摘要
低孔隙度低渗透率储层的孔隙结构复杂,连通性较差,孔隙中流体分布不均匀,Archie公式中系数m、n的确定存在较大误差。由传统统计分析方法求取的m和n参数会随孔隙度和含水饱和度的不同变化,使测井电阻率计算的含油气饱和度精度降低。从数学物理边界条件和低孔隙度低渗透率储层的地质特征出发,分析了低孔隙度低渗透率储层中胶结指数m和饱和度指数n的变化特征。从储层岩石的地质作用和岩石物理变化过程探讨低孔隙度低渗透率储层中地层胶结指数m随孔隙度变化的一般规律,并用渗滤门限理论(PPTT)解释这一变化过程,建立了地层胶结指数m和饱和度指数n的准确计算方法。应用新参数对应的饱和度关系对QL油田不同水淹程度的2口井进行了处理解释,获得了良好的效果。
When the Archie equation is applied to computation of the water saturation in shaly sand formation with low porosity and low permeability, problems in accurate prediction of the ce- ment factor rn and the saturation exponent n are commonly encountered, because of the limited experimental conditions and the parameter distribution from which the Archie equation was de- rived. In fact, the Archie equation only accommodates the clean sand formation which holds me- dium to high porosity and the fluid in it must be homogeneously distributed. For shaly sand for- mation of low porosity and low permeability, it holds complex and poorly connected pore space, and the fluid in it is usually saturated inhomogeneously, the coefficients m and n in Archie equa- tion can not be evaluated accurately. Commonly, the coefficients m and n determined by conven- tional statistical methods vary with the formation porosity and the water saturation, therefore re- sulting in an inaccurate hydrocarbon saturation derived from the well logging resistivity. Accord- ing to the math-physical boundary condition and the geological character of the shaly sand forma- tion of low porosity and low permeability, analyzed are the characteristics of the variation of the coefficients rn and n through the geological process and the petrophysical alteration of the reser- voir rock. The percolation theory has been used to explain the varying process, and established are the calculation methods for the coefficients m and n. The saturation equation with newly de- termined coefficients m and n has been applied to two boreholes in one of the reservoirs in QL oil- field, West China. Comparison of the calculated result with the core experimental data shows that our new result is quite consistent with the core analysis data, it validates the efficiency of the newly developed method.
出处
《测井技术》
CAS
CSCD
北大核心
2010年第2期108-114,共7页
Well Logging Technology
基金
中国石油天然气集团公司基础研究项目(07A10303)
关键词
测井解释
泥质砂岩
阿尔奇公式
含水饱和度
岩石电阻率
地层胶结指数
饱和度指数
log interpretation, shaly sand, Archie equation, water saturation, rock resistivity, formation cementation factor, water saturation exponent
