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由于低电阻率油气层的电阻率低于或接近邻近水层的电阻率，降低了利用电阻率识别油气层和水层的分辨率，给测井解释带来较大的难度。新疆塔北地区中新生界的泥质砂岩油气储层主要为灰色细、中－粗泥质砂岩，其孔隙性和渗透性好，并且储层厚度大，是值得重点研究的层段。该层段有二类油气储层（一般油气层和特殊油气层），基本上都属于低电阻率油气层，尤其是特殊油气层，电阻率(0.4～1.5 Ω·m）低于或接近邻近水层的电阻率。为了利用测井等资料评价新疆塔北三叠系低阻油气层，文章在分析和研究测井曲线、岩心分析资料的基础上， 提取水层、油气层测井曲线以及储层物性特征，剖析了低阻油气层成因是高矿化度地层水、高束缚水饱和度、微孔隙发育，而泥质导致油气层电阻率减小是前三个成因的综合反映。利用建立的泥质砂岩储层导电模型，通过导电模型计算含水饱和度以及相关的储层参数来区分油气层与水层，其研究成果与试油结论相符。

Characteristics of Triassic Low-Resistivity Oil and Gas Reservoirs in Tabei of Xinjiang and Their Origins

Because the resistivity of the low resistivity oil and gas reservoir is less than or approximate to that of the water bearing layer，the distinguishability of applying the resistivity to discriminating the oil and gas reservoir from the water bearing layer is decreased，which brings great difficulty on log interpretation.The Mesozoic Cenozoic argillaceous sandstone oil and gas reservoirs in Tabei of Xinjiang are worthy of being emphatically investigated intervals，being mainly composed of grey fine and median coarse argillaceous sandstones with good porosity and permeability and large reservoir thickness.These intervals include two kinds of oil and gas reservoirs，i.e. the general reservoirs and the special reservoirs，and they are basically belonged in low resistivity reservoirs，especially the latter which resisticities change from 0.4 to 1.5 Ω·m being near or less than those of adjacent water bearing layers.In order to evaluate the Triassic low resistivity oil and gas reservoirs，on the basis of analyzing logs and core analysis data，it was pointed out that the resistivity′s being reduced by shale in oil and gas reservoirs is a comprehensive reflection of the high salinity formation water，large irreducibe water saturation and well developed micropores in the low resistivity reservoirs in consideration of the logs of water bearing layers and oil and gas reservoirs and the petrophysical properties.The water saturations and relevant reservoir parameters calculated by use of the authors established argillaceous sandstone reservoir conducting model may be applied to distinguishing the oil and gas reservoirs from the water bearing layers.The research results are coincident with the production test conclutions.