Flowline Virtual Metering System
An offshore operator was operating dual flowlines with cross-over valves open and requested GATE Energy to develop a virtual meter to allow them to determine the flowrate flowing through each header based on pressure and temperature measurement as well as detect potential of flow instability through the cross-over valves (XOVs) between the two flowlines.
CHALLENGES
Some of the production flow loops suffer from malfunctioning pressure and temperature gauges.
Topside flowmeter is located downstream of comingling point between two risers leading to no means of measuring the flowrates in each flowline.
Dual flowline production through crossover valves (XOVs) may result in flow instability (e.g. slugging or stagnant header).
SOLUTION
GATE developed a flowline virtual metering system utilizing GATE’s proprietary calculation engine GATE Prho™ building blocks that, in real time, allows the operator to:
Create PT Profiles: determine the current pressure and temperature profiles through water-oil-gas multiphase hydrodynamic calculation.
Understand Flow Distribution: Calculate the production flow split / distribution through XOVs and evaluate the potential instability. This helps the operator to make decisions on topside backpressure as well as opening/closing the XOV valves.
It is important to note, prior to delivering the surveillance tool, GATE conducted an extensive benchmarking study between the tool and the available field data to ensure it is representative of the actual field conditions.
TECHNICAL BENEFITS
A standalone flowline virtual meter which allows the operator to closely monitor flowrates in each flowline.
The standalone virtual meter was successfully integrated to the operator’s monitoring system leading to real-time virtual metering and flow instability risk screening.
In future, easy to share with GATE flow assurance engineers to further support with thorough analysis, mitigation and remediation efforts if necessary.
