Best Practices and Lessons Learned From Deepwater Floating Production Unit Project

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 35303, “Anchor Project: Best Practices and Lessons From Delivering the Offshore Installation Scope,” by James M. Reiners, Ben Cheatham, and Brent A. Dampman, Chevron, et al. The paper has not been peer reviewed. Copyright 2024 Offshore Technology Conference. _ The Anchor floating production unit (FPU) is a Gulf of Mexico facility in approximately 5,000 ft of water with a nameplate capacity of 75,000 BOPD and 28 MMscf/D with future expansion capability. The Anchor development plan consists of seven high-pressure wells tied back to the FPU through dual flowlines from two drill centers with produced oil and gas transported by export pipelines. The complete paper discusses best practices and learnings from FPU transportation and installation, hookup and commissioning (HUC), subsea flowlines, export pipelines, and subsea-equipment installations. Background The Anchor project is a deepwater high-pressure project with a shut-in tubing pressure greater than 15,000 psi and flowing tubing temperature up to 275°F. The Anchor field is approximately 140 miles off the Louisiana coast (Fig. 1). Subsea development will use one multiphase pump at one of the drill centers to boost production in its flowlines between the drill center and the FPU. The 20,000-psi-rated equipment used for the Anchor project includes drilling, completions, workover and intervention, and production operations. The project’s major offshore installation work orders were executed in early 2020. In addition to overcoming preexisting technological and economic challenges, the project was further strained by the global pandemic. Flexibility and resilience were key to successful execution. The planning scope was adjusted to incorporate enabling virtual and digital solutions, conducting detailed assessments for pandemic-related effects, and focusing on efficient solutions. FPU Transportation and Installation (T&I) Overview The contracting strategy for FPU T&I revolved around capability and predictability to reduce offshore challenges and increase price certainty. A heavy-lift vessel (HLV) was selected as the main installation vessel for multiple installation campaigns. Mooring System Design and Procurement. The FPU has a 12-leg mooring system. The facility’s north direction is aligned with the grid north direction. The mooring layout is oriented symmetrically to north/south and east/west. The mooring system was designed to meet or exceed design criteria considering 100-year extreme conditions. All mooring lines have identical components for ease of installation and efficient sparring. Each mooring line has a dedicated chain jack and chain locker, with the chain entry through a watertight cover. The installation chain is stored in a dedicated locker with equal access to all mooring chain jacks. Mooring Pile Installation. The 12 mooring piles were transported from the fabricator’s yard in the spring of 2022 with a 400-ft barge with sufficient deck space to transport all piles to the site. The piles were received and installed by the deepwater construction vessel (DCV) using both port and starboard heavy-lift cranes to upright the piles. The starboard crane, fitted with a deepwater subsea block, then continued the deployment and installation of the pile. Once at depth, the vessel’s positioning system and calibrated long baseline array were used to align the piles within the preinstalled marker buoy target boxes and install the piles within design tolerances.