Study On Direct Determination Of Gas Pressure In Complex Coal Seam

Gas pressure is one of the most basic gas parameters in coal seam,and its accurate measurement is very important for the study of coal seam gas occurrence law,prediction of coal mine gas emission,evaluation of gas extraction effect,prediction and prevention of coal and gas outburst.Due to the complex occurrence conditions of coal seams in China,the success rate of accurate determination of gas pressure is relatively low,generally less than 30%.How to measure the gas pressure quickly,accurately and directly under the condition of complex coal seam occurrence has become an urgent technical problem to be solved.This study will focus on the influence factors of gas pressure determination of a detailed analysis,at the same time,the content of the corresponding solutions are given as part of the first study,the purpose is to clear pressure at work can affect pressure process and results of each link,as the theoretical basis,adjust measures to local conditions to take effective measures,to ensure smooth progress of the whole process of pressure.In this study,the occurrence conditions of complex coal seams are divided into three categories,namely,soft and broken coal seams,water gushing boreholes through multiple coal seams and ultra-long rock hole.Selection against these complex conditions,simple general type pressure measuring device and complex compound type pressure device applied to the actual test,and in order to better achieve pressure effect of two kinds of each sealing hole opener to improve the innovation: the general type selection pressure measuring device is equipped with a hollow casing seal hole opener and replica selection pressure measuring device to improve casing add rheological layer sealing hole opener.At the same time,combined with previous studies of adaptation is given hole sealing material,namely SP-I hole sealing materials with polyurethane and three-phase foam mucus.Considering the pressure measuring device and the security of drilling hole sealing material for air tightness ability is limited,you can also optimize the process flow in the process of drilling,put forward the soft and broken coal selecting reengineering rock hole technology and wear more coal water select casing drilling technology,further blocking technology to crack,also can increase the borehole stability,especially for water drilling wear more coal,a greater extent of isolating the effects of water and other coal seam.Studies using the given pressure measuring device and hole sealing materials and the technology of pressure measuring technology for soft and broken of Ernai coal mine coal seam condition,Maozhai coal mine resistant wear more coal seam water conditions and Kanghui coal mine long rock drilling hole conditions for the field test,the test results show that the pressure measurement techniques adopted under various conditions are targeted and can solve the problems in the pressure measurement and have high feasibility.The thesis contains 28 figures,7 tables and cited 61 references.