利用波速比求取致密砂岩基质矿物剪切模量新方法  

A NEW METHOD OF CALCULATION OF SHEAR MODULUS FOR MATRIX MINERALS IN TIGHT SANDSTONE BY USING VELOCITY RATIO

作　　者：尹帅[1] 丁文龙[1] 代鹏[1] 单钰铭[2] 穆文平 钱程[4] 陈孜[4] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]成都理工大学能源学院,四川成都610059 [3]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [4]中国地质大学(北京)水资源与环境学院,北京100083

出　　处：《矿物岩石》2015年第3期110-114,共5页Mineralogy and Petrology

基　　金：国家自然科学基金面上项目(41372139;41072098);国家科技重大专项专题(2011ZX05018-001-002;2011ZX05009-002-205;2011ZX05033-004)

摘　　要：实验提出一种利用波速比求取致密砂岩基质矿物剪切模量的方法,具体步骤为:首先根据Biot-Gassmann理论方程得出致密砂岩波速比(Vp/Vs)与kma,μma及α的关系,然后利用孔隙度将α进行替换,得出波速比与岩石孔隙度之间的定量关系。利用由Gassmann流体替代方程推导而来的线性化方法求取kma,最终求取岩石μma。基于上述方法对所取深层致密砂岩样品进行物性及声学测试,结果表明,岩样(Vp/Vs)2与(1-Ф)-2间满足线性关系,相关系数R2=0.991;中间参数G取值为0.832。最终计算获得该砂岩的kma=72.85GPa,μma=54.64GPa,求算结果与岩石内部矿物成分、微观接触型式及应力状态相符,表明该方法的有效性。利用该方法能较有效的估算岩石基质矿物剪切模量,对测井、地震及岩石力学等方面更深入研究具有一定参考价值。In this paper, the method of calculating shear modulus of dense sandstone matrix minerals by means of wave velocity ratio is proposed. Firstly, the relationship of （Vp/Vs）,kma,μma,α is obtain on the basis of Biot-Gassmann theory equation. Secondly,use porosity to replace a, and obtain the relationship of velocity ratio and porosity. Thirdly, calculate kma by using the linearization method derived with the Gassmann fluid replace equation,and finally calculate μma. Physical property and uniaxial acoustic testing of the deep tight sandstone are conducted on the basis on the above method. It shows that there is linear relationship between （Vp/Vs）^2 and （1-Ф）^-2 with a correlation coefficient R^2 of 0. 991. The value of parameter G is 0. 832, calculated value of kma of the sandstone is 72.85 GPa and its μma is 54.64 GPa. The calculating result is related to rock mineral composition,micro contact type and the state of stress. This method can effectively estimate shear modulus of rock matrix minerals to some extent, and has certain reference value for study of well logging, seismic and rock mechanics.

关 键 词：致密砂岩 波速比 基质矿物剪切模量 Biot-Gassmann理论 Biot系数 声学 

分 类 号：P313.1[天文地球—固体地球物理学]