Product and method for treating well bores

• US 6,655,475 B1
• Filed: 11/09/2001
• Issued: 12/02/2003
• Est. Priority Date: 01/23/2001
• Status: Expired due to Term

• Current Assignee: Wald H. Lester
• Original Assignee: Wald H. Lester
• Inventors: Wald, H. Lester
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): Smith, Matthew J.
• Application Number:
  US10/035,531
• Time in Patent Office: 753 Days
• Field of Search: 175/72, 175/64, 175/65, 175/308, 175/309, 175/68, 166/162, 166/117, 166/285, 206/524.7
• US Class Current: 175/64
• CPC Class Codes: E21B 21/00 Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor freeing objects stuck in boreholes by flushing E21B31/03
• CPC Class Codes: E21B 27/02 Dump bailers, i.e. containers for depositing substances, e.g. cement or acids

Abstract

A product, system and method for treating a well bore using a concentrated treatment composition enclosed in a soluble container. The composition-filled container is deposited in the well, preferably through the drill string, followed by a solvent, such as drilling mud or water, to form a circulating solution characterized by the ability to circulate through the well. Most of the circulating solution is recovered at the surface using a mud tank, for example. In a well “sweeping” operation a partially hydrolyzed polyacrylamide powder in a soluble tube is dropped down the drill string. The well bore is then flushed with water or drilling mud to form the liquified polymer down hole. The well is flushed with more water or mud to sweep the cuttings and polymer solution from the well bore.

Claims

1. A well treatment product for use with a treatment solvent in an elongate conduit in a well bore, the product comprising:

a concentrated well treatment composition soluble in the treatment solvent to form a circulating solution characterized by the ability to circulate through the well;

a container enclosing the composition, wherein the container is adapted to be deposited in the conduit at the surface and passed down through the elongate conduit, and wherein the container is inert to the treatment composition and is at least partially soluble in the treatment solvent to release the composition in the conduit and to form the treatment solution inside the conduit.

2. The product of claim 1 wherein the composition comprises a polymer.

3. The product of claim 1 wherein the composition comprises a partially hydrolyzed polyacrylamide.

4. The product of claim 1 wherein the composition comprises a partially hydrolyzed polyacrylamide in particulate form.

5. The product of claim 1 wherein the composition comprises a copolymer of sodium acrylate and acrylamide in particulate form.

6. The product of claim 5 wherein the solvent is drilling mud.

7. The product of claim 6 wherein the container is formed entirely of material that is soluble in the solvent.

8. The product of claim 7 wherein the container is an elongate cylindrical tube.

9. The product of claim 1 wherein the solvent comprises drilling mud.

10. The product of claim 1 wherein the container is formed entirely of material that is soluble in the solvent.

11. A method for treating a well bore comprising:

depositing in the well bore from the surface through an elongate conduit an effective amount of a treatment composition that is soluble in a selected solvent to form a circulating solution characterized by the ability to circulate through the well bore, wherein the treatment composition is enclosed in a container that is inert to the treatment composition and that is at least partially soluble in the selected solvent;

depositing an effective amount of the selected solvent in the well bore through the elongate conduit to decompose the container and dissolve the treatment composition inside the conduit and form the circulating solution therein;

circulating the circulating solution down through the conduit and back up through the annular space between the conduit and the well bore; and

recovering a significant portion of the circulating solution at the surface.

12. The method of claim 11 wherein the elongate conduit is a drill string with a drill bit on the end.

13. The method of claim 12 wherein the treatment composition comprises a polymer.

14. The method of claim 13 wherein the treatment composition comprises a partially hydrolyzed polyacrylamide.

15. The method of claim 14 wherein the treatment composition comprises a copolymer of sodium acrylate and acrylamide in particulate form.

16. The method of claim 15 wherein the container is formed entirely of material that is soluble in the selected solvent.

17. The method of claim 16 wherein the selected solvent comprises drilling mud.

18. The method of claim 11 wherein the selected solvent comprises drilling mud.

19. The method of claim 18 wherein the circulating solution is recovered using a circulating assembly.

20. The method of claim 11 wherein the circulating solution is circulated and recovered using a circulating assembly.

21. The method of claim 11 wherein the treatment composition comprises a copolymer of sodium acrylate and acrylamide in particulate form.

22. The method of claim 11 wherein the container is formed entirely of material that is soluble in the solvent.

23. A system for treating a well bore, the system comprising:

an elongate conduit sized to be inserted down the well bore;

a solvent;

a container sized to be received in the conduit and characterized in that it is at least partially soluble in the solvent while in the conduit; and

a treatment composition in the container the composition characterized as soluble in the solvent while in the conduit to form a circulating solution therein, wherein the circulating solution is characterized by the ability to circulate down through the conduit and up through the annular space between the conduit and the well;

wherein the container is inert to the treatment composition.

24. The system of claim 23 wherein the treatment composition comprises a polymer.

25. The system of claim 23 wherein the treatment composition comprises a partially hydrolyzed polyacrylamide.

26. The system of claim 23 wherein the treatment composition comprises a partially hydrolyzed polyacrylamide in particulate form.

27. The system of claim 23 wherein the treatment composition comprises a copolymer of sodium acrylate and acrylamide in particulate form.

28. The system of claim 27 wherein the solvent comprises drilling mud.

29. The system of claim 23 wherein the solvent comprises drilling mud.

30. The system of claim 29 wherein the container is further characterized as formed entirely of material that is soluble in the solvent.

31. The system of claim 30 wherein the container is an elongate, cylindrical tube.

32. The system of claim 23 wherein the container is further characterized as formed entirely of material that is soluble in the solvent.

33. The system of claim 23 wherein the container is an elongate, cylindrical tube.

34. The system of claim 23 further comprising an elongate conduit positioned in the well bore, a fluid circulating pump fluidly connected to the well bore near the surface to receive circulating solution returning from the well bore and fluidly connected to the elongate conduit to deliver circulating solution to the bottom of the well bore.

35. The system of claim 34 wherein the elongate conduit is a drill string, wherein the solvent is drilling mud, wherein the treatment composition comprises a copolymer of sodium acrylate and acrylamide in particulate form, and wherein the container is formed entirely of material that is soluble in the solvent.