Abstract

This Gulf of Suez case history presents an account of a successful primary cementing across a massive salt zone bearing a high-pressure salt water kick; this achievement had been elusive for many years. The challenge in cementing this salt zone was that the onset of the high-pressure kick zone(s) was not predictable because thin sections of anhydrites and sand streaks were lodged within the 600-m salt zone. The hole section was normally drilled with a salt-saturated mud, weighing 1.85 to 1.98 sg (specific gravity), making every effort to keep the well overbalanced. Over 20 wells had been drilled this way and practically all had either a kick while drilling the well or the well flowed while running casing, or flow occurred while waiting-on-cement (WOC). Not only did it pose a safety hazard and compromise drilling operations, but led to several days of nonproductive rig time spent in resolving the problem.

The solutions to the challenge were multi-faceted. Records of many previously drilled wells were reviewed and several improvements and suggestions made. The suggestions ranged from understanding the flow mechanism, the timing of flow, maintaining wellbore stability, providing a wellbore conducive to cementing, and cement slurry design and placement.

The lessons learned from this paper will help other locations drilling through salt sections worldwide that have similar situations of poor zonal isolation leading to sustained casing pressure, corroded casings, and in some cases collapsed pipe results in early termination of the productive life of the well.

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