埋藏条件下页岩气赋存形式研究

Shale gas occurrence under burial conditions

俞凌杰 范明 腾格尔 刘友祥

Yu Lingjie Fan Ming Tenger Liu Youxiang

中国石油化工股份有限公司 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 2. 中国石油化工集团公司 油气成藏重点实验室, 江苏 无锡 214126

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China 2. SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China

以川东南龙马溪组页岩为主要研究对象，开展埋藏条件下页岩气赋存形式定量研究。重点基于重量法等温吸附实验，分析TOC含量、温度、湿度对吸附能力的影响，并通过建立3个主要因素与吸附能力的经验关系来获取埋藏条件下的吸附气量。另外，通过总孔隙空间扣除孔隙水和吸附气占据空间来厘定游离气占据空间，并基于甲烷状态方程（PR方程）获取游离气密度，从而构建埋藏条件下游离气赋存计算方法。超压条件下吸附气随埋深呈下降趋势，而游离气增加明显并成为主要赋存形式。定量计算了焦页1井22个页岩样品（主要取自底部38 m优质层段）的赋存量。焦页1井优质段吸附气占比27.1%~47.8%，平均占比为34.3%，而游离气占比52.2%~72.9%，平均占比为65.7%。

Shale samples were collected from the Longmaxi Formation in southeastern Sichuan Basin to carry out quantitative studies of shale gas occurrence under burial conditions.The impacts of TOC content, temperature and moisture on adsorption capacity were studied using gravimetric isothermal adsorption, and some related empirical equations were established to calculate adsorbed gas content under burial conditions. In addition, free gas storage space was derived by deducting the volume of pore water and adsorbed gas from total space. The density of free gas was calculated using the Peng-Robinson equation. Therefore, a quantitative calculation method for shale gas occurrence was proposed. Under overpressure condition, adsorbed gas content decreases with the increase of burial depth, while free gas content increases and becomes dominant. Shale gas content of well Jiaoye1 was calculated using 22 samples mainly from 38 m interval. The adsorbed gas fraction is 27.1%-47.8% with an average of 34.3%, and the free gas fraction is 52.2%-72.9% with an average of 65.7%.

国家自然科学基金"古生界页岩含气性原生有机质控制作用研究"（U1663202）资助。

https://doi.org/10.11781/sysydz201604438