by john pack greg pudewell jaynesh shah edwin l. youmsi pete
TRANSCRIPT
EMERGING PETROLEUM-ORIENTED NANOTECHNOLOGIES FOR RESERVOIR ENGINEERING
By
John Pack
Greg Pudewell
Jaynesh Shah
Edwin L. Youmsi Pete
Petroleum-Oriented Nanotechnology Many nanotechnology
applications have become standard in petroleum refining.
Most obvious application for upstream operations is development of better materials
http://www.ngoilgas.com/media/media-news/news-thumb/091127/nanotechnology.jpg
Petroleum-Oriented Nanotechnology Lighter, stronger and more
resistant equipment can be produced using nanotechnology.
It could also be used to develop new metering techniques with tiny sensors to provide improved data about the reservoir
https://publicaffairs.llnl.gov/news/news_releases/2006/images/membrane409x299s.jpg
Petroleum-Oriented Nanotechnology Other emerging applications of
Nanotechnology in reservoir engineering include;Development of “smart fluids” for
enhanced oil recovery and drilling.Development of “nanofluids” which are
used to enhance some of the properties of a fluid.
Nanotechnology in reservoir engineering is however still under-investigated.
http://www.cpge.utexas.edu/nesp/
What exactly is Nanotechnology?
A lot of confusion fueled partly by science-fiction.
Currently, there is no distinction between “true” nanotechnologies and other domains of atomic and molecular science/engineering.
http://www.thelensflare.com/gallery/p_nanobot_223.php
What exactly is Nanotechnology? Fairly representative definitions include;
“Nanoscience is the study of phenomena and manipulation of material at atomic, molecular and macromolecular scales where properties differ significantly from those at a larger scale.”
“Nanotechnologies are the design, characterization, production and application of structures, devices and systems by controlling shape and size at a nanometer scale.”
Colloidal Suspensions and Association Nanocolloids in Petroleum
Importance of Native Colloids for Petroleum Properties Specialists argue that there is no
novelty Importance was emphasized
several decades ago, esp. with bitumen
Any petroleum medium represents a colloid system with a dispersed colloidal phase composed mainly of asphaltenes
Important milestones in the research of asphaltene colloidal characterization: Publications of books based on
materials of the 1993 International Symposium on the Characterization of Petroleum Colloids
A Russian-language book on disperse systems in petroleum
Asphaltene molecule from http://www.seas.harvard.edu/projects/weitzlab/aggregation_files/asphaltene.jpg
Previous Colloid Models No earlier or more recent
models include a concept of asphaltene self-assembly into a variety of nanocolloidal configurations with a well-structured phase diagram
Most models from the start consider asphaltene as a solid (quasispherical) colloidal particle with diameter between 2-10 nm
There are no complex phase diagrams of hard sphere colloids
The “only critical” boundary being not a specific phase transformation, but a precipitation onset
http://www.lloydminsterheavyoil.com/Asphaltene3.gif
Previous Colloid Models Only one additional “critical
boundary” appears in previous models
Colloidal particles are not permanently present in petroleum but are formed from molecular solutions of asphaltenes at certain critical conditions as a result of some association processes
These association processes were regarded to be similar to micellization phenomena of simple surfactants for a long time
http://www.pharmainfo.net/files/images/stories/article_images/MicelleComposedOfAmphiphilicSurfactants.jpg
Different Classes of Disperse Systems The assumption of
micellization places asphaltenes into a principally different class of disperse systems
Colloidal suspension A system of solid particles
dispersed in a liquid Association colloids
Systems with particles which are formed by reversible micellization
