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DEMO2000-Prosj.ret tekn.utv. petro.virk

Ultrasonic flowmeter for subsea fiscal gas metering, subsea liquid metering, and subsea flow metering of dense-phase CO2

Alternative title: Undervanns ultralydsmåler for fiskale målinger i olje og gass og måling av flytende og superkritisk CO2.

Awarded: NOK 5.8 mill.

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Project Period:

2022 - 2023


Ultrasonic flowmeters are widely used in the oil and gas industry because of their excellent measurement accuracy, large turn-down, and absence of pressure loss associated with most other flow measurements. This technology has so far not been available for use subsea, primarily because of its reliance on polymeric seals for acoustic isolation of transducers. Such seals are not considered suitable for subsea installations. OneSubsea has together with its partners developed new technology based on metal-to-metal sealing, enabling subsea ultrasonic flow measurements without deterioration of signal quality or measurement accuracy. This enables the use of subsea ultrasonic flowmeters in custody transfer applications with gas and liquids. The technology may also be used to measure the flow of liquid and supercritical carbon dioxide in carbon capture and storage applications. The objective of the project is to qualify the technology according to relevant industry standards and demonstrate custody transfer measurement accuracy with natural gas in a certified calibration facility. Operation and measurement performance with supercritical carbon dioxide at relevant conditions will be demonstrated in OneSubsea’s test facility outside Bergen, Norway.

Ultrasonic flow meters are used in many important applications in the oil and gas industry and elsewhere. Excellent measurement accuracy, very large measurement range, and a non-intrusive mechanical design, which also eliminates the pressure losses caused by most other flow meters, are all features that set ultrasonic flow meters apart from alternative technologies. All ultrasonic flow meters currently available use transducer assemblies sealed with O-rings and other polymeric materials to prevent leakage of acoustic energy to and from the transducers and achieve the necessary signal to noise ratio. The O-rings and polymeric materials are exposed to the process fluids. This prevents the use of this technology in subsea oil and gas applications and in applications with fluids that may cause deterioration of the polymeric materials such as super-critical CO2 and hydrogen. The primary objective of this project is to replace the O-rings and polymeric materials with metal-to-metal sealing while at the same time maintaining an acceptable signal to noise ratio. This is achieved by the introduction of a novel mechanical design of the transducer housing, which acts as an acoustic filter. The primary objective of the project is to qualify this design for relevant process conditions according to applicable industry standards. A prototype flow meter will be built and tested at a third-party calibration facility to validate that custody-transfer measurement accuracy is achieved with natural gas. The operability and measurement performance in supercritical CO2 will be demonstrated in a flow loop test with a pump developed for pumping supercritical CO2 at OneSubsea Processing’s assembly and test plant. This test will expose the flow meter to flow of spercritical CO2 at relevant pressures and flow rates. A secondary objective is to demonstrate that the flow meter also can measure the flow of liquid by testing the prototype flow meter in OneSubsea Processing’s metering flow loop.

Funding scheme:

DEMO2000-Prosj.ret tekn.utv. petro.virk