塔河油田奥陶系碳酸盐岩储层裂缝表征与主控因素分析  

Characteristics and main controlling factors of fracture development in the Ordovician carbonate reservoir,Tahe oilfield

作　　者：韩鹏远 丁文龙[1,2] 杨德彬 邓光校 王震[3] 马海陇[3] 吕晶 耿甜[3] HAN Pengyuan;DING Wenlong;YANG Debin;DENG Guangxiao;WANG Zhen;MA Hailong;LU Jing;GENG Tian(School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083,China;MOE Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism,China University of Geosciences(Beijing),Beijing 100083,China;Northwest Oilfield Company,Sinopec,rümqi 830011,China;School of Geophysics and Geomatics,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国地质大学(北京)海相储层演化与油气富集机理教育部重点实验室,北京100083 [3]中国石油化工股份有限公司西北油田分公司,新疆乌鲁木齐830011 [4]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074

出　　处：《地学前缘》2024年第5期209-226,共18页Earth Science Frontiers

基　　金：国家自然科学基金面上项目(42372171,42072173)。

摘　　要：文章利用岩心、薄片、扫描电镜和成像测井等资料,系统研究了塔河油田奥陶系碳酸盐岩储层天然裂缝的发育特征,深入分析了该地区天然裂缝发育的主控因素。研究结果表明:塔河油田奥陶系碳酸盐岩储层天然裂缝可分为构造裂缝(张性裂缝、剪切裂缝)、表生裂缝(风化缝)、成岩裂缝(缝合线、层理缝)和复合成因裂缝(构造风化裂缝、构造成岩裂缝)4大类7小类,其中构造裂缝在天然裂缝占据主导地位。裂缝走向以NE-SW、NW-SE和NNE-SSW向为主,倾向为NNW、NE和SEE倾,倾角多为大于70°,线密度介于1.5~3.5条/m之间。根据裂缝充填特征和交切关系可以将裂缝分为3期,第1期充填裂缝中的微裂缝镜下荧光反应强烈,证实充填裂缝并非完全无效的裂缝,内部微裂缝的发育依旧可以使其具有有效性。第2期裂缝内部被大量沥青质充填,有效性较差。第3期裂缝开度大、有效性强,但其内部并无荧光显示。碳酸盐岩储层裂缝的形成和发育受构造应力场、断裂、岩性和岩溶作用4个因素的控制。裂缝形成期构造应力场的大小和方向决定了裂缝的形成规模及分布模式。在走滑断裂的显著影响下,断层伴生裂缝大量发育,裂缝产状同走滑断裂带基本一致。距断裂带2048.56 m为单条走滑断裂带控缝作用的最大有效影响范围,其中0~308.25 m属于断控裂缝强发育区,超过308.25 m断控裂缝强发育程度显著降低。走滑断裂张扭段和断裂带端部裂缝发育程度好,主动盘裂缝密度高,油气充注更丰富。裂缝发育程度同脆性矿物含量呈明显正相关趋势,并显著受控于杨氏模量和泊松比值的影响,白云岩裂缝发育程度最高,灰岩小类中砂屑灰岩裂缝发育程度最好。岩溶地貌中以岩溶台地下的丘从洼地无论浅层及纵向上均有较强的裂缝发育规模,平均裂缝线密度在2.67条/m,对储层的改善效果强。The characteristics of natural fractures in Ordovician carbonate reservoirs,Tahe oilfield are systematically studied and the main controlling factors of fracture development are analysed using different experimental methods.Natural fractures can be divided into four types and seven subtypes:structural(tensile,shear),superficial(weathering),diagenetic(stylolites,bedding),and composite genetic(structural-weathering,structural-diagenetic),with structural being the dominating type.Fractures are mainly oriented NE-SW,NW-SE and NNE-SSW and dip toward NNW,NE and SEE,with dip angles mostly greater than 70°and fracture density ranging from 1.5 to 3.5 m-1.According to filling characteristics and fracture cross-cutting relationships fracture filling can be divided into three stages.Fractures with stage I filling show strong fluorescence reaction under the microscope,demonstrating filled fractures can still be effective due to internal microfractures.The formation and development of fractures in carbonate reservoirs are controlled by four factors:tectonic stress field,fault,lithology and karstification.The magnitude and direction of the tectonic stress field during the fracture formation period determine the fracture size and distribution mode.Under the significant influence of strike-slip faults a large number of fault-associated fractures are developed,and their fracturing pattern is consistent with that of strike-slip faults.The radius of influence of a single strike-slip fault zone is 2048.56 m,and the development of fault controlled fractures is strong within 0308.25 m from the fault zone and significantly reduced beyond this range.The tension-shear section of the strike-slip fault and the end of the fault zone show good fracture development,and the active plate has high fracture density with more abundant oil/gas filled fractures.The level of fracture development is positively correlated with the content of brittle minerals and significantly influenced by Young’s modulus and Poisson’s ratio.The highest level of fr

关 键 词：裂缝表征 主控因素 碳酸盐岩储层 奥陶系 塔河油田 

分 类 号：P618.130.2[天文地球—矿床学] TE122.2[天文地球—地质学]