Synthetic Crude Oil Research Articles

Application of the Avrami Theory for Wax Crystallisation of Synthetic Crude Oil

Wax crystallisation and deposition from offshore reservoirs have been causing serious problems such as plugged pipelines and reduced production flow rates. This issue is receiving more attention from the researchers and for commercial applications due to the shift in trend from using offshore production facilities to pipelines utilization. The aim of this study is the implementation of the Avrami theory to comprehend the mechanism of wax crystallisation to reveal the morphology of wax crystal using gravimetric and differential scanning calorimetry (DSC) analyses. The experiment values obtained from the Avrami’s theory for both gravimetric and DSC techniques shows that the crystals were one-dimensional with rod-like structures.

Investigation on the Tribological Behaviour of Modified Jatropha Oil with Hexagonal Boron Nitride Particles as a Metalworking Fluid for Machining Process

Bio-based oil from vegetable oils was recently explored as an alternative solution to petroleum-based oil. However, the application of vegetable oils as metalworking fluids (MWFs) for machining process is still not widespread. The objective of this study was to investigate the tribological behaviour of modified vegetable oils, in comparison with synthetic ester (SE) and crude jatropha oil (CJO). In this study, the CJO was chemically modified via transesterification process to develop modified jatropha oil (MJO5). MJO5 was then blended with the hexagonal boron nitride (hBN) particles at various concentrations ranging between 0.05 to 0.5wt.%. The friction and wear test was performed using four ball tribotester. An experiment on orthogonal cutting process was carried out to evaluate the machining performances in terms of cutting force, cutting temperature, chip thickness and tool-chip contact length. The results reveal that the mixture of 0.05wt.% of hBN particles in the MJO5-based oil (MJO5a) outperformed the SE in terms of friction and wear. MJO5a showed excellent machining performances by reducing the machining force and temperature, which related to the formation of thinner chips and small tool-chip contact length. MJO5a is the best substitute to SE as sustainable MWFs in the machining operation with regards to the environmental and health concern.

Evaluation of Variability in Greenhouse Gas Intensity of Canadian Oil Sands Surface Mining and Upgrading Operations.

We present a statistically enhanced version of the GreenHouse gas emissions of current Oil Sands Technologies model that facilitates characterization of variability of greenhouse gas (GHG) emissions associated with mining and upgrading of bitumen from Canadian oil sands. Over 30 years of publicly available project-specific operating data are employed as inputs, enabling Monte Carlo simulation of individual projects and the entire industry, for individual years and project life cycles. We estimate that median lifetime GHG intensities range from 89 to 137 kg CO2eq/bbl synthetic crude oil (SCO) for projects that employ upgrading. The only project producing dilbit that goes directly to a refinery has a median lifetime GHG intensity of 51 kg CO2eq/bbl dilbit. As SCO and dilbit are distinct products with different downstream processing energy requirements, a life cycle assessment ("well to wheel") is needed to properly compare them. Projects do not reach steady-state in terms of median GHG intensity. Projects with broader distributions of annual GHG intensities and higher median values are linked to specific events (e.g., project expansions). An implication for policymakers is that no specific technology or operating factor can be directly linked to GHG intensity and no particular project or year of operation can be seen as representative of the industry or production technology.

Bitumen partial upgrading by mild hydroprocessing in a fixed-bed reactor

Partial upgrading is an approach to processing Canadian oil sands bitumen with the objective to produce a synthetic crude oil that meets specifications for pipeline transportation (API Gravity of 19° and viscosity of 350 cSt at 7 °C). Most partial upgrading technologies under development rely predominantly on thermal conversion processes combined with additional steps such as solvent deasphalting. Owing to the chemistry of thermal conversion, the liquid product resulting from this route tends to be unstable and susceptible to potential operational issues in pipeline transportation and subsequent refining. Hydroprocessing represents another pathway for bitumen partial upgrading, with the advantage of being able to minimize product instability concerns and achieve the target product quality. The objective of this study was to evaluate the feasibility of using mild hydroprocessing in a fixed-bed reactor for the partial upgrading of Canadian bitumen. Experiments were conducted in a pilot plant that underwent various modifications to handle raw bitumen. Systematic tests at different operating conditions were completed in a time period of 1394 catalyst hours without experiencing any plugging issues. It was demonstrated that stable and pipeline-ready product can be produced at residue conversions of 52.4 wt% or above and with a hydrogen consumption level of about 1005 scf/bbl. Future research must be directed at optimizing the process to reduce hydrogen consumption and investigating catalyst deactivation patterns.

