CN111005705A - Carbon dioxide injection yield increasing method for depleted coal bed gas well group - Google Patents
Carbon dioxide injection yield increasing method for depleted coal bed gas well group Download PDFInfo
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- CN111005705A CN111005705A CN201911357323.5A CN201911357323A CN111005705A CN 111005705 A CN111005705 A CN 111005705A CN 201911357323 A CN201911357323 A CN 201911357323A CN 111005705 A CN111005705 A CN 111005705A
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- well
- coal bed
- carbon dioxide
- bed gas
- coal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/164—Injecting CO2 or carbonated water
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
Abstract
The invention belongs to the technical field of surface coal bed gas exploitation, and provides a method for increasing the yield of coal bed gas by injecting carbon dioxide into exhausted coal bed gas wells. Selecting a coal bed gas well which enters a depleted gas production block of the coal bed gas well, taking a coal bed gas well which does not produce water and gas as a carbon dioxide pressurizing injection well, directly pressurizing and injecting carbon dioxide, displacing methane gas in a coal reservoir by the pressurized carbon dioxide, driving the methane gas to enter an adjacent coal bed gas well, and closing the well when the carbon dioxide gas is detected in the well group; and stopping production until the pressure of the wellhead of the coal bed gas well injected with the carbon dioxide is increased to the fracture pressure of the coal bed when the well casing is fractured, and ending yield increase. The invention can maximize the recovery ratio of the coal bed gas by injecting carbon dioxide into the coal reservoir within the well group. The method is particularly suitable for the coal bed gas production well which enters the exhaustion stage and has no water. Accelerating the extraction of coal bed gas in the coal bed; the economic value of the exhausted coal bed gas well is increased; can realize the joint sheet production increase among the coal bed gas well groups.
Description
Technical Field
The invention belongs to the technical field of ground exploitation of coal bed gas, and particularly relates to a method for increasing production of coal bed gas by injecting carbon dioxide into depleted coal bed gas wells.
Background
The exploration and development of coal bed gas resources in China begin in the eighties of the twentieth century, and through the development of the coal bed gas industry for nearly thirty years, a part of the earliest coal bed gas well mouths are shut down and shut down due to low energy production. The coal bed gas wellhead is subjected to long-term stable drainage and production, a long-term stable pressure drop funnel is formed in an underground coal reservoir, the permeability of the coal bed around the coal bed gas well is high, and the well group effect formed by long-term drainage and production of the coal bed gas well is obvious.
Disclosure of Invention
The invention aims to provide a method for increasing the yield of coal bed gas by injecting carbon dioxide into depleted coal bed gas well groups, which utilizes the coal bed to adsorb carbon dioxide more easily and replaces the original adsorbed coal bed gas in the process of adsorbing the carbon dioxide to the coal bed, thereby realizing the overall yield increase of the coal bed gas well groups and improving the recovery ratio of coal bed gas resources in a coal reservoir.
The invention is realized by the following technical scheme: a method for increasing the yield of coal bed gas by injecting carbon dioxide into a depleted coal bed gas well group comprises the steps of selecting a gas production block of a coal bed gas well which enters failure, taking a coal bed gas well which does not produce water and gas as a carbon dioxide pressurizing injection well, directly pressurizing and injecting carbon dioxide into a coal reservoir of the well, percolating and diffusing the pressurized carbon dioxide along the range of a pressure drop funnel, gradually percolating to peripheral coal bed gas wells, displacing methane gas in the coal reservoir, driving the methane gas to enter an adjacent coal bed gas well, and immediately closing the well when the carbon dioxide gas is detected in the well group; and stopping production until the pressure of the wellhead of the coal bed gas well injected with the carbon dioxide is increased to the fracture pressure of the coal bed when the well casing is fractured, and ending yield increase.
