Methodology to a Feasibility Study to Implement an Oil/Water Subsea Separation

Currently, low oil prices pose a challenge to the financial state of the industry. Therefore, it is very important that companies optimize costs while maintaining or even increasing oil production. At the same time, with oil production declining due high water cuts and facility volume limitations in an offshore production system, it is necessary to look for solutions in order to maintain economic viability by increasing oil recovery in mature reservoirs. Among some alternatives, the subsea separator represents a good prospect for dealing with these challenges. This paper aims to describe a methodology to perform the technical feasibility study of deploying an Oil/Water Subsea Separator in Brazilian Offshore Field. The technical results were then used as part of an economic analysis which is outside the scope of the present paper. The study is comprised four wells that are linked to the manifold and the subsea separator. In the subsea separator, 70% of the produced water is separated and reinjected in a disposal well. Hence, the fluids which remains (oil, gas and 30% of water) flows up to the platform. Since this reinjected water volume is not flowing to the platform anymore, more fluid can be processed, allowing the wells to operate on larger potentials resulting in an increased cumulative oil production to the field. Computational simulation approach was followed by using the pore flow simulation, flow assurance simulation and a coupler that integrates both of these.