低阻页岩气储层含气饱和度计算方法
——以涪陵地区焦石坝区块为例

Study on calculation method of gas saturation in low-resistivity shale gas reservoir: a case study of Jiaoshiba block in Fuling area

石文睿,张占松,黄梓桑,石元会,廖勇

长江大学油气资源与勘探技术教育部重点实验室，湖北 武汉 430100 西南石油大学地球科学与技术学院，四川 成都 610500 中石化经纬有限公司，山东 青岛 266000

MOE Key Laboratory of Exploration Technologies for Oil and Gas Resources, Yangtze University, Wuhan 430100, China School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China Sinopec Matrix Corporation, Qingdao 266000, China

为克服涪陵地区五峰组—龙马溪组页岩气储层低阻导致Archie类电法测井饱和度模型计算的含气饱和度不准确的问题，根据页岩气储层含气饱和度与偶极阵列声波测井和常规测井参数之间的关系，以及含气饱和度与总有机碳质量分数（TOC）之间的关系，建立了2种非电法测井含气饱和度计算方法，并通过实例井验证了2种方法的可行性及精确度。研究表明：涪陵地区焦石坝区块五峰组—龙马溪组页岩气储层低阻现象的主要成因是页岩石墨化，并且黄铁矿发育及黏土矿物附加导电也会对储层低阻现象产生一定的影响；利用横纵波时差比和岩性密度（DEN）拟合含气饱和度的方法具有一定的地区经验性，基于TOC计算含气饱和度的方法具有较好的普适性。这2种新方法适用于低阻页岩气储层的含气饱和度评价，具有一定的推广价值。

To overcome the inaccuracy of the gas saturation calculated by the Archie-type electrical model caused by the low-resistivity of shale gas reservoir of Wufeng-Longmaxi Formation in Fuling area, two non-resistivity gas saturation models were established, in this paper, based on the relationships between the gas saturation and dipole array acoustic/conventional logging parameters as well as gas saturation and total organic carbon (TOC). The feasibility and accuracy of the proposed methods were verified with example wells. The study shows that the main cause of the low-resistivity phenomenon of the Wufeng-Longmaxi Formation shale in Jiaoshiba block of Fuling area is the "graphitization" of shale, and other factors such as the development of pyrite and the additional conductivity of clay. It is concluded that the gas saturation model of shale gas reservoir fit by S-P wave slowness ratio and the lithology density (DEN) has certain regional experience. The gas saturation model of shale reservoir based on TOC has good universality. The two new gas saturation calculation models are suitable for the evaluation of gas saturation of shale gas reservoir with low-resistivity, which have promotional value.

10.6056/dkyqt202202007