Transient temperature compensation for pressure gauges using an impulse response for gauge calibration
AssigneeMarathon Oil Company
InventorsEric B. Phelps, Gary R. Cook, Wayne O. Roszelle
Life of this patent
Estimating the term…
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 the corrected measured pressure from the raw measured pressure received from the gauge and the temperature measured adjacent to the gauge.
Claims8
A method for thermally compensating the pressure value of 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 ##EQU7## as said equation wherein p.sub.e represents pressure error, T represents temperature, t represents time, r.sub.1 is the response function for the derivative of temperature, and r.sub.2 is the response function for 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 thermally compensated pressure value using said pressure measurement, said temperature measurement, and said equation;
- and
- (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 ##EQU8## as said equation wherein p.sub.e represents pressure error, T represents temperature, t represents time, r.sub.1 is the response function for the derivative of temperature, and r.sub.2 is the response function for 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 pressure measurement, said temperature measurement, and said equation;
- (g) transmitting said thermally compensated pressure value 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.