A comparison of CBL, RBT, and PET logs in a test well with induced channels
The introduction of new ultrasonic and ratio logging techniques has dramatically transformed cement evaluation. Previous methods (cement bond logs (CBL's)) that used a low-frequency (approx. = 20 x 10/sup 3/-recycle/sec (approx. = 20-kHz)) acoustic signal and a single-transmitter/dual-receiver combination suffered from inherent measurement problems. To eliminate several of the CBL problems a new dual-transmitter/multireceiver acoustic measurement tool, the ratio bond tool (RBT), has been introduced. The RBT measures attenuation directly through ratiometric techniques, is self-calibrating, and is much less sensitive to tool centralization. For cement evaluation across ''fast formation'' intervals, a 1-ft (0.33-m) -spaced transmitter/receiver signal amplitude is measured. A ''logging well'' has been constructed by the U.S. Environmental Protection Agency (EPA) to evaluate downhole tool response to cement channels. This test well was constructed with numerous sizes and weights of casings and has specially constructed flaws on the casing circumference to produce channels of variable lengths and widths. A detailed analysis of the ability of the CBL, RBT, and PET logs to detect these channels is presented.
- Research Organization:
- Gearhart Industries, Oklahoma City, OK (US)
- OSTI ID:
- 6690115
- Journal Information:
- J. Pet. Technol.; (United States), Vol. 40:9
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BOREHOLES
RADIOMETRIC SURVEYS
ULTRASONIC TESTING
WELL LOGGING
TECHNOLOGY ASSESSMENT
CEMENTING
COMPARATIVE EVALUATIONS
EQUIPMENT
US EPA
WELL CASINGS
ACOUSTIC TESTING
CAVITIES
GEOPHYSICAL SURVEYS
MATERIALS TESTING
NATIONAL ORGANIZATIONS
NONDESTRUCTIVE TESTING
SURVEYS
TESTING
US ORGANIZATIONS
020200* - Petroleum- Reserves
Geology
& Exploration