页岩气吸附量主要受埋深、矿物成分、温度、压力等因素的影响,川南页岩气具有埋深大、高温、高压的特点,明确这类页岩储层超临界状态的吸附解吸附特征对于落实气藏储产量意义重大。综合采用室内物理模拟实验和分子动力学模拟相结合的方法,构建并优选了伊利石+干酪根复合表征模型,拓展建立了川南深层页岩气全域吸附量多元预测模型,明确了气藏的吸附解吸附特征。实验分析结果表明：随着地层压力的增加,吸附量逐渐增加,压力高于15 MPa后吸附量增幅逐步变缓;气藏原始条件下吸附气量占总气量体积的20 %~25 %;地层压力降至20 MPa时自由气采出程度约70 %~90 %,吸附气采出程度约25 %~40 %。

The adsorption capacity of shale gas is mainly influenced by the factors such as burial depth, mineral composition, temperature and pressure. The shale gas in South Sichuan has the characteristics of large buried depth, high temperature and high pressure. It has great significance to determine the adsorption and desorption characteristics of this kind of shale reservoir in supercritical state for the implementation of gas reservoir production. By the combination of indoor physical simulation experiments and molecular dynamics simulation, the composite characterization model of Illite and Kerogen is constructed and optimized, the multiple prediction model of whole area adsorption capacity of the deep shale gas in South Sichuan is developed, and the adsorption and desorption characteristics of the gas reservoir are clarified. The experimental results show that: with the increase of formation pressure, the adsorption capacity increases gradually, and when the pressure is higher than 15 MPa, the increase of adsorption capacity gradually slows down. Under the original conditions of gas reservoir, the adsorbed gas volume accounts for 20 % ~ 25 % of the total gas volume. When the formation pressure drops to 20 MPa, the recovery degree of free gas is about 70 % ~ 90 %, and the recovery degree of adsorbed gas is about 25 % ~ 40 %.