Usually exhibit a very rich phase behavior ranging from the simplest isotropic micellar phases to highly organized supramolecular nanostructures
http://sites.google.com/site/molecularsystemsengineering/asphalteneschains.jpg
For Example… Note the appearance of
enclosed phase domains (“closed loops”) at the phase diagram, representative of a so-called reentrant phase behavior
“Closed loops” are indicative of polymorphism of a system
Loops originate in liquid-liquid immiscibility phenomena and are characteristic signatures of directional noncovalent bonding in associating species
Fig 3. A complex temperature-concentration (T-C) phase diagram for nonionic surfactant penta-ethyleneglycol dodecyl ether (C12E5) in water from I. Evdokimov, SPE
Future Research into Association Colloids
Even after introducing the concept of micellization for nanoparticles of asphaltenes, petroleum researchers still remained content with the idea of single critical concentration (CMC) in surfactants
Possible analogies with known complex properties of association colloids has not been investigated
Although well-known published experimental results and recent publications provide multiple data in support of the concept of asphaltenes as “association colloids”
http://miam.physics.mcgill.ca/miam/images/research/complex/Hill_colloid_charges.jpg
T-C Phase Diagram of Asphaltenes in Petroleum – Data Accumulation
Asphaltene Phase Diagrams Phase changes in
asphaltene-containing systems can be identified by revealing “specific points” in experimental concentration and temperature dependencies of system’s parameters
Fig 4. Concentration and temperature effects on Herschel-Bulkley’s rheological parameters in asphaltene –rich model oil from I. Evdokimov, SPE
“Specific Points” The T-C area of practical importance is wide:
Pour point temperatures Asphaltene decomposition/coking “Infinitely diluted petroleum solutions” Solid Asphaltenes
This research group investigated concentration effects in dilute solutions with asphaltene contents from ~1 mg/L to ~1 g/L, close to room temperature
Detailed studies of temperature effects have been performed in the range from -50°C to ~400°C with bitumen and precipitated asphaltenes (concentrations used were from ~140 g/L to ~1200 g/L)
“Specific Points” Specific concentrations/temperatures were neither
noticed nor discussed in original publications but corresponding “specific points” are clearly seen in the published data plots
E.g., SANS study of asphaltene aggregation Provided detailed concentration dependencies of the radii of
gyration RG in solutions of asphaltenes with concentrations 3.4-117 mg/L at temperatures from 8°C to 73°C
Provided qualitative discussion of concentration/temperature effects
Did not specify obvious RG maxima at concentrations ~5, ~20-22 and ~70 g/L
Replotting their original data on RG vs. T graph clearly indicate the presence of “specific temperatures” round 28-32°C
T-C Phase Diagram of Asphaltenes in Petroleum – Current Version
Current T-C Phase Diagram Asphaltenes in Petroleum First cumulative T-C plot
of all “specific points” Fairly well-defined phase
boundaries Limited data does not
allow for statistical analysis○ Numerical values of
“critical” parameters
should Be regarded as approximate Concentration-Defined Phase Boundaries Temperature-Defined Phase Boundaries
Fig. 5 from I. Evdokimov, SPE
Concentration-Defined Phase Boundary Primary aggregation boundary (Line 1 in diagram)
Ca. 7-10 mg/l (20oC) Obtained by measuring
○ UV/vis absorption○ Viscosity○ NMR relaxation
Attribution of boundary to
primary association of
asphaltenes
monomers recently Also confirmed by fluorescence technique
Fig. 5 from I. Evdokimov, SPE
Concentration-Defined Phase Boundary Liquid-liquid demixing boundary (line 2 in diagram)
Ca. 100-150 mg/l (20oC) Revealed for solutions of
solid asphaltenes and of
heavy crudes by:○ Optical absorption○ NMR relaxation○ Viscosity○ Ultrasonic velocity, etc.
