阅读说明：本技术 一种煤层气井复合串联排采装置 (Compound series connection row of coal bed gas well adopts device ) 是由 徐凤银 袁崇亮 王勃 张江华 云箭 姜子杰 张双源 李德慧 张永成 王平 杨赟 于 2021-10-27 设计创作，主要内容包括：本发明公开了一种煤层气井复合串联排采装置,包括生产套管、双层排采套管、引导管、第一泵、第二泵、排气管和排水管,通过双层排采套管和引导管构成由第一泵、第二泵复合串联形式的二级提升系统,其中利用第一泵构成的第一级提升系统形成对排采液的二次气液分离操作,并使排采液由紊流状态转化为层流状态,提高气液分离效率,之后再由第二泵对层流状态的排采液进行第二级提升输出,从而大大降低排采液中气体的含量,极大改善煤层气井的排水效率,有效解决抽采泵效低及不出水的问题,进而获得抽采井稳定连续抽采以及气产量持续高产的有益技术效果。(The invention discloses a composite series-connection drainage and production device for a coal-bed gas well, which comprises a production casing, a double-layer drainage and production casing, a guide pipe, a first pump, a second pump, an exhaust pipe and a drain pipe, wherein a two-stage lifting system in a composite series-connection form of the first pump and the second pump is formed by the double-layer drainage and production casing and the guide pipe, the first-stage lifting system formed by the first pump is used for forming secondary gas-liquid separation operation on drainage and production liquid, the drainage and production liquid is converted into a laminar flow state from a turbulent flow state, the gas-liquid separation efficiency is improved, and then the second-stage lifting output is carried out on the drainage and production liquid in the laminar flow state by the second pump, so that the content of gas in the drainage and production liquid is greatly reduced, the drainage efficiency of the coal-bed gas well is greatly improved, the problems of low drainage pump efficiency and no water drainage is effectively solved, and the beneficial technical effects of stable and continuous drainage of the extraction well and continuous and high yield of gas yield are further obtained.)

1. A composite series-connection drainage and production device for a coal-bed gas well is characterized by comprising an in-well unit and a wellhead unit;

the well unit comprises a production casing, a double-layer discharging and mining casing, a guide pipe, a first pump and a second pump, wherein the double-layer discharging and mining casing is positioned inside the production casing, a first annular space is formed between the production casing and an outer casing in the double-layer discharging and mining casing, and a second annular space is formed between the outer casing and an inner casing of the double-layer discharging and mining casing; the first pump is positioned in the production casing and is connected with the lower end of the outer casing, and the inlet of the first pump is communicated with the drainage and production liquid of the first annular space; one end of the guide pipe is communicated with an outlet of the first pump, the other end of the guide pipe is communicated with the second annular space, and the communication position of the guide pipe and the second annular space is higher than the liquid level of the produced liquid discharged from the interior of the second annular space; the second pump is positioned in the outer casing, an inlet of the second pump is communicated with the drainage and production liquid of the second annular space, and an outlet of the second pump is communicated with the inner casing;

the wellhead unit comprises an exhaust pipe and a drain pipe, the exhaust pipe is communicated with the first annular space and the second annular space, and the drain pipe is communicated with the inner casing.

2. The composite series drainage and production device for coal-bed gas well as claimed in claim 1, wherein the well unit further comprises a heater, and the heater is in contact with drainage fluid.

3. The composite series drainage and production device for coal-bed gas wells as claimed in claim 2, wherein the heater is located in the second annular space and is in contact with drainage fluid inside the second annular space.

4. The composite series drainage and production device for the coal-bed gas well as the method as claimed in claim 3, wherein the heater adopts a heating casing short section and is connected with the lower part of the outer casing.

5. The composite series-connection drainage and production device for the coal-bed gas well as claimed in claim 4, wherein a heating rod is arranged in the heating casing pipe nipple.

6. The composite series drainage and production device for coal-bed gas wells as claimed in claim 1, wherein the wellhead unit is provided with a first exhaust pipe and a second exhaust pipe, and the first exhaust pipe is communicated with the first annular space and the second exhaust pipe is communicated with the second annular space.

7. The composite series production and drainage device for coal-bed gas wells as claimed in claim 1, wherein the well unit further comprises a screen nipple; the screen pipe nipple is positioned above the liquid level position of the liquid discharged and produced in the first annular space and above the liquid level position of the liquid discharged and produced in the second annular space, is connected with the outer casing pipe and communicates the first annular space with the second annular space.

8. The composite series drainage and production device for the coal-bed gas well as the production method thereof are characterized in that the first pump adopts a submersible diaphragm pump.

9. The composite tandem drainage and production device for coal-bed gas well as claimed in any one of claims 1 to 7, wherein the second pump is a tubing pump and further comprises a sucker rod; the sucker rod is positioned inside the inner casing, one end of the sucker rod is connected with the second pump, and the other end of the sucker rod extends out of the wellhead unit.

