Advances in borehole geophysics for hydrology
Borehole geophysical methods provide vital subsurface information on rock properties, fluid movement, and the condition of engineered borehole structures. Within the first category, salient advances include the continuing improvement of the borehole televiewer, refinement of the electrical conductivity dipmeter for fracture characterization, and the development of a gigahertz-frequency electromagnetic propagation tool for water saturation measurements. The exploration of the rock mass between boreholes remains a challenging problem with high potential; promising methods are now incorporating high-density spatial sampling and sophisticated data processing. Flow-rate measurement methods appear adequate for all but low-flow situations. At low rates the tagging method seems the most attractive. The current exploitation of neutron-activation techniques for tagging means that the wellbore fluid itself is tagged, thereby eliminating the mixing of an alien fluid into the wellbore. Another method uses the acoustic noise generated by flow through constrictions and in and behind casing to detect and locate flaws in the production system. With the advent of field-recorded digital data, the interpretation of logs from sedimentary sequences is now reaching a sophisticated level with the aid of computer processing and the application of statistical methods. Lagging behind are interpretive schemes for the low-porosity, fracture-controlled igneous and metamorphic rocks encountered in the geothermal reservoirs and in potential waste-storage sites. Progress is being made on the general problem of fracture detection by use of electrical and acoustical techniques, but the reliable definition of permeability continues to be an elusive goal.
- OSTI ID:
- 7079578
- Journal Information:
- Geol. Soc. Am., Spec. Pap.; (United States), Vol. 189
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOLOGIC DEPOSITS
HYDROLOGY
WELL LOGGING EQUIPMENT
TECHNOLOGY ASSESSMENT
ACOUSTIC TESTING
ACTIVATION ANALYSIS
BOREHOLES
ELECTRIC CONDUCTIVITY
FLOW RATE
GEOLOGIC FRACTURES
IGNEOUS ROCKS
METAMORPHIC ROCKS
NEUTRON REACTIONS
PERMEABILITY
POROSITY
RESERVOIR FLUIDS
SEDIMENTARY ROCKS
WATER SATURATION
BARYON REACTIONS
CAVITIES
CHEMICAL ANALYSIS
ELECTRICAL PROPERTIES
EQUIPMENT
FLUIDS
GEOLOGIC STRUCTURES
HADRON REACTIONS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
NUCLEAR REACTIONS
NUCLEON REACTIONS
PHYSICAL PROPERTIES
ROCKS
SATURATION
TESTING
580203* - Geophysics- Geophysical Survey Methods- (1980-1989)
580100 - Geology & Hydrology- (-1989)