Downhole assembly for treating wellbore components, and method for treating a wellbore

• US 8,950,491 B2
• Filed: 11/27/2012
• Issued: 02/10/2015
• Est. Priority Date: 01/06/2012
• Status: Active Grant

• Current Assignee: Odessa Separator, Inc
• Original Assignee: Odessa Separator, Inc
• Inventors: Frost, Cavin B.
• Primary Examiner(s): Neuder, William P
• Application Number:
  US13/686,162
• Publication Number:
  US 20130327528A1
• Time in Patent Office: 805 Days
• Field of Search: 166/300, 166/304, 166/310, 166/369, 166/910, 166/902
• US Class Current: 166/304
• CPC Class Codes: E21B 37/06 using chemical means for preventing or limiting , e.g. eliminating, the deposition of paraffins or like substances

Abstract

A downhole assembly for delivering chemical treatment to a wellbore at the level of a hydrocarbon-bearing formation is provided. The chemical treatment is in solid phase, and slowly dissolves when exposed to wellbore fluids. A method of treating a wellbore using a solid chemical is also provided.

Claims

1. A downhole assembly for delivering chemical treatment to a wellbore, comprising:

a first tubular body;

a second tubular body residing substantially concentrically within the first tubular body, the second tubular body being porous to provide fluid communication between the first tubular body and a bore within the second tubular body;

an annular region between the second tubular body and the surrounding first tubular body;

a chemical treating material, wherein;

the chemical treating material is in solid phase but is dissolvable upon contact with a wellbore fluid and is designed to (i) inhibit a build-up of precipitate on components in the wellbore, (ii) remove scale on components in the wellbore, (iii) prevent a build-up of bacteria in the wellbore, (iv) prevent a build-up of paraffin in the wellbore, or (v) combinations thereof;

the chemical treating material resides within either a bore of the second tubular body or the annular region around the second tubular body; and

the chemical treating material is a continuous solid material in the shape of one or more discs; and

the discs reside in the annular region between the second tubular body and the surrounding first tubular body; and

the second tubular body is a perforated tubing; and

the surrounding first tubular body is a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material.

2. The downhole assembly of claim 1, wherein the solid chemical treating material comprises one or more discs having a first rate of dissolution, and one or more discs having a second rate of dissolution that is slower than the first rate of dissolution, with the discs being stacked in the annular region.

3. The downhole assembly of claim 1, wherein:

the second tubular body defines a screen having slots;

the first tubular body defines a blank pipe; and

the downhole assembly further comprises;

an upper perforated tubular section having a bore, the bore being in fluid communication with the bore of the screen, and the upper perforated tubular being operatively connected to a first end of the screen;

a lower perforated tubular section having a bore, the bore also being in fluid communication with the bore of the screen, and the lower perforated tubular body being operatively connected to a second opposite end of the screen.

4. The downhole assembly of claim 1, wherein the downhole assembly is sealed at opposing ends.

5. The downhole assembly of claim 1, wherein:

the chemical treating material is a continuous solid material in the shape of one or more cylinders; and

the cylinders reside in the bore of the second tubular body.

6. The downhole assembly of claim 5, wherein:

the second tubular body is a perforated tubing; and

the surrounding first tubular body is a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material.

7. The downhole assembly of claim 6, wherein the solid chemical treating material comprises one or more cylinders having a first rate of dissolution and one or more cylinders having a second rate of dissolution that is slower than the first rate of dissolution.

8. The downhole assembly of claim 6, wherein the assembly resides within a wellbore below a downhole pump.

9. The downhole assembly of claim 6, further comprising:

a bull plug at a lower end of the screen to seal the lower end of the downhole assembly to fluid flow.

10. The downhole assembly of claim 6, further comprising:

a no-flow nipple or a collar with a blank plate at an upper end of the downhole assembly to seal the upper end of the downhole assembly to fluid flow.

