to a 34 medium 34 size proppant shall mean a proppant having a mesh size falling within the range of 20 to 40 further reference to a 34 fine 34 size proppant shall mean a proppant having a mesh size falling within the range of 60 to 140 the above mentioned definitions are not to be construed as limitations on the invention as other proppant sizes may be equally effective in realizing the objectives of the invention among such propping agents used in the prior art is 34 medium 34 sand 20 to 40 mesh used in preference to 34 fine 34 sand 60 to 140 mesh in the belief that the fine sand would pack too tightly and actually cause the fracture proppant volume to have a permeability lower than the formation generally a low ratio of proppants to fracing fluid such as 1 2 to 2 lbs of sand per gallon of fluid was utilized when used with a single relatively thick medium permeability pay zone conventional fracing techniques developed in the prior art have proved adequate however when the conventional fracing techniques are used to fracture low permeability relatively thin formations such as found in several gas sand areas in west texas the resulting production has been much less than expected as will be hereinafter explained referring now to fig1 conventional hydraulic fracturing techniques utilize a well 10 having casing 12 extending through an overburden 14 into multiple gas sand pay zones 16 with the pay zones 16 being separated by non oil or gas bearing strata such as shale layers 18 a number of perforations 20 are conventionally formed in casing 12 extending into the.