Method and system for estimating the amount of supercharging in a formation
First Claim
1. A method for estimating the amount of supercharging in a formation penetrated by a wellbore, the method comprising the steps of:
- obtaining measurements of pressure fluctuations at a position in the formation accessible from the well bore and at an adjacent position in the wellbore;
providing a formation flow model which relates variations in pressure with time at said positions to a plurality of adjustable parameters from which the amount of supercharging can be estimated, at least one of the parameters accounting for the influence on fluid flow of a wellbore filtercake layer and/or the influence on fluid flow of the formation;
adjusting the parameters to optimise the fit between the pressure variations predicted by the model and the measured pressure fluctuations; and
estimating the amount of supercharging from the parameters thus-adjusted.
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Abstract
A method is provided for estimating the amount of supercharging in a formation penetrated by a wellbore. According to the method, pressure fluctuation measurements are obtained at a position in the formation accessible from the well bore and at an adjacent position in the wellbore, and a model is provided which relates variations in pressure with time at these positions to one or more adjustable parameters from which the amount of supercharging can be estimated. The or each parameter is then adjusted to optimise the fit between the pressure variations predicted by the model and the measured pressure fluctuations, and the amount of supercharging is estimated from the adjusted parameter(s).
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Citations
16 Claims
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1. A method for estimating the amount of supercharging in a formation penetrated by a wellbore, the method comprising the steps of:
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obtaining measurements of pressure fluctuations at a position in the formation accessible from the well bore and at an adjacent position in the wellbore;
providing a formation flow model which relates variations in pressure with time at said positions to a plurality of adjustable parameters from which the amount of supercharging can be estimated, at least one of the parameters accounting for the influence on fluid flow of a wellbore filtercake layer and/or the influence on fluid flow of the formation;
adjusting the parameters to optimise the fit between the pressure variations predicted by the model and the measured pressure fluctuations; and
estimating the amount of supercharging from the parameters thus-adjusted. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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3. A method for estimating the amount of supercharging in a formation penetrated by a wellbore, the method comprising the steps of:
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obtaining measurements of pressure fluctuations at a position in the formation accessible from the well bore and at an adjacent position in the wellbore;
providing a formation flow model which relates variations in pressure with time at said adjacent positions to one or more adjustable parameters from which the amount of supercharging can be estimated; and
adjusting the or each parameter to optimise the fit between the pressure variations predicted by the model and the measured pressure fluctuations, the fit between the measured pressure fluctuations and the pressure difference variations predicted by the model being assessed in the time domain; and
estimating the amount of supercharging from the parameter or parameters thus-adjusted.
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14. A computer system for estimating the amount of supercharging in a formation penetrated by a wellbore, the system comprising:
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an input device for receiving pressure fluctuation measurements obtained at a position in the formation accessible from the well bore and at an adjacent position in the wellbore;
a memory device carrying a formation flow model which relates variations in pressure with time at these positions to a plurality of adjustable parameters from which the amount of supercharging can be estimated, at least one of the parameters accounting for the influence on fluid flow of a wellbore filtercake layer and/or the influence on fluid flow of the formation; and
a processor for optimally fitting the pressure variations predicted by the model to the measured pressure fluctuations by adjustment of said parameters, and estimating the amount of supercharging from the adjusted parameters. - View Dependent Claims (16)
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15. A computer system for estimating the amount of supercharging in a formation penetrated by a wellbore, the system comprising:
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an input device for receiving pressure fluctuation measurements obtained at a position in the formation accessible from the well bore and at an adjacent position in the wellbore;
a memory device carrying a formation flow model which relates variations in pressure with time at these positions to a plurality of adjustable parameters from which the amount of supercharging can be estimated; and
a processor for optimally fitting the pressure variations predicted by the model to the measured pressure fluctuations by adjustment of said parameters, and estimating the amount of supercharging from the adjusted parameters, the fit between the measured pressure fluctuations and the pressure difference variations predicted by the model being assessed in the time domain.
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Specification