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Perforating Through Casing Strings To Remediate Annulus Gas Leak

ADMA-OPCO had integrity problems in one of its gas wells, and abandonment was the only option available to restore the integrity of the offshore multiwell jacket and revive adjacent wells. Integrity problems included oil/gas bubbles observed on the seabed around the conductor pipe and high sustained pressures in the outer cemented casing annuli. Because the leak was determined to be located outside the casing, the perforation of several intervals was required. Some of the intervals were perforated through three casing strings, and the rest through four strings of casing, before being squeeze cemented.

Background

The example well, designed as a 7-in.-monobore gas-production well (see Fig. 1), was due for abandonment. The surface leaks in the different casing annuli had to be resolved before proper abandonment could occur. It was clear from the prejob analysis that cement-squeezing operations would be required at different depths through three and four casing annuli. Techniques for exposing these annuli for remediation included underreaming with a milling tool, abrasive jetting, and perforating. Underreaming would have been a very costly operation, and abrasive jetting is not reliable to penetrate through more than one casing string; therefore, perforating was chosen as the method for accessing the required annulus.

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 166729, “Perforating for Squeeze Through Four Casing Strings To Remediate Annulus Gas-Leak Problem,” by Mohamed El-Sayed Ibrahim, SPE, Ahmed Khalifa Al-Neaimi, SPE, Mohamed Abdelsalam Hassane, SPE, Abdul Salam Mohamed Al-Mansoori, SPE, Shanof Mohamed, SPE, and Omar Al-Mutwali, SPE, ADMA-OPCO, and Alan Salsman, SPE, Schlumberger, prepared for the 2013 SPE/IADC Middle East Drilling Technology Conference and Exhibition, Dubai, UAE, 7–9 October. The paper has not been peer reviewed.
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Perforating Through Casing Strings To Remediate Annulus Gas Leak

01 January 2014

Volume: 66 | Issue: 1

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