Physical and Numerical Simulations of Subsurface Upgrading using Solvent Deasphalting in a Heavy Crude Oil Reservoir

Ovalles, César; Rogel, Estrella; Alboudwarej, Hussein; Inouye, Art; Benson, Ian Phillip; Vaca, P.

doi:10.2118/174412-ms

Cited by 5 publications

(1 citation statement)

References 26 publications

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“…Subsurface upgrading of heavy oil via solvent deasphalting (SSU-SDA) has been reported previously under laboratory and field conditions. − The main advantage of these processes is that they do not require external energy sources because they are operated at reservoir temperature or in the presence of a warm solvent. Specifically, VAPEX involves the injection of solvent vapor (typical light hydrocarbons in the C3 to C5 range) into an upper horizontal well in a conventional steam assisted gravity drainage (SAGD) configuration pair. − The solvent dissolves into the viscous oil making it mobile enough to drain downward to the production well.…”

Section: Introductionmentioning

confidence: 99%

Subsurface Upgrading of Heavy Oils via Solvent Deasphalting Using Asphaltene Precipitants. Preparative Separations and Mechanism of Asphaltene Precipitation Using Benzoyl Peroxide as Precipitant

et al. 2017

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Subsurface upgrading of heavy oil via solvent deasphalting has been reported previously under laboratory and field conditions. However, these processes require a relatively high solvent-to-oil ratio (SvOR > 1:1 v/v) to induce subsurface asphaltene precipitation, increase oil production, and upgrade crude oil in situ. In our previous work, lab experiments demonstrated that asphaltene precipitants reduce the SvOR (∼30−50 vol %) for subsurface upgrading at initial reservoir conditions and when heat is also applied. In this work, the preparative separations were carried out using benzoyl peroxide (BP), Fe 2 O 3 , and NiO nanoparticles as asphaltene precipitants for Venezuelan and Canadian heavy crude oils. Initial experiments showed that BP is the most effective additive, producing an increase of ∼21 wt % in the asphaltene content for a 2500 mg/kg dosage. Preparative separations at 5:1 vol/wt ratio and 50 °C showed that the order of activity as asphaltene precipitants is BP > NiO > Fe 2 O 3 . In the presence of nickel-and iron-containing precipitants, most of these metals are found in the asphaltenes indicating that the nanoparticles are acting as nucleation sites. Spectroscopic and mechanistic studies using BP as precipitant suggest a free radical mechanism that involves the thermally initiated homolytic cleavage of BP, follow by abstraction of a hydrogen atom from the asphaltenes or maltenes to produce free radical species. In the termination steps, the latter species react with each other to generate new asphaltene species that are not present in the original crude oils.

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