Virtual Metering And Flow Allocation: Models, Tools And Field Results

In the framework of the production optimization, the continuous monitoring of single well production is a mandatory requirement. The measurements of single well production, in real time, usually involve the installation of expensive multi-phases flow meters. An alternative method for production estimation is represented by a virtual metering system based on the analysis of the standard process parameters, always available in a production plant.With this aim, the VMF (Virtual Flow Meter) for production allocation has been developed, based on both pressure and temperature signals upstream and downstream choke valves, and PT signals along the production line. The VMF is a software package designed to provide accurate estimates of gas and liquid flow rates. The basic requirements are the knowledge of fluid composition and system geometry. The software is based on a methodology in which several models of choke and well performances are included. The method can be applied both to critical and sub-critical flows and holds for a wide range of flow conditions (choke geometry, fluid properties, GVF etc.). The VMF was designed for well head choke application, but a suitable release for downhole control valve has already been developed for the production allocation in smart wells. In this application, single layer production in a multi-layer intelligent completion is predicted. The choke performance correlation is modified in order to take into account the effect of the lower levels production, and well performances have been used (when wellhead data were available) to tune choke performance prediction. The paper contains the results of the VMF application for different fluids (light oil, high GOR light oil, medium oil, high GOR medium oil, condensate gas) in several fields in Italy, North Africa, West Africa and GOM