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US 11,892,592 B2Granted
Pressure transient testing with sensitivity analysis
AssigneeSchlumberger Technology Corporation
InventorsKirsty Morton, Nikita Chugunov, Fikri John Kuchuk, Richard Booth, Anthony Fitzpatrick, Denis Biryukov
Life of this patent
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Abstract
Method for using sensitivity analysis to inform the design and performance of a well test are provided. In one embodiment, a method includes providing a reservoir model of pressure transient behavior and performing a sensitivity analysis to identify an input parameter of the reservoir model that can be estimated from pressure transient test data collected from a well location. This method also includes using the results of the sensitivity analysis to design a pressure transient well test for measuring the identified input parameter. Other methods and systems are also disclosed.
Claims16
A method comprising:
- providing to a computer a model of pressure transient in a discretely fractured reservoir;
- performing, via a processor or the computer, a sensitivity analysis to identify an input parameter of the model from multiple input parameters of the model to which a pressure transient output of the model is sensitive, wherein performing the sensitivity analysis comprises:
- (i) calculating global sensitivity indices for the multiple input parameters of the model;
- (ii) identifying which of the multiple input parameters contribute most to expected uncertainty in pressure and pressure derivative output of the model;
- and
- (iii) determining how contributions of the multiple input parameters to the expected uncertainty vary over a time period comprising a plurality of time ranges;
- identifying, from the sensitivity analysis, a test period at which sensitivity of the pressure transient output to the input parameter is high relative to sensitivities of any remaining input parameters of the multiple input parameters of the model such that the input parameter provides a greatest contribution to the expected uncertainty in pressure and pressure derivative output of the model during the test period, wherein the test period corresponds to a time range of the plurality of time ranges;
- designing, based on results of the sensitivity analysis, a pressure transient well test for measuring the identified input parameter using the identified test period;
- performing the pressure transient well test using the identified test period;
- modifying an operation of the pressure transient well test based on actual conditions experienced during the pressure transient well test;
- and
- updating the model based on the pressure transient well performed utilizing the identified test period.
9 more elements
A method comprising:
- receiving time-varying contributions of multiple uncertain parameters of a model of pressure transient in a discretely fractured reservoir to uncertainty in an output of the model, the time-varying contributions having been determined through a global sensitivity analysis comprising:
- (i) calculating global sensitivity indices for the multiple uncertain parameters of the model;
- (ii) identifying which of the multiple uncertain parameters contribute most to expected uncertainty in pressure and pressure derivative output of the model;
- and
- (iii) determining how contributions of the multiple uncertain parameters to the expected uncertainty vary over a time period comprising a plurality of time ranges;
- and
- devising a well test to gain additional information about an input parameter of the multiple uncertain parameters based on the received time-varying contributions of the multiple uncertain parameters, wherein devising the well test to gain additional information about the input parameter of the multiple uncertain parameters based on the received time-varying contributions of the multiple uncertain parameters includes:
- selecting a testing period corresponding to a time range of the plurality of time ranges to use in performing the well test that is based on relative sensitivity of the input parameter being high relative to sensitivities of any remaining parameters of the multiple uncertain parameters of the model such that that the input parameter provides a greatest contribution to the expected uncertainty in pressure and pressure derivative output of the model during the selected testing period;
- and
- determining one or more flow parameters to implement in the well test based on the relative sensitivity of the parameter;
- performing the well test using the selected testing period;
- and
- updating the model based on generated results of the well test performed utilizing the selected testing period and the one or more flow parameters.
10 more elements
A computer programmed to perform a method that includes:
- identifying input parameters of a model of pressure transient in a discretely fractured reservoir to which the pressure transient output of the model is sensitive;
- determining sensitivity indices of the input parameters via a global sensitivity analysis comprising:
- (i) calculating global sensitivity indices for the input parameters of the model;
- (ii) identifying which of the input parameters contribute most to expected uncertainty in pressure and pressure derivative output of the model;
- and
- (iii) determining how contributions of the input parameters to the expected uncertainty vary over a time period comprising a plurality of time ranges;
- generating a ranking of the input parameters according to their respective contributions to variance in output of the model, wherein generating the ranking of the input parameters includes generating a time-dependent ranking of the input parameters according to their respective contributions to variance in the output of the model;
- selecting a testing period corresponding to a time range of the plurality of time ranges to use in performing a well test that is based on relative sensitivity of a highest ranked input parameter of the input parameters being high relative to sensitivities of any remaining input parameters such that that the highest ranked input parameter provides a greatest contribution to the expected uncertainty in pressure and pressure derivative output of the model during the selected testing period;
- and
- updating the model based on generated results of a pressure transient well test performed utilizing the selected testing period.
7 more elements
Dependencies are inferred from the claim text.