Periodic pre-testing is the generally accepted methodology on offshore platforms to measure and characterize the flows from a number of different wells and to allocate production from individual wells. These figures are then combined for total production. Surging flows with varying viscosities tend to make separation difficult with higher costs and imprecise results. In addition, conventional separators tend to be large and heavy, as well as expensive to operate and maintain.
Cyclonic separation of the flow from individual wells delivers better measurements without the additional weight and expense of larger separators. Two-phase cyclonic separators remove saturated, or wet gas from the top where it can be metered using a Daniel measurement device. The heavier oil and water drop from the bottom where Micro Motion Coriolis meters measure both mass and density. If necessary, water and sand probes can also be employed. Pre-testing with cyclonic separators yields greater accuracy with a smaller platform footprint as compared with a conventional three-phase separator. Real-time data on production from individual wells can also be used by reservoir engineers in determining changes that may be occurring downhole and actions to be taken for effective well management. Another Global Exergy solution eliminates topside separation altogether in favor of multiphase homogeneous screening on the ocean floor.