Advances of emulsification during the lifetime development of heavy oil reservoirs

Abstract

Emulsifications are associated with the reservoir formation and lifetime development due to the characteristics of heavy oil and influence of injected fluid. The types of formed emulsions (W/O, O/W, or W/O/W) are also change as time goes. Therefore, based on the characteristics and development methods of heavy oil reservoir, emulsifications and their properties during lifetime development are summarized in detail. Heavy oil reservoirs are usually developed by water injection/steam, followed by chemical agents flooding. Tremendous stable W/O emulsions would be formed during water/steam injection due to the action of active components in heavy oil. Resulting in significant changes of viscosity, freezing point, interface characteristics and yield characteristics. Therefore, the efficient development may severely restricted. Chemical agents can emulsify heavy oil to form O/W emulsion and greatly improve the fluidity. Its formation, stability, and interface characteristics are all affected by properties, types and adsorption forms of chemical agents on interface. Researchers are also committed to the study of interface characteristics and stability mechanism, to solve the problem of efficient development of heavy oil. However, serious W/O emulsion has occurred before chemical injection. In fact, the more common type of emulsion formed is W/O/W emulsion. Its properties are also very different from O/W emulsions due to the complexity of composition and structure. The study of W/O/W emulsion formation, stability and flow behavior is more suitable for chemical flooding. Similarly, the development and evaluation of chemical agents should focus more in its emulsification on W/O emulsion in porous media. The results obtained can provide the basic theory for study of interface characteristics and micro-dynamics of heavy oil-water-chemical agent during the lifetime development of heavy oil reservoir.