annular cavity, 8, air inlet, 9, first channel, 10, annular air outlet; 11, annular connecting plate, 13, inner ring plate, 14, outer ring plate, 15, oil and gas pipe, 16, jet hole B, 17, upper tube body, 18, lower tube body, 19, annular groove, 20, annular tube, 21, air supply channel, 22, jet hole swirl block, 23, jet hole A, 24, short tapered hole, 25, fine Hole, 26, long tapered hole, 27, limiting boss, 28, steel pad, 29, annular sealing pad, 30, annular groove, 31, anti-slip gas injection hole structure; 32, casing, 33, production tubing, 34, annular space gap; 35, anti-slip accumulator, 36, anti-slip gas injector, 37, joint body, 38, central gas channel, 39, external thread, 40, internal thread; 41, perforation section, 42, screen tube, 43, Christmas tree, 44, gas injection pipeline, 45, high-pressure gas source, 46, oil and gas layer, 47, packer. DETAILED DESCRIPTION

[0045] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, the term "liquid accumulation free" is explained as follows: slippage refers to the phenomenon that in a gas-liquid two-phase pipe flow, gas exceeds the flow of liquid due to the density difference between gas and liquid; due to the existence of the slippage phenomenon, the gas phase in the wellbore of the oil and gas well is insufficient to carry the liquid phase, resulting in the liquid phase falling back to the bottom of the well, accumulating step by step to form liquid accumulation; liquid accumulation free means hindering the formation of liquid accumulation, preventing the production of oil and gas wells from being affected by the liquid accumulation in the production tubing, which is called liquid accumulation free.

[0049] The present invention is described in further detail below with reference to the accompanying drawings.

[0050] Example 1

[0051] like Figure 1-8 An embodiment of the oil and gas well liquid accumulation-free production and drainage system of the present invention is shown, comprising a casing 32 and a production string 33 which are arranged in the oil and gas well and whose bottom is inserted below the oil and gas liquid level, wherein the production string 33 is arranged in the casing 32, thereby forming an annular space 34 between the production string 33 and the casing 32; the production string 33 is formed by connecting a plurality of oil and gas pipes 15, a plurality of anti-slip liquid reservoirs 35 and a plurality of anti-slip gas injectors 36 in sequence end to end, wherein one anti-slip liquid reservoir 35 or anti-slip gas injector 36 is arranged for every several oil and gas pipes 15, and one anti-slip gas injector 36 is arranged for every several anti-slip liquid reservoirs 35, and the lower the position of the production string 33 is, the fewer the number of anti-slip liquid reservoirs 35 spaced between adjacent anti-slip gas injectors 36 is;

[0052] The anti-slip liquid reservoir 35 includes a tube body 1, a main gas channel 2 arranged at the center of the tube body 1, an annular groove 30 arranged on the inner wall of the tube body 1 and connected to the main gas channel, a gas branch channel arranged in the annular groove 30 and an annular liquid receiving groove 3 with an upward opening, and the gas branch channel passes through the annular liquid receiving groove;

[0053] The anti-slip gas injector 36 includes an anti-slip liquid reservoir 35 and an anti-slip gas injection hole structure provided on the anti-slip liquid reservoir 35;

[0054] The anti-slip gas injection hole structure includes a gas supply channel 21 arranged on the production pipe string 33 and used to connect the inside and outside of the production pipe string 33, and a jet hole swirl block 22 arranged in the gas supply channel 21. The center of the jet hole swirl block 22 is provided with a jet hole A23. The jet hole A23 includes a short tapered hole 24, a fine hole 25 and a long tapered hole 26 which are arranged and connected in sequence according to the gas flow direction. The taper of the short tapered hole 24 is greater than the taper of the long tapered hole 26.

[0055] The anti-slip gas injection hole structure is arranged on the tube body 1 of the anti-slip liquid reservoir 35, and the two ends of the gas supply channel 21 are respectively connected to the annular space gap 34 and the main gas channel 2 or the gas branch channel.

[0056] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, a limiting boss 27 is provided in the gas supply channel 21, and a steel gasket 28 (a gasket made of steel material) and an annular sealing gasket 29 are provided between the limiting boss 27 and the jet hole rotary block 22;

[0057] As an embodiment of an oil and gas well liquid-free production and drainage system of the present invention, the gas supply channel 21 is inclined in the vertical direction, and the distance between the upper end of the gas supply channel 21 and the central axis of the production tubing 33 is smaller than the distance between the bottom end and the central axis of the production tubing 33.

