基于Ruger近似式预测裂缝型储层的可行性研究  

Ruger approximate formula-based prediction of fractured reservoir

作　　者：吴姗姗[1,2] 高刚 桂志先[1,2] 王鹏[1,2] 李成毅[3] WU Shanshan;GAO Gang;GUI Zhixian;WANG Peng;LI Chengyi(Key Laboratory of Exploration Technologies for Oil and Gas Resources,Ministry of Education,Yangtze University,Wuhan 430100,China;School of Geophysics&Oil Resources,Yangtze University,Wuhan 430100,China;Geophysical Exploration Company of Chuanqing Drilling Engineering Co.Ltd.,CNPC,Chengdu 610213,China)

机构地区：[1]长江大学油气资源与勘探技术教育部重点实验室,湖北武汉430100 [2]长江大学地球物理与石油资源学院,湖北武汉430100 [3]中国石油集团川庆钻探工程有限公司地球物理勘探公司,四川成都610213

出　　处：《煤田地质与勘探》2020年第1期189-196,共8页Coal Geology & Exploration

基　　金：国家自然科学基金项目(41604099);中国石油科技创新基金项目(2015D-5006-0301)。

摘　　要：叠前纵波方位各向异性检测裂缝是目前应用最为广泛的方法,该方法主要是利用AVAZ地震资料椭圆拟合的长轴与短轴信息来评价裂缝,该方法在具体应用时,认为裂缝型储层AVAZ响应特征的变化仅由各向异性参数决定,而没有考虑非各向异性参数的影响,从而引起裂缝评价的多解性。为提高该技术的裂缝评价精度,从模型分析入手,将模型中各向异性参数及岩性参数设置为概率密度分布函数,然后采用MonteCarlo随机方法进行叠前AVAZ正演模拟。首先,对各向异性参数对椭圆拟合的影响进行简单分析,得出各向异性参数γ对椭圆扁率B/A与各向异性因子B影响最大、δ次之、ε最小。然后,进一步重点分析不同标准差的速度与密度模型的B/A与B响应特征,得出地层的速度与密度的变化在较小范围内时,该技术评价裂缝才具有一定的可行性,其中,地层纵波和横波速度的变化(尤其是纵波速度)对叠前AVAZ响应影响较大,地层密度几乎没有影响,故当横向岩性变化较大时,该方法在评价裂缝型储层时的结果具有一定的不确定性。The azimuthal anisotropy of pre-stack P-wave is the most widely used method to detect fracture.This method mainly uses the long-axis and minor axis information of the ellipse fitted by the AVAZ seismic data to evaluate the fracture.When applying it in practice,it is considered that the variation of AVAZ response characteristics in the fractured reservoirs is just determined by the anisotropic parameters,and the influence of non-anisotropic parameters is not taken into account,which leads to the multi-solution of fracture evaluation.In order to improve the accuracy of this fracture evaluation technology,we started with the model analysis,the anisotropic parameters and lithological parameters were set to normal distribution functions,then the Monte Carlo stochastic method was used to carry out the pre-stack AVAZ forward modeling.Firstly,the influence of the anisotropic parameters on the ellipse fitting was simply analyzed.It is concluded that the anisotropic parameterγhas the greatest influence on the elliptic flatness B/A and the anisotropic factor B,the second is the parameterδ,and the parameterεhas the smallest influence.Then,the B and B/A response characteristics of the velocity and density models with different standard deviations were further analyzed.It is concluded that the change of velocity and density should be limited in a small range,in which the fracture evaluation technology is reliable.In addition,the variation of primary wave and shear wave velocity(especially the primary wave velocity)has greater influence on the pre-stack AVAZ response,and the density has almost no effect.Therefore,when applying this method to evaluate the fractured reservoirs,dramatic changes in the lateral lithology will increase the results’uncertainty.

关 键 词：HTI介质 AVAZ正演 Ruger公式 MONTE Carlo随机方法 裂缝 

分 类 号：P631[天文地球—地质矿产勘探]