The measurement of fluid rates while producing from deep-water hydrocarbon reservoirs has been an important aspect of reservoir depletion decisions as it clearly affects the development plan for that reservoir. It is pertinent that rates are correctly allocated for efficient reservoir surveillance.
With the complexity of measuring a three phase flow, produced GOR and water cut must be accounted for to take good decisions in production routing options & reservoir management and handling.
A simple riser test incorporating the use of Multi Phase Flow Metering in individual wells is carried out to allocate production rates to the wells, though it only considers the present production scenarios. The technique ignores production performance history, dynamics of the producing reservoir, flow line system hydraulics, riser routing designation possibilities. This depicts inadequate representation of allocation.
This work presents an analytical evaluation of complex riser tests carried out for wells routed through the risers to the surface to cover for inaccurate Multi Phase Flow Meters (MPFM) measurements. This technique of weighted average analytical process with few counterintuitive properties, as captured in Simpson's paradox used sum of well rates comparism with FPSO readings to derive the "Well MF-d" formula to get deviation factors. The performance trends presented graphically are assessed to get final well meter factors for correcting the MPFM measured rates and the GOR calculated.
From this work, the GOR and Water cut for each producer in the Reservoir XY-1 were correctly allocated. The results showed that 59% of the well counts were dry wells and meter factors ranging from 0.72 to 1.67 were used to calculate well GOR. The Well MF-d formula can always be used to get correct allocation to wells with Multi Phase Flow Meters.