Gas-bearing coal seams U-shaped well drilling and exploiting method

Abstract

The invention provides a gas-bearing coal seams U-shaped well drilling and exploiting method, and the method comprises the steps of (1) drilling the straight well of the U-shaped well and conducting cavern completion; (2) drilling the straight well segment of the horizontal well; (3) drilling the horizontal segment of the horizontal well; and (4) perforating and fracturing the horizontal well so as to communicate a multilayer object layer of the gas-bearing coal seams. According to the invention, a non-target reservoir is deflected and the horizontal segment is drilled, like a sandstone or a limestone; a borehole is prevented from collapsing, block is prevented from falling off and the well is prevented from leaking when a target reservoir of gas-bearing coal seams is drilled; drilling efficiency is raised; drilling fluid is prevented from soaking the reservoir of the gas-bearing coal seams for a long time, particularly the coalbed gas layer and the shale gas layer; damage of particles in solid phase and drilling cuttings in the drilling fluid to the reservoir of the gas-bearing coal seams is effectively reduced; by communication between the horizontal segment of U-shaped well and the reservoir of the gas-bearing coal seams by pressing crack in a large scope, exploitation swept area and deflation area are increased; multilayer commingled production of the gas-bearing coal seams is realized; the utilization rate of the gas-bearing coal seams is raised; area well drilling quantity and total cost of well drilling are reduced; and the yield of a single well, exploitation degree and economic benefit are greatly increased.

Description

technical field [0001] The invention relates to the field of coal bed gas exploitation, in particular to a method for drilling and developing U-shaped wells of coal measure gas. Background technique [0002] Due to the advancement of engineering technologies such as drilling and fracturing, coal-measure gas has shown great development value and potential as an unconventional natural gas. However, in coal-measure gas, the thickness of coal seams varies greatly and the number of layers is large, and the shale gas, tight gas and coalbed methane developed between layers have the characteristics of continuous accumulation and coexistence in the area, which cannot meet the conditions of mechanical stratified fracturing, and it is difficult to separate them. Moreover, the economic benefits of independent development of coal-measure gas are not obvious. The "Thirteenth Five-Year Plan" proposes the combined exploitation of coalbed methane, shale gas and tight sandstone gas. The dev...

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Problems solved by technology

[0004] In order to solve the above technical problems, the present invention provides a coal-measure gas U-shaped well drilling and development method. The coal-measure gas U-shaped well drilling and development method adopts non-target storage layer horizontal well drilling, avoiding the coal-measure gas U-shaped well drilling and development method. The collapse and pollution of wells drilled in layers, and then through fracturing to communicate with multi-layer coalbed methane, tight sandstone gas and shale gas in coal-measure gas, and cooperate with vertical wells for drainage and gas production, which solves the difficulty of coal-measure gas drilling construction Large, single target layer, and multi-layer co-production of coal-measure gas

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