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nanocomposites have the potential to be shape-memorymaterials,
with the triggering of the shape change occurringas a result of
changes in temperature, infrared light, electri-
cal current, or pH. Such shape memory-soft materials wouldhelp
define a new class of smart materials (e.g., as actuators)that
could be used downhole or in surface applications.
Advanced drilling fluids based on polymers that are physi-cally
or chemically associated with nanoparticles along withamphiphilic
surfactants or polymers have been developedas stimuli-sensitive
materials. The mechanical and flowproperties of these materials can
be altered in response to achange in stimuli such as temperature,
salinity, and pH, andthese materials can be used in reservoir
conformance, flood-ing, and completion fluids. Designing specific
hydrophobicor hydrophilic character into such smart fluids,
throughthe use of novel organic chemistry on the surface of
high-surface-area functionalized nanoparticles, will
significantlyalter the mode of operating and organizing waterfloods
andsurfactant floods. Moreover, by tailoring the responsivity
ofthese smart fluids, they can be used either to block or
toincrease the porosity and tortuosity of the formations wherethey
are injected.
Engineered nanoparticles, and in particular, nanocrystal-line
materials, in combination with advanced drilling fluids,are likely
to increase drilling speeds and decrease wear ofdrilling parts
significantly. Additionally, the developmentof methods to control
the incorporation and distribution ofsuch nanocrystalline materials
in metal matrices would leadto stronger and lighter-weight
pipelines for transportation ofoil and natural gas. These are
likely to be especially impor-
tant for the exploitation of stranded gas.
Sensors and ImagingBecause of the significant alterations in
their optical, magnetic,and electrical properties (in comparison to
their bulk analogs)along with their ability to form (electrically
and/or geometri-cally) percolated structures at low volume
fractions, nanoma-terials make excellent tools for the development
of sensors andthe formation of imaging-contrast agents.
Additionally, usingthe anisotropic nature of many nanoparticles,
the percolationis a strong function of orientation, and, thus, for
appropriatelyprocessed materials, highly anisotropic electrical and
mechani-cal properties are observed in different directions.
Such nanomaterials, when combined with smart fluids, canbe used
as extremely sensitive sensors for temperature, pres-sure, and
stress downhole under extreme conditions. Perhapsthe most
significant value as sensors results both from theability to
interrogate the parameters of interest (e.g., tempera-ture,
pressure, stress) without requiring contact and from the
amplification of signals by use of unique optical
signatures(such as absorption and fluorescence) of the
nanoparticles assurrogate probes of the parameters of interest.
Similarly, when combined with significantly enhanced mag-netic
and spectroscopic probes and improved computationalmethods,
nanoparticles have substantial potential as markersfor imaging. By
chemical modification, the nanoparticles pref-erentially segregate
into different fluid regions or to the pores,allowing for improved
sizing and characterization of the reser-voir and the efficacy of
sweep methods employed to enhancethe recovery of oil by monitoring
the flow of fluids and by real-time monitoring of the reservoir.
The use of nanoparticles (asopposed to the macroscale analogs) for
such imaging is crucial
because of the size of the pores, the increased surface areaof
the nanoparticles, and the mobility associated with them.Finally,
the increased sensitivity of the probes and the strengthof the
optical and spectroscopic signatures of the nanoparticlesrequire
only small amounts of nanoparticles, which could leadto the
development of instrumentation and methods for evalu-ating small
test holes that minimize the footprint of the drilland reduce
drilling costs for exploratory wells.
NanomembranesThe convergence of top-down and bottom-up
synthesisthat is typical of nanomaterials has led to the
developmentof large-scale, lightweight, and sturdy
nanomembranes.Inspired by the success of zeolites (materials
capable ofseparating small gases such as oxygen and nitrogen) and
thedevelopment of top-down and bottom-up synthetic meth-ods, a new
generation of nanomembrane materials is beingdeveloped and deployed
for the separation of metal impuri-ties in heavy oil and impurity
gases in tight gas. By exploit-ing methods common in the
microelectronics industry, thecost of manufacturing highly uniform
and reproduciblemembranes is quite competitive. These nanomembranes
willenhance the exploitation of tight gas significantly by
provid-ing efficient methods for removing impurities, separating
gasstreams, and enabling GTL production.
The three subtopics above provide a glimpse of the appli-cation
of nanotechnology in the oil and gas industry that will
complement its large-scale use in the refining and
processingsectors. Some issues of concern include the uncertainty
ofthe health effects of nanoparticles in general, the
environ-mental effect of nanoparticles, the cost of deploying
largequantities of nanoparticles for production applications,
andthe development of appropriate quantitative tools for
theanalytical and chemical characterization of nanoparticles. Allof
these issues are being pursued actively by the scientificand
technological community and will be settled over thenext few years.
Clearly, the true exploitation of nanotechnol-ogy over the long
term would be the harmonious integrationof refining and
environmental issues (such as CO2 sequestra-tion) with
drilling.
TECHNOLOGY TOMORROW
JPT
Fig. 1—Structural materials can be enhanced signifi-cantly by
nanotechnology.
