Schlumberger

Case Study: Fast Evaluation of 9.5-lbm/galUS Cement in Shallow Wells

Isolation Scanner service definitively evaluates light cement after logging for Brunei Shell Petroleum

Challenge: Distinguish 9.5-lbm/galUS LiteCRETE cement from liquids to accurately evaluate the cement job before proceeding with the completion.

Solution: Run Isolation Scanner cement evaluation service to definitively evaluate cement job immediately after logging.

Result: Confirmed through the combination of acoustic impedance and flexural attenuation that the annulus was cement filled.

Too light for conventional evaluation

Brunei Shell Petroleum (BSP) uses lightweight slurry systems to avoid unintentional fracturing when cementing offshore wells with depleted reservoirs. However, evaluating these cement jobs has been challenging because conventional cement evaluation tools do not clearly differentiate lightweight cement from liquids or contaminated cement in the annulus because these materials have similar values of acoustic impedance. Previous evaluations using conventional technologies were often ambiguous, resulting in rig idle time while interpretations were debated and different completion methods based on uncertain data were considered.

Conclusive solid-liquid-gas mapping

Isolation Scanner cement evaluation service combines the classic pulse-echo technique of ultrasonic tools with flexural wave attenuation to discriminate between solid, liquid, and gas materials in the annulus. The results are presented in easy-to-interpret solid-liquidgas (SLG) maps.

Cement and casing placement confirmed

BSP was able to make a rapid, conclusive decision with no waste of rig time to proceed with the well completion program based on Isolation Scanner confirmation of good zonal isolation. The SLG map distinguished between liquid and 9.5-lbm/galUS LiteCRETE cement to confirm that the material in the annulus was solid cement and also mapped the position of the casing relative to the formation and outer casing.


Download: Fast Evaluation of 9.5-lbm/galUS Cement in Shallow Wells (0.14 MB PDF)

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