Study of AISI/SAE-1020 Steel Corrosion by Sulfidation from Synthetic Sulfur Compounds of Different Molecular Structures

In recent years, the petrochemical industry has been affected by the decrease in global reserves of light crude oil, which has led to increase the processing of heavy crude oils with higher concentration of different contaminants that intensify corrosive phenomena. One of corrosion types that occur most frequently in the processing of heavy crude oils is sulfidation, which is caused by organic sulfur compounds of different molecular structures such as: mercaptans, sulfides, disulfides, polysulfides and thiophenes. These organic sulfur compounds are thermally decomposed at operating conditions of atmospheric distillation towers to generate hydrogen sulfide (H2S), which reacts with the steels used in different refinery equipment, resulting in the formation of iron sulfides layers on the material surface. However, morphological properties of the iron sulfides layers formed depend on the molecular structure of the organic sulfur compounds commonly present in heavy crude oils. For this reason, in the present investigation the effect of molecular structure of different sulfur compounds on the morphological properties of corrosion products obtained by the sulfidation of AISI/SAE-1020 steel is determined. The tests are carried out using three different synthetic crude oils (SCO) prepared from a mineral oil matrix mixed with the corresponding sulfur compound: Dimethyl Sulfide, Dimethyl Disulfide and Ethanethiol. The exposure times used for the gravimetric tests were 24, 36, 48, 60 and 72 h at a constant temperature of 300 °C. Discontinuous gravimetric tests are carried out in a batch static autoclave using synthetic crude oils (SCO) with total sulfur content equal to 1 %wt. Morphological characterization of the corrosion products formed on the surface of AISI/SAE-1020 steel was carried out using the techniques Scanning Electron Microscopy (SEM), in combination with Energy-dispersive X-Ray Spectroscopy (EDS), and X-Ray Diffraction (XRD). The effect of the molecular structure of sulfur compounds on the morphological properties of iron sulfides formed on AISI/SAE-1020 steel is of great interest for the petrochemical industry due to the use of a heavy crude oil contaminant for the formation of an organic coating on the steel surface, which can inhibit corrosion by other contaminants present in the crude oil.

Reprint of: Expansion development planning of thermocracking-based bitumen upgrading plant under uncertainty

Expansion development of upgrading plants is an important decision to make for the oil sands industry. In this paper, we propose a multistage stochastic expansion development method to tackle uncertain synthetic crude oil (SCO) and CO2 tax prices. The linear decision rule based technique is applied to solve the proposed stochastic optimization model. Various analyses are conducted based on optimization results: (i) effects of the uncertainty set size, (ii) comparison of solutions for selected pessimistic, realistic, and optimistic scenarios, (iii) effects of different operating modes for an upgrading plant, and (iv) cost distribution. Results of this work demonstrate that the stochastic model provides a more flexible, economical, and robust solution compared to the deterministic solution. In addition, the CO2 tax price affects the optimal solution negligibly compared to the SCO price. Finally, expansion development of the studied upgrading plant is economically beneficial even at the current market state.

The development of a techno-economic model for the extraction, transportation, upgrading, and shipping of Canadian oil sands products to the Asia-Pacific region

The diversification of Canadian oil sands markets is imperative for the long-term economic growth of oil sands products. To ensure a competitive place in the global market, supply chain costs of oil sands must be as low as possible. This study conducts a comparative techno-economic analysis of potential pathways for the transportation of Canadian oil sands products (synthetic crude oil and diluted bitumen) to seaport destinations in the Asia-Pacific region. We developed data-intensive techno-economic models to estimate total supply chain costs from the production site in Alberta to ports in China, Japan, and India. Four pathways were developed using production (steam assisted gravity drainage), transportation (production-upgrader-port in Vancouver), upgrading, and shipping operations. A sensitivity analysis was conducted to identify cost ranges with their occurrence probability measures and evaluate the effect of key parameters for each stage of operation. Supply chain costs (C$ per barrel of bitumen) to China, Japan, and India are from 61–87, 60–86, and 62–90, respectively. Overall supply chain costs of dilbit (a blend of bitumen and diluent) and synthetic crude oil (SCO) are affected most by production and upgrading costs. The production and upgrading costs are influenced by capital cost, while pipeline lifetime and capacity highly impact transportation (pipeline) and shipping costs, respectively. The developed models can be used to predict total supply chain costs of different pathways in Canadian oil sand markets.

