Electrical device for promoting oil recovery

• US 4,466,484 A
• Filed: 05/28/1982
• Issued: 08/21/1984
• Est. Priority Date: 06/05/1981
• Status: Expired due to Fees

• Current Assignee: The Coe Manufacturing Company (USNR, LLC)
• Original Assignee: Syminex
• Inventors: Kermabon, Andre J.
• Primary Examiner(s): Novosad, Stephen J.
• Assistant Examiner(s): Dang, Hoang C.
• Application Number:
  US06/383,166
• Time in Patent Office: 816 Days
• Field of Search: 166/248, 166/65 R, 166/60, 166/302, 219/277, 219/278, 204/180 R, 204/299 R
• US Class Current: 166/60
• CPC Class Codes: E21B 36/003 Insulating arrangements
• CPC Class Codes: E21B 43/2401 by means of electricity

Abstract

The present invention relates to a method and device for promoting oil recovery.

The device according to the invention for promoting the recovery of oil contained in a reservoir formation from a well equipped with a casing, comprises an anode which is placed at the bottom of the well, below said reservoir formation, in an electro-conductive liquid, and which is connected to the positive terminal of a direct or pulsed source of unidirectional voltage. Said casing is connected to the negative terminal of said source. The method consists in applying a unidirectional voltage for periods varying between several days and several months and alternating with OFF-period (when no voltage is applied).

Claims

1. Electrical device for promoting the recovery of oil contained in a reservoir formation from a production well which is completed with a metallic casing extending at least as far as the roof of said reservoir formation and with a metallic production tubing which is electrically insulated from said casing, which device comprises:

a vertical extension of said well below said formation;

an electro-conductive medium placed in said vertical extension;

a source of unidirectional voltage situated on the surface;

an electrode electrically connected to the lower end of said production tubing, the lower end of said production tubing being equipped with a non-return valve and the upper end of said electrode being electrically connected to the body of said non-return valve, said electrode being situated in said vertical extension and being covered with an insulating sheath except over several meters at the lower end contacting said electro-conductive medium;

means electrically connecting the positive terminal of said source of unidirectional voltage to the upper end of said tubing and the negative terminal of said source to the upper end of said casing and means permitting to apply the unidirectional voltage supplied by said source, in direct or pulsed manner, for predetermined periods of several days to several months alternating with off periods of several days to several months.

2. Electrical device for promoting the recovery of oil contained in a reservoir formation from a production well which is completed with a metallic casing extending at least as far as the roof of said reservoir formation and with a metallic production tubing which is electrically insulated from said casing, which device comprises:

a vertical extension of said well below said formation;

an electro-conductive medium placed in said vertical extension;

a source of unidirectional voltage situated on the surface;

an electrode electrically connected to the lower end of said production tubing, said electrode being situated in said vertical extension and being covered with an insulating sheath except over several meters at the lower end contacting said electro-conductive medium;

means electrically connecting the positive terminal of said source of unidirectional voltage to the upper end of said tubing and the negative terminal of said source to the upper end of said casing and means permitting to apply the unidirectional voltage supplied by said source, in direct or pulsed manner, for predetermined periods of several days to several months, alternating with off periods of several days to several months, said electrode being a conductive rod which is placed vertically in said extension and which is covered with an insulating sheath except over some meters at the lower end which contact said electro-conductive medium and the upper end of said rod being secured and electrically connected to the lower end of said production tubing.

3. Electrical device for promoting the recovery of oil contained in a reservoir formation from at least two production wells remote from one another, each of which is equipped with a metallic casing and with a metallic production tubing, which device comprises:

a vertical extension of one of said wells below said formation;

an electro-conductive medium placed in said vertical extension;

two sources of unidirectional voltage situated on the surface;

an electrode placed in said vertical extension, which contacts said electro-conductive medium and which is connected in parallel to the positive terminals of said sources by connecting means insulated from said formation and from the casing of said one of said wells;

means connecting the negative terminals of said sources respectively to said casing of said one of said wells and, in parallel, to said casing and to said tubing of said at least one other well;

means permitting to apply the unidirectional voltages supplied by said sources, in direct or pulsed manner, for predetermined periods of several days to several months alternating with OFF-periods of several days to several months.