10. The composite series drainage and production device for the coal-bed gas well as the coal-bed gas well is characterized in that a pressure meter and/or a flow meter are arranged on the exhaust pipe.

Technical Field

The invention belongs to the technical field of coal and coal bed gas co-production, and particularly relates to a composite series-connection drainage and production device for a coal bed gas well.

Background

The coal bed gas is hydrocarbon gas which is stored in a coal bed, takes methane as a main component, is adsorbed on the surface of coal matrix particles as a main component, is partially dissociated in coal pores or dissolved in coal bed water, is an associated mineral resource of coal, and is a high-quality energy source and a chemical raw material. The coal bed gas generated in the coal mining process is effectively utilized, the energy structure of China can be improved to a certain extent, clean gas energy is increased, and the defects of regional distribution and supply quantity of conventional natural gas in China are overcome.

Taking Lanzhou Yajie coal-electricity Haishi Bay Jingtian as an example, the main gas component of the ore is CO₂And CH₄. Ordering as CO according to the magnitude of concentration₂>CH₄. The carbon dioxide of the second layer of the main coal bed coal is more than 50 percent, and CH is contained in the coal bed gas of the deep expanded area₄Increased concentration of CO₂The concentration is reduced. The gas production effect of three ground wells at the early stage of the east part of the mining area is good, the maximum daily gas production reaches more than 2000, and the produced gas is CO₂Mainly comprises the following steps. However, due to the large amount of CO₂The gas can be mixed with the drainage and production liquid and discharged through the oil pumping pipe, so that the phenomenon that water cannot be discharged frequently due to the reduction of pump efficiency is caused, the daily gas production is rapidly reduced and the machine is stopped, and further the drainage and production effect of the ground drainage and production well is influenced.

Disclosure of Invention

In view of the above problems, the present invention discloses a composite tandem drainage and production device for a coal bed gas well, which overcomes or at least partially solves the above problems.

In order to achieve the purpose, the invention adopts the following technical scheme:

a composite series-connection drainage and production device for a coal-bed gas well comprises an in-well unit and a wellhead unit; the well unit comprises a production casing, a double-layer discharging and mining casing, a guide pipe, a first pump and a second pump, wherein the double-layer discharging and mining casing is positioned inside the production casing, a first annular space is formed between the production casing and an outer casing in the double-layer discharging and mining casing, and a second annular space is formed between the outer casing and an inner casing of the double-layer discharging and mining casing; the first pump is positioned in the production casing and is connected with the lower end of the outer casing, and the inlet of the first pump is communicated with the drainage and production liquid of the first annular space; one end of the guide pipe is communicated with an outlet of the first pump, the other end of the guide pipe is communicated with the second annular space, and the communication position of the guide pipe and the second annular space is higher than the liquid level of the produced liquid discharged from the interior of the second annular space; the second pump is positioned in the outer casing, an inlet of the second pump is communicated with the drainage and production liquid of the second annular space, and an outlet of the second pump is communicated with the inner casing; the wellhead unit comprises an exhaust pipe and a drain pipe, the exhaust pipe is communicated with the first annular space and the second annular space, and the drain pipe is communicated with the inner casing.

Optionally, the downhole unit further comprises a heater, and the heater is in contact with the drainage fluid.

Optionally, the heater is located in the second annular space and is in contact with drainage fluid inside the second annular space.

Optionally, the heater adopts a heating casing short joint and is connected with the lower part of the outer casing.

Optionally, a heating rod is arranged in the heating casing pipe nipple.

Optionally, the wellhead unit is provided with a first exhaust pipe and a second exhaust pipe, and the first exhaust pipe is communicated with the first annular space, and the second exhaust pipe is communicated with the second annular space.

Optionally, the downhole unit further comprises a screen sub; the screen pipe nipple is positioned above the liquid level position of the liquid discharged and produced in the first annular space and above the liquid level position of the liquid discharged and produced in the second annular space, is connected with the outer casing pipe and communicates the first annular space with the second annular space.

Optionally, the first pump is a submersible diaphragm pump.

Optionally, the second pump is a tubing pump, and further comprises a sucker rod; the sucker rod is positioned inside the inner casing, one end of the sucker rod is connected with the second pump, and the other end of the sucker rod extends out of the wellhead unit.

Optionally, a pressure gauge and/or a flow meter are arranged on the exhaust pipe.

