Methods and compositions for placing particulate materials in subterranean zones penetrated by well bores. In one embodiment, the methods comprise: providing a compacted particulate material fluid that comprises a compacted particulate material, and a foam within the pore spaces of the compacted particulate material, the foam comprising a pressurized gas and a liquid solution of a foam forming surfactant; and pumping the compacted particulate material fluid into the subterranean zone.

A process for circulating an aqueous foam in a wellbore includes the steps of forming a foam from an aqueous composition having a determined pH value, injecting the foam into a well so that it circulates from the surface to the well bottom and then back from the well bottom to the surface, and then changing the pH value of the foam when it returns to the surface. The aqueous composition from which the foam is made includes at least one ionic surfactant whose charge does not practically depend on the pH value and a polyampholytic polymer whose global charge depends on the pH value. This composition gives the foam the property that when the pH of the foam is varied at the surface of the well, the charge of the polyampholytic polymer is modified and the foam becomes destabilized and breaks more readily.

A method of improving injectivity of fluid, particularly produced water, in enhanced hydrocarbon recovery is disclosed. The method includes introducing a fracturing fluid into the subterranean formation to create a fracture, and introducing proppant into the fracturing fluid to form a single layer of proppant in the fracture. The fracturing fluid can be formed from produced water. Alternatively, the produced water is introduced after a fracturing fluid, other than the produced water, has been introduced to create a fracture. By reducing the amount of proppant and by using much larger proppant, a larger flow path through the fracture is created, thereby increasing the injectivity of produced water.

Reduced friction fluids comprising an aqueous liquid, carbon dioxide, and a polymer comprising acrylamide and an acrylamide copolymer derivative. And methods of treating a subterranean formation comprising the steps of providing a reduced friction fluid comprising an aqueous liquid, carbon dioxide, and a polymer comprising acrylamide and an acrylamide copolymer derivative; and, introducing the reduced friction fluid to a subterranean formation.

The present invention provides environmentally safe foamed fracturing fluids, additives for foaming and stabilizing foamed fracturing fluids and methods of fracturing subterranean zones. The foamed fracturing fluids of this invention are basically comprised of water, a gelling agent for forming the water into gelled water and increasing the viscosity thereof, sufficient gas to form a foam, and an effective amount of an additive for foaming and stabilizing the gelled water comprised of hydrolyzed keratin.