Polyaromatic Hydrocarbon-Based Host-Guest Complex for Heavy Oil Viscosity Reduction

Bohai is rich in heavy oil. And its efficient development is significant. In this essay, ordinary heavy oil and extra one were selected, and the viscosity characteristics was also investigated referring to its internal composition. And so as the reducing viscosity effects of steam, oil-soluble viscosity reducer, diesel, emulsifier, flue gas and carbon dioxide. The experimental results show that resin and asphaltene content have positive effect on the viscosity of heavy oil. Compared with ordinary heavy oil, the drop is significantly greater when the temperature increases by 10°C. For ordinary heavy oil, the inflection point temperature is from 50°C to 70°C, and for extra-heavy oil, it is above 100°C. For ordinary heavy oil, its flow effect can be better improved without too high temperature, while it’s totally different for super heavy oil. For which, higher temperature and other auxiliary viscosity reduction methods are needed to achieve better flow performance. Diesel oil reduce viscosity of heavy oil by similar solubility principle, but the demand for diesel oil is large. At 50°C, the viscosity of super heavy oil with 0.5% emulsion viscosity reducer added is 36 mPa·s, but the water content needs to reach above 30%.Oil-soluble viscosity reducer reduces viscosity by dissolving asphaltenes and resins and dismantling aggregate structure of heavy oil aromatic flakes.However, the dosage should reach about 20 %, so that the viscosity of super heavy oil can be reduced to the level of dilute oil. Overall, for developing super heavy oil, steam compound with oil soluble viscosity reducer can be taken into account at the early production stage, and the emulsion viscosity reducer can be used in the middle development stage and wellbore viscosity reduction and lifting process. Finally, for ordinary heavy oil, flue gas’s viscosity reduction effects, nitrogen and carbon dioxide are investigated. It is found that the viscosity reduction effect of carbon dioxide is the best, followed by flue gas and nitrogen. Considering the offshore gas source, cost and carbon emission requirements, it is recommended to use flue gas in the field. The research provides theoretical guidance and technical reference for development of different types of offshore heavy oil.

Heavy oil reservoirs embrace 70% of worldwide oil reserves. A lot of challenges face such oil production like its large viscosity which can be reduced under the action of aquathermolysis reaction. Aquathermolysis reaction is the main objective used to analysis and explain the effect of nanoparticles addition on heavy oil. Several thermal recovery techniques have been implemented using different nanometals for recovery improvement of heavy oil reservoirs and viscosity reduction. These published trials focused on nanometals but none of them addressed usage of Graphene oxide nanoparticles for such improvement of heavy oil recovery, and therefore this paper represents an experimental investigation of graphene oxide effect on heavy oil production. The present work examines graphene oxide nanoparticle in heavy oil viscosity since graphene is a superlative material that has an extraordinary thermal conductivity up to ten times value of any nanometal. In order to check its efficiency for Heavy oil recovery, several published scenarios have been executed on light oil which leads to recovery reaches 12.5 %. In our work, the concentration used for these nanoparticles is ranging from 0.01: 0.5 wt. %. The viscosity of these nanoparticles with heavy oil sample has been measured to explain the expected improvement in recovery factor. The Experimental work showed a large change in the viscosity after using nano Graphene oxide reached to 40:60% reduction in its original values. In addition to the viscosity, the effect of reservoir temperature is investigated. The range of temperature used in this study varies between 40° to 100° C. These results reflect strong indications for better viscosity reduction. Therefore, better recovery factor for this heavy oil. Meanwhile, this present research provides an investigation of aquathermolysis reaction for such materials which is the main reason for heavy oil viscosity reduction, also it represents Graphene Oxide as new nanoparticles for improving Heavy Oil Recovery that will create a new era in thermal recovery for heavy oil. Also, an economic study is investigated.