The invention has the advantages and beneficial effects that:

in the composite series-connection drainage and extraction device for the coal-bed gas well, a first pump and a second pump form a composite series-connection type two-stage lifting system through a double-layer drainage and extraction sleeve and a guide pipe, a first-stage lifting system formed by the first pump is used for forming secondary gas-liquid separation operation on drainage and extraction liquid, the drainage and extraction liquid is converted into a laminar flow state from a turbulent flow state, the gas-liquid separation efficiency is improved, and then the second pump is used for carrying out second-stage lifting output on the drainage and extraction liquid in the laminar flow state, so that the content of gas in the drainage and extraction liquid is greatly reduced, the drainage efficiency of the coal-bed gas well is greatly improved, the problems that the drainage pump efficiency is low and water cannot be drained are effectively solved, and the beneficial technical effects that the drainage of the extraction well is stable and continuous and high-yield of gas is achieved are further obtained.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. In the drawings:

FIG. 1 is a schematic structural diagram of an downhole unit in a composite series-connected drainage and production device for a coal-bed gas well according to one embodiment of the invention;

fig. 2 is a schematic structural diagram of a wellhead unit in a composite series-connected drainage and production device for a coal-bed gas well according to the embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail and fully with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Referring to fig. 1 and 2, the composite tandem drainage and production device for the coal-bed gas well in the embodiment includes an inner unit 1 located inside the coal-bed gas well and a wellhead unit 2 located at the wellhead of the coal-bed gas well.

The downhole unit 1 comprises a production casing 11, a double production casing 12, a guide pipe 13, a first pump 14 and a second pump 15. The production casing 11 is arranged in the coal-bed gas well along the well depth direction, the double-layer production casing 12 is arranged in the production casing 11, a first annular space 31 is formed between the production casing 11 and the outer casing 121 in the double-layer production casing 12, and a second annular space 32 is formed between the outer casing 121 and the inner casing 122 in the double-layer production casing 12.

The first pump 14 is located inside the production casing 11 and is connected to the lower end of the outer casing 121, while the inlet 141 of the first pump 14 is in communication with the production fluid of the first annular space 31. One end of the guide pipe 13 is communicated with the outlet of the first pump 14, the other end is communicated with the second annular space 32, and the communication position of the guide pipe 13 and the second annular space 32 is higher than the liquid level of the discharged and produced liquid in the second annular space 32, so that the discharged and produced liquid in the first annular space 31 is conveyed to the second annular space 32 by the first pump 14, and a descending process after the lift of the discharged and produced liquid is formed. The second pump 15 is located inside the outer casing 121, and an inlet of the second pump 15 is communicated with the drainage fluid of the second annular space 32, and an outlet of the second pump 15 is communicated with the inner casing 122, so that the drainage fluid located in the outer casing 121 is output through the inner casing 122 by the second pump 15.

The wellhead unit 2 includes an exhaust pipe 21 and a drain pipe 22. The exhaust pipe 21 communicates with the first annular space 31 and the second annular space 32 for CO inside the first annular space 31 and the second annular space 32₂And CH₄And discharging. The drainage pipe 22 is communicated with the inner casing 122 and is used for leading out drainage and production liquid.

When the device is adopted to adopt the compound series row of this embodiment coal bed gas well to adopt, arrange the in-process of adopting liquid to carry out natural gas-liquid separation in being located first annular space, carry to the second annular space with the help of first pump with the row of being located first annular space to adopt the liquid, carry out the first time lifting operation in the well to arranging the liquid, make row adopt the liquid and form the second time gas-liquid separation in the second annular space at this in-process, thereby make row adopt the liquid by turbulent state transform laminar state into laminar flow state, later carry out the second time lifting operation and carry to ground through the inlayer sleeve pipe with the help of the second pump to the row of the laminar flow state who lies in the second annular space adopts the liquid again.

Therefore, the first pump and the second pump are connected in series in a composite mode to form the second-stage lifting system, the first-stage lifting system lifts the discharged and produced liquid in a gas-liquid mixing state in the first annular space and enters the second annular space through the guide pipe, the discharged and produced liquid is converted from a turbulent flow state into a laminar flow state, the discharged and produced liquid is subjected to second-stage gas-liquid separation in the second annular space, and then the discharged and produced liquid in the laminar flow state is subjected to second-stage lifting output, so that the content of gas in the discharged and produced liquid is greatly reduced, the drainage efficiency of the coal-bed gas well is greatly improved, and the continuous high-yield beneficial technical effects of stable and continuous extraction of the extraction well and gas yield are achieved.

Referring to fig. 1, in the combined tandem drainage and production device for a coal-bed gas well in the embodiment, the well unit 1 is further provided with a heater 16. Wherein, the heater 16 is in the form of a heating casing nipple, is positioned in the first annular space 31 and is connected with the lower part of the outer casing 121 to form contact with the drainage and production liquid in the second annular space 32, so as to form low-temperature heating effect on the drainage and production liquid in the first annular space 31 and the drainage and production liquid in the second annular space 32.

