高精度CT成像技术在致密油储层孔隙结构研究中的应用——以准噶尔盆地玛湖西斜坡风城组为例  

Application of high resolution CT image technology to the research of pore structure of tight oil reservoir:A case study of the Fengcheng formation on the Mahu west slope in Junggar basin

作　　者：孙乐[1] 王志章[2] 于兴河[1] 潘潞[3] 张国印[2] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国石化上海海洋油气分公司勘探开发研究院,上海200120

出　　处：《东北石油大学学报》2016年第6期26-34,共9页Journal of Northeast Petroleum University

基　　金：国家科技重大专项(2011ZX05008-004)

摘　　要：二叠系下统风城组为准噶尔盆地玛湖西斜坡致密油主力产层。基于CT成像的三维高精度储层表征、扫描电镜和压汞测试等方法,分析风城组致密油储层微观孔隙结构。选取并制备直径为65μm的CT实验样品进行纳米尺度扫描,构建纳米级孔隙三维结构模型,分析不同深度样品物性特征,以及孔喉大小、形态、空间分布和连通性。结果表明:在微米尺度下,实验样品孔喉大小差异大,半径为2～50μm,呈孤立状或条带状分布于粒间或粒内,数量少但占孔隙体积大;在纳米尺度下,样品孔喉半径为0.05～0.30μm,纳米级孔隙数量增多,呈管状或球状分布于矿物颗粒(晶体)内部或表面,纳米级球状微孔连通性较差,三维空间呈孤立状,多作为储集空间;计算样品孔隙度与岩心分析孔隙度结果接近。该研究结果可为研究区致密油储层进一步勘探提供指导。Permian Fengcheng formation is the main tight oil producing formation of the Mahu west slope in Junggar basin.Combined with the scanning electron microscopy(SEM),mercury injection test and other microscopic experiment technology,technology of high-resolution 3Dreservoir characterization based on the CT imaging was used to study the microscopic pore structure of tight oil reservoir in Mahu west slope,sourtheast of Junggar basin.From macroscopic to microcosmic,in accordance with the principle of 2Dto 3D,the experiments went on one by one,aiming to optimize the experiment sample.Some samples with a diameter of 65μm was derived and scanned by high-resolution Nano-CT,then a three-dimensional texture model of nano-scale pores was established and the porosity data of samples in different depth could be obtained and analyzed.A clear understanding of the size,shape,spatial distribution and connectivity of the pore throat could be obtained as well.Experimental analysis shows that,on a micrometer scale,the size of experimental sample pore throat varies violently,and their radius range from2 to 50μm,distributed in or between grains isolatedly or in a shape of a band.The pore throats are fewer but account for a large pore volume.On a nanometer scale,the radius of pores range from 0.05to0.30μm,and the quantity of nanoscale pores increases.The pore throats are arranged in the shape of tube and ball inside or on the surface of mineral particles(crystals).The ball-shaped micropores in nanoscale,often isolated in the 3Dspace,show the poor connectivity and consequently act as the reservoir space.The porosities calculated using the Nano-CT are close to the results analyzed by core samples.Our study can serve as a guide for the next step of tight oil exploration.

关 键 词：CT三维成像 致密油储层 微观孔隙结构 玛湖西斜坡 准噶尔盆地 

分 类 号：P618.13[天文地球—矿床学]