[0058] As an embodiment of a system for producing and draining oil and gas wells free of liquid accumulation according to the present invention, the gas supply channel 21 is eccentrically arranged with the central axis of the production tubing string 33 as the center in the horizontal direction.

[0059] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, an annular guide plate 4 is further provided on the top wall of the annular groove 30, the inner wall of the annular guide plate 4 is smoothly connected to the inner wall of the upper part of the pipe body 1, and the lower part of the annular guide plate 4 is inserted into the annular liquid receiving groove 3, thereby forming a bent passage 5 in the annular liquid receiving groove 3;

[0060] As an embodiment of an oil and gas well liquid-free production and drainage system of the present invention, an annular cylinder 6 is arranged on the inner wall of the pipe body 1, and the annular cylinder 6 and the inner wall of the pipe body 1 form an annular cavity 7, the main gas channel is arranged at the center of the annular cylinder 6, the annular liquid receiving groove 3 is arranged on the annular cylinder 6, and the annular cylinder 6 is also provided with a plurality of air inlets 8 connecting the main gas channel and the annular cavity 7.

[0061] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, the air inlet 8 is arranged obliquely, and the inlet end of the air inlet 8 is low and the outlet end is high.

[0062] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, the annular cylinder 6 is connected to the top wall gap of the annular groove 30, thereby forming a first channel 9 connecting the annular cavity 7 and the bent passage 5 and an annular gas outlet 10 connecting the bent passage 5 and the main gas passage;

[0063] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, the air inlet 8, the annular cavity 7, the first channel, the bent passage 5, and the annular air outlet 10 are connected in sequence to form the gas branch channel.

[0064] As an embodiment of the oil and gas well liquid accumulation-free production and drainage system of the present invention, the annular tube 6 includes an annular base arranged on the inner wall of the pipe body 1, and an annular liquid receiving groove 3 arranged on the annular base;

[0065] As an embodiment of the oil and gas well liquid accumulation-free production and drainage system of the present invention, the air inlet 8 is arranged on the annular base, and the position of the air inlet 8 is higher than the lowest point of the annular cavity 7;

[0066] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, the annular liquid receiving groove 3 is enclosed by an inner ring plate 13 and an outer ring plate 14 , and the upper surface of the inner ring plate 13 is lower than the upper surface of the outer ring plate 14 .

[0067] As an embodiment of an oil and gas well liquid accumulation-free production and drainage system of the present invention, the pipe body 1 includes an upper pipe body 17 and a lower pipe body 18, the outer wall of the upper pipe body 17 is provided with an annular groove 19, and the bottom of the lower pipe body 18 is provided with an annular pipe 20 adapted to the annular groove 19, and the annular pipe 20 is arranged in the annular groove 19 and is threadedly connected to the annular groove 19. In addition, as another embodiment, the annular pipe 20 and the annular groove 19 can also be fixed by bonding, welding, etc.

[0068] As an embodiment of a liquid-free production and drainage system for oil and gas wells of the present invention, a perforation section 41 connecting the oil and gas layer 46 and the interior of the casing 32 is provided at the bottom of the casing 32, a screen pipe 42 is provided at the bottom of the production pipe string 33, and an oil production tree 43 is also provided after the production pipe string 33 extends out of the ground. An air filling port is provided on the annular space 34, and the air filling port is connected to a high-pressure air source 45 through an air injection pipeline 44.

[0069] The perforation section 41 is provided with a plurality of jet holes B16 communicating with the oil and gas layer 46 and the interior of the casing 32 .

[0070] Example 2

[0071] Embodiment 2 is the same as Embodiment 1, except that the structure of the anti-slip gas injector 36 is different. Fig. 9 As shown, the anti-slip gas injector 36 includes an oil and gas pipe 15 joint, and an anti-slip gas injection hole structure provided on the oil and gas pipe 15 joint;

[0072] The anti-slip gas injection hole structure includes a gas supply channel 21 arranged on the production pipe string 33 and used to connect the inside and outside of the production pipe string 33, and a jet hole swirl block 22 arranged in the gas supply channel 21. The center of the jet hole swirl block 22 is provided with a jet hole A23. The jet hole A23 includes a short tapered hole 24, a fine hole 25 and a long tapered hole 26 which are arranged and connected in sequence according to the gas flow direction. The taper of the short tapered hole 24 is greater than the taper of the long tapered hole 26.

[0073] The joint of the oil and gas pipe 15 includes a joint body 37 , a central gas channel 38 arranged on the joint body 37 , and external threads 39 and internal threads 40 respectively arranged at two ends of the joint body 37 .

