Interlayer Inversion Method and Its Application Based on Horizontal Well Resistivity Logging

In order to study the spatial distribution characteristics of interlayers and reveal the distribution pattern of remaining oil, interlayers between wells were predicted and identified. Firstly, the types of interlayers were determined from core analysis, and the identification criteria was established along with logging data.Then, an inversion algorithm was designed on the basis of electric logging for the distribution of interlayers beyond horizontal wellbore. The results demonstrate that the intersection of relative density or relative value of neutron with relative value of gamma can identify two types of interlayers in the target area with absolute errors of 0.018 m and 0.017 m in the inversed thickness of calcareous interlayers and muddy interlayers, respectively. The calcareous interlayers are more developed, with wide distribution and varied change in thickness, while the muddy interlayers are fewer, with a distribution in the northeast orientation. This study, which can provide a reference in studying the distribution and tapping potential of remaining oil, proves that the prediction of interlayer distribution between wells can be more accurate after the interlayer distribution beyond the wellbore is inversed on the basis of horizontal-well resistivity and the inter-well distribution of interlayers determined with the joint control of vertical wells.