Drilling fluid and method for drilling a wellbore

• US 10,202,532 B2
• Filed: 03/06/2017
• Issued: 02/12/2019
• Est. Priority Date: 03/02/2007
• Status: Active Grant

• Current Assignee: Canadian Energy Services L.P. (Ces Energy Solutions Corp.)
• Original Assignee: Canadian Energy Services L.P. (Ces Energy Solutions Corp.)
• Inventors: Smith, Carl Keith
• Primary Examiner(s): Runyan, Silvana C
• Application Number:
  US15/451,002
• Publication Number:
  US 20170174973A1
• Time in Patent Office: 708 Days
• Field of Search: 1663051, 166 66, 1662421, 1662501
• CPC Class Codes: C09K 8/05 containing inorganic compounds only, e.g. mixtures of clay and salt
• CPC Class Codes: C09K 8/203 Wood derivatives, e.g. lignosulfonate, tannin, tall oil, sulfite liquor
• CPC Class Codes: C09K 8/206 Derivatives of other natural products, e.g. cellulose, starch, sugars
• CPC Class Codes: E21B 21/003 Means for stopping loss of drilling fluid plastering the borehole wall E21B33/138
• CPC Class Codes: E21B 21/062 by mixing components

Abstract

A method for drilling a wellbore into a formation uses a mixed metal-viscosified drilling fluid including at least 1% potassium salt and/or at least 0.05% calcium sulfate; circulating the drilling fluid through the well; and drilling into a formation. An anionic thinner may be added if the clay concentration of the drilling fluid reaches a problematic level to adversely affect pumpability of the fluid.

Claims

1. A method for drilling a borehole through a formation, the method comprising:

providing a mixed metal-viscosified drilling fluid including a mixed metal viscosifier which is a mixed metal layered hydroxide compound of the following empirical formula;

M′

_mM″

_n(OH)_{(2m+3n+qa+br)}(A^q)_a(B^r)_b.xH₂O,

where M′

represents at least one divalent metal cation and m is an amount of from greater than zero to 8;

where M″

represents at least one trivalent metal cation and n is an amount of from greater than zero to 6;

where A is an anion or negative-valence radical, and a is an amount of A ions of valence q, provided that if A is monovalent, a is from greater than zero to 8, and if A is polyvalent, a is from greater than zero to 4;

where B is a second anion or negative-valence radical, and where b is an amount of B ions of valence r and is from zero to 4;

provided (m+n) is greater than or equal to 1;

further provided qa+br cannot be greater than 2m+3n;

provided that qa cannot equal 2m+3n; and

still further provided that (2m+3n+qa+br) is less than 3; and

where xH₂O represents excess waters of hydration, with x being zero or more;

circulating the drilling fluid through the well while drilling into the formation;

identifying a condition of drilling indicative of a problematic increase in the clay concentration of the drilling fluid;

adding a potassium salt to the drilling fluid to bring the concentration to at least 1% w/v potassium salt;

adding an anionic thinner to the drilling fluid to adjust the viscosity of the drilling fluid; and

after adding the potassium salt, continuing to drill into the formation while circulating the drilling fluid through the borehole.

2. The method of claim 1 wherein providing the mixed metal-viscosified drilling fluid includes providing an aqueous-based drilling fluid including 15 to 45 kg/m3 bentonite, mixed metal viscosifier at a weight ratio of 1:

8 to 1;

12 relative to the weight of the bentonite.

3. The method of claim 1 wherein adding a potassium salt occurs during the step of providing.

4. The method of claim 1 wherein adding a potassium salt occurs after identifying.

5. The method of claim 1 wherein adding a potassium salt brings the concentration of potassium salt to 1 to 5% w/v.

6. The method of claim 1 further comprising adding any of fluid loss control additives or lost circulation materials.

7. The method of claim 1 wherein providing the mixed metal-viscosified drilling fluid provides a drilling fluid with a yield point greater than 10 Pa.

8. The method of claim 1 wherein adding an ionic thinner is initiated after identifying a condition of drilling indicative of a problematic increase in the clay concentration of the drilling fluid.

9. The method of claim 1 wherein adding an ionic thinner brings the fluid yield point to between 10 and 60 Pa.

10. The method of claim 1 wherein circulating the drilling fluid is initiated prior to drilling into a clay deposit.

11. The method of claim 1 wherein circulating the drilling fluid is maintained while a clay deposit is open to the drilling fluid.

12. The method of claim 1 wherein circulating the drilling fluid is initiated at surface.

13. The method of claim 1 wherein identifying includes determining the viscosity of the drilling fluid.

14. The method of claim 1 wherein identifying includes determining the clay concentration in the drilling fluid.

15. The method of claim 1 wherein identifying includes considering the location of the borehole relative to a known location of a clay deposit.

16. The method of claim 1 wherein the anionic thinner is selected from the group consisting of:

coal fines, lignite, lignite resin, humalite, tannin, poly-anionic cellulose, sodium acid pyrophosphate, tetra sodium pyrophosphate or xanthan gum.

