One of my professors in college made a killing by patenting "propellant fracturing of oil wells", basically putting solid fuel rocket engines into old non-productive oil wells, lighting them off, and then essentially fraccing the well. Like hydraulic fraccing but with rocket engines.

"The final PNE blast took place on May 17, 1973, under Fawn Creek, 47.5 mi (76.4 km) north of Grand Junction, Colorado. Three 30-kiloton detonations took place simultaneously at depths of 5,768, 6,152 and 6,611 ft (1,758, 1,875 and 2,015 m). If it had been successful, plans called for the use of hundreds of specialized nuclear explosives in the western Rockies gas fields. The previous two tests had indicated that the produced natural gas would be too radioactive for safe use; the Rio Blanco test found that the three blast cavities had not connected as hoped, and the resulting gas still contained unacceptable levels of radionuclides.[16]"