A method for multi-gas co-production and production capacity replacement in coal-measure strata

Abstract

The invention discloses a method for multi-gas co-production and production capacity replacement of coal-measure strata, which comprises the following steps: Step 1, selecting a block in which coal seams and tight sandstone layers are relatively developed in coal-measure strata, and drilling a U-shaped block in the block Well, wherein, the horizontal section of the U-shaped well is in an inclined state, and the horizontal section passes through multiple reservoirs at the same time; step 2, the multiple reservoirs that the horizontal well section passes through are used for joint production by fracturing, and the high Gas production in the vertical well section at the structural position, drainage and fines discharge in the vertical well section at the low structural position and gas production; step 3, when the gas production of the horizontal well section decreases, use a packer to isolate the vertical well section from the horizontal section, and use The two vertical sections of the U-shaped well produce gas from the sandstone layer; step 4, when the gas production in step 3 decreases, all the reservoirs are combined for production. The method proposed by the invention solves the problems of coal seam water production and pressure mismatch between high-pressure and low-pressure reservoirs, reduces the interference of coal seam pulverization, and realizes production capacity replacement in coal-measure gas development.

Description

technical field

[0001] The invention relates to the technical field of coal-measure gas exploitation, in particular to a method for multi-gas commingled production and productivity replacement in coal-measure strata. Background technique

[0002] my country is rich in coal resources, and a large number of coal resources contain abundant coal-measure unconventional natural gas. Coalbed methane, tight gas and even shale gas in coal-measure strata have broad development prospects. For a long time, coalbed methane, tight gas and shale gas in my country are often developed as a single type of gas reservoir, resulting in low single-well production. Because coal seams, tight sandstone layers and mud shale are alternately superimposed and distributed in coal measure strata, at the same time, in most strata, there are also disconnected interconnected layers above the alternately superimposed distribution layers of coal seams, tight sandstone layers and mud shale. For sandstone or co...

Examples

Embodiment 1

[0035] refer to Figure 1-5 , a coal-measure formation multi-gas combined production and productivity replacement method, comprising the following steps:

[0036] Step 1, in this block, the lower layer is the coal seam 2, the tight sandstone layer 1 and the shale layer 3 which are stacked and distributed at close distances, and the upper layer is distributed with the distant disconnected coal seam 2 and the tight sandstone layer 1. The U-shaped well 6 was drilled in the block. The horizontal well section of the U-shaped well 6 was inclined, and at the same time, the horizontal well section was drilled through the coal seam 2, the tight sandstone layer 1 and the mud shale layer 3 distributed in a short distance. The two vertical sections of the well are drilled vertically upward through multiple coal seams 2 or tight sandstone layers 1;

[0037] Step 2: After the completion of U-shaped well 1, the horizontal well section of U-shaped well 1 is fracturing by means of multi-stage...

Embodiment 2

[0042] Refer to the attached Figure 1-3 , 6-8, Steps 1-3 are the same as Example 1, the only difference is Step 4: When the coal seam 2 in the upper part of the formation is located below the tight sandstone layer 1, a seal can be set between the coal seam 2 and the tight sandstone layer 1 Device 6, the specific setting method is as follows: the vertical well section with high structural level is set with full isolation, and the vertical well section with low structural level is set with annular isolation 61. At this time, the vertical well section with low structural level is used for gas production and drainage. When the dynamic liquid level of the coal seam is lower than the upper sandstone layer, all packers are taken out and the overall commingled production is carried out. Among them, the vertical well section at the low structural level is drained by the pumping unit 9 arranged in the oil production pipe 7 , and the gas is produced by using the annulus between the well...

technical field

[0001] The invention relates to the technical field of coal-measure gas exploitation, in particular to a method for multi-gas commingled production and productivity replacement in coal-measure strata. Background technique

[0002] my country is rich in coal resources, and a large number of coal resources contain abundant coal-measure unconventional natural gas. Coalbed methane, tight gas and even shale gas in coal-measure strata have broad development prospects. For a long time, coalbed methane, tight gas and shale gas in my country are often developed as a single type of gas reservoir, resulting in low single-well production. Because coal seams, tight sandstone layers and mud shale are alternately superimposed and distributed in coal measure strata, at the same time, in most strata, there are also disconnected interconnected layers above the alternately superimposed distribution layers of coal seams, tight sandstone layers and mud shale. For sandstone or co...

Examples

Embodiment 1

[0035] refer to Figure 1-5 , a coal-measure formation multi-gas combined production and productivity replacement method, comprising the following steps:

[0036] Step 1, in this block, the lower layer is the coal seam 2, the tight sandstone layer 1 and the shale layer 3 which are stacked and distributed at close distances, and the upper layer is distributed with the distant disconnected coal seam 2 and the tight sandstone layer 1. The U-shaped well 6 was drilled in the block. The horizontal well section of the U-shaped well 6 was inclined, and at the same time, the horizontal well section was drilled through the coal seam 2, the tight sandstone layer 1 and the mud shale layer 3 distributed in a short distance. The two vertical sections of the well are drilled vertically upward through multiple coal seams 2 or tight sandstone layers 1;

[0037] Step 2: After the completion of U-shaped well 1, the horizontal well section of U-shaped well 1 is fracturing by means of multi-stage...

Embodiment 2

[0042] Refer to the attached Figure 1-3 , 6-8, Steps 1-3 are the same as Example 1, the only difference is Step 4: When the coal seam 2 in the upper part of the formation is located below the tight sandstone layer 1, a seal can be set between the coal seam 2 and the tight sandstone layer 1 Device 6, the specific setting method is as follows: the vertical well section with high structural level is set with full isolation, and the vertical well section with low structural level is set with annular isolation 61. At this time, the vertical well section with low structural level is used for gas production and drainage. When the dynamic liquid level of the coal seam is lower than the upper sandstone layer, all packers are taken out and the overall commingled production is carried out. Among them, the vertical well section at the low structural level is drained by the pumping unit 9 arranged in the oil production pipe 7 , and the gas is produced by using the annulus between the well...

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