17. The method of claim 1 wherein the anionic thinner is selected from the group consisting of:

coal fines, lignite, lignite resin, sulphomethylated lignite, lignosulfonate, humalite, tannin including sulfonated tannin, sodium asphalt sulfonate, poly-anionic cellulose, penta potassium pyrophosphate (PKPP), sodium acid pyrophosphate, tetra sodium pyrophosphate, sulphomethylated phenolic resin or xanthan gum.

18. The method of claim 1 wherein the potassium salt is selected from the group consisting of potassium sulfate, potassium chloride, potassium acetate and potassium formate.

19. The method of claim 1 wherein the potassium salt is potassium sulfate.

20. The method of claim 1 wherein the potassium salt is potassium chloride.

21. The method of claim 1 wherein the mixed metal viscosifier is [Mg_0.7Al_0.3(OH)₂](OH)_0.3 or Al/Mg(OH)_4.7Cl_0.3.

23. The method of claim 2 wherein providing the mixed metal-viscosified drilling fluid includes providing an aqueous-based drilling fluid including 15 to 45 kg/m3 bentonite, mixed metal viscosifier at a weight ratio of 1:

8 to 1;

12 relative to the weight of the bentonite.

24. The method of claim 2 wherein adding a calcium sulfate occurs during the step of providing.

25. The method of claim 2 wherein adding a calcium sulfate occurs after identifying.

26. The method of claim 2 wherein adding a calcium sulfate brings the concentration of calcium sulfate to 0.05 to 1.0% w/v.

27. The method of claim 2 further comprising adding any of fluid loss control additives or lost circulation materials.

28. The method of claim 2 wherein providing the mixed metal-viscosified drilling fluid provides a drilling fluid with a yield point greater than 10 Pa.

29. The method of claim 2 wherein adding an ionic thinner is initiated after identifying a condition of drilling indicative of a problematic increase in the clay concentration of the drilling fluid.

30. The method of claim 2 wherein adding an ionic thinner brings the fluid yield point to between 10 and 60 Pa.

31. The method of claim 2 wherein circulating the drilling fluid is initiated prior to drilling into a clay deposit.

32. The method of claim 2 wherein circulating the drilling fluid is maintained while a clay deposit is open to the drilling fluid.

33. The method of claim 2 wherein circulating the drilling fluid is initiated at surface.

34. The method of claim 2 wherein identifying includes determining the viscosity of the drilling fluid.

35. The method of claim 2 wherein identifying includes determining the clay concentration in the drilling fluid.

36. The method of claim 2 wherein identifying includes considering the location of the borehole relative to a known location of a clay deposit.

37. The method of claim 2 wherein the anionic thinner is selected from the group consisting of:

coal fines, lignite, lignite resin, humalite, tannin, poly-anionic cellulose, sodium acid pyrophosphate, tetra sodium pyrophosphate, or xanthan gum.

38. The method of claim 2 wherein the anionic thinner is selected from the group consisting of:

coal fines, lignite, lignite resin, sulphomethylated lignite, lignosulfonate, humalite, tannin including sulfonated tannin, sodium asphalt sulfonate, poly-anionic cellulose, penta potassium pyrophosphate (PKPP), sodium acid pyrophosphate, tetra sodium pyrophosphate, sulphomethylated phenolic resin or xanthan gum.

39. The method of claim 2 wherein the mixed metal viscosifier is [Mg_0.7Al_0.3(OH)₂](OH)_0.3 or Al/Mg(OH)_4.7Cl_0.3.

22. A method for drilling a borehole through a formation, the method comprising:

providing a mixed metal-viscosified drilling fluid including a mixed metal viscosifier which is a mixed metal layered hydroxide compound of the following empirical formula;

M′

_mM″

_n(OH)_{(2m+3n+qa+br)}(A^q)_a(B^r)_b.xH₂O,

where M′

represents at least one divalent metal cation and m is an amount of from greater than zero to 8;

where M″

represents at least one trivalent metal cation and n is an amount of from greater than zero to 6;

where A is an anion or negative-valence radical, and a is an amount of A ions of valence q, provided that if A is monovalent, a is from greater than zero to 8, and if A is polyvalent, a is from greater than zero to 4;

where B is a second anion or negative-valence radical, and where b is an amount of B ions of valence r and is from zero to 4;

provided (m+n) is greater than or equal to 1;

further provided qa+br cannot be greater than 2m+3n;

provided that qa cannot equal 2m+3n; and

still further provided that (2m+3n+qa+br) is less than 3; and

where xH₂O represents excess waters of hydration, with x being zero or more;

circulating the drilling fluid through the well while drilling into the formation;

identifying a condition of drilling indicative of a problematic increase in the clay concentration of the drilling fluid;

adding calcium sulfate to the drilling fluid to bring the concentration to at least 0.05% w/v calcium sulfate in the drilling fluid;

adding an anionic thinner to the drilling fluid to adjust the viscosity of the drilling fluid; and

,

after adding the calcium sulfate, continuing to drill into the formation while circulating the drilling fluid through the borehole.