DOFT for Monitoring and Optimization of the First Ultra Deepwater FPSO Production in the GoM

Abstract

Abstract The Digital Oil Fields Tool (DOFT) for the Cascade and Chinook fields, located in GoM, is a self-learning dynamic model available 24/7. Topsides process simulator, D-SPICETM, was integrated with a multi-phase pipeline simulator to develop the DOFT. A stable interface allows high-fidelity simulations for subsea pipelines together with topsides facilities. The DOFT model scope covers the subsea wells, flowlines, subsea boosting pumps, inlet heaters, separators, gas export flow lines and pigging. The DOFT includes four modes. The Real-time (on-line) and Look-ahead (off-line) modes are used to monitor operations throughout the process. Functionalities include monitoring of hydrate margins, tracking of various chemicals, liquid/gas holdup monitoring, virtual flow metering, and leak detection among others. The Planning simulator (off-line) is used for detailed diagnosis of problems, analyzing "what if" scenarios, and planning critical operations. The Training mode (off-line) is used to familiarize the operators with everyday operations without risking the real production facility. The Real-time simulator and the data historian are linked via a unidirectional OPC link in order to get required "live" measurements. Wherever available, real-time and simulated data are presented together for comparison. Current real-time condition of the DOFT can be transferred to the Planning simulator for off-line planning simulations. Look-ahead scenarios can be run on the Real-time simulator which displays "future" trends which warn of impending problems. Speed of at least 36 times real time can be achieved in the Look-head and Planning modes. There are numerous advantages of a system like DOFT such as verifying operating procedures, training operators, monitoring the process in real-time, performing engineering studies, helping in decision making for day-to-day operations, helping find mistakes in P&IDs, operator screens and shutdown and interlock logic. The DOFT has already been verified by a third-party to be a useful tool to prepare and check operating procedures for this project. It is beyond doubt that production in deep and ultra deep waters is extremely challenging, and hence the use of systems like DOFT is becoming more and more important.