Viscous oil recovery
In situ recovery of bitumen from oil sands …
Thermal, nonthermal and hybrid processes
Current heavy oil technology generally involves steam
injection to reduce fluid viscosity. Horizontal wells are
used for injection and production to achieve economic
rates. Solvents (or combination of solvent + steam) are
also used for viscosity reduction. In situ combustion may
also generate thermal energy required for oil mobilization.
Viscosities of oil sand bitumen may be millions of centipoise (cp),
prohibiting any primary recovery. “Heavy oil” viscosities may
exceed 1000 cp, with primary + secondary recovery below 15
percent. To enhance these recoveries, thermal, solvent, or hybrid
processes are employed. Recoveries from Steam Assisted Gravity
Drainage (SAGD) can exceed 50 percent, with improved efficien
cy by also injecting solvent or replacing steam with solvent.
Marathon is a pioneer in thermal technology, operating one of
the industry’s earliest fire flood projects in the Fry (Illinois) field
in 1961. Thermal operations were also conducted in Yates (Texas),
Pitchfork (Wyoming), and Bolney (Canada) fields. The Company
holds several patents in Thermal Assisted Gravity Drainage, and
a dual porosity-dual permeability thermal compositional simula
tor (ThermDK) was developed in house.
Marathon utilizes an integrated team to evaluate global viscous
oil opportunities. Principle areas of focus include geologic mod
els and thermal-compositional reservoir simulation.
70 percent of the world’s
oil resources are found in
oil sands (sand + bitumen)
and heavy oil in traditional
employed to produce these
› Thermal methods
› Solvent injection
› Hybrid processes (solvent +
+1 (713) 629-6600
Thermal and solvent processes/Marathon candidate reservoirs:
› CSS (Cyclic Steam Stimulation): ~ 30 percent recovery factor;
could be applied to Rocky Mountain heavy oil reservoirs.
› Thermal Assisted Gravity Drainage: Applied in Yates. Process
suitable for steam injection in the gas cap of fractured car
bonate, heavy oil reservoir. In Bolney (heavy oil), steam
based thermal extraction methods were used.
› SAGD: Several commercial applications in Athabasca oil
sand. Recovery could be higher than 60 percent. Potential
for application in Marathon assets in Birchwood, Ells River
› In situ combustion: Process tested for over five decades.
Many refinements being used in few projects around the
globe. Marathon’s Fry in situ combustion pilot in Crawford
County, Ill. (SPE#955 and 956) was one of the earliest such
projects. Technology may be applied in Pitchfork, Oregon and
Spring Creek. Variations of this process, suitable for applica
tion in Athabasca oil sands, are being developed in house.
Marathon’s viscous oil assets ~ 2 Bbbl recoverable
› Onshore U.S.: Pitch Fork, Oregon Basin, Spring Creek
(Wyoming heavy oil)
› Canada: Birchwood, Ells River, Namur and Chard (oil sands)