柴达木盆地英西地区S3-1井渐新统下干柴沟组储集空间类型  

Reservoir Space Types of Oligocene Xiaganchaigou Formation from Well S3-1 in Yingxi Area of Qaidam Basin,China

作　　者：黄成刚[1,2] 崔俊[3] 关新[4] 常海燕[2] 杨森[1] 惠媛媛[1] 吴梁宇[1] 吴丽荣[1] 

机构地区：[1]中国石油天然气集团公司油藏描述重点实验室,甘肃兰州730020 [2]中国石油勘探开发研究院西北分院,甘肃兰州730020 [3]中国石油青海油田公司勘探开发研究院,甘肃敦煌736202 [4]西南石油大学地球科学与技术学院,四川成都610500

出　　处：《地球科学与环境学报》2017年第2期255-266,共12页Journal of Earth Sciences and Environment

基　　金：国家科技重大专项项目(2016ZX05003-006);中国石油重大科技专项项目(2011E-03)

摘　　要：近年来,柴达木盆地英西地区渐新统下干柴沟组的油气勘探取得了重大发现,但其主要储集空间类型一直是争论的焦点。基于对S3-1井的岩芯观察和系统的微观岩石学、结构学特征研究,总结出其主要储集空间类型为白云石晶间孔,而非溶蚀孔。其主要证据包括:(1)高沉积速率的暗色层段难以发生暴露溶蚀;(2)白云石为岩石最重要的矿物组分之一;(3)场发射扫描电镜下可见棱角状晶间孔广泛发育;(4)岩芯上观察到的孔洞系统在偏光显微镜下可见其均发育于裂缝之中,为盐类矿物结晶所致,非溶蚀而成;(5)"特低孔-特低渗"的物性特征;(6)较高的排驱压力、较小的连通孔喉半径以及极低的退汞效率;(7)荧光显微镜下表现为整体发光特征。这些发育极广的基质孔隙储油是英西地区亿吨级油田高产稳产的主控因素之一,研究结果对下一步勘探部署具有重要的指导意义。In recent years,there is important discovery for oil and gas exploration of Oligocene Xiaganchaigou Formation in Yingxi area of Qaidam Basin.However,the main reservoir space types have been debated over.Based on core observation and systematically study of the micro petrological and structural characteristics of Well S3-1,the main reservoir space types were concluded.The results show that the main reservoir space types are intercrystalline pores of dolomite rather than dissolution pores.The main evidences include that the dark layers with highdeposition rate are difficult for exposure and dissolution;dolomite is one of the most important minerals in rocks; under the field emission scanning electron microscope,the angular intercrystalline pores widely develop;because of the crystallization of salt minerals,not dissolution,the pores and holes observed in core are all in the fractures under the polarized microscope;the physical characteristic is ＂extra low porosity-extra low permeability＂;the displacement pressure is high,the pore throat radius is small,and the efficiency of mercury withdrawal is very low;the characteristics under fluorescence microscopy is whole.Oil-bearing matrix porosity widely develop,so that it is one of the main control factors of large oilfield with high and stable yield in Yingxi area;the results have important guide for the further exploration.

关 键 词：白云石晶间孔 溶蚀孔 下干柴沟组 特低孔-特低渗 动力学屏障 准同生交代 英西油田 柴达木盆地 

分 类 号：P618.130.21[天文地球—矿床学] TE122.2[天文地球—地质学]