鄂尔多斯盆地西南部走滑断-缝体分布规律及其主控因素  

Distribution of strike-slip fault-fracture volume and its controlling factors in the southwestern Ordos Basin

作　　者：王朝 黄雷 刘池洋[1] 何发岐 殷珂 张泽宇 董迎春 WANG Zhao;HUANG Lei;LIU Chiyang;HE Faqi;YIN Ke;ZHANG Zeyu;DONG Yingchun(Institute of Oil and Gas Basin,Northwest University,Xi'an,Shaanxi,710069,China;Sinopec North China Oil and Gas Branch,Zhengzhou,Henan,450006,China)

机构地区：[1]西北大学含油气盆地研究所,陕西西安710069 [2]中石化华北油气分公司,河南郑州450006

出　　处：《中国矿业大学学报》2024年第4期793-807,共15页Journal of China University of Mining & Technology

基　　金：国家自然科学基金面上项目(42272148)。

摘　　要：鄂尔多斯盆地内部发育大量小尺度走滑断层相关的裂缝体,勘探实践已揭示这一断-缝体系对致密储层起到重要的改善作用,控制甜点区发育,然而其分布规律及主控因素尚不明确.本研究利用方差体、蚂蚁体等属性分析,结合测井、岩心及野外露头资料研究,对盆地西南部典型三维地震区内断-缝体分布规律进行研究.结果表明:鄂尔多斯盆地西南部中生界主要存在NW向和ENE向两组走滑断层,这些断层与其两侧的高角度缝为主的裂缝网络共同构成断-缝体系.盆内走滑断层两侧裂缝带较发育,而断层内部结构中的断层核欠发育.盆内断-缝体分布具有明显分层性:上古生界—三叠系,主要发育NW向断裂及其裂缝体系,裂缝沿断层呈带状分布,裂缝带宽度大、裂缝密度高;侏罗系—白垩系,发育NW和ENE向断层及相关裂缝,断层两侧裂缝带较窄、裂缝密度小,仅局部发育高裂缝区.综合认为断-缝体分布主要受到断层活动强度和断层组合样式差异性的控制作用.断层活动性强,次级裂缝带互相叠加,形成宽度大、带状分布断-缝体;断层活动性弱,单断层裂缝带窄,主要在断裂的马尾式交切处、雁列式侧接处和不同走向断层交切处等局部位置发育断-缝体.本研究有助于明晰鄂尔多斯盆地内部中生界断-缝体油藏的发育规律,为认识克拉通块体内部微断裂控藏特征提供典型实例.The fracture can improve the property of tight reservoir and benefits for petroleum accumulation in the Ordos Basin,but the distribution of the fracture related to the small-scale intrabasinal strike-slip faults is still unclear.Using variance and ant track attributes based on the 3D seismic data,combined with well logging,core and outcrop data,the distribution of fracture was analyzed in detail in this contribution.There are two sets of strike-slip faults tren-ding NW and ENE in the southwest Ordos Basin.The fault-fracture volume consists of the faults and the dominant high angle fractures around the faults.The fault zone is characterized by the dominant fractured damage zone while the fault core is underdeveloped.The distribution pattern of the fault-fracture volume varies in the different layers.In the Upper Paleozoic-Trias-sic,fractures developed bandedly on both sides of the NW-trending fault.The fault-fracture volume has a greater width and higher density of fractures in this layer.In the Jurassic-Creta-ceous,narrow fractured damage zones develop on both sides of the NW and ENE-trending faults.The fault-fracture volume has a lower density of fracture,and fractures develop hetero-geneously along the faults.Over all,the distribution of the fault-fracture volume is controlled mainly by the activity intensity and arrangement of faults.The intense activity of faults leads to the superposition of the fractured damage zone and wide banded fault-fracture volume.The weak activity of the fault leads to the narrow width of single fault zone.On this occasion,fault-fracture volume develops at the bifurcation of horsetail splays,stepovers of en echelon linkages and intersections of faults locally.The distribution of fractures in the southwest Ordos Basin is an example to understand the mechanism of micro-fault in other craton blocks.It is also helpful to clarify a new exploration target,the fault-fracture reservoir,in the Mesozoic in the Ordos Basin.

关 键 词：克拉通 鄂尔多斯 走滑断层 断-缝体 致密储层 

分 类 号：P54[天文地球—构造地质学]