11. The downhole assembly of claim 6, further comprising:

a section of blank tubing disposed at an end of the second tubular body and having a bore that is in fluid communication with the bore of the second tubular body;

wherein the bore of the section of blank pipe contains one or more cylinders of the chemical treating material.

12. The downhole assembly of claim 5, wherein:

the second tubular body comprises a first perforated section and a second perforated section;

the surrounding first tubular body comprises a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material, with a first portion of wire-wrapped screen being placed around the first perforated section, and a second portion of wire-wrapped screen being placed around the second perforated section;

the downhole assembly further comprises a section of blank tubing disposed between the first perforated section and the second perforated section;

the section of blank tubing, the first perforated section and the second perforated section are all part of a same joint of tubing sharing a same bore, with the bore containing one or more cylinders of the solid chemical treating material.

13. A downhole assembly for delivering chemical treatment to a wellbore, comprising:

a first tubular body defining a wire-wrapped screen;

a second tubular body residing substantially concentrically within the first tubular body, the second tubular body defining a section of perforated tubing that provides fluid communication between the first tubular body and a bore within the second tubular body;

a plug at a lower end of the second tubular body providing a fluid seal to a bottom of the downhole assembly;

a first section of blank pipe disposed at an upper end of the second tubular body and having a bore that is in fluid communication with the bore of the second tubular body; and

a chemical treating material, wherein;

the chemical treating material is in a solid phase but is dissolvable upon contact with a wellbore fluid and is designed to (i) inhibit a build-up of precipitate on components in the wellbore, (ii) remove scale and corrosion on components in the wellbore, (iii) prevent a build-up of bacteria in the wellbore, (iv) prevent a build-up of paraffin in the wellbore, or (v) combinations thereof;

the chemical treating material resides within the bore of the second tubular body and in the bore of the section of blank pipe; and

the chemical treating material is in the form of two or more substantially solid cylinders.

14. The downhole assembly of claim 13, further comprising:

a no-flow nipple or a collar with a blank disc at an upper end of the downhole assembly to seal the upper end of the downhole assembly.

15. The downhole assembly of claim 14, wherein the assembly resides within a wellbore below a downhole pump.

16. The downhole assembly of claim 13, wherein the solid chemical treating material comprises one or more cylinders having a first rate of dissolution and one or more cylinders having a second rate of dissolution that is slower than the first rate of dissolution.

17. The downhole assembly of claim 16, wherein the solid chemical treating material comprises one or more cylinders having a dissolvable membrane to delay dissolution of the solid chemical treating material.

18. The downhole assembly of claim 16, wherein the wire-wrapped screen comprises slots dimensioned to control a rate of dissolution of the solid chemical treating material within the second tubular body.

19. The downhole assembly of claim 13, wherein:

the section of blank pipe and the second tubular body are part of a same joint of tubing sharing a same bore, with the bore containing one or more cylinders of the solid chemical treating material.

20. The downhole assembly of claim 19, further comprising:

a vent above the section of blank pipe, the vent comprising a section of perforated tubing forming a bore, and a wire-wrapped screen around the section of perforated tubing; and

wherein the section of perforated tubing in the vent and the first section of blank pipe are part of a same joint of tubing sharing a same bore.

21. The downhole assembly of claim 20, further comprising:

a second section of blank pipe residing between a no-flow nipple or a collar with a blank disc, and the vent; and

wherein the chemical treating material further resides within the bore of the perforated tubing within the vent.

22. A method of treating a wellbore using a solid treating material, comprising:

running a downhole assembly into a wellbore, the downhole assembly comprising;

a first tubular body;

a second tubular body residing substantially concentrically within the first tubular body, the second tubular body being porous to provide fluid communication between the first tubular body and a bore within the second tubular body;

an annular region between the second tubular body and the surrounding first tubular body;

a chemical treating material, wherein;

the chemical treating material is in solid phase but is dissolvable upon contact with a wellbore fluid and is designed to (i) inhibit a build-up of precipitate on components in the wellbore, (ii) remove scale and corrosion on components in the wellbore, (iii) prevent a build-up of bacteria in the wellbore, (iv) prevent a build-up of wax or paraffin in the wellbore, or (v) combinations thereof;

the chemical treating material resides within either the second tubular body or the annular region around the second tubular body; and

the chemical treating material is a continuous solid material in the shape of one or more discs; and

the discs reside in the annular region between the second tubular body and the surrounding first tubular body; and

the second tubular body is a perforated tubing; and

the surrounding first tubular body is a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material.

