CN112855088A - Method for improving gas production rate of coal bed - Google Patents
Method for improving gas production rate of coal bed Download PDFInfo
- Publication number
- CN112855088A CN112855088A CN202110366041.2A CN202110366041A CN112855088A CN 112855088 A CN112855088 A CN 112855088A CN 202110366041 A CN202110366041 A CN 202110366041A CN 112855088 A CN112855088 A CN 112855088A
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- China
- Prior art keywords
- oil pipe
- coal bed
- coal
- hollow rod
- gas
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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
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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
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
- E21B43/122—Gas lift
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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
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
Abstract
The invention discloses a method for improving the gas production of a coal bed, which deepens the penetration depth of an oil pipe in a sleeve, wherein the penetration depth of the oil pipe can reach below the coal bed, and simultaneously, liquid in a shaft is discharged by gas lift operation, so that the liquid level in the shaft is lower than the coal bed, the range of a pressure drop funnel in the coal bed is further expanded, more layer setters are desorbed and flow into the shaft, and the gas production of the coal bed is improved.
Description
Technical Field
The invention relates to the technical field of coal bed gas exploitation, in particular to a method for improving gas production rate of a coal bed.
Background
The production of the coal bed gas well is realized in a drainage and depressurization mode, wherein the drainage and depressurization mode is to pump and drain confined water in a coal reservoir to reduce the pressure of a coal reservoir and promote the desorption of methane adsorbed in the coal bed to form free methane.
In the prior art, drainage and depressurization of a coal-bed gas well are generally performed by combining an oil pumping unit and a pump, the coal powder in a shaft of the coal-bed gas well is considered to be large, the pump is generally pumped to the position above the coal bed for drainage, and if the pump is pumped to the position below the coal bed, pump blockage accidents can be caused.
However, in the coal-bed gas well, drainage and pressure reduction are only carried out for a plurality of meters above the coal bed, the water level of underground water in the coal bed can only be reduced for a plurality of meters above the coal bed, the pressure reduction range in the coal bed cannot be further expanded, and the gas yield cannot be improved.
Therefore, how to increase the gas production rate of the coal seam becomes a technical problem to be solved urgently by the technical personnel in the field.
Disclosure of Invention
In view of the above, the present invention provides a method for increasing gas production of a coal seam, so as to increase the gas production of the coal seam.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for improving the gas production rate of a coal seam is characterized by comprising the following steps:
1) performing operation under pressure at the wellhead of the coal bed gas well;
2) pumping out a sucker rod and a rod pump in the coal bed gas well in sequence;
3) connecting a lengthened oil pipe at the upper end of the oil pipe, and lowering the oil pipe into the lengthened oil pipe in the casing of the coal-bed gas well by the depth of the lengthened oil pipe;
4) a hollow rod is arranged in the oil pipe in a downward mode until the lower end of the hollow rod is located above the check valve, nitrogen or coal bed gas is injected into the oil pipe through the hollow rod, or the nitrogen or the coal bed gas is injected into an annular space between the hollow rod and the oil pipe, gas lift operation is carried out, liquid in the oil pipe is discharged, and liquid level balance is achieved;
5) repeating the steps 3) -4) until the liquid level in the shaft of the coal bed gas well is reduced to a preset depth below the coal bed;
6) and producing coal bed gas from the annular space of the oil pipe and the casing pipe.
Preferably, in the method for improving the gas production rate of the coal seam, the distance between the lower end of the hollow rod and the check valve in the step 2) is 0.5-1.0 m.
Preferably, in the method for improving the gas production rate of the coal seam, the preset depth in the step 5) is at least 5 m.
Preferably, in the method for improving the gas production rate of the coal seam, the hollow rod in the step 4) is a steel pipe.
According to the technical scheme, the method for improving the gas production rate of the coal bed deepens the penetration depth of the oil pipe in the sleeve, the penetration depth of the oil pipe can reach below the coal bed, liquid in a shaft is discharged by gas lift operation, the liquid level in the shaft is lower than the coal bed, the range of a pressure drop funnel in the coal bed is further expanded, more layer devices are enabled to desorb and flow into the shaft, and therefore the gas production rate of the coal bed is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a prior art configuration of a coal bed gas well;
FIG. 2 is a schematic structural diagram of a hollow rod arranged in a coal-bed gas well according to an embodiment of the invention;
fig. 3 is a flowchart of a method for increasing gas production from a coal seam according to an embodiment of the present invention.
Wherein the content of the first and second substances,
1. sucker rod, 2, rod-type pump, 3, oil pipe, 4, hollow pole, 5, check valve.
Detailed Description
The invention discloses a method for improving the gas production rate of a coal bed, which aims to improve the gas production rate of the coal bed.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. 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.
