State Key Lab of Coal Mine Disaster Dynamics and Control, Chongqing University State and Local Joint
Engineering Lab of Gas Drainage in Complex Coal Bed Methane Seam, Chongqing University

为研究煤层瓦斯抽采过程中气压演化特性以及不同初始气压对抽采的影响规律,利用自主研发的多场耦合煤层气开采物理模拟试验系统,开展了不同气压条件下瓦斯抽采的物理模拟试验研究,结果表明:抽采过程中,气压随时间呈现前期下降较快而后期下降缓慢的特点,同时气压在垂直钻孔的方向上梯度较大,在平行钻孔的方向上气压梯度较小;通过绘制气压三维曲面图发现,断面气压曲面呈以抽采钻孔为中心轴的漏斗状分布,层面或纵面气压曲面呈"V"形分布;初始气压越高,抽采过程中气压绝对下降量越大、气压下降速率越快,但是抽采过程中气压相对下降率相差不大,且抽采结束时残余气体压力相近。研究结果可为现场瓦斯抽采提供指导。

In order to study the gas pressure evolution features during the seam gas drainage process and the different initial gas pressure affected to the gas drai nage, a self developed physical simulation test system of the multi coupling coalbed methane mining was applied to the physical simulation test study on the gas draina ge under the different gas pressure.The results showed that, during the gas drainage process, the gas pressure would be quickly decreased with the time passed in the initial period and would be decreased slowly at the late period.Meanwhile, the gas pressure gradient would be high in the vertical borehole and the gas pressure gradie nt in the parallel direction drilling would be low.The 3D surface map prepared showed that the cross section gas pressure curve surface would be a funnel-shaped distri bution with the gas drainage borehole as the central axis and the level and longitudinal gas pressure curve surface would be in a V shape distribution.The higher the init ial gas pressure is, the higher absolute reduction would be during the gas drainage process, the decreased speed of the gas pressure would be faster.But during the ga s drainage process, the relative decreasing rate of the gas pressure would not be high and the residual gas pressure would be closed when the gas drainage was ende d.The results can provide guidance for the site gas drainage.

国家科技重大专项资助项目(2016ZX05044002)；国家自然科学基金资助项目(51474040,51304255,51434003)；