Degradable ball sealers and methods for use in well treatment

• US 20070169935A1
• Filed: 12/18/2006
• Published: 07/26/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: Fairmount Santrol Inc. (Covia Holdings LLC)
• Original Assignee: Fairmount Minerals Incorporated
• Inventors: Akbar, Syed, Okell, Patrick, Sinclair, A.
• Granted Patent: US 7,647,964 B2
• Time in Patent Office: Days
• US Class Current: 166/284
• CPC Class Codes: E21B 33/138 Plastering the borehole wall; Injecting into the formation

Abstract

Described is an oil-degradable ball sealer for use in the oil and gas industry. The ball seal comprises a particular composition including ethylene and one or more alpha-olefins, prepared by an injection molding technique to provide a ball sealer which will dissolve in stimulation or wellbore fluids after stimulation operations are complete. The composition, when dissolved into wellbore fluids, does not pose a hazard or problem to aqueous wellbore fluids or further wellbore stimulations.

Claims

1. A ball sealer for substantially plugging perforations in a well casing, the ball sealer comprising:

a polymeric composition comprised of a copolymer of ethylene and an alpha-olefin; and

filler material, wherein the filler material is added to the polymeric composition in a amount sufficient to provide the ball sealer with a density of about 0.70 g/cc to about 1.5 g/cc.

2. The ball sealer of claim 1, wherein the amount of ethylene in the polymeric composition is about 20 wt. % to about 90 wt. %.

3. The ball sealer of claim 1, wherein the amount of alpha-olefin in the polymeric composition is about 1 wt. % to about 60 wt. %.

4. The ball sealer of claim 1, wherein the alpha-olefin is a C₃-C₁₂ alpha-olefin.

5. The ball sealer of claim 2, wherein the C₃-C₁₂ alpha-olefin is selected from the group consisting of 1-propene, 1-butene, 4-methyl-1-pentene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and styrene.

6. The ball sealer of claim 2, wherein the alpha-olefin is a substituted, un-substituted, linear, cyclic or branched alpha-olefin.

7. The ball sealer of claim 1, wherein the filler material comprises about 10 wt. % to about 40 wt. % of the ball sealer.

8. The ball sealer of claim 1, wherein the filler material is selected from the group consisting of natural organic materials, silica materials, ceramic materials, metallic materials, synthetic organic materials, and combinations thereof.

9. The ball sealer of claim 1, wherein the filler material is bauxite ceramic.

10. The ball sealer of claim 1, wherein the filler material is silica sand.

11. The ball sealer of claim 1, wherein the ball sealer is substantially spherical in shape.

12. The ball sealer of claim 1, wherein the ball sealer is polygonal in shape.

13. The ball sealer of claim 1, wherein the ball sealer has a density of about 0.8 g/cc to about 1.4 g/cc.

14. The ball sealer of claim 1, wherein the ball sealer has a density in of about 0.80 g/cc to about 0.86 g/cc.

15. The ball sealer of claim 1, wherein the ball sealer comprises a hollow core.

16. The ball sealer of claim 1 wherein the ball sealer comprises a solid core.

17. The ball sealer of claim 1 wherein the ball sealer is soluble in wellbore fluids at subterranean formation conditions.

18. A method for treating a subterranean formation surrounding a cased wellbore having an interval provided with a plurality of perforations, the method comprising:

flowing down the casing to the perforated interval a plurality of ball sealers of claim 1 suspended in a first liquid medium; and

continuing the flow of the first liquid medium until the ball sealers seal at least a portion of the perforations.