Experimental study on phase behavior of heavy oil-solvent mixture system

AbstractA novel experimental procedure was proposed to investigate the phase behavior of a solvent mixture (SM) (64 mol% CH4, 8 mol% CO2, and 28 mol% C3H8) with heavy oil. Then, a theoretical methodology was employed to estimate the phase behavior of the heavy oil–solvent mixture (HO–SM) systems with various mole fractions of SM. The experimental results show that as the mole fraction of SM increases, the saturation pressures and swelling factors of the HO–SM systems considerably increase, and the viscosities and densities of the HO–SM systems decrease. The heavy oil is upgraded in situ via asphaltene precipitation and SM dissolution. Therefore, the solvent-enriched oil phase at the top layer of reservoirs can easily be produced from the reservoir. The aforementioned results indicate that the SM has promising application potential for enhanced heavy oil recovery via solvent-based processes. The theoretical methodology can accurately predict the saturation pressures, swelling factors, and densities of HO–SM systems with various mole fractions of SM, with average error percentages of 1.77% for saturation pressures, 0.07% for swelling factors, and 0.07% for densities.

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Numerical Simulation Investigation on Foamy Oil Behavior for a System of Heavy Oil-Mixture Solvent in Porous Media

Journal of Energy Resources Technology ◽

10.1115/1.4049283 ◽

2020 ◽

pp. 1-23

Author(s):

Xinqian Lu ◽

Zeyu Lin ◽

Xiang Zhou ◽

Fanhua Zeng

Keyword(s):

Numerical Simulation ◽

Simulation Study ◽

Heavy Oil ◽

Solvent System ◽

Solvent Mixture ◽

Dew Point ◽

Simulation Studies ◽

Foamy Oil ◽

Pure Solvent ◽

Mixture System

Abstract Heavy oil resources, as a non-renewable energy resource, often requires extra enhanced oil recovery techniques such as solvent-based processes. Many kinds of solvents including pure and mixed solvent have been tested in the solvent-based applications. Compared with pure solvent, the solvent mixture has an advantage of relatively higher dew point pressure while maintaining desirable solubility in heavy oil. The characterization of foamy oil behavior in pure solvent system is different from the solvent mixture system despite their similarities. Thus, an additional numerical simulation study is necessary for solvent mixture system. This work conducted simulation studies to investigate foamy oil behavior in a heavy oil-mixture solvent (C1+C3) system from pressure depletion tests. A better understanding of foamy oil characterization and mechanism in a heavy oil-mixture solvent system is obtained. A reliable non-equilibrium model is developed to perform simulation studies. Since previous experiments suggest the behavior of foamy oil in the solvent mixture system share similarities with the heavy oil-methane system, this investigation first conducted simulation study with consideration of two reactions in the model and achieved good agreements between the simulated calculation results and experimentally measurement. Then four reactions are considered in the model for simulation study and obtained better history match results. The simulation results suggest methane has more impact on the foamy oil behaviors than propane in the heavy oil-mixture solvent system. This work also discussed effect of model parameters involved in the history matching process and conducted sensitivity analysis.

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