Extra-heavy Crude Oil Research Articles

Upgrading heavy and extra-heavy crude oil for transportation by use an iron oil-soluble catalyst

ABSTRACTHeavy or extra-heavy crude oil has difficulty in transportation, especially for off shore. Catalytic upgrade treatment with iron oil-soluble catalyst (FASFe) was used in this paper to reduce crude oil's viscosity and meet the transport demand. After optimization of reaction conditions and without hydrogen donor added, both NB35-2B43 (from Bohai offshore oilfield) and LD16-1-3 (from Liaohe oilfield) reduced their viscosities from 2,167 mPa·s and 20,600 mPa·s to 279 mPa·s and 396 mPa·s, respectively. With determinations of analyzation, it was proved that FASFe catalyst can effectively upgrade the heavy oil. Meanwhile, the mechanism of upgrading was also investigated.

Effect of SiO2-based nanofluids in the reduction of naphtha consumption for heavy and extra-heavy oils transport: Economic impacts on the Colombian market

The main objective of this study is twofold. First, we evaluate the effect of nanofluids as additives to optimize the transport of heavy crude oil using steady-state rheological measurements and dynamic flow tests. The use of these additives produces viscosity reduction for heavy (HO) and extra heavy (EHO) crude oils. Second, we show how the addition of nanofluids can lead to significant economic and environmental impacts in Colombia as a country and possibly the region through optimization in the use of naphtha for transportation. Four nanofluids were prepared using different solvents and fumed silica nanoparticles. Mixtures of nanofluids with naphtha were prepared to reduce the viscosity of the crude oil as to attain mobility targets (400–500cP at 311K). To this end, 27% and 63% v/v of naphtha were required for heavy and extra-heavy crude oils, respectively. Through steady-state rheological measurements and dynamic flow tests in a pipeline, we found that the best performing material turned out to be the nanofluid composed of 1000mg/L of SiO2 and biodiesel without surfactant. This nanofluid yielded a reduction in the consumption of naphtha of approximately 50% v/v. Our results show that the best-performing nanofluid can serve as an optimizing agent for the transport conditions of heavy and extra-heavy crude. The proposed technology was evaluated through a preliminary economic analysis that shows a potential reduction of dilution costs of almost 50%, equivalent to more than USD $2.5million per day, as well as a decreased energy consumption associated with pumping of 37%, able of generating savings of more than USD $2million per year. Additionally, a discussion on environmental impacts are presented, and the advantages of reducing naphtha consumption are discussed. A nanofluid-based technology could generate savings in both energy and fuel consumptions for the oil and gas industry and resolve national or regional issues constrained by limited access to diluent.

Viscosity reduction of extra heavy crude oil by magnetite nanoparticle-based ferrofluids

The main objective of this work is to synthesize and evaluate magnetite (Fe3O4) nanoparticle-based ferrofluids for reducing the viscosity of an extra heavy crude oil. The carrier fluid of the nanoparticles was synthesized using an engine lubricant recycled from the automotive industry and hexadecyltrimethylammonium bromide as a surfactant. Fe3O4 nanoparticles were synthesized by coprecipitation method. The effect of the concentration of nanoparticles in the viscosity reduction degree was determined for dosages between 0 and 50,000 mg/L. Different dosages of carrier fluid were evaluated between 0 and 10% v/v. The effects of the amount of brine emulsified, temperature, time, and shear rate were assessed. Overall, the results showed that viscosity and shear stress of extra heavy crude oil could be reduced up to 81 and 78% in the presence of ferrofluid, respectively. The rheological behavior of extra heavy crude oil in the presence and absence of ferrofluid was assessed by Cross, Ostwald-de Waele, and Herschel-Bulkley models.

