Abstract: A method for generating a horizontal fracture through a wellbore by causing two explosively induced shear waves to intersect. This is achieved by placing, within a coupling fluid within a wellbore, a length of high explosives whose center is adjacent the location where a fracture is desired. Both ends of the high explosive are ignited simultaneously.

Abstract: A method for stimulating oil and gas wells to increase production including filling the lower portion of the well above the pay zone level having exposed rock with a fracturing fluid, and sealing the well above the lower portion. A shock wave is then applied to the fracturing fluid, which, when applied thereby to the rock at the pay zone creates a stress wave in the rock having a rise time faster than the time required for sound to traverse one half the periphery of the rock at the pay zone, and having an amplitude which will fracture but not crush the rock.

Abstract: A method and means for stimulating oil and gas wells to increase production comprises filling a well above the pay zone level with a fracturing fluid, then suspending a cylinder of high explosive centrally within the wellbore adjacent to the pay zone. Thereafter a propellant is suspended within tens of feet above the high explosive and the well above the propellant is enclosed. The application of high explosive is chosen to cause multiple radiating fractures but will not crush the rock in the well. Also, the rise time of the shock wave created by the explosive should be less than the time required for sound to traverse one-half of the periphery of the well opening in the rock at the pay zone. The propellant is detonated first, followed by the detonation of the high explosive. The purpose of using the propellant is to maintain pressure caused by the high explosive over a longer period, thereby extending the fractures caused by the high explosive.

Abstract: Free-standing boulders or rocks are fractured and broken down into many smaller pieces by impacting the boulder with a high velocity projectile. The impact energy is delivered to the rock by a blunt nosed projectile in a time which is less than the transit time of a sound signal across the average diameter of the rock.