Focused detection logging technique

Patent · Tue Jul 05 04:00:00 EDT 1977

OSTI ID:7285441

Turcotte, R E

In accordance with an illustrative embodiment of the present invention, a method and apparatus is disclosed for determining a characteristic of the media surrounding a borehole by emitting gamma radiation in at least one tightly collimated beam toward an earth formation adjacent a borehole, by detecting from a plurality of tightly collimated paths that are focused at a zone of intersection with and aligned to intersect with each emitted beam the gamma radiation scattered by the interaction of the emitted gamma radiation and the media at the zones of intersection, by misaligning the emitted beams and the tightly collimated paths to prevent their intersection, by detecting gamma radiation scattered by the interaction of the emitted gamma radiation and the media with the emitted beams and the tightly collimated paths misaligned and by determining from the detected gamma radiation a media characteristic. In one embodiment, the detection collimater used is formed of a material that is essentially opaque to gamma radiation at the energies of interest and includes a plurality of passageways that are spherically focused at a zone of intersection with one of the emitted beams of gamma radiation and that are arranged in a number of surfaces that are curved to be azimuthally symmetrical about the axis of the intersected beam. 14 figures.

• Assignee: Schlumberger Tech. Corp.
• Patent Number(s): US 4034218
• OSTI ID: 7285441
• Country of Publication: United States
• Language: English

Related Subjects

440105 -- Radiation Instrumentation-- Radiometric Instruments-- (-1987)
440400* -- Well Logging Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
47 OTHER INSTRUMENTATION
BOREHOLES
CAVITIES
COLLIMATORS
DENSITY
DESIGN
EQUIPMENT
GAMMA-GAMMA LOGGING
PHYSICAL PROPERTIES
RADIOACTIVITY LOGGING
WELL LOGGING