Effects of asphaltene, resin and crude oil type on the interfacial tension of crude oil/brine solution

In recent years, the behavior of crude oil interfacial tension (IFT) as a function of salt concentration have been investigated. The results found in literature are highly controversial, thus the current experimental study aimed to clarify the reasons behind this by developing a methodology based on extracting asphaltene and resin from three different crude oils and performing elemental analysis on them. In addition, the effect of salinity on the IFT of three studied crude oil was compared with the synthetic crude oil consisted of different weight percent (wt%) of asphaltene and resin in toluene. The obtained results revealed that the IFT of crude oil as a function of salinity depended not only on the wt% of asphaltene and resin fractions but also on the aromaticity of asphaltene and resin. In fact, as the aromaticity of asphaltene increased, the performance of asphaltene decreased as a function of salinity while the aromaticity of resin led to a revers trend on IFT variation.

Experimental and predictive PC-SAFT modeling results for density and isothermal compressibility for two crude oil samples at elevated temperatures and pressures

Rapid growth in world oil demand is driving the oil and gas industry to search for petroleum in deep wells where elevated temperatures and pressures prevail. Accurate knowledge of thermodynamic properties such as density and isothermal compressibility at in-situ conditions is necessary to estimate the recoverable oil from these deep reservoirs. Yet, crude oil density data in the open literature for pressures exceeding 155 MPa are scarce or nonexistent.In this study, we present density data for two Gulf of Mexico crude oils at pressures from 3 to 276 MPa and temperatures up to 523 K. Measurements on the liquid fraction of the crude oil were made along three isotherms at temperatures T = (323, 423, and 523) K and at pressures from near-ambient platform to ultra-deep reservoir conditions. The liquid fraction of the crude oils or “dead” oils contained numerous components including alkanes, branched-alkanes, cyclo-alkanes, aromatics, resins, and asphaltenes. For simplicity, the composition of each dead oil was represented as three pseudocomponents - saturates, aromatics and resins, and asphaltenes. Methane gas at two concentrations (5 and 10 wt%) was added to the dead oils to obtain synthetic live crude oils. Experimental density data for the two live oil samples are also reported at four isotherms and similar pressure conditions. The uncertainty in the reported densty data is less than ±1%. A Tait relationship was used to correlate the measured density data; from this relationship, a reference value for isothermal compressibility was obtained. The present density and isothermal compressibility data have been compared with predictions from the Perturbed Chain version of the Statistical Associating Fluid Theory (PC-SAFT) without the use of any fitting parameters. A special set of new PC-SAFT parameters accurate for one-phase calculations at high-pressure, high-temperature conditions was used; these parameters were predicted with a knowledge of the measured aromaticity of the oil under investigation. Oil density values were predicted to within 1–4% of experimental values on average, and isothermal compressibility values were within 1–10% on average.

Expansion development planning of thermocracking-based bitumen upgrading plant under uncertainty

Expansion development of upgrading plants is an important decision to make for the oil sands industry. In this paper, we propose a multistage stochastic expansion development method to tackle uncertain synthetic crude oil (SCO) and CO2 tax prices. The linear decision rule based technique is applied to solve the proposed stochastic optimization model. Various analyses are conducted based on optimization results: (i) effects of the uncertainty set size, (ii) comparison of solutions for selected pessimistic, realistic, and optimistic scenarios, (iii) effects of different operating modes for an upgrading plant, and (iv) cost distribution. Results of this work demonstrate that the stochastic model provides a more flexible, economical, and robust solution compared to the deterministic solution. In addition, the CO2 tax price affects the optimal solution negligibly compared to the SCO price. Finally, expansion development of the studied upgrading plant is economically beneficial even at the current market state.