The specific method comprises the following steps:
(1) selecting a coal bed gas production block: selecting a coal bed gas well which has run into failure, does not produce water and does not produce gas after continuous drainage and mining for more than 20 years;
(2) selecting a carbon dioxide injection well head: selecting an anhydrous coal bed gas well in one of the coal bed gas well groups as a carbon dioxide injection well mouth according to the well arrangement position of the existing coal bed gas well in the block;
(3) installing equipment: installing pressurizing equipment and a carbon dioxide preparation device on a selected carbon dioxide injection well site; injecting the selected carbon dioxide into a coal bed gas well at the periphery of the coal bed gas well, stopping the machine, removing the oil pumping unit, and installing a carbon dioxide detector and a pressure detector at the periphery of the coal bed gas well;
(4) injecting carbon dioxide: injecting carbon dioxide gas into the selected coal-bed gas well, and keeping the wellhead pressure constant in the injection process;
(5) controlling the pressure of the well head: observing the wellhead pressure readings of the peripheral coal-bed gas wells, immediately recording the pressure of carbon dioxide injected into a pressurizing device on a well site when the bottom flow pressure or wellhead casing pressure of the first coal-bed gas well changes, and taking the pressure value recorded at the moment as the maximum pressure of the injected carbon dioxide; ensuring that the pressure of the pressurizing equipment is stable and is lower than the recorded maximum pressure value of the injected carbon dioxide, injecting carbon dioxide gas into the well, and monitoring the wellhead pressure of the surrounding coal bed gas well and the carbon dioxide in real time;
(6) and (5) finishing production: when a coal bed gas well in a well group detects carbon dioxide gas, immediately closing the well; and stopping production until the pressure of the wellhead of the coal-bed gas well injected with the carbon dioxide is increased to the coal-bed fracture pressure when the well casing is fractured, and increasing the yield.
And the selection of the pressurizing equipment is selected according to the fracture of the coal bed during the fracturing of the coal bed gas well.
Because the coal bed gas well is formed through a plurality of years of drainage and production pressure reduction funnels, the permeability of the coal reservoir in the range of the well group reaches the maximum through a plurality of years of drainage and production, and the recovery ratio of the coal bed gas can be increased to the maximum degree by injecting carbon dioxide into the coal reservoir in the range of the well group.
The method can improve the recovery ratio of the coal bed gas, and is particularly suitable for the coal bed gas production well which enters the exhaustion stage and is free of water. The invention improves the recovery ratio of the coal bed gas; accelerating the extraction of coal bed gas in the coal bed; the economic value of the exhausted coal bed gas well is increased; can realize the joint sheet production increase among the coal bed gas well groups.
Drawings
FIG. 1 is a schematic diagram of a method for increasing production of coal bed methane by injecting carbon dioxide into depleted coal bed methane wells according to the present invention; in the figure: SC-1 to SC-19 are production wells for gas discharge, and ZR-1 is a production well for injecting carbon dioxide.
Detailed Description
A method for increasing the yield of coal bed gas by injecting carbon dioxide into a depleted coal bed gas well group is characterized in that the permeability of a coal reservoir in the well group range is maximized after years of drainage and production because the coal bed gas well is formed through years of drainage and production of a pressure drop funnel, and the recovery ratio of the coal bed gas can be increased to the maximum degree by injecting the carbon dioxide into the coal reservoir in the well group range.
A method for increasing the yield of coal bed gas by injecting carbon dioxide into a depleted coal bed gas well group comprises the steps of selecting a gas production block of a coal bed gas well which enters failure, taking a coal bed gas well which does not produce water and gas as a carbon dioxide pressurizing injection well, directly pressurizing and injecting carbon dioxide into a coal reservoir of the well, percolating and diffusing the pressurized carbon dioxide along the range of a pressure drop funnel, gradually percolating to peripheral coal bed gas wells, displacing methane gas in the coal reservoir, driving the methane gas to enter an adjacent coal bed gas well, and immediately closing the well when the carbon dioxide gas is detected in the well group; and stopping production until the pressure of the wellhead of the coal bed gas well injected with the carbon dioxide is increased to the fracture pressure of the coal bed when the well casing is fractured, and ending yield increase.
