Kickoff Plug Best Practices for Shallow Wells in Awali Field, Bahrain

Abstract

Setting cement plugs for sidetrack operations is a critical, challenging, and time-consuming operation. In many cases, a successful sidetrack operation requires several cement plug attempts or lengthy drilling operations, resulting in increased operation cost. In the past, when required to sidetrack a well, cement kickoff plugs were regularly tagged without having achieved the desired compressive strength, with added risk of stuck pipe in soft cement and increased wait-on-cement (WOC) time. The poor cement plugs usually resulted in a time drilling operation after additional WOC time. Placing a successful kickoff-plug (KOP) consistently on the first attempt is required for a cost-effective sidetrack operation, which, by itself, is considered an additional cost to any drilling project. In the Awali field in Bahrain, drilling operations faced the challenge of increased loss time in KOP operations. Operator wanted to reduce WOC time by improving the performance of the cement KOPs. The target was to complete the sidetrack operation in well depths less than 3,000 ft and static temperatures of about 140°F within 8 to 12 hr, after the cement plug has been placed.A thorough analysis of previous design and execution cement practices was performed to identify the actions needed to optimize the previous performance of cement plugs. Advanced cement plug optimization software was used to support the evaluation of the risks associated with the placement of the slurry. Data from extensive laboratory testing of several cement slurry systems were used to evaluate the effect of the slurry properties on optimizing the system deemed most suitable for this application. The studies also included a detailed review of the industry best practices that are applicable to the conditions of the field. The results of the implemented best practices for the design and execution of KOPs in shallow wells in the field under study demonstrated an improvement of the success rate to 100% and better cement plug performance, contributing significantly to minimizing the time and cost of performing sidetrack operations.