Anomalous Heavy-Oil Rheological Thinning Behavior upon Addition of Nanoparticles: Departure from Einstein’s Theory

Heavy and extra-heavy oils generally exhibit high viscosity, which is detrimental to their production, transport, and refining. The oil & gas industry has thoroughly investigated the use of chemical agents to improve the mobility of these types of low-quality crude oils at the surface as well as under reservoir conditions for many years. In this sense, the main objective of this paper is to provide unexpected experimental evidence of heavy oil and extra-heavy crude oils viscosity reduction resulting from the presence of nanoparticles (NPs) of different chemical natures (SiO2, Fe3O4, and Al2O3), particle size, surface acidity, and concentration at low-volume fractions. The viscosity of the enhanced fluids was measured using a rotational rheometer at shear rates varying between 1 and 75 s−1. Upon addition of NPs, viscosity reduction was observed in all cases evaluated. The maximum viscosity reduction of roughly 52% was obtained at a concentration of 1000 mg/L with 7 nm SiO2 NPs at low shear rate, below 10 s−1, contrary to expectations from Einstein’s viscosity theory in particulate systems. A mathematical model based on a modification to the Pal and Rhodes Model for the viscosity of suspensions is proposed in this work. The said model was validated successfully using experimental data, as evidenced by RSME% values lower than 10%. The importance of our findings lies in the lack of previous experimental and theoretical data in the open literature showing heavy crude oils viscosity reduction in the presence of NPs.

Two phase flow in a wavy core-annular configuration through a vertical pipe: Analytical model for pressure drop in upward flow

The vertical core-annular flow of two immiscible fluids with very different viscosities provides an attractive and low cost method for heavy and extra heavy crude oils lifting in vertical wells using water as a lubricant. Since the pressure gradient are balanced by wall-shear stresses in the water, the correspondent pressure drop is comparable to the flow of water only in the same pipe at the total volumetric flow rate since the oil tends to occupy the center of the tube and it does not come in contact with the pipe wall. Assuming that in this axisymmetric wavy flow the fluid in the center is much thicker than the annulus, a differential equation governing the velocity profile and then pressure gradient in the annulus is derived by using scaling analysis. An analytical solution is proposed for the prediction of the frictional pressure drop, which depends only on pipe geometry, physical properties and flow rates of the fluids. The comparison between the model predictions and recent experimental data shows a good agreement and great enhancement from “perfect core annular flow” model (PCAF). In the PCAF model the two Newtonian immiscible fluids flow axially inside a vertical pipe in a concentric configuration with a smooth circular interface.

A Study of the Effect of Surfactants on the Aggregation Behavior of Crude Oil Aqueous Dispersions through Steady-State Fluorescence Spectrometry.

Unconventional crude oil as heavy, extra heavy, bitumen, tight, and shale oils will meet 10% of worldwide needs for 2035, perhaps earlier. Petroleum companies will face problems concerning crude oil extraction, production, transport, and refining, and some of these are addressed by the use of surfactants and other chemicals. For example, water-in-crude oil emulsions are frequently found during the production of mature wells where enhanced recovery techniques have been deployed. Nevertheless, the selection of adequate surfactant, dosage, type of water (sea, tap or oilfield), kind of crude oil (light, heavy, extra heavy, tight, shale, bitumen) affect the effectivity of treatment and usual bottle tests give limited information. We developed a fluorescence technique to study the effect of surfactants on medium, heavy, and extra heavy crude oil employing the natural fluorophore molecules from petroleum. We first carried out the characterization of commercial and synthetic surfactants, then dispersions of petroleum in water were studied by steady-state fluorometry and the size of petroleum aggregates were measured. The aggregation of petroleum incremented from medium to extra heavy crude oil and we discussed the effect of different surfactants on such aggregation.

