Gravity Drainage of Bitumen Induced by Solvent Leaching

Area of Science:

• Petroleum Engineering
• Chemical Engineering
• Environmental Science

Background:

• Steam-based thermal recovery methods for bitumen are energy-intensive and generate significant greenhouse gas emissions.
• Solvent application presents a promising strategy to mitigate the environmental impact of bitumen extraction.
• Understanding gravity drainage and convective dissolution is crucial for optimizing solvent-based processes.

Purpose of the Study:

• To investigate the gravity drainage of bitumen using solvent chamber theory.
• To establish a universal scaling relation for drainage rate based on solvent thermophysical properties.
• To develop a new critical Rayleigh number equation and compare it with existing theories.

Main Methods:

• Application of solvent chamber theory to model bitumen gravity drainage.
• Experimental data analysis using various solvents to determine scaling relations.
• Derivation of a critical Rayleigh number equation based on the power-law mixing rule (PLMR).

Main Results:

• Drainage rate is scalable with solvent thermophysical properties, directly related to density difference and inversely to viscosity.
• A universal linear scaling relation (Sh = βRa) between Sherwood and Rayleigh numbers was established for buoyancy-driven convection.
• The scaling prefactor (β) decreases with increasing mobility ratio (α), indicating reduced convective mass transfer.

Conclusions:

• The developed scaling relation accurately predicts convective mixing for various bitumen/solvent systems, especially with large viscosity contrasts.
• The study provides critical insights into buoyancy-driven convection and mass transfer mechanisms in solvent-based bitumen recovery.
• Findings facilitate the design and optimization of more environmentally friendly and efficient solvent-based bitumen extraction processes.