Transient temperature compensation for pressure gauges using discrete temperature history measurements for gauge calibration
AssigneeMarathon Oil Company
InventorsEric B. Phelps, Gary R. Cook, Wayne O. Roszelle
Life of this patent
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Abstract
Disclosed is a system wherein the compensation for temperature effects on a pressure measurement gauge are accomplished by processing the raw pressure measurement signal from the gauge through an equation to produce a thermally compensated measurement. The equation expresses the thermally compensated pressure determination as a relation between a derivative of temperature and temperature. When the gauge is placed in an oil or gas well, the equation is used to obtain a correction for the measured pressure from the temperature measured adjacent to the pressure gauge.
Claims8
A method for thermally compensating the pressure value displayed by a pressure gauge, said method comprising the steps of:
- (a) inputting, into a computer system, an equation which expresses a thermally compensated pressure value as a relation between a derivative of temperature and temperature comprising using ##EQU3## as said equation wherein p.sub.e represents pressure error, T represents temperature, t represents time, each a.sub.i is a function of temperature and each b.sub.j is a function of temperature;
- (b) measuring the pressure of the surroundings of which a pressure value is desired with said pressure gauge;
- (c) measuring the temperature of the immediate environment of said pressure gauge;
- (d) inputting said temperature measurement and said pressure measurement into said computer system containing said equation;
- (e) computing said pressure value using said temperature measurement, said pressure measurement and said equation;
- (f) displaying said thermally compensated pressure value on a display device.
A method for thermal compensation of the pressure value made by a pressure gauge within a borehole, said method comprising the steps of:
- (a) inputting, into a computer system, an equation which expresses a thermally compensated pressure value as a relation between a derivative of temperature and temperature comprising using ##EQU4## as said equation wherein p.sub.e represents pressure error, T represents temperature, t represents time, each a.sub.i is a function of temperature and each b.sub.j is a function of temperature;
- (b) placing said pressure gauge in said borehole;
- (c) measuring the pressure within said borehole with said pressure gauge;
- (d) measuring the temperature of the immediate area of said borehole surrounding said pressure gauge;
- (e) inputting said temperature measurement and said pressure measurement into said computer system containing said equation;
- (f) computing said thermally compensated pressure value using said temperature measurement, said pressure measurement and said equation;
- (g) transmitting said thermally compensated pressure value and said pressure error to a control system;
- (h) connecting said control system to fluid control valves connected to at least one adjacent borehole;
- and
- (i) controlling flow of fluid into said at least one adjacent borehole using said control system to limit said thermally compensated pressure value.
Dependencies are inferred from the claim text.