Multi-coal-seam independent gas-containing system pressure control single-pump drainage device and method

Abstract

The invention discloses a multi-coal-seam independent gas-containing system pressure control single-pump drainage device and method. The device comprises an inner casing pipe and an outer casing pipe,an oil pipe is arranged in the inner casing pipe, an oil pumping rod is arranged inside the oil pipe, the bottom of the oil pumping rod is connected with a tubular pump, a sand settling pipe is arranged at the bottom of the tubular pump, and a sifting pipe is further arranged above the sand settling pipe; a first packer and a second packer are arranged between the inner casing pipe and the outercasing pipe; a pressure meter cable and an annular flow limiting valve cable are fixedly arranged on the pipe wall of the inner side of the inner casing pipe, the bottom of the pressure meter cable isconnected with a pressure meter, the pressure meter is fixedly installed at the bottom of the inner wall of the inner casing pipe, and the bottom of the annular flow limiting valve cable is connectedwith annular flow limiting valves of all independent gas-containing systems. According to the multi-coal-seam independent gas-containing system pressure control single-pump drainage device and method, the annular flow limiting valves are installed to control the volume of water flowing into a pump port of the inner casing pipe; a movable liquid level assisting pipe can separate gas produced by all the independent gas-containing systems, and a gas flowmeter can be installed at the top of the movable liquid level assisting pipe to monitor the gas production yields of all the gas-containing systems.

Description

technical field [0001] The invention relates to the technical field of coal mine development, in particular to a pressure-controlling single-pump drainage device and a drainage method for a multi-coal seam independent gas-containing system. Background technique [0002] When CBM drainage is carried out in multi-coal seam areas, affected by factors such as reservoir heterogeneity, reservoir pressure, liquid supply capacity, permeability, coal seam gas content, and gas saturation, the relationship between different gas-bearing systems is often Interlayer interference exists, resulting in a decrease in gas well productivity. Although predecessors have carried out a lot of research work on the basic geology, fracturing and drainage of coalbed methane, they mainly focus on single coal seam as the research object, and there are few studies on independent gas-bearing systems with multiple coal seams. The production capacity of gas wells is generally low, and the device, method and...

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Problems solved by technology

[0002] When CBM drainage is carried out in multi-coal seam areas, affected by factors such as reservoir heterogeneity, reservoir pressure, liquid supply capacity, permeability, coal seam gas content, and gas saturation, the relationship between different gas-bearing systems is often There is interlayer interference, which leads to the reduction of gas well productivity

Although predecessors have carried out a lot of research work on the basic geology, fracturing and drainage of coalbed methane, they mainly focus on single coal seam as the research object, and there are few studies on independent gas-bearing systems with multiple coal seams. The production capacity of gas wells is generally low, and the device, method and technology proposed by the predecessors of "layered pressure control, combined layer drainage" can separate each coal seam vertically, but it cannot drain and reduce the pressure of each coal seam The speed is controlled, and the gas production capacity of each coal seam cannot be monitored, so it is difficult to optimize the drainage plan during the drainage process.

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