An efficient and accurate pseudo 2-d inversion scheme for multicomponent induction log data

Abstract From the Canadian patent

A fast, efficient and accurate pseudo 2-D inversion scheme (Fig. 4) for resistivity determination of an anisotropic formation (Fig. 3) uses data from a tool (3DEX) (10) comprising three transmitters (101 103, 105) and three , corresponding receivers (107 109, 111) sampling the formation in a plurality of spatial directions. An initial model (311) of the formation including invasion zones is obtained using a conventional multifrequency and/or multispacing logging tool. A pseudo 2-D inversion scheme combines an accurate full 2-D forward solution (313) of the synthetic responses of the earth model with a 1-D approximation (323) of the sensitivity matrix (317) of the horizontally …