Analysis of the effects of copper nanoparticles on in-situ combustion of extra heavy-crude oil

Catalyzed in-situ combustion of extra heavy crude-oil was studied. The effects of copper nanoparticles (Cu-NP) on combustion were quantified by measuring crude-oil oxidation kinetics and elucidated by capturing front and fuel deposition behavior. Ramped temperature oxidation experiments, coupled with isoconversional analysis, helped measure reaction kinetics. Improvement in the rate of combustion was seen when the nanoparticles were present at a concentration of 1000ppm in the aqueous phase. Chiefly, the apparent activation energy of the high-temperature oxidation region decreased. Cu-NP also serve as a reaction inhibitor of low-temperature oxidation (LTO), which is of interest because LTO reactions increase the viscosity of the virgin oil downstream of the combustion front. As a result of this, the alteration of LTO reactions, and the change in fuel formation, the presence of Cu-NP help maintain a greater front temperature. Thermogravimetric analysis shows that the oxidation behavior of the nanoparticles, namely the change of surface and bulk oxidation state, determines the rate and temperature that low-temperature oxidation and high-temperature oxidation occur for the median particle size distribution. Finally, potentiometric titration of the produced fluids shows that Cu-NP change the type of oil produced and decrease the amount of water created during the process.

Experimental and Theoretical Study of Viscosity Reduction in Heavy Crude Oils by Addition of Nanoparticles

Heavy and extra-heavy oils generally exhibit high viscosity, which is detrimental to their production, transport, and refining. The oil and gas industry has thoroughly investigated the use of chemical agents to improve the mobility of this type of low-quality crude oil at the surface as well as reservoir conditions for many years. In this sense, the main objective of this paper is to provide unexpected experimental evidence of heavy oil and extra-heavy crude oils viscosity reduction resulting from the presence of nanoparticles (NPs) of different chemical natures (SiO2, Fe3O4, and Al2O3), particle size, surface acidity, and concentration at low-volume fractions. The viscosity of the enhanced fluids was measured using a rotational rheometer at shear rates varying between 1 and 75 s–1. Upon addition of nanoparticles, viscosity reduction was observed in all cases evaluated. However, the maximum viscosity reduction of roughly 52% was obtained at a concentration of 1000 mg/L with 7 nm SiO2 nanoparticles at shea...

Effect of reaction temperature and hydrogen donor on the Ni0@graphene-catalyzed viscosity reduction of extra heavy crude oil

ABSTRACTNi0@graphene nanocomposites were prepared via a solvothermal method and used as the catalysts for the viscosity reduction of extra heavy crude oil. Higher graphene content in Ni0@graphene nanocomposite has an adverse effect on its catalytic activity. The addition of tetralin and higher reaction temperature can obviously promote the catalytic activity. The catalyst accompanied by hydrogen donor can attain a viscosity reduction rate of 84.3% after the catalytic reaction under 280°C for 24 h and reduce the viscosity of crude oil from 174,219 to 27,352 mPa s (measured at 50°C).

Extraction induced by emulsion breaking for the determination of As, Co, Cr, Mn, Mo and Pb in heavy and extra-heavy crude oil samples by ICP-MS

A novel method based on extraction induced by emulsion breaking was performed for determination of metals in crude oil samples by ICP-MS.

Flow structure and pressure gradient of extra heavy crude oil-water two-phase flow

The flow structure and pressure gradient of extra heavy crude oil (viscosity=11232.8mPa·s at 50°C) and water two-phase flow were studied in a horizontal flow loop with 25.8mm inner diameter and overall length of 30.8m. With the help of high-speed photography, local sampling and pressure gradient testing, six different flow patterns were identified. A new flow pattern—discrete water-in-oil emulsion and water annular flow (Ew/o&w dispersion-annular flow)—was found at high water fractions and high mixture velocities. The size distribution of water droplets in Ew/o flow and the periodic characteristics of Ew/o&w intermittent flow were analyzed in detail. Relative pressure gradient was introduced to characterize the oil-water two-phase flow. The pressure gradients of water dominated flow are two orders of magnitude lower than that of oil dominated flow. The water fraction and temperature have little effect on the pressure gradient of water dominated flow, particularly in annular flow. The water dominated flow should be given priority to when it comes to the transportation of extra heavy crude oil and water. The results establish a theoretical basis for water-lubricated transport of extra heavy crude oil.

