川东南页岩气储层脉体中包裹体古压力特征及其地质意义

Trapping pressure of fluid inclusions and its significance in shale gas reservoirs, southeastern Sichuan Basin

席斌斌 腾格尔 俞凌杰 蒋宏 申宝剑 邓模

Xi Binbin Tenger Yu Linjie Jiang Hong Shen Baojian Deng Mo

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

包裹体岩相学分析表明，川东南焦页A井、南页A井以及彭页A井页岩气储层石英以及方解石脉中，主要发育气液两相盐水和气2类包裹体；激光拉曼分析表明，气包裹体主要由甲烷组成。3口井气液两相包裹体的显微测温结果存在较明显的差异，其中焦页A井与南页A井的石英中气液两相盐水包裹体的均一温度最高，分别为215.8~245.4 ℃和214.4~240.8 ℃；南页A井方解石中包裹体均一温度次之，为177.8~210.4 ℃；而彭页A井气液两相盐水包裹体的均一温度最低，为128.5~156.4 ℃。包裹体古压力恢复结果表明，焦页A井与南页A井石英中包裹体捕获压力最高，分别为114.9~130.5 MPa和124.0~151.5 MPa；南页A井方解石中包裹体捕获压力次之，为114.0~122.3 MPa；而彭页A井包裹体的捕获压力较低，为32.5~43.0 MPa。结合埋藏史图可知，3口井的捕获时间均为燕山期，其中焦页A井与南页A井包裹体捕获时页岩气储层处于超压状态，而彭页A井处于正常压力范围。上述古压力系数与现今测井压力存在相似的规律，表明焦页A井与南页A井气藏的保存条件要优于彭页A井。

Facies studies on fluid inclusions revealed that aqueous and gas-bearing inclusions are distributed in quartz and calcite veins of shale gas reservoirs in wells Jiaye A, Nanye A and Pengye A in the southeastern Sichuan Basin. Raman probe analyses showed that gas-bearing inclusions mainly contain CH4. The homogenization temperature of aqueous inclusions ranges from 215.8-245.4 ℃ in quartz veins of well Jiaoye A. The homogenization temperature of aqueous inclusions ranges from 214.4-240.8 ℃ in quartz veins in well Nanye A. The homogenization temperature of aqueous inclusions ranges from 177.8-210.4 ℃ in calcite veins in well Nanye A. The homogenization temperature of aqueous inclusions ranges from 128.5-156.4 ℃ in calcite veins in well Pengye A. The trapping pressure of gas-bearing inclusions and aqueous inclusions ranges from 114.9-130.5 MPa in quartz veins in well Jiaoye A. The trapping pressure of gas-bearing inclusions and aqueous inclusions ranges from 124.0-151.5 MPa in quartz veins in well Nanye A. The trapping pressure of gas-bearing inclusions and aqueous inclusions ranges from 124.0-151.5 MPa in quartz veins in well Nanye A. The trapping pressure of gas-bearing inclusions and aqueous inclusions ranges from 114.0-122.3 MPa in calcite veins in well Nanye A. The trapping pressure of gas-bearing inclusions and aqueous inclusions ranges from 32.5-43.0 MPa in calcite veins in well Pengye A. Fluid inclusions in these wells were trapped during the Yanshanian period. Reservoirs were over pressured when fluid inclusions were trapped in wells Jiaoye A and Nanye A, but under normal conditions in well Pengye A. Pressure coefficients when trapping showed similar regularities as measured well pressure, inferring that the gas preservation conditions in wells Jiaoye A and Nanye A are better than that of Pengye A.

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）和中国石化科技部项目（P15097，P14156）资助。

https://doi.org/10.11781/sysydz201604473