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Many in situ recovery methods have been developed to extract heavy oil and bitumen from deep reservoirs. The "underground refinery" approach using a nanosize ultradispersed (UD) catalyst is one of the alternatives to surface upgrading that may become the "next generation" of oil sands industry improvement. Water-in-vacuum gas oil microemulsions containing trimetallic (W, Ni, and Mo) ultradispersed colloidal nanoparticles could penetrate inside the porous medium and react with the bitumen. This study is aimed at developing a catalytic-enhanced oil recovery method for Athabasca bitumen recovery through the viscosity reduction mechanism with the aid of trimetallic nanoparticles. In this study, series of experiments were conducted at a pressure of 3.5 MPa, residence time of 36 h, and temperatures from 320 to 340 °C in an oil sands packed bed column. Results of three consecutive categories of hot fluid injection (in the presence or absence of trimetallic nanoparticles) are presented. For the first category, the obtained experimental results showed that the recovery curve for vacuum gas oil injection without nanocatalysts was at a plateau. In the second series of tests, observations proved that adding a certain percentage of pentane enhanced the recovery performance of injection tests. The third phase of experiments was conducted in the presence of trimetallic nanocatalysts in emulsion with vacuum gas oil. Results showed the effectiveness of nanocatalysts for enhancing the recovery performance compared with the cases of no nanoparticle implementation.

Water-in-vacuum gas oil microemulsion containing ultradispersed multimetallic colloidal nanoparticles can facilitate in situ delivery of nanoparticles into a heavy oil reservoir. This study investigated the transport of multimetallic nanoparticles (W, Ni, and Mo) of potential catalytic value suspended in vacuum gas oil using different oil-sands-packed bed column breakthrough experiments at a typical pressure and temperature of the steam-assisted gravity drainage (SAGD) recovery process. The nanoparticles (34 ± 0.5 nm) were transported into two different permeability oil sands. Experiments were performed at a pressure of 3.5 MPa, residence time of 36 h, and temperatures from 300 to 320 °C in both low- and high-permeability-oil-sands-packed beds. At full breakthrough, a constant normalized concentration plateau was achieved, ranging from 0.50 for low-permeability oil sands to 0.60 for high-permeability oil sands. Deposition and transport of nanoparticles were strongly dependent upon their metallic type, temperature, and porosity of oil sands. Despite aggregation of nanoparticles at a high temperature, neither major permeability reduction nor pore plugging were observed. Therefore, propagation of multimetallic ultradispersed nanoparticles in oil sands media seems feasible under a typical pressure and temperature of the SAGD process.

An experimental study was performed to investigate the impact of low salinity water on wettability alteration in carbonate core samples from southern Iranian reservoirs by spontaneous imbibition. In this paper, the effect of temperature, salinity, permeability and connate water were investigated by comparing the produced hydrocarbon curves. Contact angle measurements were taken to confirm the alteration of surface wettability of porous media. Oil recovery was enhanced by increasing the dilution ratio of sea water, and there existed an optimum dilution ratio at which the highest oil recovery was achieved. In addition, temperature had a very significant impact on oil recovery from carbonate rocks. Furthermore, oil recovery from a spontaneous imbibition process was directly proportional to the permeability of the core samples. The presence of connate water saturation inside the porous media facilitated oil production significantly. Also, the oil recovery from porous media was highly dependent on ion repulsion/attraction activity of the rock surface which directly impacts on the wettability conditions. Finally, the highest ion attraction percentage was measured for sodium while there was no significant change in pH for all experiments.

Conventional crude oil production is declining, while the consumption of petroleum-based fuels is increasing. Therefore, bitumen and heavy oil exploitation is steadily growing. However, in the present context, heavy oil and bitumen exploitation processes are high-energy and water-intensive and, consequently, have significant environmental footprints because of the production of gaseous emissions, such as CO 2 , and generating huge amounts of produced water. In situ catalytic conversion or upgrading is a promising cost-effective and environmentally friendly technology that aims at reducing the environmental footprints of oil sand exploitation and producing of high-quality oil that meets pipeline and refinery specifications. In this study, in situ prepared Ni−W−Mo ultradisperse nanocatalysts within a vacuum gas oil matrix were used for Athabasca bitumen upgrading in a packed-bed flow reactor at a high pressure and temperature. Experiments were performed at a pressure of 3.5 MPa, temperatures from 320 to 340 °C, and a hydrogen flow rate of 1 cm 3 /min. The produced liquid was analyzed on the basis of residue conversion, microcarbon residue (MCR) content, sulfur and nitrogen contents, American Petroleum Institute (API) gravity, and viscosity. Results showed that nanocatalysts enhanced the quality of Athabasca bitumen by increasing the API gravity and decreasing the viscosity and MCR, sulfur, and nitrogen contents. Nanocatalysts effectively favored the hydrogenation reactions and inhibited the massive formation of coke that usually occurs via olefin polymerization and heavy free radical condensation during the classical thermal cracking process of heavy oils.