The specific method comprises the following steps:
(1) selecting a coal bed gas production block: selecting a coal bed gas well which has run into failure, does not produce water and does not produce gas after continuous drainage and mining for more than 20 years;
(2) selecting a carbon dioxide injection well head: selecting an anhydrous coal bed gas well in one of the coal bed gas well groups as a carbon dioxide injection well mouth according to the well arrangement position of the existing coal bed gas well in the block;
(3) installing equipment: installing a set of pressurizing equipment and a set of carbon dioxide preparation device on the well site of the selected carbon dioxide injection well; injecting the selected carbon dioxide into a coal bed gas well at the periphery of the coal bed gas well, stopping the machine, removing the oil pumping unit, and installing a carbon dioxide detector and a pressure detector at the periphery of the coal bed gas well;
(4) injecting carbon dioxide: injecting carbon dioxide gas into the selected coal-bed gas well, and keeping the wellhead pressure constant in the injection process; due to the factors of different formation pressures and different permeabilities in various regions and the like, the carbon dioxide injection rate is determined according to the actual pressure of field injection.
(5) Controlling the pressure of the well head: observing the wellhead pressure readings of the peripheral coal-bed gas wells, immediately recording the pressure of carbon dioxide injected into a pressurizing device on a well site when the bottom flow pressure or wellhead casing pressure of the first coal-bed gas well changes, and taking the pressure value recorded at the moment as the maximum pressure of the injected carbon dioxide; ensuring that the pressure of the pressurizing equipment is stable and is lower than the recorded maximum pressure value of the injected carbon dioxide, injecting carbon dioxide gas into the well, and monitoring the wellhead pressure of the surrounding coal bed gas well and the carbon dioxide in real time;
(6) and (5) finishing production: when a coal bed gas well in a well group detects carbon dioxide gas, immediately closing the well; and stopping production until the pressure of the wellhead of the coal-bed gas well injected with the carbon dioxide is increased to the coal-bed fracture pressure when the well casing is fractured, and increasing the yield. Because the mixed gas of methane and carbon dioxide is used in the later stage of displacement, the amount of the carbon dioxide gas monitored by the coal-bed gas well in the well group is determined according to the production requirement on site and the specific requirements of production enterprises on gas components.
The method can improve the recovery ratio of the coal bed gas, accelerate the extraction of the coal bed gas in the coal bed, increase the economic value of the exhausted coal bed gas well and realize the joint production increase among the coal bed gas well groups.
Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims (3)
1. A method for increasing the yield of coal bed gas by injecting carbon dioxide into depleted coal bed gas wells is characterized by comprising the following steps: selecting a coal bed gas well which enters a depleted gas production block of the coal bed gas well, taking one coal bed gas well which does not produce water and gas as a carbon dioxide pressurizing injection well, directly pressurizing and injecting carbon dioxide into a coal reservoir of the well, percolating and diffusing the pressurized carbon dioxide along the range of a pressure drop funnel, gradually percolating the pressurized carbon dioxide into peripheral coal bed gas wells, displacing methane gas in the coal reservoir, driving the methane gas into an adjacent coal bed gas well, and immediately closing the well when the carbon dioxide gas is detected in the well group; and stopping production until the pressure of the wellhead of the coal bed gas well injected with the carbon dioxide is increased to the fracture pressure of the coal bed when the well casing is fractured, and ending yield increase.
