Experimental Investigation of Expanding Solvent Steam Assisted Gravity Drainage using Multicomponent Solvents
Date
2012-12-18
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Abstract
The Steam-Assisted Gravity Drainage (SAGD) process is the only proven commercially-viable in situ bitumen recovery method for the Athabasca oil sands deposit. However, in spite of its success in recovering highly viscous bitumen, SAGD remains an expensive technique that requires large energy input in the form of steam for each barrel of produced oil. Many modifications to SAGD continue to evolve to achieve higher energy efficiency and environmental sustainability while maintaining economic viability. The application of Expanding Solvent SAGD (ES-SAGD) has the potential to significantly address the aforementioned issues. ES-SAGD is a variation of SAGD wherein solvent is co-injected with steam to mobilize bitumen through simultaneous heat and mass transfer. The inter-related effects of heat transfer, molecular diffusion and mechanical dispersion, in addition to reservoir properties and operational considerations, play an important role in identifying the appropriate solvent concentration and co-injection strategy.
This study evaluates, using a partially-scaled two-dimensional physical model, the application of ES-SAGD based on actual Long Lake reservoir properties and operating conditions, using cracked naphtha and gas condensate at different concentrations. These solvents are multicomponent, readily available, relatively inexpensive and highly effective in enhancing SAGD performance. Eight high pressure experiments were conducted using a highly instrumented physical model to accurately measure pressure, temperature and fluid flow rates. Upon completion of each experiment, extensive produced fluid and porous media analyses were conducted to evaluate the performance of ES-SAGD relative to SAGD. The results from this study conclusively demonstrate that co-injecting cracked naphtha and gas condensate with steam, under specific conditions, significantly increases oil production rates and reduces steam requirements. Solvent recovery was in the range of 72 to 99 percent and varied with solvent type, concentration and operating strategy. These promising results are expected to be instrumental in the design and implementation of an ES-SAGD field trial.
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Citation
Al-Muayri, M. T. (2012). Experimental Investigation of Expanding Solvent Steam Assisted Gravity Drainage using Multicomponent Solvents (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/26061