Abstract: A well service fluid and method using same for brine-sensitive formations is disclosed. The fluid is an invert oil emulsion comprising heavy, solids-free brine, an oil or synthetic, and sufficient emulsifier to create the emulsion. The fluid has particular applicability in gravel packing a horizontal well.

Abstract: The present invention is directed to an oil-free, water-soluble, liquid, polymer dispersion for use in thickening aqueous mediums, particularly completion and workover fluids used in the oil and gas drilling business. The dispersions of the present invention are comprised of hydroxyethyl cellulose and propylene glycol derivatives, preferably both propylene glycol polyether polyols and an aliphatic propylene glycol ether. Optionally these dispersions include water. Because of their low toxicity, these dispersions are particularly useful for drilling in offshore environments. These compositions rapidly disperse in and viscosity a variety of brines, including sea water and other light brines, with minimum shear and without fisheye formation.

Abstract: A thickening composition for use in viscosifying aqueous mediums, particularly heavy brines, comprising hydroxyethyl cellulose, 2-pyrrolidone and a mono alkyl ether of ethylene glycol which is water soluble and exerts no appreciable swelling effect on the hydroxyethyl cellulose, the weight ratio of hydroxyethyl cellulose to 2-pyrrolidone being less than about 2.6:1.

Abstract: 2,6,8-Trimethyl-4-nonanone and the triethoxylated derivative of 2,6,8-Trimethyl-4-nonanol synergistically combine to reduce the foaming of heavy brines containing zinc bromide and one or more soluble salts from the group calcium chloride and calcium bromide.