Thermal decay time logging method and apparatus

Patent · Tue May 15 04:00:00 EDT 1990

OSTI ID:6745052

Wraight, P D

This patent describes a logging system having a neutron generating means and detecting means for detaching indications of thermal neutrons, a method for determining thermal neutron decay characteristics of borehole materials. It comprises: irradiating at a first given location in the borehole, the borehole materials and earth formations with a first burst of neutrons, detecting, at respective second and third given locations in the borehole, in one or more time intervals following the first burst, count rates of indications of the concentration of thermal neutrons in the formation and borehole materials and generating respective first signals representative thereof, selecting the duration of the first burst such that after a first delay from the end of the first burst, the largest count rate detected at the second given location does not exceed the maximum counting rate of the detecting means and the thermal neutron count rate component due to borehole materials predominates in the total thermal neutron count rate detected at the second given location in one or more of the intervals associated with the first burst, and determining from the first signals, associated with the second given location, a characteristic of the thermal neutron decay of the borehole.

• Assignee: Schlumberger Technology Corp., Houston, TX (USA)
• Patent Number(s): A; US 4926044
• Application Number: PPN: US 7-112208A
• OSTI ID: 6745052
• 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
DECAY
EQUIPMENT
EXPLORATORY WELLS
GEOLOGIC DEPOSITS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NEUTRON LOGGING
NEUTRON SOURCES
NEUTRON-NEUTRON LOGGING
PARTICLE SOURCES
PETROLEUM DEPOSITS
RADIATION SOURCES
RADIOACTIVITY LOGGING
RESOURCES
THERMAL DEGRADATION
TIME MEASUREMENT
WELL LOGGING
WELL LOGGING EQUIPMENT
WELLS