EXTRACTION OF HEAVY OIL AND BITUMEN USING VAPORIZED HYDROCARBON SOLVENTS

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.