Production Well Testing of Challenging Wells with an Enhanced Multiphase Flowmeter

Abstract

Production well testing is of paramount significance for building reliable production history of oilfields. Kuwait Oil Company (KOC) requires periodic testing of oilfield wells for production, pressure, and fluid property monitoring. In some cases, accurate flow-rate measurements cannot be conducted with conventional well test separators because flow rates are out of the operating range of the individual singlephase metering devices, challenging flow conditions (geometries) exist, or wells are flowing under non- critical conditions in which backpressure from the test separators or production lines affects well productivity. Typically, production well testing operations have been executed with portable testing units instrumented with multiphase flowmeters (MPFMs) or conventional test separators. A recently introduced mobile dual-leg MPFM unit with 19- and 40-mm venturi sizes (installed side by side) in a single skid was used for the first time in several KOC wells together with other locations in the world. Dual venturi-size setup enables flow metering of a wider range of flow rates and provides enhanced phase fraction measurements via full gamma-ray spectrum analysis. We discuss the results of the well tests conducted with this recently introduced dual-leg MPFM and compare results with well test results obtained with other measurement devices and techniques. The field test wells chosen comprise high and low flow-rate production wells that have various typical flow conditions (sluggy, stable, and emulsion-prone) and are representative of both natural producers and artificial-lift wells. Enhancements in operating principles of the dual-leg MPFM results in efficiency gains and test results are comparable to previous test results across the range of operations. Also, the well test results compare favorably with the pressure/volume/temperature (PVT) properties of the reservoir fluids as well as with manual measurements taken during the test, such as water cut, or basic sediment and water (BS&W) data. The dual-leg MPFM provides an optimal solution for flow metering in oilfields and is ideal for daily mobile production testing operations.