Please refer to fig. 1-3.
The invention discloses a method for improving the gas production rate of a coal bed, which is used for improving the gas production rate of the coal bed and removing the limitation that the gas production rate of the coal bed is difficult to improve due to pump blockage.
The method for improving the gas production rate of the coal bed is implemented on the basis of the conventional coal bed gas well, and specifically comprises the following steps:
1) performing operation under pressure at the wellhead of the coal bed gas well;
2) pumping out a sucker rod 1 and a rod pump 2 in the coal bed gas well in sequence;
3) connecting a lengthened oil pipe at the upper end of the oil pipe 3, and putting the oil pipe 3 into the casing of the coal-bed gas well by the depth of the lengthened oil pipe;
4) a hollow rod 4 is put into the oil pipe 3 until the lower end of the hollow rod 4 is positioned above a check valve 5, nitrogen or coal bed gas is injected into the oil pipe 3 through the hollow rod 4 to carry out gas lift operation, and liquid in the oil pipe 3 is discharged until the liquid level is balanced;
5) repeating the steps 3) -4) until the liquid level in the shaft of the coal bed gas well is reduced to a preset depth below the coal bed;
6) and producing coal bed gas from the annular space of the oil pipe and the casing.
The operation under pressure is a method for forcibly operating without open flow and well killing under the condition that pressure exists in an oil gas well.
In the step 1), the oil sleeve annulus is blocked by the under-pressure operation device, and the oil pipe 3 is blocked due to the fact that liquid level balance is achieved between the coal-bed gas well and the stratum at the moment, namely the stratum pressure is not larger than the pressure in the oil pipe 3 and the effect of the one-way valve is added.
The sucker rod 1 and the rod pump 2 are drawn out in the step 2) so as to facilitate the hollow rod 4 to be put into the oil pipe 3 in the step 4).
And 3) connecting the lengthened oil pipe to the upper end of the oil pipe 3 in the step 3), so that the oil pipe 3 can be placed in the casing, and the check valve 5 is placed synchronously along with the oil pipe 3. The lowering depth of the tubing 3 in the casing is at most equal to the length of one extended length tubing. The lengthened oil pipe is in threaded connection with the oil pipe 3, and the upper end of the lengthened oil pipe is hung on the casing pipe through the oil pipe hanger.
The using number of the lengthened oil pipes in the step 3) is determined according to the distance between the lower end of the oil pipe 3 and the liquid level, and is not particularly limited herein.
After the oil pipe 3 goes downwards for a certain distance, the check valve 5 of the oil pipe 3 is positioned below the liquid level, the hollow rod 4 goes downwards into the oil pipe 3 at the moment, the lower end of the hollow rod 4 is positioned above the check valve 5, nitrogen or coal bed gas is injected into the annular space between the hollow rod 4 or the hollow rod 4 and the oil pipe 3, gas lift operation is carried out, and liquid in the oil pipe 3 is discharged until the liquid level is balanced. In the embodiment of injecting nitrogen or coal bed gas into the hollow rod 4, the liquid in the oil pipe 3 is discharged through the annular space between the hollow rod and the oil pipe 3, and in the embodiment of injecting nitrogen or coal bed gas into the annular space between the hollow rod 4 and the oil pipe 3, the liquid in the oil pipe 3 is discharged through the oil pipe.
Specifically, form the connectivity structure between oil pipe 3 and the pit shaft, be similar to the linker, along with hollow rod 4 injects nitrogen gas or coal bed gas into oil pipe 3, perhaps, inject nitrogen gas or coal bed gas into the annular space between hollow rod 4 and oil pipe 3, lift the liquid in oil pipe 3 to ground, the liquid pressure in oil pipe 3 is less than the liquid pressure in the pit shaft this moment, liquid in the pit shaft passes through single current valve 5 and gets into oil pipe 3, the annular space between hollow rod 4 or hollow rod 4 and oil pipe 3 constantly lifts the liquid that gets into in oil pipe 3, liquid pressure in oil pipe 3 equals the liquid pressure in the pit shaft, reach a new liquid level balance.
And (4) after the new liquid level balance is achieved, repeating the steps 3) and 4) until the liquid level in the shaft of the coal bed gas well is reduced to the preset depth below the coal bed, and finally recovering gas production. The produced coal bed gas is discharged through an annular space between the oil pipe 3 and the casing pipe.
Liquid in the oil pipe 3 is discharged through gas lift operation in the step 4), the pump blockage can be effectively avoided, and meanwhile, the liquid is discharged from the oil sleeve annulus during the gas lift operation, so that the hollow rod 4 can be prevented from being blocked.
