Effect of Injection Pressure on the Imbibition Relative Permeability and Capillary Pressure Curves of Shale Gas Matrix
- Aymen Al-Ameri (Texas Tech University) | Muhammed Abed Mazeel (Iraq Oil Ministry)
- Document ID
- Society of Petrophysicists and Well-Log Analysts
- Publication Date
- April 2020
- Document Type
- Journal Paper
- 218 - 229
- 2020. Society of Petrophysicists & Well Log Analysts
- 6 in the last 30 days
- 73 since 2007
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For the spontaneous imbibition, where the driving force is the capillary pressure only, multiple analytical models were developed to analyze the spontaneous uptake of a wetting phase by a porous medium saturated with a nonwetting phase. These models would not accurately represent the fluid loss during hydraulic fracturing because of the impact of the injection pressure. This study, is an attempt to estimate the water relative permeability and capillary pressure curves during the simultaneous effect of the spontaneous imbibition and injection pressure, and compare the results to the spontaneous imbibition case. Therefore, the impact of the pumping pressure on the imbibition capillary pressure and water relative permeability curves would be possible.
Brineflooding experiments were conducted for outcrop samples from the Eagle Ford shale to determine the performance of the upstream pressure over time. The imbibition relative permeability curves were calculated by integrating the upstream pressure versus time relationship using the trapezoidal integration method. Moreover, matching of the Corey equation to the relative permeability was considered to estimate the equivalent Corey water exponent. The calculated brine Corey exponent was two while it was four for the case of spontaneous imbibition. Therefore, the injection pressure enhances the water relative permeability.
The imbibition capillary pressure curve was calculated by simulating the flooding experiments using the ECLIPSE commercial simulator and matching the predicted results to the experimental pressure-time relationship. The injection pressure resulted in positive values for the capillary pressure; moreover, it has no effect on the spontaneous-imbibition capillary pressure.
|File Size||3 MB||Number of Pages||12|