Field test results of a borehole directional radar
- Sandia National Labs., Albuquerque, NM (USA)
The Borehole Directional Radar System is a high-power, high- resolution tool that is being developed to locate lithologic layers of fractures away from a wellbore. The prototype is a 50-kW peak- power pulsed directional radar system that determines fracture location by transmitting powerful radar pulses, 8 nanoseconds in length, in a known direction from a borehole. The frequency spectrum of the pulses ranges up to the VHF band, which is between 30 and 300 MHz. The transmitter and receiver rotate in place, permitting the tool to scan for fractures in all directions from the borehole. Because discontinuities in the rock interrupt and reflect radar signals, signals that return to the tool's receiving antenna indicate fractures. The distance of the fracture from the borehole is determined by the time delay of the return signal. The radio frequency signal is sampled and transmitted to the surface by wireline at audio frequencies, and then reconstructed at the surface using a personal computer. The key to the tool's potential is its ability to accurately measure distance and direction of a lithologic discontinuity underground. This paper presents field test results that show the capabilities of the tool for locating lithological discontinuities up to 10.5 m (34.5 ft) away from a wellbore. Unique features of the system are discussed. Potential applications of the system are described, such as locating gas and oil reservoirs below a salt dome and possibly detecting a blow-out well with or without casing. 10 refs., 8 figs.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5604548
- Report Number(s):
- SAND-89-1559C; CONF-891057--1; ON: DE89014477
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
47 OTHER INSTRUMENTATION
58 GEOSCIENCES
580203 -- Geophysics-- Geophysical Survey Methods-- (1980-1989)
BOREHOLES
CAVITIES
DETECTION
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MAPPING
MEASURING INSTRUMENTS
PERFORMANCE TESTING
RADAR
RANGE FINDERS
RESOLUTION
SPATIAL RESOLUTION
SURVEYS
TESTING