[0074] The anti-slip gas injection hole structure is arranged on the joint pipe body 37 of the oil and gas pipe 15 joint, and the two ends of the gas supply channel 21 of the anti-slip gas injection hole structure are connected to the annular space gap 34 and the central gas channel 38 respectively.

[0075] As an embodiment of the oil and gas well liquid accumulation-free production and drainage system of the present invention, a limiting boss 27 is provided in the gas supply channel 21, and an annular sealing gasket 29 is provided between the limiting boss 27 and the jet hole rotary block 22;

[0076] As an embodiment of an oil and gas well liquid-free production and drainage system of the present invention, the gas supply channel 21 is inclined in the vertical direction, and the distance between the top end of the gas supply channel 21 and the central axis of the production tubing 33 is smaller than the distance between the bottom end and the central axis of the production tubing 33.

[0077] As an embodiment of a system for producing and draining oil and gas wells free of liquid accumulation according to the present invention, in the horizontal direction, the gas supply channel 21 is eccentrically arranged with the central axis of the production string 33 as the center.

[0078] Example 3

[0079] The liquid accumulation-free oil and gas well system described in Example 1 or Example 2 can be applied to oil wells or gas wells where gas and liquid coexist.

[0080] As an embodiment of the application of the present invention, the gas well includes a natural gas well, a shale gas well, a gas lift well, etc.;

[0081] As an embodiment of the application of the present invention, the oil well includes a gas lift oil well, an electric submersible pump oil well, a screw pump oil well, etc.

[0082] As an embodiment of the application of the present invention, when the original well production cannot be pulled out, a pipe-in-pipe mode can be adopted: a production pipe string of the present invention is lowered into the original well production pipe string.

[0083] The use method and principle of the present invention:

[0084] During the production of oil and gas wells, the gas-liquid mixture in the main gas channel 2 on the production pipe string 33 is ejected upward along the production pipe string 33 under the action of the pressure difference. As the oil and gas production time increases, the pressure difference decreases. Under the action of the friction force of the inner wall of the production pipe string 33, the speed of the gas-liquid mixture in the inner wall area of ​​the production pipe string 33 decreases faster than that in the central area. This causes the liquid on the inner wall of the production pipe string 33 to slide down along the pipe wall. During the sliding process, when the liquid slides down to the anti-slip accumulator 35, it will drip into the annular receiving liquid along the annular guide plate 4 The gas-liquid mixture running upward along the main gas pipeline will partially enter the gas branch channel when passing through the gas inlet 8. During the gas running along the gas branch channel, the liquid received in the annular liquid receiving groove 3 is blown out and carried to enter the main gas channel 2 again, thereby avoiding the liquid from sliding down at the pipe wall and improving the liquid carrying capacity of the liquid. In addition, when the gas in the gas branch channel is blown out, a supporting force is formed on the liquid at the pipe wall, and the channel for the liquid on the inner wall of the production pipe string 33 to slide down is blocked, thereby avoiding the liquid from continuing to fall.

[0085] In addition, when exploiting oil and gas wells with low pressure and output, high-pressure gas can also be introduced into the annular space 34. When the high-pressure gas enters the interior of the production tubing 33 through the anti-slip gas injector 36, the setting of the jet hole A23 on the anti-slip gas injection hole structure can accelerate the gas and increase the flow speed of the gas-liquid mixture in the production tubing 33, thereby avoiding its slippage. In addition, when the gas supply channel 21 adopts an eccentric setting, the gas entering the production tubing 33 from the annular space 34 will spiral upward, forming a supporting force on the gas-liquid mixture in the production tubing 33, further avoiding its slippage.

[0086] In summary, on the one hand, the present invention improves the anti-slip injection hole structure so that it can increase the flow rate of the gas-liquid mixture in the production tubing 33. On the other hand, an anti-slip liquid reservoir 35 is added to the production tubing 33, which can reduce the slippage of the liquid without occupying the central channel of the production tubing 33, thereby improving the gas-liquid carrying capacity of the oil and gas wells, making full use of the production layer pressure, and improving the oil and gas recovery rate. The present invention can be applied not only to oil wells, but also to gas wells, solving the problem of liquid slippage in the production process of oil and gas wells, as well as the problems of gas well flooding and low natural gas recovery rate caused by the decrease in the liquid carrying capacity of the gas wells.

