Method of treating subterranean formations using sequential proppant stages

摘要

An increase in effective propped lengths is evidenced in hydraulic fracturing treatments by the use of ultra lightweight (ULW) proppants. The ULW proppants have a density less than or equal to 2.45 g/cc and may be used as a mixture in a first proppant stage wherein at least one of the proppants is a ULW proppant. Alternatively, sequential proppant stages may be introduced into the formation wherein at least one of the proppant stages contain a ULW proppant and where 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; (ii.) both the first proppant stage and the second proppant stage contain a ULW proppant; (iii.) 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 (iv.) the particle size of the second proppant stage is different from the particle size of the first proppant stage.