Required Viscosity Values To Ensure Proper Transportation of Crude Oil by Pipeline

Transportation of crude oils has recently received more attention than in the past; the main reason for this is because of the changes that petroleum production has experienced. The increasing availability of heavy and extra-heavy crude oil and the depletion of the production of light crude oil have motivated the midstream oil sector to search for methods to reduce the viscosity to values that ensure the transportation of crude oils by pipeline. The target for viscosity varies according to the type of crude oil and the region where it is transported. In order to define and propose a range of viscosity, the different reports in the literature were reviewed and it was concluded that the maximum value of viscosity to allow crude oil transportation ranges between 250 and 400 cSt at 37.8 °C.

Effect ­­­­­of ultrasonic irradiation treatment on rheological behaviour of extra heavy crude oil: A solution method for transportation improvement

AbstractThe highly viscous property of heavy oil often causes problems in its transportation in pipelines. Mixing heavy oil with light oil as well as ultrasound treatment are viable solutions to this problem. In this study, extra heavy crude oil samples were first diluted with 0, 0.05, 0.1, and 0.15 mL/mL (0, 5, 10, and 15 vol%) of a light crude oil; then the mixture was irradiated by ultrasonic waves for 0, 5, 10, 15, and 20 min; finally the viscous shear functions of all mixtures was measured at different values of shear rate at different temperature levels. The results revealed that the minimum viscosity of the diluted extra heavy crude oil samples was obtained at 10 min of ultrasonic irradiation. Moreover, the viscosity reduction rate in relation to temperature decreases as temperature increases. In other words, the maximum viscosity reduction rate occurred at 0.05 mL/mL (5 vol%) of light crude oil. Using the experimental data, the parameters of common rheological models were obtained and a new modified Power Law model was presented to calculate the effect of shear rate and temperature simultaneously.

Synthesis of porous carbon from petroleum coke using steam, potassium and sodium: Combining treatments to create mesoporosity

Bitumen upgrading involves the hydroconversion of larger molecules that require catalyst supports with meso- and/or macropores for access to the active sites. In this study, various activation processes were studied to activate delayed petroleum coke, which is a by-product of oil sands bitumen upgrading and an inexpensive source of carbon. The petroleum coke was subjected to steam, chemical (KOH, NaOH) and combined activation methods at 973 K and 1073 K. The produced materials were characterized with nitrogen physisorption at 77 K and scanning electron microscopy. Combined with the yields, the results suggested that the combination of steam with sodium or potassium increased the mesoporosity of the carbon samples possibly by a catalytic gasification mechanism. A mesopore volume of 0.39 cm3/g with a yield of 27% was achieved by simultaneously activating with sodium and steam. Washing the material after activation with sodium and before introducing steam produced the same mesoporosity but doubled the yield, confirming that steam alone is not effective at creating porosity. The accessibility of the larger pores was confirmed with the adsorption of asphaltenes from Athabasca extra-heavy crude oil. The capacity for asphaltene adsorption increased with increasing mesopore volume.

Comparative thermal study of heavy crude oils by DSC

ABSTRACTCrude oil represented 50% of primary energy consumption in the world at the beginning of this decade. For each reservoir existent of conventional petroleum or gas there is three times the amount of heavy crude oil in the planet. The present work investigates the thermal behavior of three heavy crude oils from Brazilian basins. It was possible to make an interesting comparison for the same petroleum due to the use of different DSC equipment, especially for the extra heavy crude oils. The petroleum sample with the lowest °API exhibited the highest value for specific heat capacity between all studied samples.

Correction to Aromatic Polyisobutylene Succinimides as Viscosity Reducers with Asphaltene Dispersion Capability for Heavy and Extra-Heavy Crude Oils

Correction to Aromatic Polyisobutylene Succinimides as Viscosity Reducers with Asphaltene Dispersion Capability for Heavy and Extra-Heavy Crude Oils

Relative performance of several surfactants used for heavy crude oil emulsions as studied by AFM and force spectroscopy

Abstract Through force spectroscopy, we use an atomic force microscope (AFM) to compare the forces between two extra heavy crude oil (EHCO) droplets. This is done in various aqueous environments in order to compare said forces in the presence of a variety of surfactants and ionic species. A crude oil droplet is attached to the AFM cantilever and pressed against other droplets placed on a substrate. Differences in the behavior of the forces as a function of surfactant chemistry, concentration and the velocity of the approach and retract of the droplets are observed for droplets with a range of diameters 10

