# US 4,397,352 A · In situ combustion of tar sands with injection of gases

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- Number: US 4,397,352 A
- Document ID: US4397352A
- Status: Granted
- Kind: A
- Application number: 06/260,521
- Filed: 1981-05-04
- Granted: 1983-08-09
- Earliest claimed: 1980-11-03
- Assignees: Mobil Oil Corporation
- Inventors: Costandi A. Audeh
- Web page: https://patentgrep.com/patent/US4397352A

## CPC

- E21B 43/243: Combustion in situ
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

In-situ combustion of heavy subterranean oil formations, e.g., tar sands, is improved by introducing into the oil formation a stream of a combustible gas. The stream of gas may contain a small proportion of hydrocarbons condensable at temperature and pressure conditions of the formation. The improvement is applicable to both forward and reverse in-situ combustion processes.

## Claims

### Claim 1

In a process for the recovery of petroliferous products from a subterranean formation including tar sand deposits by in-situ combustion, the improvement comprising introducing into said subterranean formation, prior to the commencement of the combustion, a stream of a combustible gas selected from the group consisting of a relatively light hydrocarbon gas having a condensation point of -173.degree. C. to -43.degree. C. at a pressure of one atmosphere and hydrogen sulfide, said combustible gas introduced in an amount to substantially saturate the formation with said gas.

### Claim 2 (depends on 1)

A process according to claim 1 wherein said stream of combustible gas is introduced into said subterranean formation at the pressure of 20 atmospheres to 100 atmospheres.

### Claim 3 (depends on 2)

A process according to claim 2 wherein said combustible gas contains 1% to 10% by volume of a condensable compound having a condensation point of not more than 100.degree. C. at ambient pressure.

### Claim 4 (depends on 3)

A process according to claim 3 wherein said condensable compound is normal butane, iso-butane, normal pentane, isopentane, hexane, heptane, isomers thereof, or mixtures thereof, methylamine, t-butylamine, ethylamine and mixtures thereof.

### Claim 5 (depends on 1)

A process according to claim 1 wherein said condensation point of said relatively light hydrocarbon gas is -163.degree. C. to -43.degree. C. at a pressure of one atmosphere.

### Claim 6 (depends on 5)

A process according to claim 5 wherein said relatively light hydrocarbon gas is introduced into said subterranean formation at the pressure of about 60 atmospheres to about 80 atmospheres.

### Claim 7 (depends on 6)

A process according to claim 6 wherein said stream of relatively light hydrocarbon gas is methane, ethane, propane, natural gas or mixtures thereof.

### Claim 8 (depends on 7)

A process according to claim 7 wherein said stream of relatively light hydrocarbon gas contains 1% to 10% by volume of a condensable hydrocarbon gas having a condensation point of not more than 100.degree. C. at a pressure of one atmosphere.

### Claim 9 (depends on 8)

A process according to claim 8 wherein said condensable hydrocarbon gas is normal butane, iso-butane, normal pentane, isopentane, hexane, heptane, isomers thereof, or mixtures thereof.

### Claim 10 (depends on 1)

A process according to claim 1 wherein said combustible gas is hydrogen sulfide.

### Claim 11 (depends on 1)

The method of claim 1 wherein said combustible gas is a relatively light hydrocarbon gas.