Integrated Simulation of Offshore Oil and Gas Production Systems During Project Design

Abstract

The conceptual stage of an oil and gas production projects comprises the identification and the subsequent evaluation of a suite of feasible alternatives for the production system. The evaluation process embraces several disciplines, both technical and economical. It is a common practice for each discipline to work individually, following its own internal process, where external information is treated as a definite input. When organized in this way, the process of evaluating the global production system tends to be complex, involving many professionals and information exchange, and time consuming, since it is performed sequentially. In addition, it is necessary to ensure that the results of each discipline converge to a common point, which is the global result for each production system scenario. In order to achieve this convergence, cycles of iteration between the disciplines may be required, which also contributes to the longer duration of the process. This paper proposes a framework that integrates individual simulation models of Reservoir and Flow Assurance with organizational economic premises. The framework was set to give as a result the NPV (Net Present Value) of each offshore production systems alternative, among other operational and economic metrics. The framework also integrates optimizers that propose the best reservoir drainage plan, FPU (Floating Production Unit) location and subsea layout for each alternative. A real case study is presented in order to exemplify its functionalities. The production system considered consists of three independent offshore reservoirs producing to the same production facility, through subsea manifolds and long tie-backs. The integrated simulation allowed for a quick and easy selection process of the production system alternative with higher economic return. There was a drastic reduction on the response time for the evaluation of the alternatives, which is essential to meet the growing dynamism of the oil and gas industry. The results confirmed the importance of the integrated simulation, both for the optimization of the alternatives evaluation process, and for the identification of gains of synergy among the several disciplines involved in project of high complexity. The use of integrated simulation is expected to continue increasing in the coming years in the oil and gas industry, as well as the robustness of the technique. The novelty of the integrated simulation framework is in the ability to efficiently run a wide number of simulations and optimizations for the production system and help to select the most suitable one.