Numerical Simulation of Array Induction Logs Time-Lapse Responses and Formation Resistivity Profile Reconstruction with 5-Parameter Inversion

摘要

In order to improve reservoir fluid recognition, sensitivities of array induction response to different invasion properties in both oil-bearing layer and water layer are analyzed. A numerical algorithm is adopted to simulate time-lapse response of array induction logs during mud invasion and signal processing of the array induction log is developed. Features of array induction responses during mud invasion were researched. A "five-parameter model" (r_1, r_2, Rxo, R_(1/2), R_t) which can match a variety of invasion conditions is approached and carried out suing a fast invasion method. Therefore, the identification of fluid type can be realized effectively by inversion of array induction log combined with time-lapse responses of array induction log. It is demonstrated that the inverted resistivity presents a typical non-monotonic variation in oil-bearing layer and a monotonic variation in water layer, which agrees well with the actual invasion property. It provides quantitative information for the discrimination of oil/gas or water zone.