A New Approach to MPFM Performance Assessment in Heavy Oil

摘要

The performance of a MPFM (Multi Phase Flow Meter) is normally assessed with an observational data model obtained by comparison with a reference meter. Typically the vendor will provide the performance from their own databases using data from a wide range of sources including JIP's, client sponsored trials, field trials and the vendors own calibration facilities. This data is processed to model the MPFM and compiled into databases over a long period of time at considerable cost. Understandably the vendor regards this data as proprietary and seeks to control access by releasing only limited subsets specific to an application. In the early stages of a project, fluid properties and flow rates may not be well understood requiring repeated requests to the vendor for performance data which can be very time consuming. This reliance on vendor data that is not transparent does little to instil confidence in users who will often conduct costly independent trials to verify the suitability of the selected MPFM, or may revert to more conventional methods of measurement. This paper presents an alternative analytical approach, developed for a heavy oil application, providing an independent assessment of a Dual Gamma Venturi MPFM performance from the physical properties of the fluids and sensors. Phase and line density performance of the Dual Gamma phase detector sensor are examined with the phase calculations taking into account the phase densities, attenuation factors and detector count rates. Mass flow rate performance of the Venturi meter is examined for a high viscosity emulsion with Reynolds Number of less than 2,000 that requires a correction to the Venturi Coefficient of Discharge. Dual Gamma and Venturi performance are combined to find overall performance of the MPFM meter for comparison with the vendor data. The "Analytical MPFM Performance" from the physical properties of the sensors and fluids goes hand-in-hand with the "Observational MPFM Performance" from comparative trials giving the user an immediate and independent verification of the MPFM performance. This speeds MPFM selection building confidence in the suitability of the MPFM and eliminating the need for costly and time consuming trials at calibration laboratories.