23. The method of claim 22, wherein the solid chemical treating material comprises one or more discs having a first rate of dissolution and one or more discs having a second rate of dissolution that is slower than the first rate of dissolution, with the discs being stacked in the annular region.

24. The method of claim 22, wherein:

the chemical treating material is a continuous solid material in the shape of one or more cylinders; and

the cylinders reside in the bore of the second tubular body.

25. The method of claim 24, wherein:

the second tubular body is a perforated tubing; and

the surrounding first tubular body is a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material.

26. The method of claim 25, wherein the assembly resides within the wellbore below a downhole pump.

27. The method of claim 26, wherein the solid chemical treating material comprises one or more cylinders having a first rate of dissolution and one or more cylinders having a second rate of dissolution that is slower than the first rate of dissolution.

28. The method of claim 25, further comprising:

a bull plug or a blank disc at a lower end of the screen to seal a lower end of the downhole assembly.

29. The method of claim 25 further comprising:

a reversible no-flow nipple or a collar having a blank disc at an upper end of the downhole assembly to seal the upper end of the downhole assembly.

30. The method of claim 24, further comprising:

a section of blank pipe disposed at an end of the second tubular body and having a bore that is in fluid communication with the bore of the second tubular body;

wherein the bore of the section of blank pipe contains one or more cylinders of the chemical treating material.

31. The method of claim 22, further comprising:

threadedly connecting the downhole assembly to the lower end of a seating nipple or a joint of production tubing as part of running the downhole assembly into the wellbore.

32. The method of claim 31, further comprising:

producing hydrocarbon fluids from the wellbore.

33. The method of claim 25, further comprising:

determining a slot width that correlates to a dissolution rate of the chemical treating material in the wellbore.

34. The method of claim 33, wherein the slot width is between about 0.006 and 0.075 inches.

35. The method of claim 30, wherein:

the section of blank pipe is between about 2 and 20 feet (0.61 and 6.1 meters) in length; and

the second tubular body is between about 6 inches and 10 feet (0.15 and 3.05 meters) in length.

36. The method of claim 35, further comprising:

providing one or more cylinders of solid chemical material having a first rate of dissolution; and

providing one or more cylinders of solid chemical material having a second rate of dissolution that is slower than the first rate of dissolution.

37. The method of claim 36, further comprising:

placing at least one of the one or more cylinders having a first rate of dissolution in the bore of the second tubular body; and

placing at least one of the one or more cylinders having a second rate of dissolution in the bore of the second tubular body.

38. The method of claim 30, wherein:

the second tubular body comprises a first perforated section and a second perforated section;

the surrounding first tubular body comprises a wire-wrapped screen having slots dimensioned to control a rate of dissolution of the solid chemical treating material, with a first portion of wire-wrapped screen being placed around the first perforated section, and a second portion of wire-wrapped screen being placed around the second perforated section;

the downhole assembly further comprises a section of blank tubing disposed between the first perforated section and the second perforated section;

the section of blank tubing, the first perforated section and the second perforated section are all part of a same joint of tubing sharing a same bore, with the bore containing one or more cylinders of the solid chemical treating material.

39. The method of claim 38, further comprising:

a vent above the section of blank tubing, the vent comprising a section of perforated tubing forming a bore, and a wire-wrapped screen around the section of perforated tubing; and

wherein the section of perforated tubing in the vent and the section of blank tubing are part of a same joint of tubing sharing a same bore.