USE OF DIVERTING AGENTS FOR INJECTION WELL STIMULATION

• US 3,707,194 A
• Filed: 07/13/1971
• Issued: 12/26/1972
• Est. Priority Date: 07/13/1971
• Status: Expired due to Term

• Current Assignee: Marathon Oil Company (Marathon Oil Corporation)
• Original Assignee: Marvin A. Svaldi
• Inventors: Svaldi, Marvin A.
• Primary Examiner(s): Novosad, Stephen J.
• Application Number:
  US05/162,288
• Time in Patent Office: 532 Days
• Field of Search: 166/35R,274,275,284,281,282
• US Class Current: 166/305.1
• CPC Class Codes: C09K 8/882 obtained by reactions only involving carbon-to-carbon unsaturated bonds

Abstract

The injectivity profile of an injection well in fluid communication with an oil-bearing, heterogeneous formation, is improved by incorporating a diverting agent into the front portion of a micellar solution or by intermittently injecting micellar solution followed by a diverting agent-the result is to stimulate the reservoir rock and to obtain a uniform injectivity profile. The total amount of micellar solution useful to stimulate the injection well is 1-500 gallons per vertical foot of oil-bearing formation. The amount of diverting agent necessary will depend upon the heterogeneity of the formation; where intermittent slugs of micellar dispersion and diverting agent are injected, the amount of diverting agent can be from about 0.1 to about 50 or more volumes per volume of injected micellar dispersion. Examples of diverting agents include aqueous and hydrocarbon solutions containing fibrous material, laminated material, glutinous material, or other like materials which tend to '"'"''"'"''"'"''"'"'block'"'"''"'"''"'"''"'"' the reservoir rock. Preferably, the diverting agent is one that is soluble in water. A third slug can be injected to solubilize the diverting agent and optionally acid can be injected after the micellar solution and diverting agent to increase the injectivity index.

Claims

2. The process of claim 1 wherein a solvent to solubilize the diverting agent is injected after the micellar dispersion is injected into the formation.

3. The process of claim 1 wherein the diverting agent is a high molecular weight organic polymer.

4. The process of claim 1 wherein the diverting agent is a partially hydrolyzed, high molecular weight polyacrylamide.

5. A process for improving the injectivity profile of an injection well in fluid communication with an oil-bearing, heterogeneous formation having substantially differing permeabilities, the process comprising injecting into the formation 1 to about 500 gallons of a micellar dispersion per vertical foot of the formation, the micellar dispersion intermittently containing a high molecular weight organic polymer in sufficient amounts to substantially '"'"''"'"''"'"''"'"'block'"'"''"'"''"'"''"'"' the more permeable zones of the formation, the result being to obtain a more uniform injectivity profile.

6. The process of claim 5 wherein a solvent is injected after the micellar dispersion to substantially remove the organic polymer from the formation in the immediate vicinity of the injection well.

7. The process of claim 5 wherein the organic polymer is a partially hydrolyzed, high molecular weight polyacrylamide.

8. The process of claim 7 wherein sodium hypochlorite or hydrazine is injected after the micellar dispersion to substantially remove any of the polyacrylamide that becomes adsorbed on the reservoir rock within the immediate vicinity of the well bore.

9. The process of claim 5 wherein an aqueous acidic solution is injected after the micellar solution to further increase the injectivity index.