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Liner Hanger Installation in Challenging Offshore Well Conditions


ERD wells are commonly associated with major challenges for operations subsequent to drilling such installation of casing and liner strings. These wells typically present high torque and drag parameters that jeopardize getting strings to total depth. In an attempt to optimize production, a major oil Company in Angola decided to re-enter the case of study well in early 2016. A sidetrack was opened in the 9 5/8 in casing, drilling continued in the 8 ½ in hole and penetrated the objective zone in the highest location. Then a 7 in production liner was run. To reach the objective zone, 5,583 ft of 8 ½ in hole was drilled with deviations varying from 45° to 87°. This trajectory was a challenge for subsequent operations of 7 in liner, T&D models showed liner rotation at TD was not possible and a surge model indicated likelihood of mud losses while running the liner. Liner hanger technologies became a very important phase of well construction, and service companies developed advanced liner hangers to overcome hostile well environments. In this case study, the short time available from planning to execution phase and the current oil market conditions, made it imperative that the right equipment, service and technology were available in country. To achieve the ideal working parameters and get the liner to bottom, a thorough assessment needed to be performed to ensure sure this risk would be mitigated. This paper presents a summary of steps considered during planning for the 7 in liner run in BAP6ST1 including a detailed engineering analysis that enabled the operator to make the best decisions based on the available resources. There are also lessons learned and best practices captured during the job that will be used for subsequent liners in similar wells