Method for high temperature steam

Abstract

A method for the recovery of upgraded oil from an oil-bearing formation is provided wherein a hot gas phase fluid comprising steam is brought into contact with a heavy oil reservoir, such as by injection, and the hot fluid heats at least a portion of the reservoir to a temperature high enough for steam cracking, and subsequently the steam is reacted with the heavy oil to produce steam cracked lighter oil.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 606,755 filed Sep. 1, 2004, and U.S. Provisional Application No. 60 / 606,756 filed Sep. 1, 2004.BACKGROUND [0002] 1. Field of the Invention [0003] This invention provides a novel concept for the mobility enhancement of heavy crude oil, thus making possible more efficient and effective recovery of oils including oils that are presently accessible using existing techniques. Such oils include not only the balance of the oil left after primary and secondary recovery operations, but heavy oils and bitumen such as found in Athabaskan oil sands. More particularly, the present invention provides a downhole crude oil processing method that improves reservoir sweep efficiency and enhances quality of the crude oil delivered to the surface. In addition, coke formed may be recovered in the form of natural gas. Cost per barrel is consequently reduced. The method of the present i...

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Benefits of technology

[0013] Free hydrogen is produced from carbon even at temperatures as low as 700 degrees Fahrenheit. Thus, hydrogen is available for in situ desulfurization of reservoir oil. Both cracking and desulfurization lower oil viscosity thereby upgrading the oil. Sweep efficiency is improved via enhancement of mobility and control of reservoir permeability as a result of the reduction of intrinsic oil viscosity. Thus effective recovery of the oil in place can exceed ninety percent.

[0014] In another embodiment of the present invention, steam at a temperature high enough for steam cracking may be produced by downhole combustion of a fuel supplied from the surface together with water. The water is converted to steam of a desired temperature downhole t

Problems solved by technology

However, it has been increasingly clear that production cannot keep up with the rapidly growing need, particularly in view of the growing demand from countries such as China and India.

Moreover, the bulk of new production must come from the politically unstable Middle East.

However, by far the bulk of such heavy oil reserves occur at depths greater than that from which it can be recovered by surfaces mining.

The oil removed tends to be the more mobile fraction of the reservoir, and the combustion emissions of the steam generator can be limiting (as in California).

Such steam flooding faces limiting technical and economic obstacles relating to conductive heat losses through the wellbore and incomplete reservoir sweep efficiency, especially in heterogeneous reser

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