中文摘要：

针对鄂尔多斯盆地苏里格气田南区上古气藏低孔低渗岩性气藏气、水分异差,低阻气层较为发育且气层识别难度大的问题,探讨造成气层低阻的原因,为低阻气层的识别提供依据。作者综合利用岩心、薄片、扫描电镜、地层水、测井和试气等资料,结合构造特征和沉积背景,重点分析了有可能影响该区地层电阻率的不动水饱和度、黏土矿物、粒度、孔隙结构、地层水矿化度和泥浆侵入等因素。结果表明,低阻气层的形成是多种因素综合影响的结果,其中微细晶间孔隙发育、孔喉结构复杂造成的高不动水饱和度是气层低阻的主控因素;低幅度构造下气水分异差、高矿化度、黏土矿物和泥浆侵入对电阻率的降低也有不可忽视的影响。该区低阻气层的识别与评价过程中要充分考虑储层微细晶间孔发育程度及孔隙结构复杂程度,以提高低阻气层的辨识率。

英文摘要：

As the reservoir in the study area is a low porosity and low permeability lithologic gas reservoir,it is difficult to find the gas-water contact and distinguish the effective low resistivity gas reservoir.This paper discusses the reason leading to the low reservoir resistivity gas reservoir in order to provide the basis to distinguish the low resistivity gas reservoir.Using the data of the core analysis,the formation water analysis,SEM,logging and testing well responses and combined with the structural characteristics and the sedimentary environment of this area,this paper analyzes the possible influencing factors responsible for the low formation resistivity of this area.These factors include the high immobile water saturation,clay minerals grain size,pore structure,formation water mineralization degree,and mud invasion.The results show that the high immobile water saturation caused by the development of the reservoir fine intergranular holes and the complicated pore structuresis the main controlling factor to form the low resistivity of the gas reservoir and the poor differentiation of gas and water,the high mineralization,clay minerals and mud invasion also have the ignorable influences on the decrease of the resistivity.