At the moment, the heater which is in contact with the drainage and production liquid in the second annular space is arranged, the drainage and production liquid is heated by the heater, and meanwhile, the temperature of the drainage and production liquid in the first annular space and the temperature of the drainage and production liquid in the second annular space are increased, so that the release of gas in the drainage and production liquid is promoted, the gas-liquid separation efficiency is improved, particularly, the secondary gas-liquid separation efficiency of the drainage and production liquid in the second annular space is improved, the content of gas in the drainage and production liquid is further reduced, and the drainage efficiency of the coal-bed gas well is improved.

In this embodiment, a heating sleeve sub provided with a heating rod is used as the heater, and an electric heating operation is performed by a cable. Of course, in other embodiments, according to different practical situations, other types of heaters may be used to heat the drainage and production fluid, so as to achieve the effect of promoting the release of gas in the drainage and production fluid.

Referring to fig. 1, in the combined tandem drainage and production device for the coal-bed gas well in the embodiment, the well unit 1 is further provided with a screen pipe nipple 17. Wherein the screen nipple 17 is located above the level of production fluid inside the first annular space 31 and above the level of production fluid inside the second annular space 32 and is connected to the outer casing 121 to connect the first annular space 31 and the second annular space 32.

Therefore, the first annular space and the second annular space are communicated through the screen pipe nipple, and the gas in the first annular space and the gas in the second annular space can be converged and then uniformly output. At the moment, only one exhaust pipe can be arranged on the wellhead unit to lead out gas, so that the structure of the wellhead unit is simplified, and the structural cost of the whole coal-bed gas well composite series-connection drainage and production device is reduced.

Of course, in other embodiments, according to actual requirements, the screen pipe nipple may not be provided, and the first exhaust pipe and the second exhaust pipe are provided at the wellhead unit at the same time, so that the first exhaust pipe is communicated with the first annular space, and the second exhaust pipe is communicated with the second annular space, so as to respectively lead out the gas inside the first annular space and the gas inside the second annular space.

In this embodiment, the first pump 14 is a submersible diaphragm pump, the second pump 15 is a conventional tubing pump, and a sucker rod 18 is also provided. The sucker rod 18 is located inside the inner casing 122, and one end is connected with the second pump 15, and the other end is extended from the wellhead unit 2, so that the second pump 15 is driven to rotate through the sucker rod 18, and the output of the discharged and produced liquid is completed. Of course, in other embodiments, the first pump may be a rodless pump of another type, such as an electric submersible progressive cavity pump, and the second pump may be a sucker rod pump of another type, such as a progressive cavity pump, depending on the application site.

Referring to fig. 2, the wellhead unit 2 of the present embodiment further includes a first cross 23, a second cross 24, and a first cross 25. Wherein, the one end along vertical direction in the first cross 23 is connected with the one end that extends to the well head in the production casing 11, both ends along the horizontal direction in the first cross 23 communicate with blast pipe 21, the one end along vertical direction in the second cross 24 penetrates the other end along vertical direction in the first cross 23 and communicates with outer sleeve pipe 121, both ends along the horizontal direction in the second cross 24 are in the encapsulated situation, the one end along vertical direction in the first tee 25 penetrates the other end along vertical direction in the second cross 24 and communicates with inlayer sleeve pipe 122, the one end along horizontal direction in the first tee 25 communicates with drain pipe 22, the other end along vertical direction in the first tee 25 then is equipped with closing cap 26. The sucker rod 18 then extends vertically through the closure 26. Like this, realize the emission to gaseous in the well through the blast pipe of being connected with first cross, realize the output to arranging the production fluid through the drain pipe of being connected with first tee bend.

In addition, a first casing head 271 and a first casing hanger 272 are provided between the first cross 23 and the outer casing 121 to act as a seal between the first cross 23 and the outer casing 121. A second casing head 273 and a second casing hanger 274 are provided between the second cross-fitting 24 and the inner casing 122 to act as a seal between the second cross-fitting 24 and the inner casing 122. Of course, in other embodiments, other types of sealing assemblies may be used to seal the first four-way connection to the outer casing and the second four-way connection to the inner casing.

Further, a pressure gauge 28 and a flow meter 29 are provided in the exhaust pipe 21 of the present embodiment. Like this, can real-time supervision well discharge gas's data with the help of manometer and flowmeter to record and aassessment to the gas storage volume of coal bed gas in production, and then regard this data as the foundation when follow-up coal bed gas that is in similar environment, predict its gas storage volume, help the expansion of follow-up row to adopt work.

While the foregoing is directed to embodiments of the present invention, other modifications and variations of the present invention may be devised by those skilled in the art in light of the above teachings. It should be understood by those skilled in the art that the foregoing detailed description is for the purpose of better explaining the present invention, and the scope of the present invention should be determined by the scope of the appended claims.