鄂尔多斯盆地西部志丹‒吴起地区延长组裂缝特征及其控藏作用  

Characteristics and Controlling Effect on Hydrocarbon Accumulation of Fractures in Yanchang Formation in Zhidan-Wuqi Area,Western Ordos Basin

作　　者：尹帅 丁文龙[3,4] 林利飞[5] 刘翰林[6] 李爱荣 Yin Shuai;Ding Wenlong;Lin Lifei;Liu Hanlin;Li Airong(School of Earth Sciences and Engineering,Xi’an Shiyou University,Xi’an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi’an Shiyou University,Xi’an 710065,China;School of Energy Resources,China University of Geosciences,Beijing 100083,China;Beijing Key Laboratory of Unconventional Natural Gas Geology Evaluation and Development,China University of Geosciences,Beijing 100083,China;Yanchang Oilfield Co.Ltd.,Yan’an 716000,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,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]西安石油大学陕西省油气成藏地质学重点实验室,陕西西安710065 [3]中国地质大学能源学院,北京100083 [4]中国地质大学非常规天然气地质评价与开发北京市重点实验室,北京100083 [5]延长油田股份有限公司开发部,陕西延安716000 [6]中国石油勘探开发研究院,北京100083

出　　处：《地球科学》2023年第7期2614-2629,共16页Earth Science

基　　金：延长油田开发部项目(No.ycsy2018ky-B-04);国家自然科学基金面上项目(No.42072173).

摘　　要：鄂尔多斯盆地西部延长组发育大量裂缝,裂缝的存在对致密油甜点具有良好的指示作用.以鄂尔多斯盆地西部志丹‒吴起地区延长组致密油储层为例,利用大量岩心、薄片、古地磁、测井、产能数据及数值模拟方法,系统研究了致密油储层裂缝发育特征及其控藏模式.结果表明,延长组主要发育垂直裂缝,根据裂缝砂岩厚度制定了裂缝发育程度分类标准;同时,结合裂缝与砂体、构造、油藏的耦合关系及油藏生产现状,系统总结了裂缝对油藏的控制作用.裂缝为延长组致密油藏运聚中良好的疏导体系;河道交汇或转向区域水流能量相对增强,砂岩分选好、脆性大,裂缝发育且利于成藏;低幅构造高点及鼻状隆起区裂缝发育且利于成藏;裂缝带与砂体走向关系耦合形成“平行砂体疏导”裂缝甜点区;裂缝主要发育于中小厚度细砂岩中,累积砂体厚度主要分布在5~15 m范围内;从砂体部位来看,裂缝主要发育于主河道翼部,其与翼部砂体粒度、颗粒可压实空间及厚度变小有关.A large number of fractures are developed in the Yanchang Formation in the western Ordos Basin,and the existence of fractures has a good indication of tight oil sweet spots.In this paper,taking the tight oil reservoirs of the Yanchang Formation in the Zhidan-Wuqi region of the Ordos Basin as an example,a large amount of core,thin section,logging,paleomagnetism,productivity data and numerical simulation methods are used to systematically study the development characteristics and control of tight oil fractures in the study area.The research results show that the Yanchang Formation mainly develops vertical fractures,and the classification standard for the degree of fracture development is established according to the thickness of the fractures.Combining the coupling relationship between fractures and sand bodies,structures,and reservoirs and the current status of reservoir production,the fracture-controlling action for oil is clarified.It is believed that the regional fractures provide a good drainage system for the Yanchang Formation tight oil reservoirs;the river convergence or diversion areas are repeatedly washed by river water,the sandstone is well sorted,brittle,and the fractures are well developed and are conducive to hydrocarbon accumulation;the low-amplitude structural high points and nose-like uplift areas have developed fractures and are conducive to hydrocarbon accumulation;the relationship between the fracture zone and the strike of the sand body is coupled to form a"parallel drainage"fracture sweet spot;the fractures are mainly developed in the medium and low thickness fine sandstone,and the cumulative thickness of the sand body is mainly distributed in the range of 5-15 m;from the point of view of the location of the sand body,the fractures are mainly developed in the wings of the main channel,which is related to the reduction of the particle size,compaction space and thickness of the sand bodies in the wings.

关 键 词：低幅构造 裂缝 沉积 构造 甜点 致密油 石油地质学. 

分 类 号：P618.13[天文地球—矿床学]