Downhole Heavy Crude Oil Upgrading Using CAPRI: Effect of Steam upon Upgrading and Coke Formation

Abstract

Heavy crude oil and bitumen are characterized by a low yield of light distillates in the range of 10–30% with a boiling point below 350 °C, high density (low API gravity), high viscosity, and high heteroatom content, which impede their exploitation. In this study, the catalytic upgrading process in situ (developed by the Petroleum Recovery Institute, Canada) add-on to the toe-to-heel air injection for the extraction and upgrading of heavy oil and bitumen downhole was investigated. The effect of steam addition and steam-to-oil ratio upon upgrading, coke formation, sulfur and metal removal were examined using a Co–Mo/γAl2O3 catalyst at a reaction temperature of 425 °C, pressure of 20 bar, gas-to-oil ratio of 500 mL·mL–1, and steam-to-oil ratio in the range of 0.02–0.1 mL·mL–1. It was observed that the coke content of the spent catalyst reduced from 17.02 to 11.3 wt % as the steam-to-oil ratio increased from 0.02 to 0.1 mL·mL–1 compared to 27.53 wt % obtained with only nitrogen atmosphere after 15 h time-on-stream. Over the same range of conditions, 88–92% viscosity reduction was obtained as steam-to-oil ratio increased compared to 85.5% in nitrogen atmosphere only, a substantial reduction from the value of 1.091 Pa·s for the feed oil. It was also found that although desulfurization increased from 3.4% in a steam-free atmosphere to 16–25.6% over the increasing range of steam flows investigated, demetallization increased from 16.8% in a steam-free environment to 43–70.5% depending on the increasing steam-to-oil ratio.

Effect of cyclohexane as hydrogen-donor in ultradispersed catalytic upgrading of heavy oil

“…The analysis was performed with a ramp temperature increase from 25 to 900°C under air flow of 50 mL·min −1 . A detailed description of these analytical instruments has been reported elsewhere [3,6,7]. The products are grouped into coke, liquid and noncondensable gas yields after the upgrading reaction and are calculated by the following Eqs.…”

“…The use of an activated carbon guard bed on top of the catalyst has been reported to reduce coke formation and sustain catalyst lifetime by removal of coke precursors and the addition of hydrogen promotes hydroconversion reactions which are shown to deposit less coke than thermal cracking [3,6,7]. Moreover, in situ hydrogen production from steam via the water-gas-shift reaction has also been investigated as a source of hydrogen to promote hydrocracking and hydrogenation reactions by Hart et al [7]. It was found that both hydrogen-addition and steam improved API gravity and viscosity of the produced oil and reduced coke formation.…”

Metallic bionanocatalysts: potential applications as green catalysts and energy materials

“…Upgrading in situ gives a cleaner production of less viscous oil, which is more easily transported without the use of diluents (Shah et al, 2010). The THAI-CAPRI (Toe-to-Heel Air Injection coupled with Catalytic Upgrading Process In situ) technology combines thermally enhanced oil recovery with down-hole catalytic upgrading of heavy oil into light fractions (Greaves and Xia, 2004;Hart et al, 2014). This catalytic upgrading, using steam, hydrogen and methane, showed significant improvements over non-catalytic thermal processes (Hart et al, 2014).…”

“…The THAI-CAPRI (Toe-to-Heel Air Injection coupled with Catalytic Upgrading Process In situ) technology combines thermally enhanced oil recovery with down-hole catalytic upgrading of heavy oil into light fractions (Greaves and Xia, 2004;Hart et al, 2014). This catalytic upgrading, using steam, hydrogen and methane, showed significant improvements over non-catalytic thermal processes (Hart et al, 2014). Conventional cracking catalysts such as supported noble metals are prohibitively expensive; one economic option could utilize regenerated catalysts from treated oils but these have lower activity (Hart et al, 2014).…”

Studies of Catalytic Properties of Inorganic Rock Matrices in Redox Reactions

“…More recent studies have shown the potential for rapid catalyst deactivation due to coke and metal deposits during the catalytic upgrading and possibilities to overcome the challenges of coke deposits by addition of hydrogen or a hydrogen donor [6]. In addition to the above methods, another promising direction is the use of sub-micron catalysts for chemical processes to upgrade heavy oil and bitumen in-situ [7].…”