Exploitation method for coalbed methane multibranch remote-end communicated well

Abstract

The invention relates to the technical field of coalbed methane exploitation, and relates to an exploitation method for a coalbed methane multibranch remote-end communicated well. The method concretely includes the following steps: 1) using a drill bit with the phi being 311.1 mm to drill to the depth of a designed surface casing during first exploitation, and placing a casing with the phi being 244.5 mm to seal an upper layer section which is unstable and prone to leakage and collapse; 2) using a drill bit with the phi being 215.9 mm to drill to a designed target point during secondary exploitation, wherein the inclination angle of the well reaches 84 degree, and placing a technical casing with the phi being 177.8 mm to enhance the well and seal a stratum which is prone to leakage; 3) using a drill bit with the phi being 155.6 mm to drill to a designed target point in an inclined section during third exploitation; and 4) using drill bits with the phi being 155.69 mm to drill to designed target points in branch well sections. Compared with a vertical well and a horizontal well, the multibranch horizontal well is improved in conductivity increased in sweep area and greatly improvedin single well output. The method adopts drilling along the downdip direction of a reservoir stratum, which is beneficial to the well trajectory control, can help water in a coal seam flow into the bottom of the production well under the action of gravity, and can improve the efficiency of drainage and gas recovery of the production well.

Description

technical field [0001] The invention relates to the technical field of coalbed methane exploitation, in particular to a development method for multi-branched remote connected wells of coalbed methane. Background technique [0002] In the process of coalbed methane exploitation, there are mainly problems of low drilling rate and low recovery rate, and the development efficiency of simple structure wells is lower. Therefore, it is necessary to design production wells that can be developed efficiently through drilling engineering according to the geological characteristics of coalbed methane. [0003] The existing technology adopts the vertical well development scheme, and arranges multiple wells in the coalbed methane block to form a development well pattern, which greatly increases the number of wells, high operating costs, and low development efficiency; another scheme uses horizontal wells and vertical wells connected, considering The problem of water drainage and gas recov...

AI Technical Summary

Problems solved by technology

[0002] In the process of coalbed methane mining, there are mainly problems of low drilling rate and low recovery rate, and the development efficiency of simple structure wells is lower. Therefore, it is necessary to design production wells that can be developed efficiently through drilling engineering according to the geological characteristics of coalbed methane.

[0003] The existing technology adopts the vertical well development scheme, and arranges multiple wells in the coalbed methane block to form a development well pattern, which greatly increases the number of wells, high operating costs, and low development efficiency; another scheme uses horizontal wells and vertical wells connected, considering The problem of water drainage and gas recovery is an improvement to the original plan, but the oil and gas recovery has a small range and the recovery factor still needs to be improved

Generally speaking, the existing technology is not high for single well production of CBM exploitation

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