Porous-grain–upper-boundary model and its application to Tarim Basin carbonates  

多孔颗粒上界限模型及其在塔里木碳酸盐岩中的应用(英文)

作　　者：郭玉倩[1,2] 马宏达 石开波 曹宏[2] 黄录忠[1] 姚逢昌[1,2] 胡天跃 

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中国石油勘探开发研究院,北京100083 [3]WesternGeco,Schlumberger

出　　处：《Applied Geophysics》2013年第4期411-422,511,共13页应用地球物理（英文版）

基　　金：supported by the National Basic Research Program of China(2013CB228602);the National High Technology Research Program of China(2013AA064202);the National Science and Technology Major Project of China(Grant No.2011ZX05004-003)

摘　　要：Most of the carbonates in the Tarim Basin in northwest China are low-porosity and low-permeability rocks. Owing to the complexity of porosity in carbonates, conventional rock- physics models do not describe the relation between velocity and porosity for the Tarim Basin carbonates well. We propose the porous-grain-upper-boundary （PGU） model for estimating the relation between velocity and porosity for low-porosity carbonates. In this model, the carbonate sediments are treated as packed media of porous elastic grains, and the carbonate pores are divided into isolated and connected pores The PGU model is modified from the porous-grain-stiff-sand （PGST） model by replacing the critical porosity with the more practical isolated porosity. In the implementation, the effective elastic constants of the porous grains are calculated by using the differential effective medium （DEM） model. Then, the elastic constants of connected porous grains in dry rocks are calculated by using the modified upper Hashin-Shtrikman bound. The application to the Tarim carbonates shows that relative to other conventional effective medium models the PGU model matches the well log data well.塔里木盆地碳酸盐岩属于低孔隙度低渗透率,且孔隙形状复杂,常规岩石物理模型不能很好的描述塔里木地区碳酸盐岩孔隙度-速度关系。本文提出一种新的岩石物理模型-多孔颗粒上界限(PGU)模型来估计低孔隙度下碳酸盐岩的速度-孔隙度关系。在这个模型中,将岩石视为压实的弹性多孔斑块介质,从沉积过程角度把岩石中孔隙类型分为孤立孔隙和连通孔隙。这个模型是多孔颗粒硬砂岩(PGST)模型的改进,将临界孔隙度修改为更接近于实际的连通孔隙度。首先采用差分等效介质模型(DEM)来计算含孤立孔隙的岩石沉积晶体等效模量,利用改进的Hashin-Shtrikman上界限来估算含有连通孔隙的干岩模量。本文将该模型在塔里木地区测井数据应用,模型预测与测井数据匹配很好。与其他几种常用的速度-孔隙度模型对比,结果显示PGU模型预测结果更稳定,误差更小。

关 键 词：Porous-grain-upper-boundary （PGU） model CARBONATES Porosity Velocity 

分 类 号：P631.84[天文地球—地质矿产勘探]