含水页岩甲烷吸附特性实验研究

Experimental study on methane adsorption characteristics of hydrous shale

 陈志礼 宁正福 王庆 黄亮 齐荣荣 王金伟

中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249 中国石油大学（北京）石油工程学院，北京 102249

State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China College of Petroleum Engineering, China University of Petroleum, Beijing 102249, China

 由于含水页岩的甲烷吸附规律认识不清，Langmuir模型适应性存在争议。为此，设计了页岩饱和水分装置，开展含水页岩等温吸附实验研究（35 ℃），并通过Langmuir模型拟合了实验数据。结果表明：甲烷吸附量随含水饱和度的增加呈现“双滑梯型”下降趋势，存在临界含水饱和度现象，这是由于页岩中有机质、无机质对甲烷、水分的吸附具有差异性；低含水饱和度阶段（0~6%），水分对Langmuir模型适用性影响较小，而当含水饱和度■增加到10%时，确定系数远小于0.950 0，Langmuir模型不再适用于描述含水页岩吸附规律；页岩突破临界状态对甲烷吸附量影响显著，而对Langmuir模型适应性无明显影响，两者的平均相对变化率分别为36.993 0%，-0.003 4%；临界含水饱和度与压力无关，受有机碳质量分数、有机质成熟度和孔隙结构等因素影响显著，相关系数分别为-0.918 9，-0.983 4和0.956 8。

 Because the understanding of methane adsorption in hydrous shale is not clear, the adaptability of Langmuir model is controversial. The device used to saturate shale with water was designed to carry out the experimental research on isothermal adsorption of hydrous shale(35 ℃), and the experimental data was fitted by using the Langmuir model. The researches show that methane adsorption quantity shows a downtrend of "double slide type" with the increase of water saturation, and there is a critical water saturation phenomenon which is mainly due to the difference in the adsorption of methane and water by organic matter and inorganic matter in shale; water content(0￣6%) has less influence on the applicability of Langmuir model in the stage of low water saturation; when the water saturation equals 10%, and the coefficient of determination is far less than 0.950 0, the Langmuir model is no longer suitable for describing the adsorption law of hydrous shale; the breakthrough of shale critical state has a significant effect on the adsorption capacity of methane, but not significant to the adaptability of Langmuir model, and the average relative change ranges are 36.993 0% and -0.003 4% respectively; the critical water saturation is mainly affected by the organic carbon content, organic matter maturity, pore structure and other internal factors but independent of the pressure, and the correlation coefficients are -0.918 9, -0.983 4 and 0.956 8 respectively.

10.6056/dkyqt201804022