湘东南龙潭组页岩气储层特征与勘探前景浅析

Characteristics and Exploration Prospect of the Longtan Shale Gas Reservoir in the Southeastern Hunan

基于钻井、野外地表露头资料,应用扫描电镜、薄片观察、有机岩石学分析、压汞实验、等温吸附实验等分析测试成果,对湘东南上二叠统龙潭组页岩的储层特征进行了详细的分析,并对页岩气气藏的勘探前景进行了初步探讨。结果表明:研究区有机碳含量普遍较高,中北部地区和东南地区差距明显,前者含量更高;龙潭组下段泥页岩的分布主要集中在湘南的郴耒地区,形成了2个重点区域,平均厚度为30 m,最厚可达200 m;R o普遍较高,总体属于高成熟—过成熟阶段,并形成了以耒阳—永兴为轴心,向四周辐射降低的趋势;泥页岩孔隙以小、中孔隙为主,但孔喉分选性较好。黏土含量高,吸附性较好;中北部攸县和东南永兴一带是研究区页岩气勘探的有利区域,中北部条件相对较好。

Based on drilling and field,outcrop data and the results of scanning electron microscopy(SEM),thin section observation,organic petrology analysis,mercury injection test and isothermal adsorption test,the characteristics of shale reservoir of Longtan Formation,Upper Permian,in the southeastern Hunan,are analyzed in detail,and the exploration prospect of shale gas reservoir is preliminarily discussed.The results indicate that the organic carbon content in the study urea is high generally,with relatively higher content in the central north than the southeast;Lower Longtan shale is mainly developed in Chenlei in the southern Hunan,with the average thickness of 30 m and the maximum thickness of 200 m;organic matters have entered into high mature- post mature stage with R_0 decreased around Leiyang-Tongxing;the pore structure mainly consists of micro-mesopores,and the pore throat is well sorted;the high contents of clay minerals lead to high adsorbaility;Youxian in the central north and Yongxing in the southeast are favorable prospects for shale gas exploration,and particularly the central north provides tetter conditions.