Interpretation of E-Logs. Final Report, June 1989-September 1991

摘要

There are roughly 500,000 electric logs (E-logs) for wells in the U.S. Many of these are in cased wells, precluding the possibility of further resistivity logging. Thus, these old E-logs are an invaluable resource for the possible reentry of older fields, but they are very difficult to interpret. Software has been developed to generate E-logs from an earth model. Also, software has been developed to predict an earth model directly for the individual curves in an E-log, which typically consists of three curves representing the resistivity of different volumes of rock. The generation of an E-log from an earth model has been accomplished by numerically approximating the controlling physical relations and solving the complex of equations. The generation of an earth model for each of the curves in an E-log has been accomplished using an iterative process known as Levenberg-Marquardt inversion.