Variation law of water seepage field in roadway surrounding rock of drilling and circulating hot coal seam injection
LI Maolin
Abstract：Based on the theories of seepage mechanics and heat transfer,a numerical calculation model of fluid-heat coupling was estab-lished.Numerical simulation research was conducted on the changes in the water seepage field of surrounding rock in coal seam road-ways under different sealing depths of heat injection drilling,using two methods of intermittent hot injection between single drilling and alternating hot injection between adjacent drilling for hot injection.Research shows that when using a single drilling cycle for heat injec-tion,as the number of heat injection cycles increases,the fluid pressure in the coal seam gradually transfers from the drilling to both sides.In the process of extraction,the peak value of coal seam fluid pressure is transferred to both sides of the drilling.In the area near the roadway wall,the high fluid pressure area increases with the decrease of the hole sealing depth.When adjacent drilling are used for alternating heat injection,the peak pressure of the surrounding rock in the roadway appears alternately at the two drilling positions.As the number of heat injections increases,the range of pressure rise continues to expand;the larger the spacing of heat injection drilling,the larger the range of high fluid pressure areas in the coal seam.As the depth of sealing decreases,the high fluid pressure area within the stress concentration zone in the coal seam increases.The risk of hot water leakage in the surrounding rock of the roadway decreases with the increase of the injection cycle and the depth of the sealing hole.The risk of hot water leakage under the same sealing depth and injection cycle conditions is in the following order:single drilling cycle heat injection＜alternating injection of heat between adjacent drilling(with a spacing of 2 meters)＜alternating injection of heat between adjacent drilling(with a spacing of 4 meters).
Keywords：coalbed methaneheat injection enhanced coalbed methane extractionroadway surrounding rockwater seepage field
Publication Date：2024-10-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 12-18,23 )