鄂尔多斯盆地陇东地区侏罗系/三叠系不整合结构特征及其对油气成藏的作用  

Characteristics of Jurassic/Triassic unconformity structure in Longdong area,Ordos Basin and its effect on hydrocarbon accumulation

作　　者：段祎乐 李元昊 马婷钰 王首良 DUAN Yile;LI Yuanhao;MATingyu;WANG Shouliang(School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi'an 710065,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]陕西省油气成藏地质学重点实验室,陕西西安710065

出　　处：《复杂油气藏》2023年第1期55-61,共7页Complex Hydrocarbon Reservoirs

摘　　要：陇东地区位于鄂尔多斯盆地西南缘,三叠纪末的印支运动导致鄂尔多斯盆地抬升侵蚀,形成了陇东地区前侏罗纪古地貌。测井、地震等资料研究发现不同古地貌单元不整合结构特征存在差异,并对侏罗系油藏有一定的控制作用。结果表明:不整合之上岩层主要为河道充填砂岩,测井曲线呈现高电阻率、低自然伽马特征;风化黏土层是不整合结构中物性较差的层,岩性主要为泥岩,测井曲线呈高自然伽马、低密度特征;风化淋滤带具有多种岩石类型,且储层连通性较好,井径曲线锯齿化明显,电阻率低值。不整合结构对油气成藏的影响主要体现在两个方面:一是风化淋滤带提供了油气向上运移的通道,二是风化黏土层的分布控制了油气进入侏罗系储层的位置。The Longdong area is located on the southwest edge of the Ordos Basin.The Indosinian movement at the end of the Triassic led to the uplift and erosion of the Ordos Basin,forming the pre-Jurassic paleo-morphology in the Longdong area.Through the study of logging and seismic data,it was found that there are differences in the structural characteristics of the unconformities in different paleomorphic units,and have a certain control on the Jurassic reservoirs.The results show that the strata above the unconformity are mainly channel-filled sandstone,and the logging curve is characterized by high resistivity and low natural gamma ray.The weathered clay layer is a poor physical layer in the unconformities.Its lithology is mainly mudstone,and its logging curve is characterized by high natural gamma and low density.The weathered leaching zone has a variety of rock types,and the reservoir is well connected,with obvious sawtooth diameter curves and low resistivity values.The impact of unconformity structure on oil and gas accumulation is mainly reflected in two aspects:firstly,the weathered drainage zone provides a channel for the upward transport of hydrocarbons,and secondly,the distribution of weathered clay layers controls the location of hydrocarbons into Jurassic reservoirs.

关 键 词：古地貌 油气运移 风化淋滤带 不整合结构 陇东地区 

分 类 号：TE122[石油与天然气工程—油气勘探]