The Effect of Technological Operations on Induction Logging-While-Drilling

Abstract

The presented study demonstrates the effect of different technological activities of drilling through a reservoir interval on induction logging while drilling and near wellbore resistivity. The drilling operations include drilling with different penetration rates, shutdowns for drill-pipe addition, back reaming and so on. To estimate this effect, numerical modeling has been applied for simulation of mud filtrate invasion followed by electromagnetic modeling of induction tool signals. When modeling the invaded zone, the developed algorithm takes into account the drilling mode and mudcake formation. The computed near wellbore distributions of invasion zone parameters such as water saturation and salinity are then used to determine the resistivity distribution in the near wellbore area. The obtained geoelectric model of the well and the invaded zone makes it possible to compute the induction signals measured while drilling. It has been shown that neglecting features of the drilling operation may lead to improper interpretation of logging measurements.