AMSTERDAM -- GDF Suez Norge is using a flow assurance system (FAS) designed by SPT Group to optimize production at the Gjoa field in the Norwegian North Sea, which came on stream early last month.
The light oil and gas field is being developed via 13 subsea production wells tied back via flowlines to Gjoa's semi-submersible platform. Statoil supervised the development, with GDF Suez taking over as operator for the production phase.
SPT Group designed Gjoa's automated Flow Assurance System (FAS), which incorporates OLGA Online (a real time monitoring solution for multiphase production systems). It is connected to the platform's historical database OSI PI, which collects data from the process control system equipment, supplied by Kongsberg Maritime, and the subsea control system, provided by FMC Technologies. As such, the FAS receives regular plant measurements from throughout the subsea and topsides facilities.
The FAS can be used to provide simulations of the various facets of the production process in real time, and also what-if simulations of the impact of a changing production scenario.
The system has many applications tailored to GDF Suez's needs. According to SPT Group Account Manager Gjermund Weisz, speaking today at DOT, the most critical capabilities include:
- Monitoring parameters such as temperature, due to concerns over potential wax and hydrate formation following shutdowns (early on, certain equipment such as the compressors are scheduled for regular maintenance)
- Predicting the potential for slugs forming and entering the separators topside. These slugs could be generated by modifications to production patterns, but real-time simulations can avoid mistakes being made.
- Detecting potential water breakthrough and gas coning. "Some of the phase 1 oil producer wells will eventually be switched to gas producers following reservoir depletion,"" Weisz explained, but this process should not be allowed to happen too quickly, because of the risk of coning. If an incident is detected, the operator can take action, maybe to choke back pressure on an individual wellhead."
The FAS can also be used to provide virtual flow meters for each well as a back-up for the subsea multiphase flow meters.
GDF Suez operates the FAS remotely from a base onshore in Stavanger Norway. SPT Group provided training to GDF Suez personnel to familiarize them with the system prior to the start of production, and has a long-term agreement to provide flow assurance support services to the Gjoa development and operation.