Closed loop phase boundary is
a well known feature of demixing systems○ Boundaries 2 and 3 in diagram seem to be part of a closed loop
“Upper” and “lower” “critical solution temperatures” present in diagram
Fig. 5 from I. Evdokimov, SPE
Concentration-Defined Phase Boundary “Former CMC” boundaries (lines 3a and 3b in diagram)
Most documented one ~ 1-10 g/l Published “CMC” data tend to
concentrate at 2 sub-ranges ○ 1-3 g/l and 7-10 g/l
Asphaltenes do not exhibit
true CMC behavior so CNAC
(critical nanoaggregrate
concentration) was introduced Diagram shows that “Former CMC” boundaries reflect phase
transformations in secondary systems of complex nanocolloids formed at the demixing boundary
At least one of the “former CMC” lines may be just a continuation of a demixing (liquid-liquid separation)closed loop
Fig. 5 from I. Evdokimov, SPE
Concentration-Defined Phase Boundary
Highest-Concentration boundaries (lines 4 and 5 in diagram) Strong effects observed at
20-35 g/l and contributed to
a “second aggregation
concentration”
Detailed SANS studies “Dilute regime” (from 3 to 4)
○ Aggregates are independent
entities with radii of few nanometers “Semi-dilute regime” (above boundary 4)
○ Internal structure of aggregates remains unchanged○ Aggregates interpenetrate and form soft fractal objects, imparting high fluid
viscosities “Concentrated regime” (above boundary 5, above 70-90 g/l)
○ Large flocculated asphaltene domains may form “spatially-organized two-phase textures”
Fig. 5 from I. Evdokimov, SPE
Temperature-Defined Phase Boundaries Several temperature-controlled phases of aggregated asphaltenes
(right-hand side of diagram) Freezing
○ Exhibit heat capacities consistent with an ordered solid α-phase (25-30 °C)
○ Amorphous (glassy) phase○ Structure controlled by interactions between polar alkane side chains
β-phase (30-100°C)○ Phase transition acquire more dense structures○ Controlled by bonding to pericondensed aromatic segments
γ-phase (100-150°C)○ Phase with crystalline order
Higher Temperatures○ Amorphous asphaltenes soften and
liquefy○ Crystalline domains melt at 220-240°C○ Above 350°C asphaltenes decompose
and form liquid crystalline mesophaseFig. 5 from I. Evdokimov, SPE
Immediate Relevance to the Properties of Native
Petroleum
Immediate Relevance to the Properties of Native Petroleum Some skeptics wonder why we need these scientific
speculations and nice picturesIt is true that we cannot make any suggestion about the
details of nanocolloid phases in “live” petroleum○ More complicated and costly experiments are needed
Detailed inspection of the world’s “dead” petroleum fluids show surprisingly strong
effects which may originate in
the phase diagram of
asphaltene nanocolloids (fig 5)○ Highlights some of the
previously overlooked featuresFig. 5 from I. Evdokimov, SPE
Plot of viscosity vs asphaltene content Log- log plot for 200 crudes of various
geographical/geological origin Solid line is insignificant, only to
emphasize apparent viscosity
extreama Stastics have to be improved,
especially in the low asphaltene
contents Even “raw” data in fig 6 clearly demonstrate a coincidence of shaprp
viscosity anomalies with all but one phase boundaries (phase 1) Applies to 0.001 wt% Most current databases classify <0.01 wt% as “zero asphaltene content”
Almost absence of native free-flowing crude oils with asphaltene contents above the phase boundary 5 May be a natural “solubility limit” of asphaltene in native crude oils
Fig. 6 from I. Evdokimov, SPE
Well-known interdependence of viscositiesand densities in crude oils
Noticeable peaking of specific gravities at asphaltene phase boundaries showin in fig 7
Asphalene decomposition table with “Resin and Asphaltene Content of various Crude Oils” (from source)○ Properties of 20 crudes with non-zero
asphaltene content from diverse
locations (Canada, Venezuela, Mexico,
USA, Russia, Brazil, Iraq, France, Algeria)○ Plot of specific gravity vs asphaltene
content from table shown in fig 8○ When compared to figures 6 and 7, one
can see the same peaks of specific
gravity to the same asphaltene phase
boundaries○ Boundary 3b not seen due to lack of
data points
Specific Gravity vs Asphaltene Content
“Asphaltene Deposition and Its Control”: http://tigger.uic.edu/~mansoori/Asphaltene.Decomposition.and.Its.Control_html
Fig. 7 from I. Evdokimov, SPE
Fig. 8 from I. Evdokimov, SPE
PropertyTransformations
Fig 9: Properties from boundary A in fig 5 Left Hand Side
