Abstract

In this paper, a new method for production optimization is tested on a Petrobras offshore floating production storage and offloading (FPSO) unit from Campos Basin, Brazil. The FPSO/platform has two subsea templates, with 7 and 3 wells respec- tively. In addition there are 7 topside wells. Both of the subsea templates have two pipelines connected to the platform, one production and one test pipeline. The purpose of the optimization method is to find the optimal routing of well streams, choke settings and gas lift rates for all wells such that total production of oil is maximized. The method makes sure that the pressure drops throughout the system are feasible and gas available for gas lift is limited and needs to be distributed properly among the wells. Further, it takes into account that the handling capacity of gas, water and liquid is limited and make sure that this is obeyed.

The method finds the optimal solution to this problem in less than 20 seconds, which are two orders of magnitudes faster than the current state-of-the-art methods available on the marked. This enables a totally different production engineer workflow, since instant re-optimizations could be conducted on-the-fly during e.g. a well optimization meeting. It essentially automates the what-if study conducted to find the best choke, routing and gas lift settings, and enables the production engineer to focus on other important questions like; what is the preferred operational envelope for each well, and is the inflow performance ratio predicting the well behavior accurately for the recommended (optimal) production strategy, etc.

The computational speed-up is achieved by utilizing the structure of the production network, and by using efficient well and pipeline proxy models inside the optimization algorithm. The paper outlines the principles of the optimization method and how it was applied to a real field problem. Further, it reports on the results and discusses the potential benefits of such a method.

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