Predicting the weathering of fuel and oil spills: A diffusion-limited evaporation model

The majority of the evaporation models currently available in the literature for the prediction of oil spill weathering do not take into account diffusion-limited mass transport and the formation of a concentration gradient in the oil phase. The altered surface concentration of the spill caused by diffusion-limited transport leads to a slower evaporation rate compared to the predictions of diffusion-agnostic evaporation models. The model presented in this study incorporates a diffusive layer in the oil phase and predicts the diffusion-limited evaporation rate. The information required is the composition of the fluid from gas chromatography or alternatively the distillation data. If the density or a single viscosity measurement is available the accuracy of the predictions is higher. Environmental conditions such as water temperature, air pressure and wind velocity are taken into account. The model was tested with synthetic mixtures, petroleum fuels and crude oils with initial viscosities ranging from 2 to 13,000 cSt. The tested temperatures varied from 0 °C to 23.4 °C and wind velocities from 0.3 to 3.8 m/s. The average absolute deviation (AAD) of the diffusion-limited model ranged between 1.62% and 24.87%. In comparison, the AAD of a diffusion-agnostic model ranged between 2.34% and 136.62% against the same tested fluids.

Immobilized ionic liquids based on molybdenum- and tungsten-containing heteropoly acids: Structure and catalytic properties in thiophene oxidation

Comparative analysis of heterogeneous catalysts for the peroxide oxidation of thiophene is conducted. The catalysts are imidazole ionic liquids (ILs) containing anions of phosphomolybdic and phosphotungstic acids immobilized on mineral supports. Immobilization is implemented by the covalent bonding of an IL fragment to a silica surface or by adsorption on alumina. The catalysts are active not only in the model oxidation of thiophene in isooctane, but also in the desulfurization of a straight-run diesel fraction and the “synthetic crude oil” derived from oil shale.

Mechanistic Study of Water Droplet Coalescence and Flocculation in Diluted Bitumen Emulsions with Additives Using Microfluidics

Synthetic crude oils derived from mined oil sands processed via the Clark hot water extraction process do not meet current specifications for pipeline transport and are corrosive to upgrader equipment by virtue of the high residual water content (2–5%) and salts. Formulated chemical additives used in this process can improve the oil quality by accelerating and enhancing the separation of water from oil. The identification and selection of these formulated additives is typically based on performance data collected in field testing for each component or blend. Herein, two methods are reported to study the effect of chemical additives on the phase separation behavior of water in diluted bitumen emulsions prepared in microfluidic devices. First, water droplets in diluted bitumen were created in the presence of chemical additives and the kinetics of droplet coalescence were compared for various additives and concentrations. Second, using a custom-made device geometry, water droplets in diluted bitumen were for...

Forecasting equilibrium quantity and price on the world natural rubber market

Natural rubber on the world market has had small increases in demand and big increases in supply. Therefore, demand and supply are imbalanced and this impacts the natural rubber price of the world market causing a decline. This study aimed: (1) to develop demand and supply models to predict the world natural rubber quantity using simultaneous equations; (2) to predict all explanatory variables in the demand and supply models using the simple moving average technique; and (3) to estimate the equilibrium quantity and price for world natural rubber during 2017–2026. First, in the demand model, there was a positive relationship of the explanatory variables of world natural rubber production quantity, synthetic rubber price, percentage year of year (%YOY) of gross domestic product (GDP), and the exchange rate, while the negative relationship variable was natural rubber price. In the supply model, the positive relationship variables were natural rubber price, mature area, rainfall, and crude oil price, while the negative relationship variables were world natural rubber stock and urea price. Second, the predicted variables indicated that production, %YOY of GDP, exchange rate, amount of stock, and the mature area tended to gradually increase, while the synthetic rubber price, urea price, rainfall, and crude oil price tended to slowly decrease from 2017 to 2026. Finally, the equilibrium quantity forecast tended to gradually increase from 953.75 to 957.15 thousand tonnes, and the equilibrium price tended to fluctuate and decrease from 169.78 to 162.05 thousand yen from 2017 to 2026. Consequently, this study may be helpful to the governments of the world's important natural rubber producing countries to plan policies to reduce natural rubber production costs and stabilize the natural rubber price in the future, such as by setting suitable areas of world natural rubber plantation in each country, and defining appropriate and sustainable alternative crop areas in each country.

