Since its introduction almost 50 years ago, hydraulic fracturing has been the prime engineering tool for improving well productivity, either bypassing near wellbore damage or actually stimulating performance. Historically (and in many instances erroneously) the emphasis for propped fracturing was on fracture penetration or length, culminating in massive treatments for tight gas sands using several million pounds of proppant with design 1/2 lengths in excess of 1500 feet (460 m). More recently, the importance of fracture conductivity has become appreciated. This has led to exciting "new" applications of propped fractures in better quality reservoirs as illustrated by North Sea wells, stimulations in Prudhoe Bay, and "frac-pack" operations in the Gulf of Mexico and Indonesia.
While better understanding and new technologies are being used today, the actual application of fracturing to higher permeability formations is not new. During early development of fracturing, nearly all applications were for moderate to high permeability zones (since low permeability rock was of little interest at oil prices of $3/BBL).
While tremendously successful at increasing PI, these early high permeability treatments were doing little more than bypassing damage. More recent development of improved, artificial proppant, cleaner fluid systems, and new technologies have changed this, making it possible to truly alter reservoir flow and stimulate production from moderate to high permeability reservoirs. The primary new tool in the engineers arsenal is the development of "tip screenout" fracturing. While higher permeability formations provide the "new" applications, the actual philosophy shift for fracturing occurred with the massive, tight gas stimulations. while outwardly a traditional, straight forward, application of fracturing to poor quality reservoirs, in actual fact these treatments represented the first engineering attempts to alter reservoir flow in the horizontal plane.
