The present invention provides methods of fracturing high temperature subterranean zones and viscous aqueous foamed fracturing fluids therefor. A fracturing fluid of this invention comprises water, a terpolymer of 2-acrylamido-2-methylpropane-sulfonic acid, acrylamide and acrylic acid or salts thereof, a gas, a foaming agent and a viscosity breaker for effecting a controlled reduction in the viscosity of the fracturing fluid.
Novel polycarboxylic acid copolymer gelling agents and viscosified treatment fluids comprising these gelling agents, and their associated methods of use and manufacture are provided. In one embodiment, a method comprising: providing a viscosified treatment fluid comprising an aqueous base fluid, and a gelling agent that comprises a polymerizable polycarboxylic acid and that is at least partially crosslinked by a crosslinking reaction comprising a crosslinking agent; and introducing the viscosified treatment fluid into a subterranean formation is provided.
Disclosed herein is a method of treating a subterranean formation utilizing a fluid having a splittable foamer, i.e., a fluid that creates a stable foam when it contacts the formation but that loses its ability to foam as it remains in contact with the formation for extended time. The present method has the advantage that the fluid can be recovered from the well unhindered by the difficulties involved with recovering a foamed fluid from a well. The present method does not require the use of breakers, though the splitting of the foam can be accelerated by introducing an organic or inorganic acid into the well, if so desired.
