Upload
others
View
4
Download
0
Embed Size (px)
Citation preview
SPE Distinguished Lecturer Program
Primary funding is provided by
The SPE Foundation through member donations and a contribution from Offshore Europe
The Society is grateful to those companies that allow their professionals to serve as lecturers
Additional support provided by AIME
Society of Petroleum Engineers Distinguished Lecturer Programwww.spe.org/dl
This year marks the 50th
anniversary of the SPE Distinguished Lecturer program. Please visit our site to learn more about this amazing program.
www.spe.org/go/DL50
From Black to Gold:Nanotechnology in Upgrading of Heavy
Asphaltic Crude Oils
Murray R GrayDepartment of Chemical and Materials Engineering
University of Alberta
Edmonton, Canada
Society of Petroleum Engineers Distinguished Lecturer Programwww.spe.org/dl
4
Outline
Heavy oil and its propertiesBenefits and challenges of upgrading heavy oilsNanotechnology – definition and significance for the petroleum industryDefinition of asphaltenes and their significanceMolecular compositionOpportunities for nanotechnologyIn situ upgrading technologies
5
Heavy OilDense crude oil with APIo < 20Significant resources worldwideLower H, higher S, N and metals than light crudesHigh proportion of the barrel cannot be distilled, even under vacuum, circa 50% residuum
Wafra Field SteamfloodNeutral Zone
Chevron Joint Venture
Wafra – 14-18 oAPIHigh Sulfur
6
Viscosity of Heavy Oil
Crude oil viscosity normally increases with density Bitumen with 9oAPI, 1,000,000 cP at 15oC1-methyl naphthalene: 9.8 oAPI, viscosity 2.6 cPMercury: APIo=-121 and viscosity 1.5 cP
Why?
Why is heavy oil viscous?
Viscosity of liquids is due to intermolecular forcesLarger molecules in heavy oil give more interactionAsphaltene fraction gives aggregates in the oil phase, size 5-20 nmOverlap of aggregates gives very high viscosity
7Rev. Inst. Fr. Petrole, 2004
Incentives for Upgrading of Heavy Oil
Transportation: Reduce viscosity to enable transport without adding a solvent (Canada, Venezuela) or heating pipeline (Alaska)Price: Increase the API gravity, reduce sulfur content
Refineries value high API crude oilsViscosity is not a significant issue for refineries
Example Upgrader Configurations
UpgraderProduction Pipeline Refinery
Diluent to reduce viscosity
Upgrading Economics
Complex expensive installationsCapex: $30K-$100K per (barrel/day) of throughput
Typical scale: 50-150 kBBL/DTotal cost circa $10 billion
Operating costs $5-$10/BBLSignificant loss of volume to byproducts
10
Upgrading Yield and Quality
11
Capital cost: Hydroconversion > Coking > Deasphalting
Canadian Light-Heavy DifferentialPar price – Hardisty Blend (US IEA)
12
Iconic Image of Nanotechnology
Franks (1987) defined nanotechnology as “..technology where the dimensions and tolerances in the range 0.1 – 100 nm (from the size of an atom to the wavelength of light) play a critical role”
Ultrafine powders of nanoscale particlesNanoelectronics – “molecular electronics”, including both semiconductor, organic and hybrid systems
How does this relate to heavy oil?STM image of xenon atoms on Ni, Don Eigler, 28 Sep 1989
Profitable NanotechnologyCatalysts for making low-sulfur diesel and gasolineCo+Mo or Ni+Mo on alumina with high-pressure hydrogenFirst used in 1940’sSTM shows brim sites of high activity“BRIM” catalysts commercialized in 2004
Besenbacher et al., 2008
15
Asphaltenes: Turning adversaries to allies
Most difficult fraction in heavy oilsSoluble in toluene, and insoluble in n-heptaneUnderstanding asphaltenes unlocks the value of bitumen/heavy oil resources (i.e. upgrading)Nanotechnology is the key
Understand, measure, and control behavior at length scale < 0.1 μm
Imaging of Individual Molecules
Gross et al., Science, 2009
Nakamura et al, Science, 2007
STM - Attach CO molecule to tip of probeTEM – Isolate molecule in a carbon nanotube
17
Image of Nano-Aggregates of Asphaltenes
30 minute immersion of silicon wafer in dilute solution of asphaltene in tolueneAtomic force microscopy images courtesy JH Masliyah and Z Xu
1 μm
Hokusai, 1817“The Blind Men and the Elephant”
What do asphaltenes look like?
