Integrated Active Heating and Subsea Boosting Technologies to Unlock Long Tie-Back Reservoirs with Flow Assurance Challenges

Abstract

Subsea oil and gas production can utilize a number of technical solutions to ensure efficient and cost- effective operation. There are two main technologies applied to address flow assurance challenges in case of particularly long tieback reservoirs: subsea active heating and subsea boosting. The production from distant reservoirs with challenging flow assurance conditions may require application of both mentioned systems. In such case, one challenge relies on the selection of a power supply infrastructure for both systems, considering all possible optimization aspects. In the conventional approach, the implementation of both systems is realized independently. Subsea active heating system and subsea boosting system are supplied and monitored from topside by the separate power strings. However, the development of subsea technologies allows to review the approach and consider integration of both systems, enabling reduction of topside infrastructure for general cost savings. The purpose of this article is to present the integrated system composed of Electrically Trace Heated Pipe in Pipe (ETH-PIP) and subsea boosting pumps where Variable Speed Drive (VSD) is required. The role of both system is shortly presented. Next, a proposal of an integrated power system for subsea heating and boosting is illustrated and discussed on a case study example. The analysed field layout is characterized by a long tie-back to a production facility where both subsea boosting and active heating systems are necessary operating in the relevant power modes. The results of analysis allow to conclude that the presented solution can be valuable alternative to traditional approach of complex subsea system topologies.