TL;DR: The Astro-Flow II process as mentioned in this paper uses a highly energetic, hydrazine-based family of liquid explosives known as Astrolite, which can be divided into two nonexplosive pumpable components that can be handled safely.
Abstract: A safe, reliable chemical explosive fracturing process has been demonstrated and prototype equipment for its use has been successfully field tested.Called the Astro-Flow II process, it utilizes a highly energetic, hydrazine-based family of liquid explosives known as Astrolite. A unique property of these explosives is that they can be divided into 2 nonexplosive pumpable components that can be handled safely. The 2 components are pumped independently and simultaneously into the well and blended together downhole to form the explosive which is circulated in place or displaced into formation fractures. Explosive hazards to surface equipment and personnel are eliminated. Extensive testing of the physical and chemical stability of the mixed explosive indicates that the material can be reliable and safely used at elevated temperatures, pressures, and in the adverse chemical environment often found in deep oil and gas wells. These tests of prototype equipment proved that the 2 components could be independently pumped with precision and blended together to form the desired explosive formulation. How the process works is described.