Influence of Anionic and Amphoteric Surfactants on Heavy Oil Upgrading Performance with Nickel Tallate under Steam Injection Processes

Steam-basedthermal enhanced oil recovery techniques are widelyapplied methods to unlock heavy oil and natural bitumen resources.In this paper, two oil-soluble surfactants, as a subset of chemicaladditives, are introduced to favor the in situ catalytic hydrothermalupgrading of heavy oil. The solubility, salt tolerance, and thermalstability of both surfactants are experimentally investigated. Thesurfactant-assisted catalytic hydrothermal treatment of heavy oilwas carried out in a batch reactor with a stirrer coupled with a gaschromatography device. The outputs of heavy oil upgrading processeswere evaluated by comprehensive analysis of SARA fractions and elementaland structural changes of crude oil. Moreover, the distribution oflow-molecular-weight alkanes in saturates and alkyl benzenes in aromaticsare examined by gas chromatography-mass spectroscopy (GC-MS).The results confirmed the synergistic effect of catalytic nanoparticlesand surfactants on the destructive hydrogenation of fused polynucleararomatic rings such that the contents of resins and asphaltenes werereduced by 12.5 and 43.3%, respectively. In addition, surfactantscontributed to hydrogen addition and inhibition of carbon rejectionprocesses such that the H/C ratio increased from 1.32 to 1.72 withimproving hydrodesulfurization and hydrodenitrogenation processes.Moreover, the amphoteric surfactant significantly enhanced the emulsificationpotential of the steam phase by decreasing the interfacial tension(IFT) between heavy crude oil and the steam phase, which positivelyaffects the steam chamber propagations and hence leads to the incrementaloil recovery in case of field-scale applications. On the basis ofthe achieved laboratory-scale results, the surfactant is a promisingsteam additive for improving heavy oil production.

Automated summary

Steam-based thermal enhanced oil recovery techniques are commonly used to extract heavy oil and bitumen resources. This study investigates the use of oil-soluble surfactants to enhance the catalytic hydrothermal upgrading of heavy oil. The results show that the surfactants effectively reduce the content of resins and asphaltenes, increase the H/C ratio, and enhance steam chamber propagations, leading to improved oil recovery.