Short-term analysis technique for pressure buildup test using simultaneously measured transient sandface flow rate and pressure
When a well is shut-in at the surface for a pressure buildup test, fluid continues to flow into the wellbore. This phenomenon is referred to as the wellbore storage effects, or afterflow. Conventional pressure buildup analysis does not provide reliable results until afterflow has ended, which might take days and sometimes even weeks. This research used the afterflow period to develop a simple and accurate method which will significantly reduce the shut-in time and allow one to estimate the formation permeability, the skin factor, and the initial reservoir pressure. The convolution integral (Duhamel's theorem) utilized by Van Everdingen and Hurst has been used, and the afterflow was approximated by a polynomial of degree n. Data required for the application of this method are obtained by simultaneously measuring the sandface flow rate and pressure immediately before the well is shut-in and during the buildup period. Field and simulated data for both oil and multiphase flowing wells were used. A comparison of the results to those obtained by conventional methods have established that the proposed method is easy to use, accurate, and reliable.
- Research Organization:
- Louisiana Tech Univ., Ruston, LA (United States)
- OSTI ID:
- 6947813
- Country of Publication:
- United States
- Language:
- English
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