Metal phosphides, including Ni2P, MoP, WP, and CoP, are novel active hydrotreating catalysts with high potential as high-performance catalysts due to their higher hydrogenation activity, which is essential in the hydrodesulfurization of bulky sulfur-containing molecules and in hydrodenitrogenation, compared to conventional Mo- and W-based metal sulfide catalysts. However, the preparation of metal phosphides is more challenging than that of metal sulfides. In the present study, three preparation methods, including in-situ reduction, H2-plasma reduction, and sulfidation-reduction, are introduced, and the effects of preparation conditions on the structure and catalytic performances in hydrodesulfurization are briefly discussed. In addition, H2S passivation is compared with O2 passivation for the preparation of Ni2P catalysts.
In the last two decades, the level of investigation into low salinity water (LSW) flooding has sharply increased. LSW with adequate composition and salinity is injected into the reservoir, which changes the properties of the reservoir rock, thus improving oil recovery. However, for certain reservoirs there might be no improvement at all. This has led for further studies on what exactly governs the lack of improvement upon LSW injection in different reservoirs. Focus was placed on acidic and basic components present in crude oil. They are characterized by measuring total acid number (TAN) and total base number (TBN). This study investigates the wettability alteration of Berea sandstone rock with different crude oil acid and base numbers at specific LSW concentrations and compositions. For this purpose, the sessile drop method was used in specified times. Moreover, the experiments were conducted in two stages, which included crude oil A and B. The experimental results revealed that a significant change in wettability was experienced by the LSW composition of cations K+ and Na+ for the crude oil composition with lower acid number.
In this study, two types of plants based natural cationic surfactants, named Mulberry and Henna are introduced and the application of these natural surfactants in wettability alteration of reservoir rock and reducing the interfacial tension of water-oil system is investigated. For this purpose, two natural-based surfactants were extracted from the leaves of the trees of addressed plants and then the interfacial tension (IFT) values between oil and natural surfactant solution and also the contact angle values between natural surfactant solution and rock sample were measured. The results demonstrated that Mulberry extract was able to lower the interfacial tension between oil and distilled water from 43.9 to 4.01 mN/m, while Henna extract could reduce the IFT from 43.9 to 3.05 mN/m. These natural surfactants were also able to reduce the contact angle of rock/fluid system which shows the wettability is altering to water wet system and so it may increase recovery factor by reducing residual oil saturation and Henna extract could reduce the contact angle more than that of Mulberry leaf extract. According to these results in addition to the low price of generating natural surfactants, the feasibility of using these kinds of surfactants in future oil recovery processes is of major concern.