柴达木盆地三湖坳陷区域性盐壳发现及生物气勘探地质意义  

Discovery of regional salt crust and geological significance of biogas exploration in Sanhu Depression of Tsaidam Basin

作　　者：周铁锁[1] 张文伟[1] 鞠俊成[1] 韩宏伟[1] 王宇斯 杨时杰[1] 曹宇森 ZHOU Tiesuo;ZHANG Wenwei;JU Juncheng;HAN Hongwei;WANG Yusi;YANG Shijie;CAO Yusen(Research Institute of Exploration and Development of Liaohe Oilfield Company,PetroChina,Panjin,Liaoning 124010,China)

机构地区：[1]中国石油辽河油田分公司勘探开发研究院,辽宁盘锦124010

出　　处：《东北石油大学学报》2020年第1期77-84,I0005,I0006,共10页Journal of Northeast Petroleum University

基　　金：中国石油天然气股份有限公司科技重大专项(2017E-16)。

摘　　要：利用地震解释、X线衍射全岩定量分析,结合孔隙度、渗透率等资料,分析三湖坳陷北斜坡带陵间断裂带东段近水平、穿时的盐壳生物气成藏地质意义,确定盐壳分布范围、岩性、物性及形成时间等。结果表明:柴达木盆地三湖坳陷盐壳分布面积为812 km 2,厚度近60 m,以石盐为主,岩性致密,具有极好的封盖能力;盐壳形成时间早于生物气大规模排放期,与生物气的生成、运移形成良好的时间配置,为有效的封盖层;来源于中央凹陷区的生物气以水溶气形式伴随地层水自南向北运移,地层水矿化度增加,天然气不断析出,在盐下背斜圈闭和盐壳侧向封堵圈闭中聚集成藏;预测盐壳发育区生物气资源量为920×108 m 3,盐下背斜型圈闭和盐壳侧向封堵型圈闭资源量为500×108 m 3,勘探潜力巨大。该结果为三湖坳陷下一步生物气勘探提供指导。In order to analyze whether the horizontal salt crust in the east of Lingjian Faults in Sanhu Depression is of geological significance for biogas accumulation,we studied the distribution,lithology,physical properties and formation time of the salt crust using seismic interpretation,X ray diffraction quantitative analysis,porosity and permeability analysis.The results show that the salt crust has an area of 812 km 2,a thickness of nearly 60 m,mainly composed of salt,dense lithology and excellent sealing ability.The salt crust formed earlier than the large-scale discharge period of biogas.It has a good time allocation with the generation and migration of biogas,and is an effective seal layer.The biogas from the central depression area moves from south to north with the formation water in the form of water-soluble gas.As the salinity of formation water increases,natural gas is continually released and accumulates in subsalt anticline traps and salt crust lateral sealing traps.The biogenic gas resource in the salt crust development area is estimated to be 92 billion cubic meters.The resources of the subsalt anticline type traps and the salt crust lateral sealing type traps are 50 billion cubic meters and have great exploration potential.The results of this study are instructive for the next biogas exploration in the Sanhu Depression.

关 键 词：柴达木盆地 三湖坳陷 第四系 区域性盐壳 生物气 成藏模式 资源潜力 地质意义 

分 类 号：P618.13[天文地球—矿床学]