Abstract

In situ bitumen recovery directly depends on the reduction of bitumen viscosity. Solvent injection is an alternative to thermal bitumen recovery by steam injection. Injection of solvents containing n-alkanes like butane, propane and naphtha may lead to asphaltene precipitation and deposition in the porous media and a possible negative effect on the ultimate oil recovery. Addition of an asphaltene inhibitor (stabilizer) to solvents is a way to prevent asphaltene precipitation and deposition in a reservoir. Efficiency of an asphaltene inhibitor depends on the characteristics of the inhibitor and bitumen properties.In addition to aromatic hydrocarbons, various natural and synthetic polar heteroatom species can be used as asphaltene inhibitors. Results of the study show that deasphalted bitumen is an effective asphaltene inhibitor and it is of the same strength as environmentally hazardous aromatic hydrocarbons. Resins prevent asphaltene precipitation and are similar to expensive synthetic inhibitors. Addition of less than 8 vol. % of resins to low boiling point n-alkanes provides total asphaltene stabilizationin the process of bitumen recovery. When n-alkanes are used as solvents, it is important to know the amount of precipitated asphaltenes in the reservoir. To obtain such data, an experimental study has been conducted to simulate bitumen recovery. A specially designed experimental set-up was used in the study. The experiments allowed a set of chemical additives to be selected to improve colloidal stability of asphaltenes in bitumen.

You can access this article if you purchase or spend a download.