Patent ID: 6191586
Filing Date: 2001-02-20
Classification: G01V

Abstract:
An improved well logging tool for making azimuthally sensitive resistivity measurements within a formation surrounding a drill string positioned within a borehole, said improved well logging tool comprising:at least one transmitting antenna positioned on said drill string within said borehole, said transmitting antenna for generating a primary electromagnetic field within said surrounding formation, thereby inducing currents to flow within said formation which in turn generate a secondary electromagnetic field within said formation, said borehole, and said drill string;at least one receiving antenna positioned on said drill string, in spaced relationship with said transmitting antenna, said receiving antenna for measuring characteristics of said secondary electromagnetic field through induction of a current within said receiving antenna indicative of said characteristics;at least one conductive shield associated with said drill string in a manner as to partially shield said transmitting antenna or said receiving antenna or both;wherein said conductive shield defines a window through which said primary electromagnetic field may be generated or said secondary electromagnetic field may be detected by said transmitting or receiving antennas.