Heavy Crude Oil In Presence Research Articles

Effect of decalin as hydrogen-donor for in-situ upgrading of heavy crude oil in presence of nickel-based catalyst

The effect of decalin as hydrogen-donor on the catalytic and non-catalytic hydrothermal upgrading of heavy crude oil was studied. The donating (dehydrogenation) capacity and conversion of decalin in presence of nickel-based catalyst (nickel (II) stearate) were evaluated. In addition, the changes in composition of dehydrogenated products, release and consumption of hydrogen during decalin dehydrogenation in presence and absence of Ni-stearate and heavy crude oil were studied. All of the upgrading and dehydrogenation experiments were carried out at 300 °C, 72 bar (1044.27 psi) and 24 h of reaction time. The upgrading of heavy crude oil in presence of decalin and Ni-stearate exhibited a good performance for conversion of decalin as well as for promoting the in-situ upgrading of heavy crude oil. The maximum decalin conversion level was found to be 21.95% in the presence heavy crude oil, water and nickel stearate. Ni-stearate was mainly in-situ transformed into particles of NiO and Ni3S2, which took the role of active phases for catalyzing the dehydrogenation of decalin and promoting heavy crude oil upgrading. The use of decalin as a hydrogen-donor together with catalyst resulted in high viscosity reduction (69.2%), increase of saturates content (especially low molecule weight alkanes C10-C20), decrease of resins and asphaltenes content, and removal of sulfur and nitrogen.

Rheological modeling and drag reduction studies of Indian heavy crude oil in presence of novel surfactant

ABSTRACTViscosity and rheology modeling of heavy crude oil were studied at different shear rate and temperature with and without naturally extracted surfactant Mahua. Drag reduction analysis was done in 2”-ID, 2.5 m horizontal pipeline at different temperatures and flow rates. Viscosity was reduced by 60.4% after addition of 1000 ppm Mahua at 50°C. Modeling analysis showed that crude oil-surfactant samples followed Power law model with high regression coefficients. Maximum drag reduction of 94.8% occurred after adding 2000 ppm Mahua to 85% heavy oil+15% water at 40°C and at a flow rate of 50 LPM.

Emulsions with heavy crude oil in presence of nanoparticles

A study about the use of silica nanoparticles in crude oils from the Castilla field and the effects on stability, drop size and emulsion viscosity was carried out. The interest in the use of this type of nanoparticles is created by the inversion effect that these produce in the W/O emulsion at high water cuts upper than 48%. The emulsion is transformed in W/O/W being the latter the least viscous due to the water is the external phase and it allows to the crude oil slides easily on any surface. In this study, two types of naturally emulsified crude oil with different water cuts and a synthetic emulsion were used. This kind of behavior created by nanoparticles over the emulsion could be an alternative solution to the viscosity, fluidity and mobility problems that affect the extraction and transportation in heavy crude oil.

Dispersed Systems in Heavy Crude Oils

Due to very large reserves, heavy crude oils represent an important challenge for the oil industry. Their production has to handle very viscous hydrocarbons and involves the use of advanced methods such as cold production or steam injection. Cold production is faced with the foamy oil phenomenon: while extracted, a heavy crude oil is submitted to a depletion that can induce the formation of dispersed gas bubbles and makes it appear as a foam. With steam injection, water is invariably produced and emulsions may be formed. These two situations show how heavy crude oils are concerned with dispersed systems. The aim of the article is to evaluate the impact of this dispersed phase, either bubbles or droplets, on the flow properties of heavy crude oils. To do so, measurements have been carried out with a controlled stress rheometer under pressure and temperature. Live samples were obtained by recombining a stock tank oil with methane inside the pressure cell of the rheometer. The first part of the article is dedicated to the foamy oil phenomenon. It demonstrates that contrary to spherical bubbles, deformed bubbles can give rise to significant viscosity reduction, which is governed by the capillary number. The second part deals with water-in-oil emulsions. Again, experimental results show that dispersed droplets increase viscosity unless they get sufficiently elongated by the applied shear rate. The last part of the article is particularly original as it studies some rheological experiments of heavy crude oils in presence of both gas bubbles and water droplets. It investigates to what extent the presence of water influences the bubbly characteristics of live heavy crude oils. The experimental work suggests that for optimum design and operations, it is essential to determine oilfield viscosities i.e. under pressure and temperature on live and changing dispersed systems.