Testing wells, which produce 1-2% liquid in the presence of 99-98% gas volume, is very difficult. The mixture is far from homogeneous, and task is similar to looking for a needle in a haystack. Yet, in the case of condensates, the dollar value of the liquid may equal that of the gas. Biggest economic justification is the case of Gas Lift, where proper gas injection control can make a significant contribution to the profitability of the operation. If the gas contains water, the treatment is very expensive, so knowledge of the exact nature of the produced fluid is essential for proper reservoir control and optimization. In gas wells applications for example, it is crucial to measure the small amounts of liquid to the highest degree of accuracy, since this data is necessary to monitor and control hydrate formation. The difficulty is in the accurate measurement of 2% of the total flow. For 5% accuracy of reading of the liquid flow rate, one requires 0.02 × 0.05 = 0.001, or 0.1% accuracy of the total flow. Moreover, additional knowledge is required to know the water content of the condensates. In the case of multi-layered production, this knowledge contributes a lot to profitability. The difficulty in achieving this high degree of accuracy is compounded by the nature of the flow. Since the liquid tends to stick to the pipe walls, and is being dragged behind the gas, which is flowing at high velocity in the center of the pipe (Annular Flow). The gas is also carrying with it liquid droplets torn from the walls. Due to uneven terrain or vertical risers, pockets of liquid form at the lowest points, which are shot out in the form of slugs flowing at near the velocity of the gas. Knowledge of these slugs flow helps the design of compressors, slug-catchers, etc. Field experience with Multi-Phase Flow Meters which operate at Gas lift and Wet gas applications is described in this paper.
Keywords:
AGAR, multi-phase flow metering, high GOR, FLOMEKO 2000, wet gas metering, flow meters, multi-phase, three phase flow
