Field Trial of a Downhole, Fiber Optic, Two-phase Flowmeter in PDO's Nimr Field

Abstract

Abstract A field trial was conducted in June, 2001, of a downhole fiber optic two-phase flowmeter in two wells at PDO's Nimr field in Oman. The fiber optic flowmeter provides real-time measurements of volumetric flow rate and water cut. The purpose of the field trial was to evaluate the performance of the flowmeter for potential application at Nimr. Specifically, objectives were to determine the deployability of the flowmeter at Nimr, to determine the ability to operate with heavy, viscous Nimr crude, and to determine the ability of the flowmeter to distinguish between high water cut legs in dual lateral completions with artificial lift. Accuracy goals for the flowmeter were ±3% on water cut and ±10% on total volumetric flow rate. The fiber optic flowmeter was successfully installed in two wells at Nimr. In one of the wells the meter was installed in the completion string just below an electrical submersible pump (ESP) and in the other well it was installed just below a beam pump. A surface Coriolis mass flow meter served as a reference for the two-week field trial. In the beam-pumped well it was found the noise environment is not compatible with the physical measurement principle of the optical flowmeter, and a comparison against the surface-measured rates was not possible. In the ESP-pumped well, comparison of the flow rates and water cut measured by the fiber optic flowmeter and the Coriolis meter were better than expected, -1% to +2% on water cut and -1% to +3% on total rate, and well within specifications.