Use of cmc in drilling fluids

• US 20070135311A1
• Filed: 10/15/2004
• Published: 06/14/2007
• Est. Priority Date: 10/17/2003
• Status: Active Grant

• Current Assignee: Dow Global Technologies, Inc. (Dow, Inc.)
• Original Assignee: Akzo Nobel N.V. (Nouryon BV)
• Inventors: Van Der Horst, Peter
• Granted Patent: US 7,939,469 B2
• Time in Patent Office: Days
• US Class Current: 507/110
• CPC Class Codes: C09K 8/10 Cellulose or derivatives thereof
• CPC Class Codes: C09K 8/206 Derivatives of other natural products, e.g. cellulose, starch, sugars

Abstract

The invention relates to a water-based drilling fluid composition comprising a carboxymethyl cellulose (CMC), wherein the CMC is characterized by forming a gel at 25° C. after high-shear dissolution in a 0.3 wt % aqueous sodium chloride solution, the final content of the CMC in the aqueous sodium chloride solution being I wt % for a CMC having a degree of polymerization of >4,000, 1.5. wt % for a CMC having a DP of >3,000-4,000, 2 wt % for a CMC having a DD of 1,500-3,000, and 4 wt % for a CMC having a DP of <1,500, the gel being a fluid having a storage modulus (G′) which exceeds the loss modulus (G″) over the entire frequency region of 0.01-10 Hz when measured on an oscillatory rheometer operating at a strain of 0.2.

Claims

1. A water-based drilling fluid composition comprising water and a carboxymethyl cellulose (CMC), wherein the CMC is characterized by forming a gel at 25°

C. after high-shear dissolution in a 0.3 wt % aqueous sodium chloride solution, the final content of the CMC in the aqueous sodium chloride solution being 1 wt % for a CMC having a degree of polymerization (DP) of >

4,000, 1.5 wt % for a CMC having a DP of 3,000-4,000, 2 wt % for a CMC having a DP of 1,500-<

3,000, and 4 wt % for a CMC having a DP of <

1,500, the gel being a fluid having a storage modulus (G′

) which exceeds the loss modulus (G″

) over the entire frequency region of 0.01-10 Hz when measured on an oscillatory rheometer operating at a strain of 0.2.

2. The drilling fluid composition of claim 1, wherein the CMC has a Brookfield viscosity of more than 9,000 mPa·

s after high-shear dissolution in a 0.3 wt % aqueous sodium chloride solution, the final content of the CMC in the aqueous sodium chloride solution being 1 wt % for a CMC having a degree of polymerization (DP) of >

4,000, 1.5 wt % for a CMC having a DP of >

3,000-4,000, 2 wt % for a CMC having a DP of 1,500-3,000, and 4 wt % for a CMC having a DP of <

1,500.

3. The drilling fluid composition of claim 1 further comprising a smectite type of clay.

4. The drilling fluid composition of claim 3 wherein the smectite type of clay is bentonite, a mixed metal layer hydroxide, attapulgite, sepiolite, or mixtures thereof.

5. The drilling fluid composition of claim 2 further comprising a smectite type of clay.

6. The drilling fluid composition of claim 5 wherein the smectite type of clay is bentonite, a mixed metal layer hydroxide, attapulgite, sepiolite, or mixtures thereof.