[0087] Effect example: Application example of SuXX-XXH natural gas self-flowing well

[0088] Since the contents of each operation section before and after the construction are different and the time used is quite different, it is impossible to compare and analyze the changes of the drainage one by one. Therefore, in the inducing stage of the natural gas self-flowing well, the present invention compares the changes of the gas lift drainage and the hourly drainage volume of the gas lift inducing the gas lift and the gas lift inducing the gas lift inducing the gas lift ( Fig.10 ), and after the well is handed over, the gas production data when the present invention is used for stable production is recorded ( Fig.11 ), the result is as follows:

[0089] 1. The first gas lift induced blowout (the traditional gas lift induced blowout before the production string of the present invention is run): the well was opened for 3 hours before gas lift, 4 hours after gas lift, and the well was opened for 46 hours after stopping the well lift, a total of 53 hours, the highest casing pressure was 20.8MPa, the lowest was 2.1MPa, and the cumulative liquid output was 61.5m 3 , the maximum liquid output per hour is 8.4m 3 The average liquid output per hour is about 1.16m 3 ;

[0090] 2. Second gas lift induced blowout (using the production string of the present invention): After the production string 33 of the present invention replaced the production string 33 of the conventional gas lift technology, i.e. the technology of the present invention, the gas lift was performed for 26 hours, the well was shut down after the lifting was stopped for 29 hours, a total of 55 hours, and the cumulative liquid output was 129.8m 3 , the maximum liquid output per hour is 8.1m 3The average liquid output per hour is about 2.36m 3 .

[0091] From the above results we can see that:

[0092] 1. After the gas lift well is transformed according to the present invention, when the time used for gas lift exceeds that before the transformation, the average liquid output per hour of the gas lift is still more than twice the average liquid output per hour before the transformation.

[0093] 2. In the traditional gas lift technology, the maximum pressure of the gas lift operation is 20.8MPa, but after applying the present invention, the maximum gas lift pressure is only 13.58MPa. Therefore, it can be explained that compared with the traditional gas lift technology, the gas lift pressure required by the present invention is lower.

[0094] Lower pressure required for post-start wells;

[0095] 3. From Fig.10 It can be seen that during the first gas lift to induce blowout, the pressure in the casing 32 suddenly dropped after the gas lift was opened, and the pressure in the casing 32 was 5.9 MPa when the pump was stopped, resulting in insufficient pressure in the casing 32 during blowout. However, when the present invention is used, when the pressure reaches a maximum of 13.58 MPa, a slow drop occurs, and after the gas lift is stopped, the casing pressure is 13.05 MPa and the pressure still keeps dropping slowly. Therefore, it can be proved that the present invention can make full use of the pressure stored in the casing 32 during gas lift to ensure stable production.

[0096] 4. Fig.11 This is the production situation 12 days after the well was handed over. It is divided into 4 stages from left to right: The first stage is the blue area, which is the first well opening after the well was handed over for 20 hours. Judging from the production temperature, the water content is relatively high. The second stage is the black area, and the production situation in this area is shut-in. The third stage is the red area. During this stage, the production fluctuation is relatively large, and large amounts of gas and liquid are discharged intermittently. It is judged that the well-killing fluid entering the bottom layer is being produced. (After the gas lift is completed after the construction, the remaining fracturing fluid and well-killing fluid in the well total 201m 3 ); The fourth stage is the green area. After a large amount of liquid is produced in the well, the production tends to be stable and stable gas-liquid mixed production begins.

