Abstract: This invention relates to fluid compositions used in treating a subterranean formation. In particular, the invention is aqueous wellbore treatment compositions which are foams containing a viscosifying agent, a foam extender, a gas component, and a surfactant, as well as methods of forming such fluids, and uses thereof. The viscosifying agent may be a hydratable polymer, viscoelastic surfactant, or heteropolysaccharide. The foam extender may be a material such as a polyoxyalkyleneamines, ethylenepolyamines, tertiary polyamines, bicarbonate, carbonate, phosphate, or sesquicarbonate.

Abstract: This invention relates to fluid compositions used in treating a subterranean formation. In particular, the invention is aqueous wellbore treatment compositions which are foams containing a viscosifying agent, a foam extender, a gas component, and a surfactant, as well as methods of forming such fluids, and uses thereof. The viscosifying agent may be a hydratable polymer, viscoelastic surfactant, or heteropolysaccharide. The foam extender may be a material such as a polyoxyalkyleneamines, ethylenepolyamines, tertiary polyamines, bicarbonate, carbonate, phosphate, or sesquicarbonate.

Abstract: Methods using foamed fluids to perform subterranean formation treatments, the fluid containing methanol having a decreased concentration of gelling agent, while retaining excellent rheological properties in the foamed state, and processes for preparing foamed fluid for use in treating subterranean formations.

Abstract: A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least a stoichimetric amount of oxidant per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, .DELTA.t, of less than 105.degree. F.

Abstract: A method for removing iron(III), copper(II), zinc(I) and nickel(II) from an effluent containing chelant (EDTA, DEPA, HOEDTA) comprising treating the effluent with a soluble calcium compound (e.g., Ca(OH).sub.2) CaCl.sub.2, Ca(NO.sub.3).sub.2) in a molar equivalent to the chelant in combination with a monovalent hydroxide to a pH greater than 12.4 and then adding an effective amount of a dialkyldithiocarbamate (e.g.; sodium-N,N-diethyldithiocarbamate) to precipitate the metal hydroxides and nickel dialkyldithiocarbamate. Heating the solution to about 180 F. further speeds up the removal of the nickel(II). The nickel concentration of spent chelant cleaning solution can be reduced to less than 1 ppm.

Abstract: A chemical method of removing thiourea from spent hydrochloric acid cleaning solutions comprising the steps of: adjusting the pH to not less than 12 by addition of base to remove metal hydroxides; oxidizing thiourea to urea by the addition of at least 4 moles of hydrogen peroxide per mole of thiourea; and further oxidizing urea to nonregulated/nonhazardous compounds by the addition of at least 3 moles of a hypochlorite per mole of urea. UV analysis confirms a greater than 98% removal of thiourea from solutions containing 0.4 to 2.7 wt. % thiourea after as little as 3 hours with an exotherm, .DELTA.t, of less than 105.degree. F.