Well logging sonde with shielded collimated window

Patent · Tue Apr 28 04:00:00 EDT 1987

OSTI ID:6776862

Holenka, J M

This patent describes a well logging sonde adapted for generating indications of the characteristics of the formation surrounding a borehole in which a borehole mudcake may have formed, the sonde comprising: a first section including source means for irradiating the formation with gamma rays; a second section including; a shielded housing having a collimated window facing the formation, the window being substantially transparent to gamma rays including low energy gamma rays of energies below 100 keV; a near detector disposed in the housing in the path of the collimated window; the window being disposed so that the high energy gamma rays reaching the detector have been singly scattered in a first region in the formation primarily beyond the borehole mudcake; and means responsive to the near detector for generating signals representative of the density of the first region and of the photoelectric absorption of the formation surrounding the borehole; wherein the shielded housing has a collimated window comprising; an inner cylindrical shell fabricated of a gamma ray opaque material and having a conduit formed in its wall at an angle with respect to its axis; an outer substantially ''U'' shaped metallic outer shell partially enveloping the inner shell and having an axial length; an arcuate closing member; an arcuate pad fabricated of a gamma ray opaque material.

• Assignee: Schlumberger Technology Corp., Houston, TX
• Patent Number(s): US 4661700
• OSTI ID: 6776862
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
440400 -- Well Logging Instrumentation
47 OTHER INSTRUMENTATION
BOREHOLES
CAVITIES
COLLIMATORS
DETECTION
EQUIPMENT
GAMMA DETECTION
GAMMA LOGGING
GEOLOGIC DEPOSITS
MEASURING INSTRUMENTS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
OPENINGS
PETROLEUM DEPOSITS
PROBES
RADIATION DETECTION
RADIATION DETECTORS
RADIOACTIVITY LOGGING
RESOURCES
SHIELDS
WELL LOGGING
WELL LOGGING EQUIPMENT
WINDOWS