Feasibility Of Environmentally Friendly Solvent in Bitumen Recovery Through Solvent-Steam Processes
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Steam flooding is the most widely used and reliable thermal enhanced oil recovery (EOR) process to recover bitumen. However, the excessive water required to generate steam causes environmental concerns. Thus, a noble idea to reduce the sole dependency on steam alone is to co-inject solvent with steam to improve miscibility aside from the oil displacement mechanisms from steam itself. However, the usage of industrial grade solvents are toxic, hence difficult to handle. These chemicals will cause long term health issues as well as environmental pollution. Thus, the aim of this research is to investigate the feasibility of a plant-based environmentally friendly solvent to replace the toxic industrial grade solvents as well as reduce the dependency on steam alone. Eight core flooding experiments were conducted on a Canadian bitumen by varying propane, hexane, toluene, benzoyl peroxide, MS environmentally friendly solvent, and steam. Results obtained indicated good oil recoveries through solvent-steam processes especially using the MS solvent. The produced and residual oil were analyzed through asphaltenes separation which showed that the MS solvent produced more of the asphaltene in the produced oil. Meanwhile, the other solvents precipitated more asphaltenes in the residual oil on the spent rock since they are asphaltene precipitants except for toluene. Polar asphaltene should react with polar liquid water to form emulsion based on literature. However, the asphaltene content in produced oil did not correlate with the emulsion severity during investigation. Thus, control experiments involving individual SARA fractions were conducted to understand the role of each fraction in emulsion formation. Results showed that the mutual interaction between aromatics and resins induced the formation of emulsion before being stabilized by the asphaltenes. At the same time, it was found that emulsion formation intensifies during steam temperature and exist as foam before condensing into more stable water droplets at a lower temperature. These results meant that the MS environmentally friendly solvent could potentially replace the toxic chemicals during solvent-steam processes to mitigate the environmental footprint. Other than that, the role of asphaltene as an emulsion stabilizer instead of as an emulsion inducer will alter emulsion treatment and inhibition chemicals by targeting the deasphalted oil instead to improve the oil quality by removing the emulsion. This behavior of asphaltene will also shed light onto the fundamentals of asphaltene which still remains to be a complex molecule to understand.
Ng, Alwin Zhen Yang (2018). Feasibility Of Environmentally Friendly Solvent in Bitumen Recovery Through Solvent-Steam Processes. Master's thesis, Texas A & M University. Available electronically from