# US 5,341,875 A · Injection of phosphorus nutrient sources under acid conditions for subterranean microbial processes

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- Number: US 5,341,875 A
- Document ID: US5341875A
- Status: Granted
- Kind: A
- Application number: 07/994,859
- Filed: 1992-12-22
- Granted: 1994-08-30
- Earliest claimed: 1992-12-22
- Assignees: Phillips Petroleum Company
- Inventors: Gary E. Jenneman; Bennett Clark
- Web page: https://patentgrep.com/patent/US5341875A

## CPC

- C09K 8/58: Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE

## Abstract

The present invention provides a process for injecting microbial nutrients into a subterranean formation wherein microorganism are provided a phosphorus nutrient source, and said phosphorus nutrient source into said formation under acid conditions.

## Claims

### Claim 1

In a process for injecting microbial nutrients into a subterranean formation wherein microorganisms are provided a phosphorus nutrient source, the improvement which comprises introducing as said phosphorus nutrient source a solution of an inorganic phosphate wherein said inorganic phosphate solution is acidified by the addition of an acid in an amount sufficient to achieve a pH in the range of about 1.0 to about 5.5, and then injected into said formation.

### Claim 2 (depends on 1)

A process according to claim 1 wherein said inorganic phosphate solution to be injected has the pH of about 4.5.

### Claim 3 (depends on 1)

A process according to claim 1 wherein said acid conditions are achieved by the addition of an acid selected from the group consisting of hydrochloric acid, phosphoric acid, nitric acid, and sulfuric acid to said inorganic phosphate solution prior to addition of same to said formation.

### Claim 4 (depends on 3)

A process according to claim 3 wherein said acid is hydrochloric acid.

### Claim 5 (depends on 1)

A process according to claim 1 wherein said acid conditions are additionally achieved by the pre-flooding of a reservoir with a strong acid in an amount sufficient to dissolve acid-soluble minerals, and said acid is selected from the group consisting of hydrochloric acid, phosphoric acid, nitric acid and sulfuric acid.

### Claim 6 (depends on 5)

A process according to claim 5 wherein said acid is hydrochloric acid.