Abstract: Temperature indicating compositions of dispersions in an aqueous binder of a color changing electron donating compound having a melting point greater than about 300.degree. F. and a polymeric electron accepting resin reactive with the electron donating compound to produce a visible and permanent color change and having a T.sub.g and non-volatility effective to provide a color change to coatings containing the composition upon exposure to a predetermined heat history. Temperature indicating materials are also disclosed containing a support coated on at least one surface thereof with the temperature indicating composition to the present invention.

Abstract: A method of controlling crosslinking reaction rate in a water based polymer fracturing fluid that involves using a mixture of a crosslinker, in combination with a crosslinking rate accelerator or a crosslinking rate retarder at a ratio such that the crosslinking reaction rate is controlled. This decreases the shear effects upon the polymer fracturing fluid during pumping which affects downhole stability of the fluid and decreases pumping and frictional pressures. The ratio of rate accelerator or rate retarder to crosslinker for a desired crosslinking reaction time is dependent upon pH, surface temperature, polymer concentration, salt concentrations, fluid loss additives, surfactant types and concentrations, mutual solvents and alcohol. The preferred polymer fracturing fluid is a high pH aqueous salt solution including a hydroxypropyl guar polymer. The preferred crosslinkers are transition metal chelates. The preferred crosslinking rate accelerators are polyamines.

Abstract: A time/temperature device for monitoring and indicating variations in the ambient temperature of a space being monitored above a predetermined temperature level is encapsulated in a plastic bag, and uses a carrier to be impregnated with a fusible diffusing medium having a sharp melting point at the predetermined temperature being monitored adapted above the melting point to change from the solid phase to substantially the molten or liquid phase and vice versa below the melting point, a dye composition is formed into a mixture in a given concentration so that it can be coated at one end of the carrier, and the concentration will be in ratio to the volume of the diffusing medium so that the dye composition has a finite and reproducible diffusion rate through the diffusing medium whenever the diffusing medium is in the liquid state and exhibits no diffusion when the diffusing medium is in the solid state, and an indicating section on the face of the carrier for the time/temperature device will provide a visible

Abstract: Foam fracturing fluids and methods for fracturing well formations using foam as the carrier for the propping agent are disclosed. The foams are stiff stable foams formed of a relative large amount of gas and a relative small amount of liquid. The foams are stable at surface pressures and remain stable when delivered into the well formation at the bottom of the well.