Study of the formation and breaking of extra-heavy-crude-oil-in-water emulsions—A proposed strategy for transporting extra heavy crude oils

At present, many petroleum copmpanies in the world are facing processing problems about crude oil extraction, production and refining. For example, conventional pipelines are not suitable for pipelining of extra heavy oils and bitumen from the reservoirs to the refineries. According to the aforesaid, a procedure was developed for the formation of an oil-in-water emulsion employing a Mexican crude oil and its subsequent phase separation as a strategy for the pipelining of extra heavy crude oils. An O/W emulsion considerably decrease the viscosity of an extra heavy crude oil and facilitating its transport through pipelines, but crude oil must be dehydrated before further processing. We carried out a screening of commercial and synthetic surfactants for emulsion preparation as well as for breakage. The emulsion was characterized by calorimetry, optical techniques, particle size and dynamic viscosity. The stability of emulsions was evaluated by the kinetics of water separation in the presence of surfactants and heating. We also developed a factorial 2k design to study emulsion breakage with factors such as temperature, surfactant concentration and pH. All surfactants developed by ours are low toxic and full biodegradable since they atre synthesized from glucose and glycine, respectively. Thus, we developed an environmental friendly approach to facilitate crude oil transport through pipelines.

Synthesis of silica/metatitanic acid nanocomposite and evaluation of its catalytic performance for aquathermolysis reaction of extra-heavy crude oil

A lipophilic silica/metatitantic acid (denoted as SiO2/H2TiO3) nanocomposite was synthesized by hydrothermal reaction with surface-modified SiO2 as the lipophilic carrier. As-synthesized SiO2/H2TiO3 nanocomposite was used as a catalyst to promote the aquathermolysis reaction of extra-heavy crude oil thereby facilitating the recovering from the deep reservoirs at lowered temperature. The catalytic performance of the as-synthesized SiO2/H2TiO3 catalyst for the aquathermolysis reaction of the heavy oil at a moderate temperature of 150 °C was evaluated in relation to the structural characterizations by TEM, FTIR, XRD and FESEM as well as the determination of the specific surface area by N2 adsorption–desorption method. Findings indicate that as-synthesized SiO2/H2TiO3 nanocomposite exhibits an average size of about 20 nm as well as good lipophilicity and dispersibility in various organic solvents; and it shows good catalytic performance for the aquathermolysis reaction of the extra-heavy oil extracted from Shengli Oilfield of China. Namely, the as-synthesized SiO2/H2TiO3 catalyst is capable of significantly reducing the viscosity of the tested heavy oil from 58,000 cP to 16,000 cP (referring to a viscosity reduction rate of 72.41%) at a mass fraction of 0.5%, a reaction temperature of 150 °C and a reaction time of 36 h, showing potential application in downhole upgrading heavy crude oils.

Predicción de variables operacionales en el proceso de Producción de Crudos por Segregación Gravitacional Asistida por Vapor (SAGD)

(Recibido: 2015/04/16 - Aceptado: 2015/05/29)Este trabajo presenta las variables de yacimiento y operacionales que influyen en la implementación del proceso de Segregación Gravitacional Asistida por Vapor (SAGD) para la Producción de Crudos Pesados y Extra-pesados. Este proceso consiste en la perforación de dos pozos horizontales paralelos, uno por encima del otro, donde el pozo superior es usado para inyectar vapor y el pozo inferior es usado como productor. La eficiencia del proceso se ve altamente afectada por los parámetros del yacimiento y por los parámetros operacionales (espaciamiento vertical de los pozos, presión de inyección, período de precalentamiento, entre otros). Además, se determinó de manera teórica la predicción de la tasa máxima de extracción de petróleo, mediante un ejemplo aplicativo utilizando datos reales que se disponen actualmente del Campo Pungarayacu - Bloque 20, a nivel de yacimiento.