Separação Submarina Oleo/CO2 : concepção tecnológica, modelagem e controle avançado

Abstract

Discoveries of oil reservoirs in deep and ultra-deepwater have imposed several new challenges for the production development. In special the high amount of CO2 found in the Brazilian area known as Pre-Salt has led to a cost-energetically process for CO2 removal and its proper destination. Subsea CO2 separation is seen as an alternative to the conventional process. Hydrocarbons mixtures with high CO2 amounts present complex phase behavior showing VLE, LLE and LLVE. The coexistence of at least two liquid phases in equilibrium namely, an oil phase and a CO2 rich phase, may occur in typical reservoirs conditions and allows the employment of subsea gravity separators to separate and and reinject CO2 rich phase in the reservoir. In this study a feasible CO2 subsea separation process was proposed taking into account the complex phase behavior of hydrocarbon mixtures with CO2 and water eventually. The process was designed to deal with a 150 103 bpd reservouir fluid flow at 150 bar and 40` C. A differential algebraic system was developed to evaluate the process dynamic through simulations. Process control was also evaluated from two distincts approachs, Model Predictive Control (MPC) and classical PID multi-loop.