A fully instrumented compact multiphase Inline Water Separation (IWS) system1 has been developed to separate a significant portion of the produced water from a production stream, with the remaining production fluids (gas, oil and the rest reduced amount of the water) sent to existing processing facilities. The quality of the separated water meets the requirement for water injection or direct disposal. The system consists of a Gas-Liquid Cylindrical Cyclone (GLCC©2), a Liquid-Liquid Pipe Separator (LLPS), a Liquid-Liquid Cylindrical Cyclone (LLCC©3) and a two-stage Liquid-Liquid Hydrocyclones (LLHC). The compact IWS can be installed either at the wellhead or downstream of a production manifold to handle multiple wells on land, offshore platform or sea floor. The benefit of such a system includes increasing field water handling capacity, reducing the size and cost of the downstream separation facility, and reviving dead low-pressure wells.
A prototype compact IWS system has been tested under field conditions. Initially the individual compact separator units have been tested separately and optimized for maximum separation efficiency. The results of the IWS system tests show that it is feasible to integrate GLCC, LLCC, LLPS and LLHC into a compact multiphase separation system for bulk produced water removal from a production stream. The overall water separation efficiency, defined as the percentage of water removed from the total water production, up to 80%. The outlet water quality is less than 200 ppm oil concentration, which meets the expection of this study. A second stage LLHC can be used for further polishing the water quality to meet the requirement of water injection or direct disposal. The control systems for GLCC liquid level control and LLHC differential pressure ratio control were also tested under slug flow conditions.