Variations of the pour point of a Tatarstan crude
after 1 hour thermal pre-treatments, Temp close to phase boundary A Properties
○ 895 g/l 3.5 wt% asphaltenes○ 20 wt% resins 0.3 wt% waxes
Most Dramatic Pour point Deviation
○ -16.2 to +11.2 oC (at pre-treatment Temp of 36.5oC) Right Hand Side
Dramatic Density Deviation near
boundary A in fig 5 Measured by refractive index With no phase boundary, expected
gradual decrease with density at top
marginally smaller than the bottom Expected behavior below 28oC and above
37oC Between 28 and 37oC (at boundary A) there
is a strong transient stratification of density
and presumably of composition of the oil
Fig. 5 from I. Evdokimov, SPE
Fig. 9 from I. Evdokimov, SPE
Deposits at steel surfaces
Study of deposits from petroleum fluids with high asphaltene content (12.3 g/l) on steel surfaces
Fig. 10Filled in symbols
○ Deposits from fluids which “thermal history” never crossed boundary A
Open symbols○ Deposits from a fluid that
was heated at least once
above 28-29oC○ Afterwards, Increase of
deposition persisted below the
phase boundary (at 12-29oC)
for at least one month
Fig. 10 from I. Evdokimov, SPE
Nanophase-Resembling Phenomena in Brine-Petroleum Dispersions
Nanophase-Resembling Phenomena in Brine-Petroleum Dispersions
Oil well output typically consists of water in a crude oil
Water/oil mixtures are not “nanosystems” as are nanocolloids but there are similaritiesBoth have well-defined phase diagramsWater/oil dispersion controlled by oil’s
“indigenous surfactants” including nanocolloidal asphaltenes
ips.org
Water/Oil Mixtures “Nano-Resemble” Nanoemulsion Systems
Microwave heated from 20-25 °C
Sharp variations of specific heat due to abrupt changes in morphology Resembles those observed
in nanoemulsion systems “Percolation threshold” at
water cuts ≈ 0.2 “Bicontinuous morphology”
at water cuts ≈ 0.4 “Close packed” at water cuts
≈ 0.6
I. Evdokimov, SPE
Water/Oil Mixture Measurements of Density
Water cuts from 0.4-0.6 indicative of an asphaltene-mediated “middle phase”
T-C contours of excess, non-ideal densities show strong correlation to the bicontinuous domains of the T-C phase diagram for association nanocolloids
I. Evdokimov, SPE
Demulsification Efficiency Demulsification: Breaking of liquid-liquid emulsions Improved demulsification efficiencies attributed to
“percolation” (0.2) and “bicontinuous” (0.4-0.6) phenomena
I. Evdokimov, SPE
How Nanocolloidal Research can be Useful in Reservoir Engineering
Avoid any lengthy operations in the vicinity of the temperature-defined boundary “A” (Fig. 5) to avoid increase in viscosity and pour point (Fig. 9)
However, storage at this boundary “A” may result in increases stratification of petroleum light/heavy components (Fig. 9)
Approaching a nanophase boundary by blending crude oils may result in viscosity and density peaking (Figs. 6,7)
ere2007.com
Conclusions
Conclusions In petroleum engineering,
nanotechnologies are not considered important enough for widespread use, except for in refineries and “smart fluids” for EOR
This research shows there is enough evidence to consider oils as “association nanofluids”
Emerging technologies should account for complex phase diagrams of nanocolloids
capp.ca
Further Research This research is far from complete Much more investigation need be done on the complex
phase diagrams regarding asphaltene nanocolloids Other types of nanocolloids should be investigated and
their phase diagrams drawn up as well Various other colloids (such as water) should be
investigated in regards to property changes
careers-scotland.org.uk
References Evdokimov, Igor N., Nikolaj Yu. Eliseev, Aleksandr P. Losev, and
Mikhail A. Novikov. "Emerging Petroleum-Oriented Nanotechnologies for Reservoir Engineering." (2006). Society of Petroleum Engineers. Web. 10 Mar. 2010. <http://www.onepetro.org/mslib/servlet/onepetropreview?id=SPE-102060-MS&soc=SPE>.
Ratner, M. A., and Ratner, D.: Nanotechnology: A Gentle Introduction to the Next Big Idea, Prentice Hall, New Jersey, 2002.
Crane, C., Wilson, M., Kannangara, K., Smith, G., and Wilson, W.: Nanotechnology: Basic Science and Emerging Technologies, CRC Press, 2002.
Jackson, S. A.: Innovation and Human Capital: Energy Security and the Quiet Crisis. Am. Petrol. Inst., 2005.
Asphaltene Deposition and Its Control”: http://tigger.uic.edu/~mansoori/Asphaltene.Decomposition.and.Its.Control_html
Questions