Evaluation of PhaseWatcher Multiphase Flow Meter (MPFM) Performance in Sour Environments

Abstract

Abstract Accurate oil, water and gas flow rate measurements from individual wells are essential in order to properly manage both the wells and reservoirs, as well as to obtain reliable data for production performance monitoring, optimization, allocation and simulation models1, 2, 3, 4, 5. Over the past three decades, there has been great advancement in the multiphase metering technology. These advancements have resulted in a significant improvement in measurement accuracy as well as in reducing the physical size of these meters which is a crucial element in limited-space environments as in offshore platforms. The intent of this paper is to present results of a compact Multiphase Flow Meter (MPFM) " PhaseWatcher?? based on information gathered from Saudi Arabia, where more than one hundred meters have been installed so far in several fields covering wide ranges of fluid properties and operating conditions. Moreover, the paper will discuss in detail the effect of crude sourness (H2S concentration) and pressure on the meter's measurement accuracy. Multiphase Flow Meter (MPFM) Design The PhaseWatcher is designed to measure the total volumetric flow rates of oil, water and gas at line conditions. These flow rates are converted to standard onditions via a pressure-volume-temperature (PVT) package, which can be either the default Black Oil Model or a specific model derived using a client supplied PVT data. The meter comprises of five basic components, Fig. 1:A Venturi meter with pressure transducers across it to measure the differential pressure between the inlet and throat of the Venturi.A nuclear dual energy fraction meter consisting of a Smart Detector and Barium Source, measures the count range of photons transmitted from the source to the detector at two different photon energy levels (the high energy level is used to measure the density of the mixture, while the low energy level is used to calculate the water-oil ratio).Process fluid temperature transducers, which measure the fluid temperature upstream of the Venturi section and the ambient temperature.A Blind Tee Static Mixer, used to homogenize the flow stream ahead of the Venturi meter.A process flow computer used to manipulate the measured data.