Alberta Oil Sands Technology and Research Authority

Texaco Canada Resources, Ltd.

Alexander S McKay

Declan B Livesey

Tawfik Noaman Nasr

Philip Harris

It has been discovered that the production or recovery of oil or bitumen produced or recovered in the form of an oil-in-water emulsion form a porous water containing oil or bitumen producing formation is maintained and improved by maintaining the temperature of the produced oil or bitumen in the form of an oil-in-water emulsion at a temperature not lower than and preferably greater than Tc, wherein Tc is the minimum temperature for the oil or bitumen, such as in the form of an oil-in-water emulsion, to flow through the porous water-containing oil or bitumen producing formation. In a special practice of this invention to prevent water coning, a substantially water impermeable barrier can be produced in a water saturated formation by depositing therein a bitumen or oil-in-water emulsion barrier or zone at a temperature below Tc.

Control of flow and production of water and oil or bitumen from porous

Laboratory coreflood experiments were conducted on Athabasca oil sands using hot water and caustic or carbon dioxide. Production temperatures were maintained at 150.degree. C. or lower and at an injection pressure of 3.55 MPa (500 psi). The objective of the experiments was to determine the conditions under which oil-in-water (O/W) emulsion could be produced in-situ. In addition, the study was to investigate the potential benefit of adding carbon dioxide to hot water to improve bitumen recovery. The results prove that when the pH of injected fluids is between 10.5 and 11.5, the O/W emulsion predominates. The emulsion is stable and has a viscosity much lower than that of the oil itself, due to the continuous water phase, and should beneficial in the recovery of heavy oil and bitumen. When the injected fluids have a pH less than 10.5, the water-in-oil (W/O) emulsion predominates. The laboratory data indicate that even this type of emulsion behaves as an O/W in the core but it is unstable and when produced the droplets quickly coalesce and immediately form the observed W/O emulsion. The addition of carbon dioxide to hot water at low temperatures proved to be effective in improving bitumen recovery over that from hot water alone. This is believed to be due to the effect of carbon dioxide absorption in reducing bitumen viscosity which resulted in improved bitumen mobilization. Another beneficial effect is the increase in pressure gradient due to the presence of free carbon dioxide, beyond the solubility limit, in the injected stream. The hot water-CO.sub.2 runs produces mostly W/O emulsion. The best recovery was achieved when the produced fluids temperatures was around 130.degree. C.

Recovery of bitumen or heavy oil in situ by injection of hot water of

The invention is a method of recovering hydrocarbons from underground hydrocarbon formations penetrated by at least one injection well and at least one production well, which comprises injecting into the formation a mixture of hot water and about 0.1% to about 5% by weight of a hydrocarbon liquid having an aromatic content greater than about 30%. The hot water and hydrocarbon mixtures should be injected at a temperature of at least about 80.degree.C. Hydrocarbons and other fluids are recovered from a production well after a suitable period of time.

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Las Vegas, NV, United States of America

Alexander S McKay