The high viscosity and low fluidity of heavy crude oil hinder its sorption by conventional porous sorbents, so the efficient clean-up of such heavy crude oil spills is challenging. Recently, Joule heating has been emerging as a new tool to reduce the viscosity of heavy crude oil dramatically. However, this direct-contact heating approach presents a potential risk due to the high voltage applied. To develop a non-contact recovery of viscous crude oil, here, a new approach for the fabrication of a series of ferrimagnetic sponges (FMSs) with hydrophobic porous channels is reported, whose surface can be remotely heated to 120 °C within 10 s under an alternating magnetic field (f= 274kHz, H= 30 kA m-1 ). Compared with the solar-driven superficial heating, the integral magnetic heating in FMSs can result in a higher internal temperature of the sponges because of the confinement of thermal transport in the porous channels, which contributes to a dramatic decrease in oil viscosity and a significant increase in oil flow into the pores of FMSs. Furthermore, FMSs assembled with a self-priming pump can achieve continuous recovery of viscous crude oil (33.05g h-1 cm-2 ) via remotely magnetic heating.

The high temperature, high pressure and high density inside a collapsed acoustic bubble are the mechanisms and the foundation of sonication in liquid. The development of acoustic cavitation in theory and in experiment is reviewed briefly from the first stage of the 20th century. The bottleneck problem of sonication in liquid on the industry scale is analyzed emphatically and up to now, it is still unsolved. In this paper, optimizing the spatial distribution of acoustic cavitation is investigated to overcome the bottleneck. The experiments show that it is feasible. Based on the experiments, an ultrasonic batch processing prototype of 10kW for reducing the viscosity of heavy crude oil is designed and developed. A pilot test is done in the oil field in the northwest of China. The pilot test shows that it can be used to reduce the viscosity of heavy crude oil for the practical production and transportation on the industrial scale. At last, the perspective of the acoustic processing is discussed.

Viscosity reduction is one of the key issues for heavy oil reservoir development and its transportation. Up to now, the mechanisms for ultrasonic viscosity reduction still remain unclear, especially for that of heavy crude oil which needs to be studied urgently. Parameters have been studied on the effect of viscosity reduction. The parameters for viscosity reduction were optimized to achieve the excellent result of viscosity reduction. Experiments show that ultrasonic irradiation leads to a substantial decrease up to 86% of the viscosity of heavy oil. As for heavy crude oil, the parameters influencing viscosity reduction are in the order of ultrasonic power output, treatment time, water cut and temperature. Ultrasonic wave has an obvious influence on quantity, magnitude, and distribution of paraffin crystals. This proves the existence of synergistic effect between ultrasonic irradiation and viscosity depressant. Ultrasonic wave has an apparent effect on viscosity reduction of heavy oil.

High viscosity is a major concern in the recovery of heavy oil and bitumen. Viscosity reduction could be achieved by mixing bitumen with solvents. Cragoe(1) and Shu(2) have developed widely used methods for liquid mixture viscosity predictions. However, in these two models, the viscosities or densities of the heavy oil/bitumen and solvents have to be known at some reference condition. Low field nuclear magnetic resonance (NMR) relaxometry is an effective, non-destructive alternative for determining the petrophysical properties of oil reservoirs. It has also been shown to successfully predict the viscosity of conventional oils, heavy oils, and mixtures of oils with solvents. In this paper, a regression model of experimental data, Cragoe(1), Shu(2), and NMR models are compared with experimental data which were obtained from four heavy oil/bitumen samples mixed with six solvents in different ratios. NMR-based predictions are found to be similar to those of the Shu(2)model and superior to the predictions of the Cragoe(1) model. Introduction Viscosity and density reduction of a heavy oil or bitumen could be achieved by mixing it with a solvent. The information about the viscosity of a heavy oil/bitumen-solvent mixture is vital for designing solvent floods and for input into reservoir simulators, both for recovery processes and reserves assessment. Several correlations have been proposed for estimating the viscosity of a mixture of liquids. Cragoe(1) and Shu(2) have developed two widely-used methods for mixture viscosity predictions. In both of the models, viscosities of the heavy oil or bitumen and solvents have to be known for prediction. Sometimes, it is hard to measure the viscosity accurately using conventional viscometers when it is too high or too low, and a conventional viscometer is not a convenient method for in situ measurements. Low field nuclear magnetic resonance (NMR) relaxometry is an effective, non-destructive alternative for determining the petrophysical properties of an oil reservoir. It was also shown to successfully predict the viscosity of conventional oils(3) and heavy oils(4). The greatest advantage of NMR is its potential to translate these density and viscosity measurements to in situ measurements, which could be implemented in a logging tool, allowing density and viscosity to be estimated without having to extract oil samples in the lab. The NMR viscosity model is especially significant for use in designing a solvent injection process for heavy oil recovery. Experimental Procedure Four oils were used in the solvent experiments(5). They were from Peace River, Cold Lake, Edam, and Atlee Buffalo, and have viscosities of 670,000 mPa's, 130,000 mPa's, 14,000 mPa's, and 6,000 mPa's, respectively, at 25 °C. Kerosene, toluene, naphtha, heptane, hexane, and pentane were added to the oils in several predefined mass fractions: 100% oil, 99%, 96%, 93%, 90%, 85%, 80%, 70%, 50%, 30%, and 0% (100% solvent). The samples were slightly heated and mixed by stirring, and the resulting solventoil mixtures were cooled. NMR spectra were measured at 25 °C using an Ecotek FTB bench top relaxometer.

