王集油田相对低电阻率油层成因及识别

泌阳凹陷王集油田核桃园组三段的油水分布受构造、断层、沉积微相、地层水共同控制,正常电阻率油层与低电阻率油层、高电阻率水层共存,且测井曲线特征相似,影响正确判断含油性。岩矿分析、地层水分析以及测井资料综合研究表明,储集层岩石颗粒间普遍富集与充填有黏土矿物,以高龄石（局部地区高达66.2%）、蒙脱石为主,微孔隙发育,使束缚水饱和度增高,油层束缚水矿化度高,导电性增强,这是油层显示相对低电阻率的主要原因。利用多参数判别分析法,纵波等效弹性模型差比值法等方法,可有效地识别相对低电阻率油层。图5表2参12

Origin and identification of low resistivity oil layers in Wangji Oilfield, Biyang Sag

The major controlling factors of petroleum accumulation in Wangji Oilfield are tectonic, fault, micro-fades and formation water. Well log response of the reservoir is complex. There are normal resistivity oil layer, low resistivityoil layer and high resistivity water-bearing layer, and their well logging curves are similar. Based on the characters, causes and distributions of low or high resistivity reservoir, the oil layer could be identified, suggesting that main causes of low resistivity oil layers are the high bound water saturation and the correlation between oil and water layer resistivity has been changed; the multivariate discriminate analysis method and equivalent elastic modules difference ratio method are effectively applied to identify low resistivity oil layer.