An experimental study featuring two phase gas-viscous oil flow was conducted in the NEL multiphase flow loop to assess the homogenisation effectiveness of the blind-t mixing spool that is commonly associated with many multiphase flow meter (MPFM) installations. The variance in phase distribution at the exit of the blind-t is described, alongside the effects of inlet flow structure on mixing performance. The phase area distribution is captured using an electrical capacitance tomography (ECT) system in parallel with a high speed video logger before flow acceleration through a transparent Perspex venturi tube. The results show that the mixing capacity of the blind-t is dependent on the inlet flow pattern and oil viscosity which consequently influences the phase dispersion and slip characteristics through the venturi section.


The oil and gas industry is becoming increasingly reliant on the advantages associated with multiphase processing technologies (1). Traditionally, critical well testing would utilise separation to isolate the individual flow components and replicate conditions required for allocation and fiscal metering. Although this is a well practiced technique, it relies on excessive piping lengths and large separation equipment, such as a gravity separation vessel, that can take over the already limited space on many offshore production platforms. Direct measurement of multiphase flows is much more complex and often comes at the price of a greater theoretical uncertainty. However, it can be argued that the advantages associated with multiphase metering, such as low CAPEX and OPEX costs (as compared to the single phase measurement process) and the ability to capture real-time well performance characteristics outweigh the disadvantage of reduced measurement accuracy (2), especially for subsea applications.

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