基于孔隙度扰动模型致密砂岩弹性性质变化特征数值分析  

NUMERICAL VALUE ANALYSIS ON VARIABLE CHARACTERISTICS OF ELASTIC PROPERTY OF TIGHT SANDSTONE BASED ON POROSITY PERTURBATION MODEL

作　　者：周广照 徐程宇[2] 王珊[3] 尹帅[4] 刘红岐 

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500 [2]中国石油塔里木油田分公司勘探开发研究院,新疆库尔勒841000 [3]中石油塔里木油田分公司油气工程研究院,新疆库尔勒841000 [4]页岩气资源战略评价国土资源部重点实验室,中国地质大学,北京100083

出　　处：《矿物岩石》2016年第2期112-120,共9页Mineralogy and Petrology

基　　金：西南石油大学校级科技基金(2012XJZ004)

摘　　要：孔隙度对致密砂岩弹性性质具有重要影响，深入开展两者关系研究对致密砂岩储层物理模拟、钻完井设计、地震及测井解释等方面具有重要参考价值。研究以沁水盆地南部地区山西组和太原组致密砂岩为研究对象，从微观孔隙尺度层面入手，考虑了岩石骨架的非均匀性，基于孔隙度扰动模型探讨了孔隙度有效应力系数（n）对致密砂岩弹性性质的影响。研究结果表明，孔隙度扰动模型能较好的描述所研究致密砂岩弹性性质的变化规律。对于岩石体积模量（Ks）与未封套体积模量（Ks′）间的关系，当n=1时，未考虑孔隙度扰动，此时Ks=Ks′；当，n〈1时，Ks〉Ks′；当n〉1时，Ks〈Ks′。随着n值从1到0逐渐降低的过程中，岩石不封套孔隙体积模量（Kφ）逐渐降低。目的层致密砂岩的n值主要分布在0．4～0．8范围内，平均值约为0．6。当n取平均值0．6时，随着岩石孔隙度从2．2％增加到4．8％的过程中，岩石Kφ从23GPa降到了6GPa。降幅较为明显。Kφ与岩石孔隙度间具有较好的负相关性，当不考虑孔隙度扰动（n=1）时，会在一定程度上高估地层岩石Kφ值。Porosity has an important effect on formation rock elastic properties.The study of relation between porosity and rock elastic properties plays an important role in the physical modeling,design of well drilling and completion and interpretation of seismic well logging.Therefore,the effect of porosity effective stress coefficient on the elastic properties of tight sandstone of Shanxi and Taiyuan Formation in southern Qinshui basin is discussed on the basis of the micro pores and heterogeneity of rock skeleton.It shows that the porosity perturbation model can be used to describe the change rule of tight sandstone elastic properties.For the relationship of rock bulk modulus Ks and the unpacked rock bulk modulus Ks′,when n=1,the porosity perturbation is not considered,then Ks=Ks′;when n〈1,Ks〉Ks′;when n〉1,Ks〈Ks′.In the process of gradually reduce of n from 1to 0,the rock unpacked pore volume modulus KΦis gradually reduced.The value of n in the study tight sandstone layer mainly distributes in the range of 0.4-0.8,with average value of 0.6.When the value of n is 0.6,as the rock porosity increases from 2.2% to4.8%,the corresponding rock KΦdecrease obviously from 23 GPa to 6GPa.Negative correlation exists between the rock porosity and KΦ,when porosity perturbation is not considered（n=1）,KΦwill be overestimated to some extent.

关 键 词：孔隙度扰动模型 致密砂岩 弹性性质 孔隙度有效应力系数 

分 类 号：P313.1[天文地球—固体地球物理学]