According to the method for improving the gas production rate of the coal bed, the penetration depth of the oil pipe 3 in the casing is deepened, the penetration depth of the oil pipe 3 can reach the position below the coal bed, liquid in a shaft is discharged by gas lift operation, the liquid level in the shaft is lower than the coal bed, the range of a pressure drop funnel in the coal bed is further enlarged, more layer devices are enabled to desorb and flow into the shaft, and therefore the gas production rate of the coal bed is improved.
Specifically, after the hollow rod 4 is lowered into the oil pipe 3 in the step 2), the lower end of the hollow rod 4 is located above the check valve 5, preferably, the distance between the lower end of the hollow rod 4 and the check valve 5 is 0.5-1.0m, so that liquid flowing into the oil pipe 3 through a shaft can be discharged to a greater extent, and the falling height of the liquid level after the oil pipe 3 is deepened in a single time is increased to the greatest extent.
Preferably, the liquid level in the shaft of the coal seam gas well in the step 5) is reduced to a preset depth below the coal seam, wherein the preset depth is at least 5 m.
In a particular embodiment of the solution, the hollow bar 4 used in step 4) is a steel tube.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (4)
1. A method for improving the gas production rate of a coal seam is characterized by comprising the following steps:
1) performing operation under pressure at the wellhead of the coal bed gas well;
2) pumping out a sucker rod (1) and a rod pump (2) in the coal bed gas well in sequence;
3) connecting a lengthened oil pipe at the upper end of the oil pipe (3), and lowering the oil pipe (3) into the casing of the coal-bed gas well to the depth of the lengthened oil pipe;
4) a hollow rod (4) is lowered into the oil pipe (3) until the lower end of the hollow rod (4) is positioned above the check valve (5), nitrogen or coal bed gas is injected into the oil pipe (3) through the hollow rod (4), or the nitrogen or the coal bed gas is injected into an annular space between the hollow rod (4) and the oil pipe (3), gas lift operation is carried out, liquid in the oil pipe (3) is discharged, and liquid level balance is achieved;
5) repeating the steps 3) -4) until the liquid level in the shaft of the coal bed gas well is reduced to a preset depth below the coal bed;
6) and producing coal bed gas from the annular space between the oil pipe and the casing pipe.
2. The method for improving the gas production rate of a coal seam according to claim 1, wherein the distance between the lower end of the hollow rod (4) and the check valve (5) in the step 2) is 0.5-1.0 m.
3. The method for enhancing gas production from a coal seam according to claim 1, wherein the predetermined depth in step 5) is at least 5 m.
4. The method for improving gas production of a coal seam according to claim 1, wherein the hollow rod (4) in the step 4) is a steel pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110366041.2A CN112855088B (en) | 2021-04-06 | 2021-04-06 | Method for improving gas production rate of coal bed |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110366041.2A CN112855088B (en) | 2021-04-06 | 2021-04-06 | Method for improving gas production rate of coal bed |
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| Publication Number | Publication Date |
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| CN112855088A true CN112855088A (en) | 2021-05-28 |
| CN112855088B CN112855088B (en) | 2023-04-07 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107558962A (en) * | 2017-07-21 | 2018-01-09 | 山西晋城无烟煤矿业集团有限责任公司 | Concentric tube type batch-type gaslift drainage technology |
| CN108661603A (en) * | 2018-05-15 | 2018-10-16 | 西南石油大学 | Nitrogen injection induces coal seam and improves Methane Recovery Recovery method from transformation |
| CN109025911A (en) * | 2018-08-23 | 2018-12-18 | 山西晋城无烟煤矿业集团有限责任公司 | A kind of coal bed gas well gaslift draining reservoir protection device and water discharge method |
| CN109798095A (en) * | 2019-03-08 | 2019-05-24 | 南阳市天达同兴石油技术有限公司 | A kind of coal-bed-gas production-increase pressure disturbance device and method for increasing yield of coal bed gas |
-
2021
- 2021-04-06 CN CN202110366041.2A patent/CN112855088B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107558962A (en) * | 2017-07-21 | 2018-01-09 | 山西晋城无烟煤矿业集团有限责任公司 | Concentric tube type batch-type gaslift drainage technology |
| CN108661603A (en) * | 2018-05-15 | 2018-10-16 | 西南石油大学 | Nitrogen injection induces coal seam and improves Methane Recovery Recovery method from transformation |
| CN109025911A (en) * | 2018-08-23 | 2018-12-18 | 山西晋城无烟煤矿业集团有限责任公司 | A kind of coal bed gas well gaslift draining reservoir protection device and water discharge method |
| CN109798095A (en) * | 2019-03-08 | 2019-05-24 | 南阳市天达同兴石油技术有限公司 | A kind of coal-bed-gas production-increase pressure disturbance device and method for increasing yield of coal bed gas |
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| CN112855088B (en) | 2023-04-07 |
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