Crude Oil Research

This page contains Abstracts of research on Crude oil done by the Transportation of Dangerous Goods Directorate.

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Abstract – Crude Oil Equation of State Final Report – October 18, 2019

More and more crude oil is being shipped by rail, and there is growing interest in understanding the risks of this kind of transport.

During a rail accident, tank cars carrying crude oil may be exposed to extreme fire temperatures for long periods of time. Because crude oil can have widely different compositions, it is hard to predict how it may behave when this happens. Another complication is that tank cars have pressure relief devices, which may allow some crude oil to escape (vent) from the tank car. Venting can change the crude oil still inside the tank car.

The Transportation of Dangerous Goods Directorate commissioned this study, which had two key objectives:

  1. To better understand how crude oil behaves in closed containers (such as tank cars) exposed to fire conditions up to 950°C. Specifically, to understand how this changes due to boiling, venting and chemical reactions.
  2. To develop a computer model that can predict crude oil properties at high temperatures, and compare its predictions to lab test results.

This work was done with CanmetENERGY, Natural Resources Canada.

Research results

  • We developed a computer model that can predict properties of various crude oils at high temperatures. This initial model was able to account for venting but not chemical reactions.
  • Building on the initial model, we added some chemical reactions to create a “reacting model.” This model could predict thermodynamic properties and crude oil composition in liquid and vapour phases, at high temperatures and pressures.
  • We tested three crude oils in a lab at high temperatures and pressures. How those crude oils behaved was very similar to what the computer model predicted.
  • Case studies with the reacting model showed that how crude oil behaves in closed containers is different when chemical reactions are added. Because of this, the amount of crude oil pressure relief valves can vent goes down depending on the type of crude oil.

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To get a copy of the report, please contact us.

Abstract – Task 3: Combustion Experiments and Modeling – August 26, 2019

The United States (U.S.) Department of Energy (DOE) launched the Crude Oil Characterization Research Study in 2015, with the US Department of Transportation (DOT) and with the Sandia National Laboratories (SNL) serving as technical lead.

Transport Canada is working with U.S. DOE and DOT on this research. Together, they will evaluate whether crude oils transported in North America, including those produced from "tight" formations, exhibit physical or chemical and combustion properties that are distinct from conventional crudes during transportation and handling.

The SAND2019-9189 report, released in August 2019, presents results from Task 3: Combustion Experiments and Modeling, which is part of SNL's comprehensive Crude Oil Characteristics Research Sampling, Analysis and Experiment (SAE) Plan (PDF, 286 KB). The report can be accessed at: https://www.osti.gov/biblio/1557808.

The report describes an experimental study of physical, chemical, and combustion characteristics of selected North American crude oils, and how these associate with thermal hazard distances resulting from pool fires and fireballs.

The emergence of large volumes of tight oils within the North American Transportation system over the last decade coupled with several high-profile train accidents involving crude oils, has raised questions about the role of oil properties in general, and tight oils in particular, in affecting the severity of hazard outcomes in related crude oil fires.

Study Methods

The objective of the pool fire experiments was to measure parameters necessary for hazard evaluation, namely, burn rate, surface emissive power, flame height, and heat flux to an engulfed object. To carry out this objective, a series of 2-m diameter indoor and 5-m diameter outdoor experiments were performed.

The objective of the fireball experiments was to measure parameters required for hazard evaluation which include fireball maximum diameter, height at maximum diameter, duration, and surface emissive power using 400-gallons of crude oil per test.

The crude oil samples used for the experiments were obtained from several U.S. locations, including tight oils from the Bakken region of North Dakota and Permian region of Texas, and a conventionally produced oil from the U.S. Strategic Petroleum Reserve stockpile. These samples spanned a measurable range of vapor pressure and light ends content representative of domestic conventional and tight crudes.

Research Results

The results indicate that all the oils tested in the study have comparable thermal hazard distances and the measured properties are consistent with other alkane-based hydrocarbon liquids.

If you have any questions or comments about this study, please contact us.

Abstract – Heavy Crude: Closed vs. Open Sampling and the Effect on Light End (C1- C6) Composition over Time – March 2019

Transport Canada (TC) studied heavy crude oil to learn whether one method of sample collection was better than the other in capturing crude oil samples for the purpose of compositional analysis.

Several methods exist to collect crude oil samples in the field. In two previous sampling and analysis campaigns, TC used a closed floating piston cylinder to collect crude oil, but the method was challenging for some heavy crude oils due to their high viscosity.

