Methods and apparatus for borehole-corrected spectral analysis of earth formations

Patent · Tue Apr 28 04:00:00 EDT 1987

OSTI ID:6504350

Grau, J A

A method is described for analyzing an earth formation traversed by a borehole, comprising: moving a logging tool, including a pulsed high-energy neutron source and a gamma ray detector, through the borehole, irradiating the borehole/formation environment with pulses of high-energy neutrons from the source; detecting gamma rays with the detector which result from the capture of thermal neutrons by chemical elements of the borehole and formation constituents; determining from the detected gamma rays elemental gamma ray yields, Y/sub E/, indicative of the presence of specific chemical elements, E, in the borehole/formation measurement environment; determining sensitivity factors, S/sub E,M/, representative of the efficiency of detecting the chemical elements, E, in predetermined borehole and formation constituents, M; and deriving for each of predetermined constituent regions, R, in the borehole/formation measurement environment which contains a chemical element, E.

• Assignee: Schlumberger Technology Corp., New York, NY
• Patent Number(s): US 4661701
• OSTI ID: 6504350
• 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
BARYONS
BOREHOLES
CAVITIES
DETECTION
ELEMENTARY PARTICLES
EQUIPMENT
FERMIONS
GAMMA DETECTION
GEOLOGIC DEPOSITS
HADRONS
IRRADIATION
MEASURING INSTRUMENTS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NEUTRON LOGGING
NEUTRON SOURCES
NEUTRON-GAMMA LOGGING
NEUTRONS
NUCLEONS
PARTICLE SOURCES
PETROLEUM DEPOSITS
PULSED IRRADIATION
PULSED NEUTRON TECHNIQUES
RADIATION DETECTION
RADIATION DETECTORS
RADIATION SOURCES
RADIOACTIVITY LOGGING
RESOURCES
SENSITIVITY
THERMAL NEUTRONS
WELL LOGGING
WELL LOGGING EQUIPMENT