含黏土矿物岩心电频散特性实验研究

Experimental Study on Resistivity Dispersion of Highly Clay Mineral Content Core

为研究黏土矿物对岩石电阻率频散的影响关系,制作4种共16块人工柱塞状岩心,分别为纯砂岩,含蒙脱石、高岭石、伊利石3种黏土矿物砂岩。对其真空加压饱和2.5×10~3 mg/L的CaCl_2溶液,利用煤油驱替改变含水饱和度并进行电阻率频谱测量。分析岩心的电频散与含水饱和度、孔隙度、温度、黏土矿物种类及含量的关系,利用薄膜极化假说解释了含黏土矿物岩心异于常规的电频散现象,为电阻率频谱测井解决非常规复杂油气藏问题提供理论依据。

In order to study the effect of clay minerals on resistivity dispersion of rock,16 plungeshaped artificial cores were made.The lithology of these cores are pure sandstones,sandstones with montmorillonite,kaolinite and illite,respectively.These cores were saturated with 2.5×10^3 mg/L CaCl2 solution.In order to measure the resistivity spectrum（measured by the 4294 A impedance analyzer）under different water saturation conditions,kerosene was used to displace the water in the core.Based on experiment,the relationship between the electric frequency dispersion of cores and water saturation,porosity,temperature,especially the types and content of clay minerals were analyzed in this paper,and the abnormal electric dispersion characteristics of the cores with clay mineral were also explained by the film polarization hypothesis.This study provides a theoretical basis for complex resistivity logging to solve unconventional and complex reservoir problems.