Modified carbon black for oilfield fluids
First Claim
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1. An organic drilling fluid comprising:
- an invert emulsion including a continuous organic phase and an emulsified aqueous phase;
a surface treated carbon black having a OAN structure of greater than 150 mL/100 g by ASTM D2414 and a BET surface area of less than 500 m2/g dispersed in the invert emulsion at a concentration of at least 0.5% by weight; and
wherein the carbon black includes an attached organic group comprising either a) an aryl group, an alkyl group and a C═
O group and/or C—
O—
C group, or b) a fluorinated aryl group, the organic group being attached to the carbon black at a surface loading of 0.1 to 1.5 μ
mol/m2, andwherein the conductive organic drilling fluid has a volume resistivity of either a) less than 105 ohm-m or b) at least a factor of 100 less than the resistivity of the organic phase in the absence of the surface treated carbon black.
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Abstract
Surface treated modified carbon black particles and oil-based drilling fluids are described. The carbon blacks are incorporated into the oil-based drilling fluids to reduce the electrical resistivity of the oil-based drilling fluids. The surface treated carbon blacks can include a hydrophobic organic group and are readily dispersible in oil-based drilling fluids.
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Citations
8 Claims
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1. An organic drilling fluid comprising:
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an invert emulsion including a continuous organic phase and an emulsified aqueous phase; a surface treated carbon black having a OAN structure of greater than 150 mL/100 g by ASTM D2414 and a BET surface area of less than 500 m2/g dispersed in the invert emulsion at a concentration of at least 0.5% by weight; and wherein the carbon black includes an attached organic group comprising either a) an aryl group, an alkyl group and a C═
O group and/or C—
O—
C group, or b) a fluorinated aryl group, the organic group being attached to the carbon black at a surface loading of 0.1 to 1.5 μ
mol/m2, andwherein the conductive organic drilling fluid has a volume resistivity of either a) less than 105 ohm-m or b) at least a factor of 100 less than the resistivity of the organic phase in the absence of the surface treated carbon black. - View Dependent Claims (2, 3, 4)
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5. A method of producing an electrically conductive organic drilling fluid, the method comprising:
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emulsifying a brine in a non-conductive organic liquid to produce a two-phase system, the brine making up less than 40% by weight of the two-phase system; dispersing a plurality of surface treated carbon black particles having a OAN structure of greater than 150 mL/100 g by ASTM D2414 and a BET surface area of less than 500 m2/g in the two phase system to produce the conductive organic drilling fluid; and wherein the carbon black includes an attached organic group comprising either a) an aryl group, an alkyl group and a C═
O group and/or C—
O—
C group, or b) a fluorinated aryl group, the organic group being attached to the carbon black at a surface loading of 0.1 to 1.5 μ
mol/m2, andwherein the drilling fluid has an electrical resistivity of less than 105 ohm-m, a volume resistivity at least 100 times greater than that of the organic liquid in the absence of the carbon black particles, or both. - View Dependent Claims (6, 7, 8)
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Specification