An increasing global
population and a sharply upward trajectory
of per capita energy consumption continue to drive the demand for
fossil fuels, which remain integral to energy grids and the global
transportation infrastructure. The oil and gas industry is increasingly
reliant on unconventional deposits such as heavy crude oil and bitumen
for reasons of accessibility, scale, and geopolitics. Unconventional
deposits such as the Canadian Oil Sands in Northern Alberta contain
more than one-third of the world’s viscous oil reserves and
are vital linchpins to meet the energy needs of rapidly industrializing
populations. Heavy oil is typically recovered from subsurface deposits
using thermal recovery approaches such as steam-assisted gravity drainage
(SAGD). In this perspective article, we discuss several aspects of
materials science challenges in the utilization of heavy crude oil
with an emphasis on the needs of the Canadian Oil Sands. In particular,
we discuss surface modification and materials’ design approaches
essential to operations under extreme environments of high temperatures
and pressures and the presence of corrosive species. The demanding
conditions for materials and surfaces are directly traceable to the
high viscosity, low surface tension, and substantial sulfur content
of heavy crude oil, which necessitates extensive energy-intensive
thermal processes, warrants dilution/emulsification to ease the flow
of rheologically challenging fluids, and engenders the need to protect
corrodible components. Geopolitical reasons have further led to a
considerable geographic separation between extraction sites and advanced
refineries capable of processing heavy oils to a diverse slate of
products, thus necessitating a massive midstream infrastructure for
transportation of these rheologically challenging fluids. Innovations
in fluid handling, bitumen processing, and midstream transportation
are critical to the economic viability of heavy oil. Here, we discuss
foundational principles, recent technological advancements, and unmet
needs emphasizing candidate solutions for thermal insulation, membrane-assisted
separations, corrosion protection, and midstream bitumen transportation.
This perspective seeks to highlight illustrative materials’
technology developments spanning the range from nanocomposite coatings
and cement sheaths for thermal insulation to the utilization of orthogonal
wettability to engender separation of water–oil emulsions stabilized
by endogenous surfactants extracted during SAGD, size-exclusion membranes
for fractionation of bitumen, omniphobic coatings for drag reduction
in pipelines and to ease oil handling in containers, solid prills
obtained from partial bitumen solidification to enable solid-state
transport with reduced risk of damage from spills, and nanocomposite
coatings incorporating multiple modes of corrosion inhibition. Future
outlooks for onsite partial upgradation are also described, which
could potentially bypass the use of refineries for some fractions,
enable access to a broader cross-se...