Thermal cracking of Athabasca bitumen was carried out in an oilsand packed-bed column, in the presence and absence of in situ prepared trimetallic nanocatalysts at a pressure of 3.5 MPa, residence time of 36 h, and temperatures of 320 and 340°C. In this part of the study, the effects of reaction severity (time and temperature) as well as the presence of nanocatalysts in packed media on solid and gaseous products were investigated. Results showed that the presence of trimetallic nanocatalysts enhanced the hydrogenation reactions and, consequently, led to significant reduction of coke formation (51.3%) and CO 2 emission reduction. Further, the analysis of the gaseous products and deposited solids confirmed the previous findings reported in part 1 (10.1021/ef401716h) of this study. The accumulative volume of coke precursor gases, such as ethylene and propylene, increased with the reaction severity. However, reaction severity has no significant effect on the atomic metallic ratios (metal/total metal) of the employed trimetallic nanocatalysts, which clearly demonstrates the stability of injected ultradispersed (UD) nanocatalysts (metal/total metal: Mo, 0.6267; Ni, 0.1808; and W, 0.1924) in the porous media at high pressure and temperature. Nonetheless, aggregation of nanocatalysts inside the porous media was observed and graphically demonstrated by environmental scanning electron microscopy (ESEM) images. Overall, the presence of trimetallic nanocatalysts in porous media not just enhanced bitumen upgrading but also improved the produced liquid quality and reduced the coke content as well as CO 2 emission by 50%.

In this study, the effect of initial water saturation on the oil recovery for carbonate rocks is investigated using spontaneous imbibition experiments. The experiments are performed using 20 times diluted sea water as imbibing fluid and the sea water as initial water. In addition, the impact of pH and Ca 2+ , Mg 2+ , Na +, and K + cations concentration change of imbibing fluid are investigated during tests. These results help to identify the active cations in the wettability alteration process of carbonate rocks during the low-salinity water injection. A mechanism is proposed to describe the effect of initial water saturation on the oil recovery by low-salinity water injection. The impact of initial water saturation on the wettability alteration might be positive or negative depending on its value and the rock permeability. The comparison of divalent cations concentrations shows that the minimum adsorption of Ca 2+ and maximum desorption of Mg 2+ lead to maximum oil recovery of spontaneous imbibition. The results confirm that three cations of Ca 2+ , Mg 2+ , and Na + are active for wettability alteration of carbonate rocks in the presence of sea water as initial water and diluted sea as imbibing fluid, whilst the amounts of potassium remain constant.

The worldwide global demand for oil has grown to 80 million barrels per day, and is estimated to grow by 50% in next 20 years while conventional resources are declining. Unconventional reserve of heavy oil and bitumen has been considered as long term replacement for conventional resources. There are a large number of research projects in order to achieve this goal with technological efficiency. In situ upgrading of heavy oil and bitumen using Ultra Dispersed (UD) submicronic catalysts is a promising idea to improve the quality of produced liquid. In this process, hydrogen and a catalytic suspension are injected to the reservoir to react with heavy oil in the porous media. Nano catalyst particles enhance the recovery of oil by viscosity reduction. Series of experiments have been designed in an elemental model under typical reservoir condition. Tests are performed at a pressure of 500 Psi, residence time of 36 h, and temperatures from 300 to 340 (°C). This paper presents the results of the in situ upgrading obtained along with the recovery of bitumen evidenced using ultra dispersed catalysts in an experimental rig. These experiments involve the injection of UD catalyst particles and hydrogen into a sand pack which is saturated with Athabasca bitumen. Produced liquids were analyzed with different techniques and results were demonstrated in recovery curves. Also, results of each experiment have been compared with base steam injection case to evaluate recovery performance of the catalyst suspended in a hot fluid. Temperature profile distributions and produced gas analysis are demonstrated to justify the quality of reaction through porous media. Produced liquids from media have higher API gravity and lower viscosity which shows a successful in situ upgrading process.