Studies with narrow cement thickness lead to improved CBL in concentric casings
- Society of Petroleum Engineers (AIME), Dallas, TX (USA)
The authors show that formation characteristics affect the cement bond log (CBL) signal in most wells, prove that high-amplitude CBL's obtained in concentric casing-string configurations are often an artifact resulting paradoxically from the excellent quality of the cement job, and propose procedures for running CBL's in concentric casings to eliminate this artifact. Experiments performed to study the influence of the cement/formation or cement/external-casing interface show that, in all cases, these interfaces induce perturbations on the received waveform. The strength of these perturbations depends mainly on the impedance contrast at the interface. Field logs confirm the laboratory results and clearly show that high CBL amplitudes in well cemented concentric casings are an artifact that could easily be eliminated by appropriate setting of the measurement windows.
- OSTI ID:
- 5278279
- Journal Information:
- Journal of Petroleum Technology; (USA), Vol. 41:11; ISSN 0022-3522
- Country of Publication:
- United States
- Language:
- English
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