[0097] The above-described embodiments are only preferred embodiments of the present invention, and are not exhaustive of the feasible implementations of the present invention. For those skilled in the art, any obvious changes made thereto without departing from the principles and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A liquid accumulation-free production and drainage system for oil and gas wells, comprising a casing (32) and a production string (33) arranged in the oil and gas well and having its bottom inserted below the oil and gas liquid level, wherein the production string (33) is arranged in the casing (32), thereby forming an annular space (34) between the production string (33) and the casing (32); characterized in that: The production string (33) is formed by connecting a plurality of oil and gas pipes (15), a plurality of anti-slip liquid reservoirs (35) and a plurality of anti-slip gas injectors (36) end to end in sequence, one anti-slip liquid reservoir (35) or one anti-slip gas injector (36) is provided for every plurality of oil and gas pipes (15), and one anti-slip gas injector (36) is provided for every plurality of anti-slip liquid reservoirs (35), and the lower the position of the production string (33), the fewer the number of anti-slip liquid reservoirs (35) spaced between adjacent anti-slip gas injectors (36); The anti-slip gas injector (36) comprises an anti-slip liquid reservoir (35) or an oil and gas pipe joint, and an anti-slip gas injection hole structure arranged on the anti-slip liquid reservoir (35) or the oil and gas pipe joint; the anti-slip gas injection hole structure comprises a gas supply channel (21) arranged on the production pipe string (33) and used to connect the inside and outside of the production pipe string (33), and a jet hole swirl block (22) arranged in the gas supply channel (21); a jet hole A (23) is arranged at the center of the jet hole swirl block (22); the jet hole A (23) comprises a short tapered hole (24), a fine hole (25) and a long tapered hole (26) arranged in sequence and connected according to the gas flow direction, and the taper of the short tapered hole (24) is greater than the taper of the long tapered hole (26); The anti-slip liquid accumulator (35) comprises a tube body (1), a main gas channel (2) arranged at the center of the tube body (1), an annular groove (30) arranged on the inner wall of the tube body (1) and connected to the main gas channel, a gas branch channel arranged in the annular groove (30) and an annular liquid receiving groove (3) with an opening facing upward, the gas branch channel passing through the annular liquid receiving groove; an annular guide plate (4) is also arranged on the top wall of the annular groove (30), the inner wall of the annular guide plate (4) is smoothly connected to the inner wall of the upper part of the tube body (1), and the lower part of the annular guide plate (4) is inserted into the annular liquid receiving groove (3), thereby forming a bent passage (5) in the annular liquid receiving groove (3); an annular tube is arranged on the inner wall of the tube body (1) (6), the annular cylinder (6) and the inner wall of the tube body (1) enclose an annular cavity (7), the main gas channel is arranged at the center of the annular cylinder (6), the annular liquid receiving groove (3) is arranged on the annular cylinder (6), and the annular cylinder (6) is also provided with a plurality of air inlets (8) connecting the main gas channel and the annular cavity (7); the annular cylinder (6) is connected to the top wall gap of the annular groove (30), thereby forming a first channel (9) connecting the annular cavity (7) and the bending passage (5) and an annular air outlet (10) connecting the bending passage (5) and the main gas channel; the air inlet (8), the annular cavity (7), the first channel (9), the bending passage (5), and the annular air outlet (10) are connected in sequence to form the gas branch channel.

2. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: A limiting boss (27) is provided in the air supply channel (21), and a steel pad (28) and an annular sealing pad (29) are provided between the limiting boss (27) and the jet hole rotary block (22); The gas supply channel (21) is arranged obliquely in the vertical direction, and the distance between the upper end of the gas supply channel (21) and the central axis of the production pipe string (33) is smaller than the distance between the lower end of the gas supply channel (21) and the central axis of the production pipe string (33).

3. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: In the horizontal direction, the gas supply channel (21) is eccentrically arranged with the central axis of the production pipe string (33) as the center.

4. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: The annular cylinder (6) comprises an annular base arranged on the inner wall of the tube body (1), and an annular liquid receiving groove (3) arranged on the annular base; The air inlet (8) is arranged on the annular base, and the position of the air inlet (8) is higher than the lowest point of the annular cavity (7); The annular liquid receiving groove (3) is enclosed by an inner ring plate (13) and an outer ring plate (14), and the upper surface of the inner ring plate (13) is lower than the upper surface of the outer ring plate (14).

5. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: When the anti-slip gas injection hole structure is arranged on the tube body (1) of the anti-slip liquid reservoir (35), the two ends of the gas supply channel (21) are respectively connected to the annular space (34) and the main gas channel (2) or the gas branch channel.

6. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: The oil and gas pipe joint comprises a joint pipe body (37), a central gas channel (38) arranged on the joint pipe body (37), and external threads (39) and internal threads (40) respectively arranged at two ends of the joint pipe body (37); The anti-slip and air injection hole structure is arranged on the joint pipe body (37), and the two ends of the air supply channel (21) of the anti-slip and air injection hole structure are respectively connected to the annular space gap (34) and the central gas channel (38).

7. The oil and gas well liquid accumulation-free production and drainage system according to claim 1, characterized in that: The bottom of the casing (32) is provided with a perforation section (41) communicating with the oil and gas layer (46) and the interior of the casing (32); the bottom of the production pipe string (33) is provided with a screen pipe (42); the production pipe string (33) is further provided with a Christmas tree (43) after extending out of the ground; the annular space (34) is provided with a gas charging port, and the gas charging port is connected to a high-pressure gas source (45) through a gas injection pipeline (44).

8. Use of the oil and gas well liquid accumulation-free production and drainage system as claimed in any one of claims 1 to 7 in an oil well or gas well where gas and liquid coexist.

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