Experimental Optimization of Catalytic Process In-Situ for Heavy Oil and Bitumen Upgrading

Abstract

The worldwide conventional crude oil demand is on the rise and because of the rising prices, unconventional oils are becoming more economically attractive to extract and refine. However, technological innovation is needed, if heavier oil supplies are to be further exploited. Toe-to-heel air injection (THAI), and its catalytic add-on (CAPRI) processes combine in-situ combustion with catalytic upgrading using an annular catalyst packed around the horizontal producer well. These techniques offer potentially higher recovery levels and lower environmental impact than alternative technologies, such as steam-based techniques. An experimental study is reported concerning the optimization of catalyst type and operating conditions for use in the THAI-CAPRI process. Experiments were carried out using microreactors containing 10 g catalyst, with oil flow of 1 ml.min -1 and gas flow of 0.5 l.min -1 , under different temperatures, pressures and gas environments. Catalysts tested included alumina supported CoMo, NiMo and ZnO/CuO. It was found that there was a trade off in operation temperature between upgrading performance and catalyst lifetime. At a pressure of 20 bar, operation at 500 °C led to an average of 6.1 °API upgrading of THAI oil to 18.9 °API, but catalyst lifetime was limited to 1.5 hours. Operation at 420 °C was found to be a suitable compromise, with upgrading by an average of 1.6 °API, and sometimes up to 3 °API, with catalyst lifetime extended to 77.5 hours. Coke deposition occurred within the first few hours of the reaction, such that the catalyst pore space became blocked. However, upgrading continued, suggesting that thermal reactions or reactions catalysed by hydrogen transfer from the coke itself play a part in the upgrading reaction mechanism. The CAPRI process was relatively insensitive to changes in reaction gas medium, gas flow rate and pressure, suggesting that the dissolution of hydrogen or methane from the gas phase does not play a key role in the upgrading reactions. By careful control of the temperature and oil flow rate in the in-situ CAPRI process, additional upgrading compared with the THAI process alone may be effected, resulting in a more valuable produced oil, which is easier to transport.

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

“…Process variables, such as temperature, pressure, gas-to-oil ratio, catalyst-to-oil ratio and residence time used in this study were optimised values obtained from previous studies in the fixed-bed CAPRI reactor [3,5,19]. The effect of cyclohexane (CH) as a hydrogendonor solvent for ultradispersed catalytic upgrading was tested using a stirred batch reactor (100 mL capacity), Baskerville UK.…”

“…Separate studies are being carried out to evaluate how the catalyst could be contacted with oil in the reservoir. The reactions were carried out at a temperature of 425°C, catalyst-to-oil ratio 0.02 (g·g −1 ), agitation 500 rpm and 10 minute reaction time, as determined in previous fixed-bed and ultradispersed catalyst investigations [5,19]. The reactor was pressurised to an initial pressure of 17.5 bar (nitrogen or hydrogen), which increased to 65-70 bar with the rising temperature and gas production due to cracking reactions.…”

“…Catalyst deactivation due to coke and metal deposition during in situ catalytic upgrading of heavy oil is potentially a major problem for the implementation of conventional CAPRI [5]. 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].…”

Experiment on the Influence Factors of Steam Distillation Rate of Crude Oil in Porous Media

“…As the pore structure and connectivity of the rock may pose certain influence on the steam distillation rate of the crude oil [12], the influence of permeability on the steam distillation rate of crude oil is respectively measured at three levels at four different temperature points, and the experimental results are as shown in Table 1. Table 1 indicates that under the constant experimental temperature and pressure, the steam distillation rate of the same oil slightly increases with the rise of permeability with no significant difference found.…”

“…If conditions permit, the increase in injection rate is conducive to improving the steam dryness at the bottom and the effect of steam distillation [12]. However, with the same dryness, the influence of steam injection rate on the steam distillation rate of crude oil is not clear.…”