Patent ID: 7210528

Claim:
A method of hydraulically fracturing a hydrocarbon-bearing subterranean formation which comprises: pumping a first proppant stage either into a propagated fracture or into the formation at a pressure sufficient to fracture the formation; and pumping a second proppant stage into the fracture wherein at least one of the following conditions prevails: (i.) the density differential between the first proppant stage and the second proppant stage is greater than or equal to 0.2 g/cc and either the first proppant stage and/or the second proppant stage contains an ultra lightweight (ULW) proppant; (ii.) the proppant of the first proppant stage and/or the second proppant stage contains a ULW proppant and the rate of injection of the second proppant stage into the fracture is different from the rate of injection of the first proppant stage; or (iii.) the proppant of the first proppant stage and/or the second proppant stage contains a ULW proppant and the particle size of the proppant of the second proppant stage is different from the particle size of the proppant of the first proppant stage.