Multiphase and Wet Gas Flow Measurement - It's Not That Simple

Abstract

Abstract During the period since their inception around 1990 until today, multiphase flow meters (MPFMs) and wet gas flow meters (WGMs) have gone from a state of unreliable hardware and questionable answers, to a point where their reliability is becoming acceptable, while providing information that is essential for proper operation of oil and gas production systems. Because the use of these devices is so much more common today than it was in the past, an illusion may exist in the minds of some that to select, operate, and maintain them at a satisfactory level of performance is straightforward - that they are "plug- and-play" instruments for the modern oilfield. While this remains a prime objective of meter development, it has yet to be achieved. It is clear that multiphase and wet-gas flow meters have the potential to provide good answers over a broad range of conditions. However, achieving such performance requires more than just a cursory knowledge of upstream measurement. From selecting the right meter(s); in their commissioning, operation, and maintenance; and especially in the use of MPFM and WGM data, an in-depth understanding of many different aspects of the technology must be called upon. Will nature of the well production change significantly over the life of the field, for example moving from a liquid-dominant flow to one that is primarily gas? If the fluid properties of the production change with time, will the meter be capable of accounting for this, or will it require a sample for re-calibration, and is sample collection feasible? Will there be chemicals injected upstream of the meter that might cause confusion in the meter readings? To adequately address these questions and account for changes in the system, users must track Key Performance Indicators (KPI) through the Life of the Field (LoF). This and other practical questions in the use of these important instruments are addressed and illustrated.