(337f) Optimal Synthesis and Design of Three-Phase Separator for Upstream Oil and Gas Processes

Three-phase separator (3PS) is the heart of wellhead processes. The extracted well stream is a multiphase flow containing sands, water, light and heavy hydrocarbons. The stream, after extraction is directed to the so called ?topside? processes where it first enters the 3PS. It is then separated into three streams: produced water, crude oil and natural gas. Each of these streams afterwards undergoes various processes until reaching export/discharge qualities. Three-phase separator is therefore the most critical upstream process. If it is designed correctly, the three outlet streams will require less quality adjustment. Traditionally, a series of two or three 3PS have been used. Separators vary in internal design to handle different well stream qualities. For example, when water cut is low, boot type separator is used while for high cut, weir or gutter arrangement might be used. Coalescer might be arranged inside the separator to decrease water oil particles in produced water. When a network of a few separator is used then a combination of different internal designs might be selected. Synthesis of 3PS network followed by efficient sizing is therefore a complex problem which if solved properly can result in significant downstream operation cost savings. This paper outline the development of a mixed integer nonlinear program to handle this problem, and presents modelling work and case studies.