Woodside Greater Enfield IMMR Documentation

Benefits

• Provided client with a structured break down of the subsea asset and systematic development of documentation • Through application of process, identified integrity threats at the beginning of FEED and developed an action register for the risks to be addressed through the design process • Applied a “justify-in” philosophy to ensure all final IMMR responses are necessary • Improved operation of client’s IMMR tools

Background

The Greater Enfield Development subsea development is located in 850 m to 350 m water depth consisting of 5 systems; oil production, water injection, gas lift, multi-phase pump controls, and main controls, was being developed for Northern Western Australia. During FEED and Detailed Design, the development was challenged by the internal corrosion management of a carbon steel production line (to lower CAPEX) and erosion management. The development was a combination rigid and flexible flowlines and flexible dynamic risers to an FPSO in 350 m water depth. In addition, the following facilities were included in the final design: subsea to subsea inspection pigging, corrosion monitoring spools, acoustic sand detectors, virtual pipeline monitoring system, multi-phase pumps.

Work Performed by Atteris

Atteris provided integrity management services for the development of preliminary and final integrity management documentation using a number of different processes. The following documents where developed at the beginning of FEED and at the end of Construction; IMMR Plan, Register of Integrity Threats and IMMR Responses, System Diagrams, RBI Assessment, Operating Envelope, Design Envelope, and Integrity Envelope.

Initially, the systems were split up in accordance with ISO 14224 taxonomic structures. Atteris held workshops with Project Package Engineers identify integrity risks and potential mitigation measures. Monitoring was prescribed as a primary response to reduce unnecessary inspection tasks. Integrity management through the life of the asset leveraged value from the baseline inspection with OPEX being driven by a cost risk analysis. All information was captured in a spreadsheet tool which contained various controls to facilitate easy data manipulation and presentation of results