Patent ID: 6997257

Claim:
An apparatus for determining the dip of an underground formation traversed by a cased or uncased borehole, said apparatus comprising: a housing adapted to be lowered and raised within said hole; means for generating pulsed neutrons into said underground formation, said generating means comprising a non-chemical based neutron source selectable to generate neutrons or remain non-radioactive, said generating means positioned within said housing; a plurality of directional detectors for measurement of a quantity of gamma radiation induced by said neutrons received at said apparatus from a specific direction within said underground formation in response to said pulsed neutrons, said detectors positioned within said housing; means for determining a depth to which said housing is lowered into said bore hole; means for determining an azimuthal orientation of said housing within said borehole with respect to a radial orientation reference; and means for correlating a measured gamma reading with a specific depth within said borehole and a specific azimuth of said housing; wherein said correlated gamma reading is indicative of a characteristic of said underground formation at a specific depth within said borehole and at a specific azimuthal orientation for said housing and wherein a comparison of a plurality of said gamma measurements made in sequence facilitate a determination of changes in said underground formation and an angle of said formation as a result of said measurements.