Solids composition based on clay minerals and use thereof

• US 6,025,303 A
• Filed: 06/25/1998
• Issued: 02/15/2000
• Est. Priority Date: 06/28/1997
• Status: Expired due to Fees

• Current Assignee: SKW Polymers GmbH
• Original Assignee: SKW Trostberg Aktiengesellschaft (Rag-Stiftung)
• Inventors: Keilhofer, Gregor, Plank, Johann
• Primary Examiner(s): TUCKER, PHILIP C
• Application Number:
  US09/104,580
• Time in Patent Office: 600 Days
• Field of Search: 507/140, 507/901, 507/904, 252/184
• US Class Current: 507/140
• CPC Class Codes: C09K 8/145 characterised by the composition of the clay
• CPC Class Codes: C09K 8/206 Derivatives of other natural products, e.g. cellulose, starch, sugars
• CPC Class Codes: Y10S 507/904 Process of making fluids or additives therefor

Abstract

A solids composition based on clay minerals and consisting of a) 40-99.8 wt. % of a clay mineral with a reduced moisture content of ≦7 wt. %, b) 0.01-30 wt. % of a mixed metal hydroxide and c) 0.01-30 wt. % of a solid base, and if necessary other additives, is described. The solids composition of the invention is an easy-to-use thickening agent for water-based drilling fluids, and has a long-term stability of at least three months.

Claims

1. A solids composition based on clay minerals, comprising:

a) 40-99.8 wt. % of at least one clay mineral with a reduced moisture content of ≦

7 wt. %;

b) 0.01-30 wt. % of a mixed metal hydroxide derivative, and

c) 0.01-30 wt. % of at least one solid base.

2. The composition of claim 1, wherein said clay mineral has a reduced moisture content of ≦

5 wt. %.

3. The composition of claim 1, wherein said clay mineral is selected from the group consisting of bentonite, sepiolite, attapulgite synthetic clays and combinations thereof.

4. The composition of claim 1, wherein said mixed metal hydroxide derivative comprises magnesium and aluminum.

5. The composition of claim 1, wherein said base is selected from the group consisting of Na₂ CO₃, CaO, Ca(OH)₂, NaAlO₂, Al(OH)₃, and Ba(OH)₂.

6. The composition of claim 1, further comprising from 0.5-60 wt. % of a filtrate-reducing agent relative to the total weight of components a), b) and c).

7. The composition of claim 6, wherein said filtrate-reducing agent comprises at least one polysaccharide.

8. The composition of claim 7, wherein said polysaccharide is selected from the group consisting of guar gum, cellulose, starch, carob seed flour, and cassia.

9. A method of preparing a water-based drilling fluid, comprising stirring the solids composition of claim 1 with water, wherein the quantity of solids composition is calculated such that the solids content is 1 to 25 wt. % relative to the total weight of the drilling fluid.

10. The composition of claim 7, wherein said polysaccharide is partially etherified with a moiety selected from hydroxyethyl, hydroxypropyl, carboxymethyl and mixtures thereof.

11. The composition of claim 7, wherein said polysaccharide is partially esterified with a moiety selected from hydroxyethyl, hydroxypropyl, carboxymethyl and mixtures thereof.

12. The composition of claim 3, wherein said synthetic clay is hectorite.

13. The composition of claim 2, wherein said clay mineral is selected from the group consisting of bentonite, sepiolite, attapulgite synthetic clays and combinations thereof.

14. The composition of claim 2, wherein said mixed metal hydroxide derivative comprises magnesium and aluminum.

15. The composition of claim 3, wherein said mixed metal hydroxide derivative comprises magnesium and aluminum.

16. The composition of claim 3, wherein said base is selected from the group consisting of Na₂ CO₃, CaO, Ca(OH)₂, NaAlO₂, Al(OH)₃, and Ba(OH)₂.

17. The composition of claim 13, wherein said base is selected from the group consisting of Na₂ CO₃, CaO, Ca(OH)₂, NaAlO₂, Al(OH)₃, and Ba(OH)₂.

18. The composition of claim 2, further comprising from 0.5-60 wt. % of a filtrate-reducing agent relative to the total weight of components a), b) and c).

19. The composition of claim 3, further comprising from 0.5-60 wt. % of a filtrate-reducing agent relative to the total weight of components a), b) and c).