From Prospect to Life of Field Service – The Role and Impact of Well Installation/ Intervention from a Subsea EPC Contractor's Point of View

Being a global Subsea and Topside EPC contractor is often synonym with having an extensive portfolio of subsea production system solutions, sometimes including installation and well intervention systems such as landing string systems, riser based intervention systems and riser less intervention systems. However, unlike companies who focus specifically on subsea well intervention, and typically targets life of field opportunities, these EPC contractors might have this technology is in-house which enables cross discipline discussions already during concept studies and Front End Engineering Design studies (FEEDs). This enables contractor and client to select suitable technology not only based on equipment functionality and hardware cost, but highlights the operational impact such selections have both regarding installation of the equipment, and well intervention service throughout the lifetime of the field. In a reference project a global EPC company is the main contractor for the engineering, procurement, construction and installation of the Subsea Production System (SPS) equipment in projects related to two large field developments West of Africa for a major operator. A total of 92 vertical subsea x-mas trees (VXTs) was awarded between 2013-2014 designed to be installed in depths down to approximately 2000m. In this case it was decided to install the tubing hangers using simplified landing string technology, while a riser based light intervention system was selected to provide flexible options for VXT installation, well clean-up/ flow back and life of field well intervention. A cross-vendor workover control system was selected to be used in both installation and intervention modes, allowing the operator to perform well interventions on existing subsea infrastructure in the region with 3rd party XT vendors, in addition to the planned field developments. This paper will discuss how an EPC contractor can exploit the benefits of being both a subsea EPC contractor and an installation and well intervention service provider. The referenced project will be used as a case study, starting with the early phase studies, to show how decisions related to installation and intervention systems can greatly impact the XT selection and life of field strategy, and hence the configuration of the overall SPS and corresponding tooling. The philosophies around rig related services such as this connects the operator spend on SPS, SURF and drilling scope, and can greatly impact the overall project economics due to synergies across the distinct areas of investment. Furthermore, the paper discusses the importance of having a holistic approach when considering an intervention system for late life management, why it is beneficial to discuss such strategies at an early stage, and the benefits this brings to the end client over time.