Un-Locking Subsea Reserves Through a System-Based Approach for Tie-Back Solutions

Offshore developments must evolve if the industry is to unlock subsea reserves and increase recovery. A novel method of achieving these goals is through use of a systematic approach to subsea tiebacks that combines new technologies with minor modifications to the existing topsides equipment. The tieback strategy is a system-based approach with a combination of qualified disruptive technologies and field-proven solutions that will improve costs, reduce the number of interfaces, minimize the modifications needed on the topsides, critical for platforms with space and weight limitations, and maximize the use of existing assets. Significant investment was made to qualify disruptive and groundbreaking technologies to make this possible. The following summarizes the main components of the subsea system: –Seabox subsea water treatment and injection provides higher quality water for reservoir injection and increased recovery–Subsea chemical storage that allows longer subsea tiebacks and mitigates weight and space limitations on topside structures; only power and communication are needed from the topside–Subsea treatment of produced water subsea for either discharge directly to sea or to re-inject–Subsea automatic pig launcher combined with a single pipeline that ensures continuous flow at a lower capex–All-electric controls and valves eliminate the need for utility pipelines and expensive umbilicals–Applying field-proven tie-in systems integrated with flexible pipe solutions and customized subsea structures In addition to exploring the above components, this paper also explores combining the components into a comprehensive system. The system-based approach will unlock previously uneconomical reservoirs.