Patent ID: 8296113

Claim:
A logging tool that comprises: a set of transmitter coils, wherein the set of transmitter coils includes three orthogonally oriented transmitter coils; a first set of receiver coils separated from the set of transmitter coils by a first distance, wherein the first set of receiver coils includes three orthogonally oriented receiver coils; wherein the three orthogonally oriented transmitter coils are each parallel to a corresponding one of the three orthogonally oriented receiver coils in the first set of receiver coils; a second set of receiver coils separated from the set of transmitter coils by a second distance different than the first distance, wherein the second set of receiver coils includes three orthogonally oriented receiver coils each oriented parallel to a corresponding one of the three orthogonally oriented receiver coils in the first set of receiver coils; a controller that selectively excites transmitter coils in the set of transmitter coils, and gathers a set of measurements of attenuation and phase differences between signals received by the first set of receiver coils and signals received by the second set of receiver coils; the set of measurements is utilizable as a sole input data set to determine an attenuation and phase difference measurement associated with any virtual orientation of the transmitter coils relative to the receiver coils, for any transmitter coil orientation; wherein the logging tool has a long axis, wherein the set of transmitter coils, the first set of receiver coils, and the second set of receiver coils each have a coil oriented along the long axis, herein respectively represented by T Z , R 1z , R 2z , wherein the set of transmitter coils, the first set of receiver coils, and the second set of receiver coils each have two coils oriented perpendicular to the long axis, herein respectively represented by T x and T y , R 1x and R 1y , R 2x and R 2y , and wherein the controller separately excites each of the transmitter coils to determine measurements of the following ratios: { C 2 ⁢ xx C 1 ⁢ xx , C 2 ⁢ xy C 1 ⁢ xy , C 2 ⁢ xz C 1 ⁢ xz , C 2 ⁢ yx C 1 ⁢ yx , C 2 ⁢ yy C 1 ⁢ yy , C 2 ⁢ yz C 1 ⁢ yz , C 2 ⁢ zx C 1 ⁢ zx , C 2 ⁢ zy C 1 ⁢ zy , C 2 ⁢ zz C 1 ⁢ zz } , where C juv denotes the electromagnetic coupling between the transmitter T v (V ∈{x,y,z}) and receiver R ju (j ∈{1,2}, and u ∈{x,y,z}).