Dominant Controlling Factors and Displacement Performance in Heavy Oil Recovery Processes

Area of Science:

• Petroleum Engineering
• Reservoir Engineering
• Multiphase Flow

Background:

• Heavy oil recovery involves complex multiphase flow (oil-water, oil-steam).
• Viscous, capillary, and gravitational forces interplay, affecting oil recovery efficiency.
• Understanding these forces is crucial for optimizing production strategies.

Purpose of the Study:

• To establish a unified dimensionless framework for analyzing force competition in heavy oil reservoirs.
• To quantitatively characterize the interactions among viscous, capillary, and gravitational forces.
• To develop a predictive model for oil recovery in both conventional and super-heavy oil systems.

Main Methods:

• Core-scale physical simulation experiments were conducted.
• A dimensionless framework was developed to analyze force competition.
• Residual oil variation was analyzed under diverse operational parameters (injection rates, temperature, permeability, steam quality, inclination).

Main Results:

• Conventional heavy oil-water flooding is primarily controlled by capillary forces, showing a negative correlation with the modified capillary number.
• Super-heavy oil-steam flooding is dominated by gravity-driven flow and thermal viscosity reduction.
• A composite model based on the thermogravimetry number (N_TG) achieved high predictive accuracy (R=0.9692).

Conclusions:

• The study provides a quantitative understanding of force competition in different heavy oil recovery scenarios.
• The developed dimensionless framework and predictive model offer a basis for optimizing heavy oil reservoir development parameters.
• Accurate characterization of dominant forces is essential for enhancing oil recovery efficiency.