Patent ID: 8030935
Filing Date: 2011-10-04
Classification: G01V

Abstract:
1. A method of measuring one or more borehole and formation properties, the method comprising: providing a logging tool comprising three or more reception tensors and only one corresponding transmission tensor in a borehole, where the three or more reception tensors comprise at least a main tensor and a set of bucking tensors, where each of the three or more reception tensors is characterized by a distance from that tensor to the transmission tensor, where each of the three or more reception tensors and the only one corresponding transmission tensor includes one or more coils, where each coil has a coil axis and is characterized by coil parameters including:  where one or more of the coil parameters of the three or more reception tensors are selected to minimize sensitivity to borehole current, at least in part, by configuring the tensors of the three or more reception tensors to satisfy a first equation to balance at least a main tensor pro and a set of bucking tensor products, where:  where one or more of the cross-sectional area and the number of turns of one or more of the coils of the three or more reception tensors, and the distance from one of the three or more reception tensors to the only one corresponding transmission tensor, is selected to minimize direct coupling between the only one corresponding transmission tensor and one or more of the three or more reception tensors; transmitting a set of signals with the transmission tensor; receiving a corresponding set of signals with one or more of the three or more reception tensors; and determining one or more borehole and formation properties based on the corresponding set of signals received by one or more of the three or more reception tensors.