碳酸盐岩地层裂缝层控性发育特征研究——以柯坪地区奥陶系碳酸盐岩为例  

STUDY ON THE STRATA-BOUND CHARACTERISTICS OF VERTICAL FRACTURE IN CARBONATE ROCKS:A CASE STUDY OF ORDOVICIAN CARBONATE FORMATION IN KALPIN AREA

作　　者：陈兰朴 张恒 蔡忠贤[2,3] CHEN Lanpu;ZHANG Heng;CAI Zhongxian(Research Institute of Erploration and Development,Jianghan Oilfield Com pany,Sinopec,Wuhan,Hubei 430223,China;Key Laboratory of Theory and Technology of Petroleum Erploration and Development in Hubei Province,China University of Geosciences,Wuhan,Hubei 430074,China;Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan,Hubei 430074,China)

机构地区：[1]中国石油化工股份有限公司江汉油田分公司勘探开发研究院,湖北武汉430223 [2]湖北省油气勘探开发理论与技术重点实验室,湖北武汉430074 [3]中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉430074

出　　处：《矿物岩石》2023年第1期85-95,共11页Mineralogy and Petrology

基　　金：国家自然科学基金项目(批准号:42002179);中国科学院战略性先导科技专项(A类)(项目编号:XDA14010302)。

摘　　要：下古生界碳酸盐岩地层是塔里木盆地油气勘探的重点层系,而裂缝系统是影响碳酸盐岩储层非均质性的重要因素,裂缝的空间发育分布不仅影响着储层的岩溶改造,还在一定程度上控制了油气的运移聚集。近年来,随着在塔里木盆地阿满过渡带的走滑断裂带取得一系列重大油气勘探发现,断裂的控储、控藏作用逐渐得到重视。为研究碳酸盐岩地层中裂缝的空间发育规律及控制因素,结合前人研究成果,对柯坪地区奥陶系碳酸盐岩野外露头剖面进行了详细解剖。结果表明,裂缝在垂向地层中具有层控性发育的特征,层序边界、岩性界面、岩层界面等沉积界面控制了碳酸盐岩地层裂缝的发育,裂缝的终止端多位于该类界面处或附近;同时,裂缝的发育还受岩层厚度的影响,当岩层厚度较小时,裂缝密度总体上随岩层厚度的增大而增大,而当岩层厚度超过一定值1.0~1.5 m时,裂缝密度趋于恒定。碳酸盐岩地层裂缝的层控性发育对流体在地层中的流动具有重要影响,力学界面处裂缝的大量终止促使裂缝系统内流体的主要流动方向发生改变,从而影响岩溶作用的发育和分布,力学界面附近是形成区域性岩溶孔洞、洞穴系统的有利部位。The Lower Paleozoic carbonate strata are the key formation of oil and gas exploration in Tarim basin,and the fracture system developed in the carbonate is an important factor that affects the heteroge-neity of carbonate reservoirs.The spatial distribution of fractures not only affects the karst reconstruction of reservoirs,but also controls the migration and accumulation of oil and gas to a certain extent.In recent years,with a series of important oil and gas exploration discoveries in the strike-slip fault zone of the Ammanian transitional zone in the Tarim Basin,more and more attention has been paid to the role of faultcontrolled reservoir and fault-controlled accumulation.Combined with previous research findings,the outcrop profile of Ordovician carbonate rocks in Kalpin area is studied in detail to reveal the spatial development law and control factors of fractures in carbonate rocks.The results show that fractures are stratabound in vertical layers.Sedimentary interfaces such as sequence boundary,lithology interface and rock layer interface control the development of fractures in carbonate layers,and the tips of fractures are mostly located at or near these interfaces.In addition,the fracture development is also affected by the thickness of the rock layer.When the rock layer is thin,the fracture density increases with the increase of the layer thickness on the whole.However,when the rock layer thickness exceeds a certain value of 1.O to 1.5 m,the fracture density tends to be constant.It is suggested that the strata-bound development of fractures in carbonate rocks has an important influence on the flow of fluids in the layers.The termination of a large number of fractures at the mechanical interface changes the main flow direction of fluids in the fracture system,thus affecting the development and distribution of karstification.The vicinity of the mechanical interface is a favorable location for the formation of regional karst vug and cave systems.

关 键 词：奥陶系 碳酸盐岩 裂缝 层控 力学界面 岩溶 

分 类 号：P618.13[天文地球—矿床学]