API Publ 2566:2004 pdf download.State of the Art Multiphase Flow Metering
2- NOMENCLATURE AND TERMS USED IN MULTIPHASE FLOW
A number of terms and definitions are employed in describing multiphase flow and measurements. The Norwegian Society For Oil and Gas Measurement (NFOGM) have catalogued these terms in their Handbook Of Multiphase Metering” in reference XII-3. As a contribution to further the use of common terminology, and acknowledgement to the NFOGM efforts, this report has adopted these terms rather than develop new definitions. These terms and nomenclature, described in Appendix 1, are taken from reference XII-3 and will be used in this report to describe multiphase flow and measurement processes.
3- THE NEED FOR MULTIPHASE AND WET GAS METERS
Multiphase meters are devices that measure oil, gas, and water flow rates of a well stream without separating these components into individual phases. The new multiphase metering techniques were developed to replace the conventional two and three-phase gravity based test separators that have been making multiphase measurements in production operations. Well tests are conducted routinely to monitor the flow rates from wells and forecast production. The well test data are also used for reservoir management, production diagnostics and optimization and in some cases even production measurement. To obtain accurate and consistent test results from conventional well testing systems, the equipment requires high maintenance, field personnel intervention, and time to perform tests.
The oil industry has recognized the potential benefits of the new multiphase meters (II- 10 to 16). A systematic effort was undertaken in the 90’s by several North Sea operators to identify potential multiphase metering applications, reservoir engineering needs, and meter performances for a number of asset developments in North Sea (II-22). For the past 10 years, considerable effort has gone into developing multiphase meters that can measure gas, oil, and water flow rates at wellhead conditions (II-1). These efforts have led to the development and marketing of several types of multiphase meters. In the past five years, the meter manufacturers and operators have jointly tested multiphase meters under a variety of field conditions to evaluate their performances. In the next sections of this paper, we shall look at the trends in installations of multiphase metering systems. Wet gas metering is a more recent area of development in multiphase measurements. Wet gas metering covers a variety of measurements in production streams with high to very high gas volume fractions. There is a need for direct measurement of gas under these conditions in such applications as gas condensate and high GOR fields as well as many production operations where gas from separation systems may contain liquid (III-1). Furthermore, significant amount of gas will be produced in the future from remote and subsea fields where production, capital investment, and operating costs must be optimized.