断陷湖盆致密粗砂岩、砂砾岩储层空间类型与有利储层成因  

Reservoir Space and Its Origin in Tight Sandstone-Sandy Conglomerate Reservoirs of the Faulted Basin

作　　者：郝杰 周立发[1,2] 袁义东 杨燕[1] 张鹏 邱煦宇[3] Hao Jie;Zhou Lira;Yuan Yidong;Yang Yan;Zhang Peng;Qiu Xuyu(Department of Geology,Northwest University,Xi＇an 710069,China;Shaanxi Provincial Institute of Energy Resource ＆ Chemical Engineering,Xiran 710050,China;Xi＇an Changqing Chemical Group Co.,Ltd.,Xi＇an 710000,China)

机构地区：[1]西北大学地质学系,西安710069 [2]陕西省能源化工研究院,西安710050 [3]西安长庆化工集团有限公司,西安710000

出　　处：《地质科技情报》2018年第4期134-140,共7页Geological Science and Technology Information

基　　金：国家科技重大专项课题(2017ZX05009-002)

摘　　要：分析徐家围子断陷沙河子组致密储层储集空间类型和有利储层的地质成因,可以为储层预测提供依据。通过岩心观察、物性测试、偏光显微镜、扫描电镜、储层孔隙演化等综合分析认为,研究区粗砂岩、砂砾岩储层主要是扇三角洲背景下近物源、快速搬运堆积的产物,属于低孔、超低渗储层;孔隙类型包括溶蚀孔、原生粒间孔、晶间孔、压裂缝、溶蚀缝等,长石溶孔、岩屑溶孔为主要的储集空间,其次是方解石晶间孔、黏土矿物晶间孔,压裂缝、溶蚀缝对砂砾岩的渗透性具有改善作用。分选、淘洗程度相对较高的扇(辫状河)三角洲前缘水下分流河道、河口坝微相是有利储层发育的沉积基础,成岩初期强烈的压实作用与成岩中晚期的胶结作用是导致储层致密的主要原因,早成岩期绿泥石包壳、方解石胶结对原生孔隙具有一定的保护作用,中成岩期有机酸对储层中长石、岩屑的大量溶蚀是形成有利储层的关键。To provide the basis for the reservoir prediction,this paper analyses the reservoir space type and the geological cause of the favorable reservoirs in Shahezi Formation of Xujiaweizi Fault Depression.The conclusion is achieved through the comprehensive analysis of core observation,physical property test,polarizing microscope,scanning electron microscope,reservoir pore evolution.The coarse sandstone-sand conglomerate reservoirs are the product of rapid transportation and accumulation under the fan delta facies.Pore types include dissolution pores,primary intergranular pores,intergranular pores,compressive fractures and dissolution joint,feldspar solution pores.Cuttings dissolved pores are the main reservoir space,followed by intergranular micropore of authigenic clay mineral and compressive fracture.Fractures can improve the permeability of gravel rock.Distributary channel and mouth bar microfacies of the fan（braided river）delta where grit rocks and sandy conglomerates are washed and sorted to a relatively high degree are the basis of favorable reservoirs.The protection of primary porosity by chlorite cladding and calcite cementation in the early diagenetic stage and the dissolution of feldspar and debris in the middle diagenetic stage are the factors for the formation of favorable reservoirs.

关 键 词：致密砂岩 储层 储集空间 成因 沙河子组 徐家围子断陷 

分 类 号：P618.130.21[天文地球—矿床学]