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Analysis of Heat Loss Effects on Thermal Pressure Falloff Tests
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, ECMOR XIV - 14th European Conference on the Mathematics of Oil Recovery, Sep 2014, Volume 2014, p.1 - 20
Abstract
Analysis of pressure falloff tests gives initial estimates of swept volume, essential for the evaluation of a thermal recovery process. The analysis is based on a two-zone composite reservoir model with highly contrasting fluid mobilities, where the swept zone is assumed to behave as a closed reservoir for a short period exhibiting pseudo steady state behavior.
The upward buckling of the pressure derivative curves at late times in some cases could not be explained using the conventional composite models. This issue and some of the errors associated with the estimation of swept volume may possibly be related to heat loss which could have significant effects on the pressure behavior and dominate the pseudo steady state flow.
A model for the analysis of falloff tests with significant heat loss was suggested by Stanislav et al. (1989) . However, there are limitations in the application of this approach to practical steam falloff tests. Moreover, permeability should be known in advance for further analysis.
In this paper, a modified method of analysis considering heat loss is discussed which makes the flow regime identification easier and removes some of the practical limitations. Results of the analysis show improvement over the estimates obtained by other methods.