巴彦油田碎屑岩储层阵列感应测井负差异响应机理及应用

Negative difference response mechanism and application of inductive logging of clastic reservoir array in Bayan Oilfield

巴彦油田于2018年投入规模勘探开发,是内蒙古西部首个年产百万吨级整装油田。其位于河套盆地临河扮陷,是我国陆相断陷盆地最深的碎屑岩油藏,主要含油层系为古近系临河组的临一段和临二段。利用典型井的阵列感应测井资料进行了实例分析,油层的阵列感应测井响应在临一段呈正差异而在临二段呈负差异。根据泥浆侵入理论,对不同泥浆侵入动静态因素下的地层电阻率进行数值模拟计算,结果表明,临二段油层呈现的阵列感应负差异特征是由于在泥浆矿化度低于地层水矿化度、束缚水含量高的情况下,在淡水泥浆侵入过程中高矿化度地层水被泥浆滤液混合、扩散作用淡化引起地层电阻率的增加量大于驱替作用对电阻率的减小量。因此,在巴彦油田临二段不能简单根据阵列感应正负差异判断油水层,本文通过引入侵入梯度因子,有效区分油层和水层阵列感应负差异特征。

Bayan Oilfield was invested into largescale exploration and development in 2018,and is the first integrated oil field with an annual output of one million tons in western Inner Mongolia.It is located in the Hetao basin,which is the deepest clastic rock reservoir in the continental subsidence basin of China.The main oil-bearing system is the first and second sections of the ancient near river group.Using the array induction logging data of typical well,the array induction logging response of oil layer showed positive difference in the adjacent section and negative difference in the adjacent section.According to the mud intrusion theory,the formation resistivity of different mud intrusion dynamic and static factors was simulated,and the results show that the negative dfference in the formation induction is lower than that of the formation water salinity and high bound water content.Therefore,in the second section of Bayan oil field,the oil and water layer cannot be simply judged according to the positive and negative difference of array induction.In this paper,the intrusion gradient factor can effectively distinguish the negative difference feature of oil layer and water layer array induction.