In our latest study, we wanted to learn if collecting heavy crude oils using open sampling under atmospheric pressure would cause significant loss of light ends from the oils (i.e. hydrocarbon gases such as methane (C1) and propane (C3)) as compared to the closed floating piston cylinder method.

We presumed that heavy crude oils contain trace amounts of light ends. As well, because heavy crude is so viscous, it could be harder for light ends to diffuse out of the crude oil. So we also presumed there would be a negligible loss of light ends, regardless of the type of sampling method used.

In the study, we collected four crude oils – three heavy and one light – using both open and closed methods. We analyzed the samples for light end hydrocarbons (C1 – C6) and retention of light ends over a 4-week period. The comparison of results from Week 0 to Week 4 supported the hypothesis that, in heavy crude oil samples, light ends are present in low to trace amounts and diffusion of light ends out of heavy crude oil at atmospheric pressure is minimal.

We concluded that, when handled and stored properly, collecting heavy crude samples using an acceptable open sampling method does not lead to a significant loss of light end hydrocarbons compared to a closed method.

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To obtain a copy of the report, please contact us.

TP: 1540SE

Catalogue Number: T86-55/2018E-PDF

ISBN : 978-0-660-29113-0

Abstract: Crude Oil Sampling and Testing Methods Literature Review - February 8, 2017

The Transportation of Dangerous Goods Program commissioned a literature review comparing sampling and analysis methods and their appropriateness to a number of Canadian crude oils. Currently there are significant variations in the type of sampling and analysis techniques used for crude oil classification prior to the oil being transported in Canada. A specific sampling method may only be suitable for certain types of crude oils and certain analytical methods. By the same token, for a specific analytical test, one sampling method may work better than another, depending on the type of crude oil. As a result, InnoTech Alberta, a provincial research corporation, undertook this work. The literature survey concluded that sampling into open containers under atmospheric pressure is suitable for collecting samples of dead crude oils, heavy crude oils, and for test methods where the loss of light components will not affect the accuracy of analytical techniques. Sampling under closed conditions should be done whenever there are any concerns about the loss of volatiles and for light oils including condensates, and diluted bitumen. In terms of test methods, those that allow direct sample introduction from a pressurized cylinder into the instrument (such ASTM D8003) and eliminate evaporative losses prior to analysis are preferred. Density and hydrogen sulfide content measurements can also be affected by the loss of volatiles and therefore methods that call for closed sampling are recommended.

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To obtain a copy of the report, please contact us.

Abstract - Task 2: Sampling and Analysis Method Evaluation - February 8, 2017

The United States (US) Department of Energy (DOE) launched the Crude Oil Characterization Research Study in 2015, with the US Department of Transportation (DOT) and with the Sandia National Laboratories (SNL) serving as technical lead.

Transport Canada is working with US DOE and DOT on this research. Together, they will evaluate whether crude oils transported in North America, including those produced from "tight" formations, exhibit physical or chemical and combustion properties that are distinct from conventional crudes during transportation and handling.

SNL's comprehensive Crude Oil Characteristics Research Sampling, Analysis and Experiment (SAE) Plan (PDF, 286 KB) makes recommendations it describes as distinct tasks. These tasks describe the research needed to improve understanding of tight crude oil properties, especially as they compare to conventional crude oil properties and relate to transportation.

Task 1, a literature review entitled 'Review and Evaluate New and Emerging Crude Oil Characterization Data' is complete; TC did not participate on this task. You can find a report at http://prod.sandia.gov/techlib/access-control.cgi/2015/151823.pdf (PDF, 7.3 MB).

The SAND2017-12482 report (released in December 2017) presents results from Task 2: Sampling and Analysis Method Evaluation.

The aim of Task 2 was to identify commercially available methods that accurately and reproducibly collect and analyze crude oils for vapor pressure and composition, including dissolved gases. The project team selected several sampling and analysis methods, then compared their performance to that of a well-established mobile laboratory system; the current baseline instrument system for the U.S. Strategic Petroleum Reserve Crude Oil Vapor Pressure Program.

Specifically, using crude oil sampled from two specific locations in the US, the experimental matrix evaluated performance for both:

  1. capturing, transporting, and delivering hydrocarbon fluid samples from the field to the analysis laboratory
  2. analyzing for properties related to composition and volatility of the oil, including true vapor pressure, gas-oil ratio, and dissolved gases and light hydrocarbons

The report SAND2017-12482 was revised (June 2018) and a new report (SAND2018-5909) "Revision 1 – Winter Sampling" was issued. This report incorporates additional seasonal data and compositional analysis results that have become available since the publication of the prior report, SAND2017-12482, in December 2017.