2. The method for increasing the yield of the coal bed methane by injecting the carbon dioxide into the exhausted coal bed methane well group according to the claim 1, is characterized in that: the specific method comprises the following steps:
(1) selecting a coal bed gas production block: selecting a coal bed gas well which has run into failure, does not produce water and does not produce gas for more than 20 years after continuous drainage and production;
(2) selecting a carbon dioxide injection well head: selecting an anhydrous coal bed gas well in one of the coal bed gas well groups as a carbon dioxide injection well mouth according to the well arrangement position of the existing coal bed gas well in the block;
(3) installing equipment: installing pressurizing equipment and a carbon dioxide preparation device on a selected carbon dioxide injection well site; injecting the selected carbon dioxide into a coal bed gas well at the periphery of the coal bed gas well, stopping the machine, removing the oil pumping unit, and installing a carbon dioxide detector and a pressure detector at the periphery of the coal bed gas well;
(4) injecting carbon dioxide: injecting carbon dioxide gas into the selected coal-bed gas well, and keeping the wellhead pressure constant in the injection process;
(5) controlling the pressure of the well head: observing the wellhead pressure readings of the peripheral coal-bed gas wells, immediately recording the pressure of carbon dioxide injected into a pressurizing device on a well site when the bottom flow pressure or wellhead casing pressure of the first coal-bed gas well changes, and taking the pressure value recorded at the moment as the maximum pressure of the injected carbon dioxide; ensuring that the pressure of the pressurizing equipment is stable and is lower than the recorded maximum pressure value of the injected carbon dioxide, injecting carbon dioxide gas into the well, and monitoring the wellhead pressure of the surrounding coal bed gas well and the carbon dioxide in real time;
(6) and (5) finishing production: when a coal bed gas well in a well group detects carbon dioxide gas, immediately closing the well; and stopping production until the pressure of the wellhead of the coal-bed gas well injected with the carbon dioxide is increased to the coal-bed fracture pressure when the well casing is fractured, and increasing the yield.
3. The method for increasing the yield of the coal bed methane by injecting the carbon dioxide into the exhausted coal bed methane well group according to the claim 2, is characterized in that: and the selection of the pressurizing equipment is selected according to the fracture of the coal bed during the fracturing of the coal bed gas well.
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Citations (6)
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| CN1135782A (en) * | 1994-04-01 | 1996-11-13 | 阿莫科公司 | Method for disposing carbon dioxide in a coalbed and simutaneously recovering methane from the coalbed |
| CN1213689A (en) * | 1997-09-22 | 1999-04-14 | 瓦斯塔资源有限公司 | Chemically induced stimulations of subterranean carbonaceous formations with aqueous oxidizing solutions |
| CN102720473A (en) * | 2011-03-31 | 2012-10-10 | 中联煤层气有限责任公司 | Method for exploiting coal bed gas |
| US10052668B1 (en) * | 2017-04-26 | 2018-08-21 | Tsinghua University | Process for treating waste from a pithead power plant and for sequestrating carbon dioxide discharged therefrom |
| CN109403924A (en) * | 2018-09-29 | 2019-03-01 | 山西晋城无烟煤矿业集团有限责任公司 | A kind of single coal bed gas well injection hot water driving gang of wells method for increasing |
| CN110425003A (en) * | 2019-08-14 | 2019-11-08 | 中国矿业大学 | It is a kind of improve cbm development straight well, in directional well well group coal bed gas recovery ratio recovery method |
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2019
- 2019-12-25 CN CN201911357323.5A patent/CN111005705A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1135782A (en) * | 1994-04-01 | 1996-11-13 | 阿莫科公司 | Method for disposing carbon dioxide in a coalbed and simutaneously recovering methane from the coalbed |
| CN1213689A (en) * | 1997-09-22 | 1999-04-14 | 瓦斯塔资源有限公司 | Chemically induced stimulations of subterranean carbonaceous formations with aqueous oxidizing solutions |
| CN102720473A (en) * | 2011-03-31 | 2012-10-10 | 中联煤层气有限责任公司 | Method for exploiting coal bed gas |
| US10052668B1 (en) * | 2017-04-26 | 2018-08-21 | Tsinghua University | Process for treating waste from a pithead power plant and for sequestrating carbon dioxide discharged therefrom |
| CN109403924A (en) * | 2018-09-29 | 2019-03-01 | 山西晋城无烟煤矿业集团有限责任公司 | A kind of single coal bed gas well injection hot water driving gang of wells method for increasing |
| CN110425003A (en) * | 2019-08-14 | 2019-11-08 | 中国矿业大学 | It is a kind of improve cbm development straight well, in directional well well group coal bed gas recovery ratio recovery method |
Non-Patent Citations (2)
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| 孙可明: "低渗透煤层气开采与注气增产流固耦合理论及其应用", 《岩石力学与工程学报》 * |
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Application publication date: 20200414 |