Coal seam group well-ground combined layered fracturing and combined layer drainage method

Abstract

The invention discloses a combined separated layer fracturing, grouping and layer-combining mining method for a coal bed well group. The method comprises the following steps of: (1) arranging a roadway, and digging an mining roadway in a top coal bed or a coal bed top plate; (2) establishing a fracturing pump room on the ground, constructing vertical wells and connection roadways, and enabling the connection roadway to be connected with the vertical wells and the roadway in the top coal bed; (3) paving high-pressure resistant pipelines; (4) constructing downwards in the roadway of the top coal bed to form a test drill hole, testing physic parameters of each coal bed below the top coal bed through the testing drill hole; (5) grouping the multiple coal beds below the top coal bed based on the physic characteristics of a coal storage layer; (6) implementing a fracturing and mining unit. The combined separated layer fracturing, grouping and layer-combining mining method for the coal bed well group ensures scope of influence of hydraulic fracturing, reduces cost taken for digging wells, can efficiently avoid mutual interference of fluid flowing among coal storage layers due to too great difference of physic characteristics of the storage layers.

Description

technical field [0001] The invention relates to a multi-coal seam gas extraction method, in particular to a coal seam group well-ground combined layered fracturing and combined layer gas extraction method. Background technique [0002] Coalbed methane is a new type of clean energy. my country is rich in coalbed methane resources. A new round of resource evaluation shows that the geological resources of coalbed methane buried below 2000 m in my country are about 36.81 trillion m3, ranking third in the world, with huge development potential. , Coal bed methane is also a strong greenhouse gas, and its greenhouse effect is 21.5 times that of the same amount of carbon dioxide. However, as a dangerous factor, the gas explosion and coal and gas outburst caused by it have become the biggest hazard to the safety production of coal mines in my country, and have become the bottleneck restricting the safe and efficient production of mines. [0003] The fundamental measure of gas control...

AI Technical Summary

Problems solved by technology

However, the gas drainage radius of conventional underground boreholes is small, and the drainage effect is poor. sampling at the cost of

Patent CN103174453 A proposes a multi-coal seam layered hydraulic fracturing method, but this method only uses downhole fracturing equipment, the power is limited and the fracturing range is small, and the multi-coal seam is not grouped for coal seam drainage. Differences between layers often cause serious interference between layers, and even backflow phenomenon seriously affects production capacity

In recent years, there have been a large number of tests of downhole permeability enhancement measures. Among them, hydraulic fracturing has achieved good results, but some problems have also been exposed. For example, due to space constraints, downhole fracturing equipment often sacrifices power to reduce equipment size. During the fracturing process, fracturing failure due to insufficient power occurred, and the expected effect could not be achieved

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