Thermochemical fracturing as an alternative of the conventional hydraulic fracture treatment, initial experimental phase

Hydraulic fracturing is a widely used technique to stimulate oil & gas wells drilled especially in tight and unconventional reservoirs, enhancing their production to a profitable level. In the last two decades, this technique has advanced significantly to stimulate horizontal wells with multiple hydraulic fractures (Zoback&Kohli, 2019), requiring high-power pumps to initiate them and substantial quantities of water. This paper proposes a methodology to test a novel technique that creates fractures close to the borehole, through a powerful exothermic chemical reaction with two ammonia salts injected into the reservoir, creating pressures up to 210 MPa, steam and nitrogen. It will reduce significatively pumps’ horsepower to initiate hydrofracs, decreasing carbon and environmental footprint at well location. Initial experiments were conducted with cement blocks at ambient conditions, but to scale it, high-pressure/high-temperature laboratory tests are planned with 5.1 cm diameter and 12.91 cm height cement cylinders of 1.853 Tn/m3 density and a 4.88 cm diameter concentric hole, like an open hole completion, from which an ammonia mixture will be injected to initiate fractures. The lab tests will help to design a safety procedure for a field test in a tight oil reservoir, western Venezuela, measuring pressures, temperatures and fractures.