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US 2006/0137442 A1Published application
Temperature compensated strain measurement
AssigneeSchlumberger Technology Corporation
InventorMasahiro Kamata
Life of this patent
Estimating the term…
Abstract
The present invention provides methods and apparatus for measuring subterranean strain. The methods and apparatus use fluid expansion principles to compensate for temperature variations and increase the accuracy of the strain measurements. The methods and apparatus contemplate the use of multiple fluid chambers according to some embodiments in order to remove temperature dependence from stress or strain measurements.
Claims48
A method of monitoring subterranean parameters comprising:
- measuring fluid volume change of a first fluid in response to stress or strain, the first fluid comprising a first thermal expansion coefficient;
- measuring fluid volume change of a second fluid comprising a second thermal expansion coefficient;
- compensating the fluid volume change measurement of the first fluid for temperature using the fluid volume measurement of the second fluid.
(canceled)
A method of monitoring subterranean parameters comprising:
- providing a first fluid chamber sensitive to strain or stress, the first fluid chamber comprising a first volume of fluid;
- providing a second fluid chamber insensitive to strain or stress, the second fluid chamber comprising a second volume of fluid;
- measuring fluid displaced from the first fluid chamber in response to strain or stress;
- measuring expansion of the second volume of fluid in response to temperature variations;
- compensating measured fluid displaced from the first fluid chamber for temperature by the measured expansion of the second volume of fluid.
2 more elements
A method of monitoring subterranean parameters comprising:
- providing a first fluid chamber of a first exterior size sensitive to strain or stress and having a first volume of fluid;
- providing a second fluid chamber of the first exterior size sensitive to strain or stress and having a second volume of fluid, the second volume of fluid being less than the first volume of fluid;
- measuring displacement of the first volume of fluid from the first chamber in response to strain or stress and in response to temperature changes;
- measuring displacement of the second volume of fluid from the second chamber in response to strain or stress and in response to a fraction of the temperature changes;
- compensating strain or stress measurements for temperature using the fractional displacement change due to temperature changes in the second chamber.
2 more elements
A method of measuring subterranean stress or strain comprising:
- filling a first chamber of a volumetric strainmeter with a first fluid;
- filling a second chamber of the volumetric strainmeter with a second fluid;
- measuring a volume of fluid displaced from the first chamber in response to stress or strain;
- measuring fluid expansion of the clue to temperature variations;
- compensating the measurement of first fluid displaced from the first chamber for the temperature variations,
- wherein the first chamber comprises a strain-sensitive chamber and the second chamber comprises a strain-insensitive chamber.
3 more elements
(canceled)
(canceled)
A method of monitoring subterranean parameters comprising:
- measuring changes in volumetric fluid capacity of a first chamber containing a first fluid in response to tectonic stresses and temperature variations, the first fluid comprising a first thermal expansion coefficient;
- measuring changes in volumetric fluid capacity of a second chamber containing a second fluid in response to tectonic stresses and temperature variations, the second fluid comprising a second thermal expansion coefficient, the second thermal expansion coefficient being different than the first thermal expansion coefficient;
- calculating volumetric strain independent of temperature.
A method of monitoring subterranean parameters comprising:
- measuring changes in volumetric fluid capacity of a first chamber containing a first fluid in response to tectonic stresses and temperature variations, the first chamber being sensitive to strain;
- measuring changes in volumetric fluid capacity of a second chamber containing a second fluid in response to temperature variations only, the second chamber being insensitive to strain;
- calculating volumetric strain compensated for temperature by subtracting the measured changes in volumetric fluid capacity of the second chamber from the measured changes in volumetric fluid capacity of the first chamber.
A volumetric strainmeter, comprising:
- a housing;
- a stain measurement chamber filled with a first fluid;
- a temperature compensation chamber filled with a second fluid;
- a first fluid meter operatively connected to the strain measurement chamber for measuring fluid displaced from the strain measurement chamber;
- a second fluid meter operatively connected to the temperature compensation chamber for measuring fluid displaced from the temperature compensation chamber,
- wherein the strain measurement chamber deforms in response to stress or strain in the earth, and the temperature compensation chamber does not deform in response to stress or strain in the earth.
3 more elements
(canceled)
A volumetric strainmeter, comprising:
- a housing;
- a strain measurement chamber filled with a first fluid;
- a temperature compensation chamber filled with a second fluid;
- a first fluid meter operatively connected to the strain measurement chamber for measuring fluid displaced from the strain measurement chamber;
- a second fluid meter operatively connected to the temperature compensation chamber for measuring fluid displaced from the temperature compensation chamber,
- wherein the strain measurement chamber and the temperature compensation chamber deform substantially identically in response to stress or strain in the earth, and wherein the first ad second fluids have different, known thermal expansion coefficients.
3 more elements
A volumetric strainmeter comprising:
- a housing;
- a strain measurement chamber filled with a first fluid;
- a temperature compensation chamber filled with a second fluid;
- a first fluid meter operatively connected to the strain measurement chamber for measuring fluid displaced from the strain measurement chamber;
- a second fluid meter operatively connected to the temperature compensation chamber for measuring fluid displaced from the temperature compensation chamber;
- a quantum-metered overcapacity valve operatively connected to the strain measurement chamber.
3 more elements
A volumetric strainmeter, comprising:
- an outer housing;
- a reinforced inner housing resistant to deformation due to stress or strain in the earth;
- a first fluid disposed between the outer housing and the reinforced inner housing;
- a second fluid disposed in the reinforced inner housing;
- a first capillary tube fluidly connected to the first fluid;
- a second capillary tube fluidly connected to the second fluid;
- a first differential transformer connected to the first capillary tube;
- a second differential transformer connected to the second capillary tube.
5 more elements
(canceled)
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A method of monitoring subterranean parameters comprising measuring changes in subterranean temperature using two fluids having different fluid expansion to compensate for strain variations.
Dependencies are inferred from the claim text.