泥质砂岩储集层测井解释实践——金家油田低电阻油层评价

INTERPRETATIONS FOR LOG DATA FROM MUDDY SANDSTONE RESERVOIR -Evaluation of the Low-Resistivity Reservoir in Jinjia Oilfield

胜利石油管理局地质科学研究院

Geological Research Institute, Shengli Petroleum Adminastration

泥质砂岩中有效粘土所具有的可交换阳离子的存在将降低地层的电阻率。在低矿化度(高电阻率)的淡地层水地层中,这种影响尤其突出。金家油田目的层含有大量的有效粘土矿物,实验分析平均阳离子交换能力达0.188m mol/g;地层水相对很淡,一般在3000±500ppm范围内,地层温度下地层水电阻率为1.2Ωm左右。 本文针对该油田有效粘土含量高、地层水淡的特点,结合有关实验分析资料,运用韦克斯曼-史密斯方程对粘土的附加导电影响作了详细的分析与计算,提出了金家油田低电阻率目的层含油饱和度测井解释关系式,并利用有关资料对解释效果作了分析,指出运用韦克斯曼-史密斯方程解释金家油田地层可以获得满意的效果。

In muddy-sandstone,the formation resistivity will be reduced owing to the existance of the exchangeable cation in effective clay. In formation with low-mineralised (high resistivity)fresh water,such effects are especially outstanding. In Jinjia oilfield,there art a large amount of effective clay in the target stratum. According to experiments,its capacity of cation-exchange could reach 0. 188m mol/g. The formation water is relatively fresh, its mineralization is, generally,within the range of 3,000±500ppm,and under the field condition,the resistivity of formation water is about 1. 2Ωm.Grounded on the high effective-clay content and the fresh formation water as well as the data from experiments, by using the Wilkesman-Smith function,the additional effects in conductivity was derived and examined at full length. Relations between log data and oil saturation of the low resistivity target in Jinjia oilfield were therefore made clear. Results from interpretation were verified by the data from other origins. It has been proved that satisfactory result could be obtained in this area by use of the Wilkesman-Smith function.