The value of heavy-oil production is reduced because extra refining is required to market the oil and a diluent may be needed to transport the oil. In some reservoirs, insitu pyrolysis reactions can remove this limitation.

The oil in most reservoirs produced by steam-drive is not hot long enough for pyrolysis to drastically change properties of the oil. However, deep, high permeability, thick formations like the Orinoco tar belt offer a new opportunity. When steam is injected at a pressure above 8.93 M Pascal (1300 psi), and the production is constrained, large volumes of 10 API oil can be upgraded underground to 25 API oil. Moreover, production from the reservoir more than doubles, and the coke and sulfur are left underground. Since the viscosity of the produced crude is reduced several orders of magnitude, no diluent would be needed to transport the crude. Finally, much lighter oil arrives at the refinery, so extra investment in distillation and cracking equipment is unnecessary.

Thus, in situ upgrading could reduce the investment needed to market heavy oil, generate higher profits and make smaller reservoirs more attractive for development.

Keywords:
situ, enhanced recovery, sagd, upstream oil & gas, heavy oil upgrading, permeability, thermal method, injector, increase production, spe 62560
Subjects:
Processing Systems and Design, Improved and Enhanced Recovery, Unconventional and Complex Reservoirs, Heavy oil upgrading, Thermal methods, Oil sand, oil shale, bitumen, Well Operations and Optimization
copyright 2000, Society of Petroleum Engineers
You can access this article if you purchase or spend a download.