How are asphaltene molecules constructed?
Based on Sheremata et al., 2004; Strausz 1999
Bridged RingGroups
CondensedAlkyl Aromatics
20
Pyrolysis apparatusInduction furnace
To vent or gas bag (GC)
Liquid N2
Curie point alloy strips coated with asphaltenes
Classes of products:Gas chromatography-mass spectrometry
Cold Lake C7 asphaltenes
(1 ring includes olefins) 21
AbundanceSmall BlocksBoiling < 538oC
Large BlocksBoiling > 538oC
One blockTwo blocks
Three blocksFour+ blocks
Asphaltenes built up from 1-10 large and small building blocks
# Rings 0 1 2 3
Paraffins n-C12 to n-C30
Cycloalkanes
Aromatics
Thiophenes
S S
S
Sulfides
S S S
4 5 6 7
S S
S S
23http://www.ldeo.columbia.edu/res/fac/micro/images.section/pages/velcro.html
Why do asphaltenes aggregate so strongly?
Asphaltenes = “Molecular velcro”Much more difficult to analyze than DNARange of functional groups interactKinetics may be important
Asphaltene Assembly
24
Blue = Water and acid-base interactions Purple = Metal – base interactionsOrange = hydrophobic domain Green = aromatic stacking
Nanotechnology Opportunities
Design catalysts for large molecules in heavy oilAtomic level imaging + computer simulation + controlled synthesis of catalysts
Design dispersants to prevent aggregation of asphaltenes
Control molecular behavior during upgradingControl viscosity?
26
In Situ Upgrading
Why not upgrade in situ to avoid capital expense?
Reduce viscosity – crack large moleculesReduce density – increase H content, reduce S & NSignificant reactions require temperatures > 300oC
Two approaches under development:Partial combustion to generate hydrogen in situCoke the oil in place
In Situ Combustion with Horizontal Wells (THAI Process)
Image from Petrobank Resources
THAI Heavy Oil Pilot
In situ Combustion PLUS Catalysis
Harness the CO from partial combustion:CO + H2O = H2 + CO2
Catalyst needed to combine the hydrogen with the oilTwo approaches:
CAPRI - Place catalyst around production well bore to make use of gases to hydrogenate oil:Inject nanoparticle catalysts (MoS2) into the formation
Catalysts require high temperature (>300oC), high PH2, long time (1 h)
Pack annulus around production tubing with catalyst
Flowing Nanocatalyst Particles
Zamani et al., 2010 – 44 cm sand pack with 200 nm particles
How to inject catalyst into flowing oil?
Image from Petrobank website
In Situ Combustion: Production Versus Upgrading
Interesting and challenging production technologyControl of processSensitive to reservoir heterogeneities Oxygen breakthrough?
Upgrading requires exposure of oil to high temperature
Tradeoff between using heat to mobilize oil versus upgradingHigh complexity of subsurface process
Shell In Situ Upgrading Process (IUP)
350-400oC
• Shell Canada tested technique at Peace River• Electrical heaters raise temperature to 380-430oC• Coke the heavy oil in situ, vaporizing the cracked products• Vapor collected in wells above the heaters
New Technology Magazine, June 2008
Pilot Test at Peace River, Canada
Pilot testing in Peace River on bitumenProject began in 2004, completed in 200829 wells for the field test
18 well for electric heaters,3 producing wells8 observation wells
Produced over 100,000 barrelsLight oil product – 30 to 49oAPI from 8-10oAPI bitumenRecovery 50% of OOIP
Only achieve 20% with steamProblems with unreacted bitumen in product wells
Prospects for Shell In Situ Upgrading Process
Benefits:Heat transfer is slow but predictableSignificant upgrading achieved
Disadvantages High energy input for high TSimulations suggest 8:1 output/input ratioNeed to run downhole heaters on cracked gases, not electricity
37
Conclusions
Heavy oils are complex nanofluidsChemically complex asphaltenesNano-aggregation behavior of asphaltenes dominates phase behavior and processing
Example of catalysts for sulfur removal suggests a path forward
Combine modern tools for imaging and computationControl nanoscale behavior
Upgrading of heavy oils is advancing based on nano-science
38
Acknowledgements
Centre for Oil Sands Innovation at the University of AlbertaColleagues: Jacob Masliyah, H Yarranton (U of C), Zhenghe XuKuangnan Qian and Howard Freund (ExxonMobil)Student Arash Karimi
Society of Petroleum Engineerswww.spe.org
Join SPE!www.spe.org/join