Subsea wet gas meter

Paul Boughton

Emerson Process Management has launched its next generation Roxar subsea Wetgas Meter for accurate production measurement, reduced risk, and improved flow assurance in gas and gas condensate fields.

Hydrates, corrosion, scaling and water coning in the reservoir represent the biggest challenges to offshore gas producers and are all caused by formation water breakthrough into the well.

The new meter allows the earliest possible detection of water from gas wells. The new meter comes with unparalleled water sensitivity, accuracy and rapid response together with the industry’s first built-in salinity measurement system.

The meter’s microwave-based measurements and multivariate analysis functionality are operational in all field conditions and fluid compositions. The meter detects changes in water content of the flowing well at as little as 0.2ppm (parts per million) - sensitivity that has never been reached before and that represents less than a droplet of water finely distributed in a volume equal to that of four car fuel tanks.

The next generation Roxar subsea Wetgas Meter generates an uncertainty specification of ±0.02% abs WVF (Water Volume Fraction) at GVF (Gas Void Fraction) 99-100%. Other key benefits to operators include:

* Improved hydrocarbon and allocation metering strategies. The wet gas meter provides real-time, accurate hydrocarbon measurement for operators’ fiscal allocation obligations. This is due to the meter’s multivariate analysis functionality and true three-phase measurement based on a highly accurate microwave and gamma densitomer. The multivariate analysis functionality also provides PVT (Pressure, Volume, Temperature) independence on water fractions - especially in high GVF flows.

* Accurate salinity and formation water measurement. The new meter includes the industry’s first dedicated online salinity measurement system that tells the reservoir engineer whether formation water is entering the flow. Combined with highly sensitive and accurate water measurement, this provides a powerful and unique tool for the early detection of formation water breakthrough and the optimization of injection rates for MEG, scale and corrosion inhibitors.

* Maximum speeds, flexibility and robustness for all reservoir conditions. The meter is ideally suited for the changing operating conditions and varying fluid compositions seen in gas and gas condensate fields. Measurement speeds at 20 times per second enable immediate actions to be taken to protect subsea system integrity and maintain flow assurance.

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