Sk. Das et Rm. Butler, EXTRACTION OF HEAVY OIL AND BITUMEN USING VAPORIZED HYDROCARBON SOLVENTS, Petroleum science and technology, 15(1-2), 1997, pp. 51-75
The huge natural resources present in the form of heavy oil and bitume
n may be the principal source of fuel for human civilization in the co
ming century. However, due to very high viscosities of these crudes th
e use of conventional recovery techniques is not feasible. The viscosi
ty decreases drastically with increase in temperature; this principle
is utilized in thermal recovery processes like SAGD. Using long horizo
ntal wells, very high production rates can be achieved in this process
. However, steam processes suffer from energy inefficiency largely due
to heat losses to the cap and base rock. This can be avoided if inste
ad of steam, solvent is used to reduce viscosity. In the proposed proc
ess, ''Vapex'', vaporized hydrocarbon solvents are used to extract hea
vy oil and bitumen using the concept of gravity drainage. Hydrocarbon
solvents, when present in sufficient concentration, causes deasphaltin
g of these crudes. Although deasphalting improves the quality of the p
roduced crude, the possibility of reservoir plugging due to asphaltene
deposition is an important concern for using this process.