Patent ID: 8154951
Filing Date: 2012-04-10
Classification: G01V

Abstract:
1. A method of determining a relative bearing of a directional receiver disposed in a borehole extending into a subterranean formation for which a 3D model is provided, the method comprising: using the directional receiver to receive a direct compressional arrival generated by at least one source at a known location to generate 3C data; rotating the 3C data to a true Earth frame using an estimated relative bearing angle; measuring a polarization vector from the rotated 3C data; estimating an incident ray vector of the direct compressional arrival at the directional receiver using ray-tracing through the 3D model; and selecting a new relative bearing angle of the directional receiver from a plurality of candidate relative bearing angles based on the candidate relative bearing angle that minimizes an error determined based at least in part on a linear hodogram of an inverse cosine of a dot product of the incident ray vector and the polarization vector.