致密砂岩储层自适应岩石物理建模方法  

Self-adaptive rock physics modeling method for tight sandstone reservoirs

作　　者：张金强[1,2,3] 刘振峰 刘喜武[1,2,3] 韩磊 ZHANG Jinqiang;LIU Zhenfeng;LIU Xiwu;Han Lei(SINOPEC Petroleum Exploration and Production Research Institute,Beijing 102206,China;State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development,Beijing 102206,China;State Energy Center for Shale Oil Research and Development,SINOPEC,Beijing 102206,China)

机构地区：[1]中国石化石油勘探开发研究院,北京102206 [2]页岩油气富集机理与有效开发国家重点实验室,北京102206 [3]国家能源页岩油研发中心,北京102206

出　　处：《石油地球物理勘探》2021年第4期792-800,808,I0011,共11页Oil Geophysical Prospecting

基　　金：中石化科技项目“鄂南探区致密油甜点地震预测技术研究”(P17020-4);国家科技重大专项“陆相页岩油甜点地球物理识别与预测方法”(2017ZX05049-002)联合资助。

摘　　要：常规岩石物理建模方法建立在岩石矿物组分已知的前提下,并以Voigt-Reuss-Hill模型求取岩石基质的等效弹性模量。在致密砂岩物理建模的实践中,经常会遇到由于测井资料不全,无法给出精确的矿物成分解释,使常规岩石物理建模方法精度受到影响。针对这一问题,提出了自适应的岩石物理建模方法。首先通过联立Gassmann方程和临界孔隙度模型,求取岩石基质的弹性模量;再根据解释的泥质含量曲线,应用最小二乘方法和Voigt、Reuss模型,求取砂质、泥质成分的弹性模量的上、下限。在此基础上,利用模拟退火反演算法确定砂、泥质成分的弹性模量近似值,并按照纵波模量不变的原则进一步对砂、泥质成分的弹性模量进行微调,最终获得合理的岩石物理建模参数。应用该方法对鄂尔多斯南部M工区进行了岩石物理建模,结果显示泥岩与致密砂岩的弹性参数有较好的可区分性,泥岩表现出较高的纵横波速度比和较低的纵波速度,砂岩的纵横波速度比及纵波速度随孔隙度增大而降低。In traditional rock physics modeling,the mineral components are known,and the equivalent elastic modulus of the rock matrix is solved with the Voigt-Reuss-Hill model.In the practice of rock physics modeling for tight sandstone reservoirs,accurate mineral component interpretation cannot be provided due to incomplete logging data.As a result,the accuracy of conventional rock physics modeling is affected.To tackle the problem,we propose a self-adaptive method for the rock physics modeling of tight sandstone reservoirs.The method uses both the Gassmann equation and the critical porosity model to estimate the elastic modulus of the rock matrix.According to the interpreted shale content curves,the upper and lower bounds of elastic moduli of shale and sandy components are estimated with the least square method and Voigt and Reuss models.A simulated annealing algorithm is employed to find the approximate elastic moduli of shale and sandy components.The values are fine-tuned according to the principle of constant P-wave modulus,and finally,the reasonable parameters for rock physics modeling are obtained.Area M in the southern Ordos Basin is subject to rock physics modeling with this method and the results show that the elastic parameters of shale and tight sandstone can be well distinguished.Shale is characterized by a high P-wave/S-wave velocity ratio and a low P-wave velocity.For sandstone,the Pwave/S-wave velocity ratio and the P-wave velocity decline as the porosity increases.

关 键 词：致密砂岩 自适应岩石物理建模 GASSMANN方程 临界孔隙度模型 Voigt-Reuss-Hill模型 

分 类 号：P631[天文地球—地质矿产勘探]