Analysis of oxidised heavy paraffininc products by high temperature comprehensive two-dimensional gas chromatography

Heavy petroleum fractions are produced during crude and synthetic crude oil refining processes and they need to be upgraded to useable products to increase their market value. Usually these fractions are upgraded to fuel products by hydrocracking, hydroisomerization and hydrogenation processes. These fractions are also upgraded to other high value commercial products like lubricant oils and waxes by distillation, hydrogenation, and oxidation and/or blending. Oxidation of hydrogenated heavy paraffinic fractions produces high value products that contain a variety of oxygenates and the characterization of these heavy oxygenates is very important for the control of oxidation processes. Traditionally titrimetric procedures are used to monitor oxygenate formation, however, these titrimetric procedures are tedious and lack selectivity toward specific oxygenate classes in complex matrices. Comprehensive two-dimensional gas chromatography (GC×GC) is a way of increasing peak capacity for the comprehensive analysis of complex samples. Other groups have used HT-GC×GC to extend the carbon number range attainable by GC×GC and have optimised HT-GC×GC parameters for the separation of aromatics, nitrogen-containing compounds as well as sulphur-containing compounds in heavy petroleum fractions. HT-GC×GC column combinations for the separation of oxygenates in oxidised heavy paraffinic fractions are optimised in this study. The advantages of the HT-GC×GC method in the monitoring of the oxidation reactions of heavy paraffinic fraction samples are illustrated.

Simultaneous breaking and conversion of petroleum emulsions into synthetic crude oil with low impurities

An environmentally-benign supercritical fluid route is developed to demulsify and treat highly intractable petroleum emulsions containing hazardous acidic compounds, heavy fractions, heteroatoms, and metallic impurities without using external catalysts and molecular hydrogen. The produced synthetic crude oil exhibits asphaltene-free fractions with low amounts of impurities, which could be suitable for use in current petroleum refineries. The degree of reductions of asphaltenes and non-distillate fraction are 98.5% and 94.0%, respectively. The deacidification tendency of supercritical methanol results in 90.2% reduction of total acid number. Ni, Ca, and N are removed below detection limits (0.1ppm for Ni/Ca and 0.01wt% for N). V and S are reduced with efficiency of 85.0% and 33.6%, respectively.

A techno-economic assessment of bitumen and synthetic crude oil transport (SCO) in the Canadian oil sands industry: Oil via rail or pipeline?

The growth in bitumen and synthetic crude oil (SCO) production in the Canadian oil sands industry has superseded pipeline capacity growth in recent years, leading to the increased interest in the transport of crude oil by rail to desired markets. However, the specific techno-economic parameters that facilitate increased competitiveness of either transportation mode against the other is seldom addressed in the existing literature. This paper involves the development of a rail and pipeline techno-economic transport model, which is used to ascertain the transportation cost of both options for a market distance range of 1–3000 km and a production scale of 100,000–750,000 barrels per day (bpd). The transportation cost for either option is highly sensitive to the market distance, transportation scale and crude grade being transported; however, pipelines are generally more competitive for large transportation scales, while the cost-effectiveness of rail transport is realized particularly at smaller transportation scales. In general, pipelines are cost efficient for the transportation of crude oil in the majority of scenarios investigated. Rail can be more economical than pipeline under certain conditions. The use of insulated rail cars for the transport of raw bitumen is the area with greatest potential for cost competitiveness against pipelines.

Design of Bitumen Upgrading and Utility Plant through Integrated Optimization

This paper proposes a new integrated model for simultaneous design optimization of upgrading plants in the oil sands industry and the associating utility plants. In the past, work has been mainly focused on the energy infrastructure of upgrading plants, and predesigned power and hydrogen plants were considered as utility plants. The novelty of this work is the incorporation of a detailed polygeneration energy system model with the bitumen upgrading plant model. In this way, optimal configurations can be found to meet the various energy requirements of upgrading plants in the oil sands industry. On the basis of the proposed optimization model, optimal configurations under different scenarios are discussed. Effects of upgrading plant capacity, being able to export power to the public grid, natural gas and electricity prices, and the margin between diluted bitumen and synthetic crude oil prices are studied. According to the results, the presented model is a practical tool to design the optimal upgrading plant and its utility plant for the oil sands industry.

