In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

Abstract

The low-temperature catalytic oxidation of heavy crude oil (Xinjiang Oilfield, China) was studied using three types of catalysts including oil-soluble, watersoluble, and dispersed catalysts. According to primary screening, oil-soluble catalysts, copper naphthenate and manganese naphthenate, are more attractive, and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil. The heavy oil compositions and molecular structures were characterized by column chromatography, elemental analysis, and Fourier transform infrared spectrometry before and after reaction. An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity-temperature characteristics. Results show that the two oil-soluble catalysts can crack part of heavy components into light components, decrease the heteroatom content, and achieve the transition of reaction mode from oxygen addition to bond scission. The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil (oil viscosity and contents of heavy fractions). It is found that the temperature, oil composition, and internal molecular structures are the main factors affecting its flow ability. Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.

Thermal Characteristics, Kinetic Models, and Volatile Constituents during the Energy Conversion of Bituminous SARA Fractions in Air

“…Also, both resins and asphaltenes primarily consist of naphthenic rings, alkyl side chains, condensed aromatic rings, and heteroatoms. 37 …”

Recent Approaches, Catalysts and Formulations for Enhanced Recovery of Heavy Crude Oils

“…Over the past few decades, thermal methods accounted for nearly 70 % of the world's EOR [60,61]. Five thermal EORs are widely recognised, namely, the cyclic steam stimulation (CSS), steam-assisted gradient drainage (SAGD), steam and hot water flooding, steam/solvent hybrid system which all involve fluid injection, and in-situ combustion (ISC) or fire flooding.…”

“…The applicable catalysts are divided into oil-soluble catalysts and water-soluble [135]. An array of transition metal-based oil-soluble catalysts has been reported in the literature [61,136]. Instrumental evidence has shown that, during the aquathermolysis, iron(III) tris(acetylacetonate) can form in-situ magnetic nanoparticles (MNPs) which can exhibit synergy with organic solvents to give high conversion of resins into lighter components [137].…”

Non-Newtonian Flow Characteristics of Heavy Oil in the Bohai Bay Oilfield: Experimental and Simulation Studies

“…The viscosity of oil sample #5 was 586.8 mPa•s, which was double than that of oil sample #6 at 30 °C. This is due to the interaction force between various molecules because they increase as the asphaltene content rises, resulting in an easier asphaltene aggregation and a stronger network structure [7,8,19,64].…”