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辽河凹陷西部东营组油层电阻率普遍偏低,一般低于8Ω·m,常常与邻近水层电阻率相近或者出现倒置,这种现象严重影响了测井识别精度。在研究区岩石物理实验资料和测井、试油等资料的基础上,综合分析了各地质因素与电阻率之间的关系,结果表明:影响研究区油层电阻率偏低的主要控制因素为砂泥岩薄互层;其次是储层不动水饱和度高,高不动水主要是由于储层岩性细、孔隙结构复杂和泥质含量高等3个因素综合引起,这3个因素单独对储层电阻率影响较小;而储层导电矿物含量、地层水矿化度和泥浆侵入对储层电阻率基本无影响。通过建立东营组Ⅱ主力油层厚度与电阻率的交会图,确定低阻油层厚度界限为0.8~2.7m,电阻率界限为2.5~5.6Ω·m,将低阻油层的界限应用到其他主力油层二次测井解释中,再结合试油结果 ,识别符合率达到80%以上。
The resistivity of the reservoir in the Dongying Formation of western Liaohe sag is generally low, generally lower than 8Ω · m, which is often similar to the resistivity of nearby water layers or inverted. This phenomenon has seriously affected the logging identification accuracy. Based on the data of petrophysical experiment, well logging and oil testing in the study area, the relationship between geological factors and resistivity is comprehensively analyzed. The results show that the main controlling factors affecting the low resistivity of the reservoir are sand Mudstone and thin interbed; secondly, the immobile reservoir water saturation is high and the immobile water is mainly caused by the combination of three factors: reservoir lithology, complex pore structure and high clay content. These three factors are independent of storage Layer resistivity has little effect on the reservoir resistivity. However, the content of conductive mineral, formation water salinity and mud invasion have little effect on the reservoir resistivity. By establishing the cross-plot of the thickness and resistivity of the main oil layer in Dongying formation Ⅱ, the thickness limit of the low resistivity reservoir is determined to be 0.8 ~ 2.7m and the resistivity limit is 2.5 ~ 5.6Ω · m. The limit of low resistivity reservoir is applied to other main reservoirs Log interpretation, combined with the test results, the recognition rate of 80% or more.