Solvent flooding to recover viscous oils

Patent · Tue Apr 16 04:00:00 EST 1985

OSTI ID:5286815

Fitch, J L; Mullins, L D

Oil may be recovered from viscous oil-containing formations including tar sand deposits by providing at least one injection well and at least one spaced-apart production well which extend downwardly from the surface and which extend to, and generally horizontally through, the bottom of the oil-containing formation with fluid communication of the horizontally extending portions of each well with the oil-containing formation. A predetermined amount of solvent, preferably 0.05 to 0.30 pore volume is injected into the bottom of the formation via the injection well and fluids including oil are recovered from the formation via the production well. After the desired amount of solvent has been injected into the formation, production is terminated and both the injection well and production well are shut-in to allow the formation to undergo a soak period for a variable time, preferably for a time between 2 to 20 days per foot of vertical thickness of the oil-containing formation. During the soak period, there is substantial mining of the heavy oil and the solvent in the formation by gravity-driven convection wherein the viscosity of the heavy oil is reduced, thereby making it easier to produce. A driving fluid such as water is then injected into the formation via the injection well and oil of reduced viscosity is produced until there is an unfavorable amount of driving fluid, preferably at least 90 percent.

• Assignee: Mobil Oil Corporation
• Patent Number(s): US 4510997
• OSTI ID: 5286815
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040401* -- Oil Shales & Tar Sands-- In Situ Methods
True & Modified
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
DISPLACEMENT FLUIDS
ENERGY SOURCES
ENHANCED RECOVERY
FLUID INJECTION
FLUID INJECTION PROCESSES
FLUIDS
FOSSIL FUELS
FUELS
INJECTION WELLS
MATERIALS
OIL SANDS
OIL WELLS
RECOVERY
SOLVENTS
VISCOSITY
WATERFLOODING
WELL SPACING
WELLS