低电阻率油层解释方法

储层岩性变化形成的低电阻率油层是测井解释的一大难题，因为它的电阻率接近或低于临近的水层，使解释常常出现失误，它的成因主要是储层岩石颗粒的相对变细和泥质含量的相对增高，导致束缚水饱和度增加，在沉积单元上，一般出现在河流相砂体的顶部，三角液水下分流河道的天然堤和三角洲前缘末端的朵状砂体等部位；在物性上表现为高孔隙度和低渗透率，在电性上表现为高时差，低电阻率和高自然伽马，解释时给出了时差曲线与孔隙度，渗透率关系的模型，即岩石颗粒愈细，时差值越高，含油饱和度的计算采用修正后的阿尔奇公式，所提方法对于正确认识储层，提高解释符合率有一定的指导意义。

Interpretative Method of Reservoir with Low-resistivity

The causes of low-resistivity reservoir are various. Interpretation of oil layer with low resistivity is very difficult by lithological variation because the resistivity of the oil layer is near to or lower than that of the neighbor water layer,so,often making wrong interpretations. The main reason lies in the fineness of reservoir grains and the increase of shale content, thereby increasing irreducible water saturation. In sedimentary unit, the low-resistvity oil layers generally existed at the top of the fluvial facies sand, natural levee of delta deep channel sands and the lobe of delta front sands. The layers show high porosity, low permeability in rock analysis,and high interval transit time, low resistvity, and high gamma ray in electric logging. The interpreting model is given.The finer the grains, the higher the interval transit time.The method introduced in the paper is helpful to know different reservoirs rightly in the future and improve the interpreting results accurately.