E&P Notes (February 2017)

E&P Notes Petroleum Engineering Schools Begin To See Enrollment Declines Stephen Rassenfoss, JPT Emerging Technology Senior Editor Enrollment in US petroleum engineering programs has peaked and is on the downslide, matching the short-lived surge in the 1980s, when a generation of engineers were graduated. Lloyd Heinze, the petroleum engineering professor at Texas Tech University who compiles this annual survey, does not think the current downturn “will be as bad” as the one 3 decades ago. The big question is: Will that long trough be repeated after a decade where the industry stepped up its recruiting to hire college graduates in time for the many workers nearing retirement? That will depend on the level of industry hiring in coming years, which he said is impossible to reliably predict because hiring plans are subject to sudden changes. Four Misconceptions That Lead to Drilling Automation Failure Trent Jacobs, JPT Senior Technology Writer Drilling automation is one of the most promising emerging technologies that the oil and gas industry has to look forward to. The potential benefits span the spectrum from health and safety to lower costs and repeatable well results. But before this technology leaps from pilot to center stage, early adopters will be challenged to create new managerial strategies that improve the interaction of human crews with automated rig systems, according to one expert. “In all the projects that I have worked on, what I have found is that the issues involving people were much bigger than the technical issues,” said Bill Koederitz, chief technology officer at GK Plus Innovations, during a presentation at a recent SPE Gulf Coast Section event. Commercial GTL Project Opens in Southeast Texas Stephen Whitfield, Staff Writer Infra Technology, a company specializing in the development of synthetic fuels from natural gas, coal, and biomass, opened the first completed small-scale commercial gas-to-liquids (GTL) project in the state of Texas. Located in Wharton, a small town 60 miles southwest of Houston, the plant will produce synthetic crude oil from natural and associated gas. The Wharton plant is Infra’s first plant in the US. The company has been operating pilot plants in Russia for the past 7 years. Modularly constructed, the plant utilizes GTL technology based on the Fischer-Tropsch process, where hydro-carbons are created through a series of chemical reactions. The plant will operate in two stages. The first stage involves the production of synthesis gas (syngas) through a reformer that converts solid fuel into gaseous reactants. The technology processes feedgas with varying density, from dry methane to heavy gases. Energy Policy Uncertain in the Wake of Brexit Referendum Stephen Whitfield, Staff Writer With an uncertain future spawning from the Brexit referendum, the British government is seeking to maintain as much consistency in its energy policy as possible. A representative from the British Consulate of Houston said there will be changes to the way goods, services, and people move from the UK to the EU, and while very few concrete statements can be made about how Brexit will impact the oil and gas industry, investment in Britain’s offshore and onshore assets will be critical for the country moving forward. In a presentation hosted by the SPE Gulf Coast Section’s International Study Group, Cynthia Conner examined the potential challenges and opportunities facing the oil and gas industry in the wake of Brexit. Conner is a senior policy lead at the British Consulate of Houston and a member of the Global and Economic Policy Group at the British Embassy in Washington, DC.

Life Cycle Analysis of Bitumen Transportation to Refineries by Rail and Pipeline.

Crude oil is currently transported primarily by pipelines and rail from extraction sites to refineries around the world. This research evaluates energy use and greenhouse gas (GHG) emissions for three scenarios (synthetic crude oil and dilbit with and without diluent return) in which 750 000 bpd of Alberta's bitumen is transported 3000 km to determine which method has a lower environmental impact. Each scenario has a pipeline and rail pathway, and the dilbit without diluent return scenario has an additional heated bitumen pathway, which does not require diluent. An Excel based bottom-up model is developed using engineering first-principles to calculate mass and energy balances for each process. Results show that pipeline transportation produced between 61% and 77% fewer GHG emissions than by rail. The GHG emissions decreased by 15% and 73% for rail and pipelines as the capacity increased from 100 000 to 800 000 bpd. A Monte Carlo simulation was performed to determine the uncertainty in the emissions and found that the uncertainty was larger for pipelines (up to ±73%) and smaller for rail (up to ±28%). The uncertainty ranges do not overlap, thus confirming that pipelines have lower GHG emissions, which is important information for policy makers conducting pipeline reviews.