Many oil and gas wells are drilled in "tight" formations having a very low permeability which limits the flow of fluid from them. A number of prior art techniques have been developed to increase the production of petroleum from such tight formations. In general, these prior art production enhancement techniques include various uses of explosives, chemicals, or hydraulic pressure fracturing to increase fluid flow in the geologic formation. Common explosive techniques include nitro shooting and bullet perforations. Chemical techniques include the use of acids, organic solvents, and surfactants.
Most prior art hydraulic fracturing techniques involve some form of injection of fluid into the well bore under sufficient pressure to cause the formation in question to fracture. One of the problems with prior hydraulic fracturing techniques, however, is the inability to repeatedly deliver forces needed to increase the amount of formation fracture at a desired depth within the well.