Treatment of oil wells

• US 20050126784A1
• Filed: 12/10/2003
• Published: 06/16/2005
• Est. Priority Date: 12/10/2003
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Dalton, Dan
• Granted Patent: US 7,216,712 B2
• Time in Patent Office: Days
• US Class Current: 166/304
• CPC Class Codes: C09K 8/524 organic depositions, e.g. paraffins or asphaltenes

Abstract

Hydrocarbon solids are removed from an oil well by feeding into the oil well a composition comprising at least 40 vol. % dense phase carbon dioxide and at least 30 vol. % of a C₁-C₃ alkanol component and optionally one or more surfactants, under a pressure of 300 to 10,000 psia and a temperature of 90° F. to 120° F., holding the composition in the well to solubilize hydrocarbon solids, and then removing from the well a liquid composition comprising solubilized hydrocarbon solids and alkanol.

Claims

1. A method for removing hydrocarbon solids from an oil well comprising

(a) feeding into an oil well having hydrocarbon solids therein a feed composition comprising at least 40 vol. % dense phase carbon dioxide and at least 30 vol. % of an alkanol component selected from the group consisting of alkanols containing 1 to 3 carbon atoms and mixtures thereof, and optionally one or more surfactants, under a pressure of 300 to 10,000 psia and a temperature of 90°

F. to 120°

F.,

(b) allowing the feed composition to remain in the well, whereby hydrocarbon solids in the well solubilize with said composition, and then

(c) removing from said well a liquid product composition comprising said solubilized hydrocarbon solids and alkanol.

2. A method according to claim 1 wherein the feed composition that is fed in step (a) also comprises a surfactant component.

3. A method according to claim 2 wherein the surfactant component is present in said feed composition when the feed composition is fed into said oil well.

4. A method according to claim 1 further comprising feeding a surfactant component into said oil well after said feed composition is fed into said oil well, and before said liquid product composition is removed from said well.

5. A method according to claim 1 wherein said feed composition comprises at least 50 vol. % dense phase carbon dioxide.

6. A method according to claim 5 wherein said feed composition is fed at a temperature of 90°

F. to 110°

F.

7. A method according to claim 1 wherein said feed composition is fed at a temperature of 90°

F. to 110°

F.

8. A method according to claim 1 wherein said feed composition is free of aromatic compounds.