基于高压压汞与核磁共振的致密砂岩孔隙结构研究——以苏里格气田山西组与下石盒子组为例  

Study on Pore Structure of Tight Sandstone Based on High Pressure Mercury and Nuclear Magnetic Resonance--Take Shanxi Formation and Shihezi Formation in Sulige Gas Field as Examples

作　　者：崔哲治 孙卫[1] Cui Zhezhi;Sun Wei(State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, Shaanxi 710069, China)

机构地区：[1]西北大学地质学系大陆动力学国家重点实验室,陕西西安710069

出　　处：《非常规油气》2020年第2期49-55,共7页Unconventional Oil & Gas

基　　金：西北大学大陆动力学国家重点实验室开放课题基金“陆相页岩相微纳米孔喉结构差异性与形成机理及其对气体赋存状态的控制机理研究”(18LCD01);国家自然科学基金项目“致密砂岩油藏成岩-烃类充注时序对微纳米孔隙结构的约束机制及石油充注孔喉下限研究”(41702146);陕西省青年科技新星项目“陆相页岩微纳米孔喉结构非均质性及对页岩气赋存状态的控制机理”(2019KJXX-054)资助。

摘　　要：本文结合高压压汞孔喉分布,利用推导的T2弛豫时间与孔喉半径的对应关系,将岩心100%饱和水核磁共振T2谱转化为核磁孔喉分布曲线,利用核磁孔喉曲线信息完整的特性,反映样品中的孔喉结构,确定样品可动流体孔喉半径截止值,并结合X-衍射分析结果及镜下观察结果对样品所在层位进行评价。取鄂尔多斯盆地苏里格气田山西组与下石盒子组的5块样品,分析其结构表明,核磁孔喉分布曲线反映的孔喉信息明显优于高压压汞孔喉分布,样品中的孔隙主要以小孔隙为主,孔喉半径大都处于0.01~1μm之间,可动流体截止半径在0.0259~0.5235μm之间,最终评价L1样品所在层位储层物性最好,为苏里格气田的勘探开发提供了科学依据。In this paper,the high-pressure mercury-hole pore throat distribution is used to convert the 100%saturated water nuclear magnetic resonance T2 spectrum into the nuclear magnetic pore throat distribution curve by using the corresponding relationship between the T2 relaxation time and the pore throat radius.The nuclear magnetic pore throat curve information is complete.The characteristics reflect the pore throat structure in the sample,determine the cutoff value of the pore radius of the movable fluid of the sample,and combine the X-ray diffraction analysis results with the microscopic observation results to evaluate the layer position of the sample.Five samples from Shanxi group and Xiashi box group of Sulige gas field in the Ordos Basin were selected as samples.The analysis structure showed that the pore throat information reflected by the nuclear magnetic pore throat distribution curve was significantly better than that of the high pressure mercury pore throat distribution.Small pores are dominant,the pore throat radius is mostly between 0.01 and 1μm,and the movable fluid cutoff radius is between 0.0259 and 0.5235μm.The final evaluation of the L1 sample is the best in the reservoir of the horizon,providing exploration and development for Sulige gas field.

关 键 词：苏里格气田 核磁共振 高压压汞 

分 类 号：P618.13[天文地球—矿床学]