Interaction between hydrophobic chitosan derivative and asphaltene in heavy oil to reduce viscosity of heavy oil

Cavitating jet technology is used to change the quality and to reduce the viscosity of heavy oil because bubble collapse can cause extreme conditions such as high pressure and temperature. The experimental study on the viscosity reduction of heavy oil using a cavitating jet was performed through a self-designed experimental system for heavy oil viscosity reduction by a cavitating jet. Tetrahydronaphthalene was used as the hydrogen donor, and after adding different amount of tetrahydronaphthalene, the viscosity change of the heavy oil was studied before and after treatment by the cavitation jet. The experimental results show that cavitating jet technology can be used to improve the quality and reduce the viscosity of heavy oil, and the addition of tetrahydronaphthalene can effectively reduce the viscosity of heavy oil. With the increase in the amount of tetrahydronaphthalene added, the viscosity reduction effect on the heavy oil improved, and the viscosity reduction rate increased. When a certain amount of tetrahydronaphthalene was added, the viscosity of the heavy oil decreased gradually and plateaued with the increase in the cycles of cavitation jet treatment. The addition of tetrahydronaphthalene can dilute the heavy oil and effectively reduce the viscosity and improve the quality of heavy oil by providing active hydrogen to close the macromolecular hydrocarbon free radicals generated by the cavitation effect.

Comparison of correlations based on API gravity for predicting viscosity of crude oils

Asphaltenes in heavy crude oil: Designation, precipitation, solutions, and effects on viscosity

Ionic-liquid-enhanced solvent extraction mechanism: A novel concept

This paper investigates the effect of the viscosity of crude oil and stress acting on buried oil pipelines inside dune sand. Due to the increase in energy demand, transportation of all hydrocarbons is obligatory. However, transportation of this oil is very tedious, owing to its viscosity. Thereby, the reduction of viscosity of oil is mandatory before transportation. This paper investigates the blending and emulsification method in the reduction of viscosity. The addition of blends naphtha and kerosene with silica nanoparticles decreases the viscosity of heavy crude oil by 80%–90%. Moreover, the introduction of the surfactant also decreases the viscosity of the oil significantly. Adding to the preceding, the problem faced by the petroleum pipelines under the ground overload is discussed in this study. The estimation of ground overload is imperative to ensure the safe operation of oil pipelines. Provided that when the ground load is raised, the stress on the pipeline enlarges considerably. On the one hand, parameters such as the Von Mises stress, plastic strain, and ovality also increased subject to a higher ground load. On the other hand, the pipe reacted to all stages and deformed to the original position due to the removal of the loads.

Heavy-oil recovery by combined geothermal energy and cosolvent/water flooding

The potential use of microorganisms to reduce heavy crude oil viscosity in situ and hence, improve recovery was investigated. Batch-flask tests, using pure cultures of selected microorganisms and indigenous microorganisms that were enriched from oil, sand and water samples taken from the reservoir, were performed under anaerobic conditions at 30°C. The use of heavy oil as a sole carbon source and, the change in oil viscosity and in carbon numbers vs. boiling point were determined. Although none of the cultures tested was able to reduce the viscosity of the heavy oil, the simulated distillation analysis revealed that pure strain of Bacillus licheniformis could increase the recovery of light-end products. The oil fraction containing carbon numbers less than C40−was increased by about 30% after 21 days of anaerobic treatment.

The main objective of this work is to synthesize and evaluate magnetite (Fe 3 O 4 ) 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. Fe 3 O 4 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.