Enhanced resolution processing of compensated neutron logs

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:6975367

Galford, J E; Flaum, C; Gilchrist, Jr, W A; Duckett, S W

Compensated neutron logging employs a two-detector system that was developed to reduce borehole effects. The ratio of counting rates from the detectors provides the basic tool response from which a porosity index is obtained. Each of the detectors in this system has a different vertical resolution because of its spacing. A new method of processing the count rates has been developed to enhance the vertical resolution capabilities of the neutron porosity index by exploiting the better vertical resolution of the near detector. Since no additional or new measurements are required, data from older wells can easily be reevaluated. Results from the new method have been compared with microspherically focused logs and electromagnetic propagation logs. They show repeatable thin-bed resolution of the order of 1 ft for data sampled at 6-in. intervals; the typical vertical resolution from ratio processing is approximately 2 ft. The statistical precision of the high resolution processing is superior to that of the standard ratio method. An additional parameter, obtained in the new processing method, provides information about borehole effects. This parameter can be used for qualitative indications of gas when invasion is not deep and environmental effects are not large.

• Research Organization: Schlumberger Well Services
• OSTI ID: 6975367
• Report Number(s): CONF-861080-
• Resource Relation: Conference: Society of Petroleum Engineers annual technical conference and exhibition, New Orleans, LA, USA, 5 Oct 1986
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
NEUTRON LOGGING
DATA PROCESSING
RESOLUTION
SOURCE ROCKS
BOREHOLES
CARBONATE ROCKS
COMPARATIVE EVALUATIONS
ELECTRIC LOGGING
ENVIRONMENTAL EFFECTS
GAS SATURATION
NATURAL GAS
NATURAL GAS DEPOSITS
NEUTRON DENSITY
NEUTRON DETECTION
NEUTRON DETECTORS
PETROLEUM DEPOSITS
POROSITY
SANDSTONES
STATISTICS
THICKNESS
WELL LOGGING EQUIPMENT
CAVITIES
DETECTION
DIMENSIONS
ENERGY SOURCES
EQUIPMENT
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC DEPOSITS
MATHEMATICS
MEASURING INSTRUMENTS
MINERAL RESOURCES
PROCESSING
RADIATION DETECTION
RADIATION DETECTORS
RADIOACTIVITY LOGGING
RESOURCES
ROCKS
SATURATION
SEDIMENTARY ROCKS
WELL LOGGING
020200* - Petroleum- Reserves
Geology
& Exploration
030200 - Natural Gas- Reserves
Geology
& Exploration