The 1st year of this study was spent assessing the technical, operations and safety issues associated with subsea production and subsea well systems. Assessment involved discussions with regulators, operators, construction/engineering contractors and equipment manufacturers. The focus of topics is as follows: Subsea Processing Flow Assurance Well Intervention Long-term Well Monitoring and Safety & Environmental concerns.
State of the art multiphase models such as PIPESIM and OLGA along with numerical reservoir simulation software like ECLIPSE were used to predict multiphase flow behavior with various deepwater production strategies. Presently, developing analytical techniques to investigate the effects of backpressure on reservoir energy. The reservoir energy is being utilized to move fluids through long flowlines thus reducing the availability of energy to recover more fluids from the reservoir. These analytical methods had demonstrated the disadvantages of setting up subsea facilities without some form of subsea processing. Subsea processing has shown in the past to be beneficial to the recovery of more hydrocarbons from the subsea reservoir, thus aiding in project economics and adequate utilization of non-renewable resources.
Literature review concentrated on the challenges faced by operators when operating deepwater fields in the offshore GOM region. Many of the oil fields being exploited by subsea production systems are being abandoned due to high wellhead pressure (1800-3000 psi) due to the backpressure created by long pipelines. This is causing production rates to be reduced and is affecting the ultimate recovery from subsea well fields. The literature review has concentrated on the reasons for this and also highlights ideas from operators and service companies alike to overcome this problem.
Numerical Simulation to demonstrate that techniques like multiphase pumping and subsea processing and pumping can be effective in improving ultimate recoveries, a reservoir model in conjunction with a numerical subsea production facilities model has been developed and is being used to predict improvements in hydrocarbon recoveries. This model had been refined and applied to a generic GOM reservoir.
Analytical modeling reservoir energy is constantly being utilized to move fluids through long flowlines and deepwater risers to the surface facility. An analytical model to investigate just how much reservoir energy is being wasted to move fluids through the lines was developed. This helps in utilizing some means of subsea processing to aid in decreasing the wastage on reservoir energy which will be helpful to operators and service companies alike.
Industry interaction has taken form in the place of meetings with operators and subsea equipment vendors at a Subsea Tieback Forum held in early 2003 and a presentation at the 2003 SPE exhibition in Colorado in October 2003.