Correction of coriolis flowmeter measurements due to multiphase flows
First Claim
1. A Coriolis flowmeter which measures densities of materials including combinations of gas and liquids, gas and solids, or solids and liquids, said flowmeter comprising:
- at least one flowtube;
a driver that vibrates said at least one flowtube at a fundamental frequency based on a drive signal, said fundamental frequency corresponding to a density of material flowing through said at least one flowtube;
pickoffs affixed to said at least one flowtube that generate pickoff signals responsive to said material flowing through said at least one flowtube; and
meter electronics configured to;
determine said density of said material flowing through said at least one flowtube based on at least one of said pickoff signals, monitor a drive gain in said at least one flow tube for a change in value to determine if said material flowing through said at least one flowtube comprises a multiphase flow, and if said material flowing through said at least one flowtube comprises a multiphase flow, then determine said density of said material flowing through said at least one flowtube based on a stored density value.
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Accused Products
Abstract
A Coriolis flowmeter is operable as a vibrating tube densitometer where a flowtube is driven to vibrate at a fundamental frequency from which density of the material flowing through the flowtube may be calculated. The drive gain is monitored as an indicator of multiphase flow including gas and liquid components where a substantial increase in drive gain indicates gas damping of the flowtube vibrations due to a transient bubble entering the flowtube. The gas damping effects of the transient bubble and the correspondingly reduced density readings are remediated by the use of historical density measurements corresponding to periods of flow when no transient bubble has entered the flowtube.
183 Citations
18 Claims
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1. A Coriolis flowmeter which measures densities of materials including combinations of gas and liquids, gas and solids, or solids and liquids, said flowmeter comprising:
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at least one flowtube;
a driver that vibrates said at least one flowtube at a fundamental frequency based on a drive signal, said fundamental frequency corresponding to a density of material flowing through said at least one flowtube;
pickoffs affixed to said at least one flowtube that generate pickoff signals responsive to said material flowing through said at least one flowtube; and
meter electronics configured to;
determine said density of said material flowing through said at least one flowtube based on at least one of said pickoff signals, monitor a drive gain in said at least one flow tube for a change in value to determine if said material flowing through said at least one flowtube comprises a multiphase flow, and if said material flowing through said at least one flowtube comprises a multiphase flow, then determine said density of said material flowing through said at least one flowtube based on a stored density value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
circuitry configured to close a valve to stop a well test in progress on a fluid flowing from a production well.
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10. The flowmeter as set forth in claim 1 further comprising:
means for indicating an alarm indicative of said multiphase flow.
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11. A method of operating a Coriolis flowmeter to measure densities of materials, said method comprising the steps of:
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vibrating at least one flowtube of said Coriolis flowmeter at a fundamental frequency corresponding to a density of material flowing through said at least one flowtube;
generating pickoff signals that represent motion of said at least one flow tube as said material flows through said at least one flowtube;
determining said density of said material flowing through said at least one flowtube based on at least one of said pickoff signals;
monitoring a drive gain in said at least one flowtube for a change in value to determine if said material flowing through said at least one flowtube comprises a multiphase flow; and
if said material flowing through said at least one flowtube comprises said multiphase flow, then determining said density of said material flowing through said at least one flowtube based on a stored density value. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification