All-Electric Boosting-Control System Simplifies, Improves Operating Processes

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31943, “Introduction to New Technology Applications, Data-Acquisition Capabilities, and Features of the All-Electric Boosting Control System,” by Kjetil Bergtun, Carsten Mahler, and Trond Melheim, OneSubsea. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission. The complete paper describes an all-electric system (AES) and how its implementation will simplify operating processes, reduce topside and subsea weight and cost, and lower the risk of hazardous fluids escaping into the ocean. The authors place special focus on the electrical actuators that were introduced in this project as well as the challenges faced during project execution. Vigdis Field The Vigdis field was discovered in 1986 between the Snorre, Statfjord, and Gullfaks fields in the Tampen area of the North Sea. The development consisted of seven subsea templates and two satellite wells producing to the Snorre A (SNA) facility, which contains a dedicated processing module for Vigdis. In 2002 the plan for development and operation of the Vigdis extension was approved. An unprocessed wellstream is transported from Vigdis to the Snorre A platform by two flowlines. Stabilized oil is transported by pipeline from Snorre A to Gullfaks A for storage and export (offloading). The second platform (SNB) in the Snorre field is 11 km north of SNA. The Snorre field is approximately 130 km from the Norwegian coast, nearly at the same latitude as Florø. When the Vigdis field came onstream in 1997, recoverable resources were estimated at 200 million bbl of oil. The field has now produced 394 million bbl, and recoverable resources have been increased to 455 million bbl of oil. Production from the field was limited by the capacity of the production lines and pressure drop across the topside chokes. Reservoir deliverability was limited by low reservoir pressure in some parts of the field, together with increasing water cut, leading to reduced energy into the system, which in turn caused dropping wellhead pressures.