US 4,068,715 AGranted

Method for recovering viscous petroleum

AssigneeTexaco Inc.

InventorChing H. Wu

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Abstract

Disclosed is a method for recovering viscous oil from subterranean, viscous oil containing formations, particularly from shallow formations which overlie water zones. The production well is completed in the entire oil zone and small amount in the water zone. At least two separate injection means are established in the injection well, the first being in communication with the lower part of the oil formation and upper part of the water formation, with the second injection means being in communication with the upper part of the oil formation. Heated air is injected via the first injection means into the lower part of the oil formation near the oil-water interface, the air channeling through the upper part of the water zone and causing an in situ combustion reaction to occur at the oil water contact. Air injection supports an in situ combustion reaction in the oil water contact zone which heats the oil above by conduction as well as hot gas convection through the oil saturated interval. Steam is then injected into the upper portion of the oil saturated interval by the second injection means while continuing injecting air into the lower portion of the formation to expand the burned out zone upward.

Claims18

Dependent claims

A method for recovering viscous petroleum from a subterranean, permeable, viscous petroleum-containing formation overlying and in contact with a water-saturated formation, said petroleum formation being penetrated by at least two wells which penetrate the water-saturated zone by a distance of at least 5% of the thickness of the petroleum-containing zone, comprising:

a. establishing a first fluid injection means in the first well between the surface and in communication with the bottom 5-25 percent of the petroleum-containing zone and a similar distance into the water-saturated zone;
p1 b. establishing a second fluid injection means in the first well separate from the first fluid injection means between the surface and in fluid communication with at least a portion of the petroleum containing zone above the portion thereof with which the first fluid injection means communicates;
c. establishing fluid communication between the second well and the full thickness of the petroleum-containing zone plus a distance into the top of the water-saturated zone equal to from about 5 to 15 percent of the thickness of the petroleum-containing zone;
d. injecting heated air into the formation near the oil water contact via the first fluid injection means to establish an in situ combustion reaction at the point of contact between the bottom of the oil-containing zone and the top of the water-saturated zone;
e. continuing injection of air into the bottom of the oil-containing zone and the top of the water-saturated zone until the temperature in the petroleum formation above the zone in which the combustion reaction is occurring has been raised to at least 200.degree. F;
f. injecting a thermal fluid comprising steam into the formation substantially above the oil water contact via the second fluid injection means while continuing injecting air into the first fluid injection means and producing petroleum from the production well.

3 more elements

a. establishing a first fluid injection means in the first well between the surface and in communication with the bottom 5-25 percent of the petroleum-containing zone and a similar distance into the water-saturated zone;
b. establishing a second fluid injection means in the first well separate from the first fluid injection means between the surface and in fluid communication with at least a portion of the petroleum containing zone above the portion thereof with which the first fluid injection means communicates;
c. establishing fluid communication between the second well and the full thickness of the petroleum-containing zone plus a distance into the top of the water-saturated zone equal to from about 5 to 15 percent of the thickness of the petroleum-containing zone;
d. injecting heated air into the first fluid injection means to establish an in situ combustion reaction at the point of contact between the bottom of the oil-containing zone and the top of the water-saturated zone;
e. continuing injection of air into the bottom of the oil-containing zone and the top of the water-saturated zone until the temperature in the petroleum formation above the zone in which the combustion reaction is occurring has been raised to at least 200.degree. F;
f. injecting water into the formation at a point about equal to the original oil-water contact to resaturate the burned out zone;
and
g. injecting a thermal fluid comprising steam into the second fluid injection means while continuing injecting air into the first fluid injection means and producing petroleum from the production well.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/699,752Filed 25 Jun 1976 · continuation in part
Priority: 8 Oct 1975
Granted: 17 Jan 1978
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

E21B 43/24
Enhanced recovery methods for obtaining hydrocarbons: using heat, e.g. steam injection
E21B 43/168
Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium: injecting a gaseous medium
E21B 43/243
Using heat, e.g. steam injection: combustion in situ
E21B
Earth or rock drilling