Pneumatic system and process for fracturing rock in geological formations

A tunable pneumatic fracturing system and process useable in some instances to extract oil and gas. Some embodiments provide a pneumatic fracturing tool with an elongated body that (a) contains (i) a propellant supply source intermediate opposed propellant gas discharge assemblies, (ii) a control system, and (iii) a communications port, and (b) has roller assemblies at opposed ends of the body. The tool can be tuned to provide gas pulse amplitudes and frequencies that react with the resonant frequency or other aspect of an adjacent earth formation. Some tool embodiments can variably sweep a rock formation and adjust the pressure pulse amplitude and frequency to disrupt the formation in a more productive manner. Some tools can penetrate vertical bore wells as well non-vertical bore wells. In some systems, the tool is transported and operated by a control truck and can be commanded to download operational data during or after use.