Going forward, the project team will use methods that performed well in Task 2 in:

  • Task 3 (Combustion Experiments and Modeling)
  • Task 4 (Compositional Analyses of Multiple Crude Types)

You can access the original Task 2 report (SAND 2017-12482 report released in December 2017) at https://www.osti.gov/scitech/biblio/1414422-doe-dot-crude-oil-characterization-research-study-task-test-report-evaluating-crude-oil-sampling-analysis-methods.

You can access the Revision 1 of the Task 2 report (SAND2018-5909, June 2018) at (https://www.osti.gov/biblio/1458999-doe-dot-crude-oil-characterization-research-study-task-test-report-evaluating-crude-oil-sampling-analysis-methods).

If you have any questions or comments about this work, please contact us.

Abstract: Crude Oil Sampling and Analysis Final Report - August 10, 2015

The July 6, 2013 Lac-Mégantic derailment and other incidents in Canada and the United States have raised many questions about the safe transport of crude oil by rail. They also put a spotlight on the need to further investigate crude oil properties and behaviour.

This report describes the testing the Transportation of Dangerous Goods Directorate has done to assess the composition and properties of crude oils transported by road and rail in Canada. We:

  • Verified the applicability of the current classification requirements described in the Transportation of Dangerous Goods Regulations (TDGR) Part 2, for Class 3, Flammable liquids; and Class 2, Gases.
  • Focussed on assessing other hazards that crude oil may pose during transport.

Study Methods

68 samples of crude oil were collected and analysed. The crude oil was destined for transport by rail or road in Canada and represents a wide range of crude oils from condensates to bitumen, under controlled conditions. We also subjected the samples to a variety of tests including but not limited to:

  • Flash point determination
  • Initial Boiling Point determination (IBP)
  • Reid Vapor Pressure (RVP)
  • True Vapor Pressure (TVP)
  • Compositional analysis and Gas Oil Ratio by gas chromatography (GC)
  • Hydrogen sulphide (H2S) analysis in the vapor phase and flammable gas testing

Research Results

  • The GC method found IBPs that put 56 out of the 68 samples in Packing Group I, the highest hazard group for Class 3 Flammable Liquids.
  • The ASTM D86 method, a commonly used standard for IBP testing of flammable liquids, found IBPs consistently higher than the GC tests.
  • The Report recommends using the method that combines GC data from two ASTM standards (D8003/ D7169) as a more accurate method for determining IBP of crude oil containing light ends (methane, ethane, propane and butane).
  • Most TVP values were above atmospheric pressure (101 kPa) at 50 oC.
  • TVP values were higher than the RVP values for the crude oil samples tested by both methods.
  • Based on compositional analysis, one crude oil sample contained enough amounts of light ends to result in a TVP above 300 kPa at 50 oC, which meets the TDGR's definition of a gas.
  • Vapour phase measurements of H2S ranged from 0-65000 ppm, with 42 of the 68 crude oil samples having values below 1000 ppm.

We performed this testing with Alberta Innovates-Technology Futures (AITF), an Alberta provincial research corporation.

To support the published report, the crude oil data collected during this project is now available upon demand.

The data set is presented in Microsoft Excel and contains the following information on the samples:

  • Region of origin;
  • Sample type (e.g., heavy oil, condensate, etc.);
  • Sampling method (atmospheric or pressurized);
  • Inbound and outbound mode of transportation (rail, pipeline, truck);
  • Hydrogen sulphide (H2S) concentration in the vapor phase (ppm);
  • Flash point (°C);
  • Water and sediment content (%);
  • Density (kg/m3);
  • Initial Boiling Point (IBP) (°C);
  • Reid Vapor Pressure (RVP) (kPa);
  • True Vapor Pressure (TVP) (kPa);
  • Gas Oil Ratio (m3/m3);
  • Simulated distillation profile; and
  • Compositional analysis (%).

Note: The data set does not name the companies that own or operate the facilities at which we took samples or the exact geographic point of sampling.

To obtain a copy of the report or of the dataset, please contact us.

Contact us

Email: TC.TDGScientificResearch-RecherchescientifiqueTMD.TC@tc.gc.ca.

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