多场耦合作用下煤层气的渗流特性与数值模拟

Multi-field coupling effect on coalbed methane seepage characteristics and numerical simulation

根据实验研究煤样在轴向应力、围压、气压、温度单一因素作用下的渗流规律。利用Ansys12.0数值模拟了单场与多场耦合作用下煤层气的渗流规律,煤体的变形、孔隙压力、渗流场的分布规律。数值模拟得出:单场作用下煤层气在煤体中的渗流规律实验与数值模拟结果基本相同;多场耦合作用下煤的渗透率与平均有效应力曲线呈负指数关系;对试件变形的影响应力场大于渗流场,轴向应力对试件的变形大于围压;围压对渗流场的影响大于轴向应力,轴向应力对孔隙压力的影响大于围压,多场作用下孔隙压力大于单场作用。多场作用下数值模拟的结果与实验研究是一致的,因此研究煤层气的渗流规律必须考虑气固热的同时作用。

This paper studies the seepage of coal samples under the influence of each single factor,the axial stress,confining pressure,gas pressure,and temperature by experiments.It uses Ansys12.0 to numerically simulate the law of coalbed methane seepage,coal deformation,pore pressure,the distribution of flow field under the influence of each single field and multi-field coupled.The numerical simulation show that the result of numerical simulation of gas seepage law in the coal under each single fields is basically the same as the experimental result.The curve of gas seepage and average effective stress under the condition of multi-field coupled is negative exponential relationship.Stress influenced the deformation of the specimen is greater than the seepage field.The axial stress on the deformation of the specimen is greater than confining presses The influence on the flow field by confining pressure is greater than axial stress,the influence of axial stress on the pore pressure is greater than confining pressure,pore-pressure under the action of multi-field is bigger than pro-pressure under each single field.To study the seepage law of coalbed methane,it should consider the influence of gas-solid-heat at the same time.