鄂尔多斯盆地L地区致密低阻气层成因研究

摘要

低电阻率油气层(简称低阻油气层)在国内外分布十分广泛,低阻油气层的识别与评价是一个难点也是一个重点,然而对于低阻油气层成因的确定是其识别与评价的基础.针对鄂尔多斯盆地L地区致密气层的低阻成因,基于铸体薄片实验资料确定导电矿物的含量,基于X衍射实验资料确定粘土矿物的类型与含量,基于岩石电阻率实验与半渗透隔板实验资料确定储层的含水量,排除了导电矿物、粘土附加导电与高不动水作用是导致鄂尔多斯盆地L地区致密气层出现低阻气层的主要原因;基于双相流体的孔隙介质的渗流力学理论结合阿尔奇模型对储层感应测井响应值进行数值模拟,对比测井实测值与模拟值,确定了钻井液的侵入为鄂尔多斯盆地L地区致密气层出现低阻气层的主要原因,为实现研究区块或其他区块低阻气层识别与评价提供参考与借鉴.%The low resistivity reservoirs (the low-resistivity pay) is widely distributed at home and abroad.The identification and evaluation of low resistivity reservoir is a difficulty and a key point,too.However,the formation of low resistivity reservoir is the basis of identification and evaluation.Aiming at the genesis of low resistivity of tight gas reservoir in L area of Ordos Basin,we think the determination of conductive minerals will come out of experimental data in cast thin section,basing on determination of clay mineral types and contents by X diffraction experiment data.Regarding to rock resistivity experiment,we have found semi permeable clapboard experiment data will determine reservoir water content,excluding conductive minerals.The additional conductive clay and high immobile water is the main reason for the formation of low resistivity gas reservoirs in the L area of Ordos Basin.Based on seepage mechanics theory of two-phase fluid in porous media,numerical simulation is carried out for reservoir induction log response to combine with Archie model,by contrasting measured value of well logging and simulation value.The main reason for formation of low resistivity gas reservoirs is invasion of drilling fluid in the L area of Ordos Basin to provide reference and reference for identification and evaluation of low resistivity gas reservoirs in research blocks or other blocks.