论文部分内容阅读
提高低渗透煤层气产量是我国煤层气开采中急需解决的关键问题,而加速煤层CH4解吸过程的注气增产方法是提高低渗透煤层气产量的有效途径。针对低渗透深埋煤层在较高地应力、地温和孔隙压下固流热耦合作用对CO2储存效应和CH4/CO2吸附—解吸—置换—扩散—渗流过程的影响更为突出的特点,利用三轴渗透仪进行不同温度、孔隙压力和有效体积应力条件下的煤体渗流试验。结果表明:在非超临界状态下,CO2密度与温度呈负指数关系;动力黏度均与温度呈正指数关系;CO2密度和动力黏度随压力的增加均呈线性递增;渗透率和渗透系数与温度的关系表现为在低于超临界时为指数递增关系,超过临界温度为负指数递减关系,温度升高引起CO2气体渗透率的变化规律取决于温度引起的煤热应力和CO2黏度两者的共同作用;渗透率与孔隙压力呈正指数关系;渗透率与有效体积应力呈负指数关系。
Improving the production of low permeability coalbed methane (CBM) is a key issue to be solved urgently in coalbed methane exploration in our country. However, the method of gas injection and stimulation to accelerate CH4 desorption in coal seams is an effective way to increase the production of low permeability CBM. In view of the more prominent effect of the coupled effects of high thermal stress, geothermal and pore pressure on the CO2 storage and CH4 / CO2 adsorption-desorption-displacement-diffusion-seepage processes, Infiltration instrument for different temperature, pore pressure and effective volumetric stress conditions of coal seepage flow test. The results showed that under non-supercritical conditions, the relationship between CO2 density and temperature showed a negative exponential relationship. Both dynamic viscosity and temperature had a positive exponential relationship. Both the CO2 density and the dynamic viscosity increased linearly with the increase of the pressure. The permeability and permeability coefficients varied with the temperature Relationships show an exponential increasing relationship below the supercritical temperature and a negative exponential declining relationship with the critical temperature. The law of CO2 gas permeability changes with temperature rises depends on the combined effect of temperature-induced coal thermal stress and CO2 viscosity ; Permeability and pore pressure showed a positive exponential relationship; permeability and effective volume stress showed a negative exponential relationship.