Hydraulic fracking is one of the most popular methods of well stimulation. KFU's World-Class Research Center in Liquid Hydrocarbons (WCRC LH) has experimented with thermo-gas-chemistry technology for this particular purpose.
Junior Research Associate of WCRC LH Mojtaba Rezaei Koochi explains, "We are injecting two nitrogenous substances: nitrate and sodium nitrite. With the correct selection of the catalyst, nitrogen dioxide is formed during the reaction. Dissolved in water, nitrogen dioxide gives a dense acid."
A series of experiments in high pressure and high temperature reactors (HPHT) were designed to understand the performance and efficiency of a thermo-gas-chemical reaction and determine the optimal binary composition to achieve maximum temperature, pressure and acid formation to ensure long conductive fractures. The dependence of the breakdown pressure and temperature was simulated in parallel. In addition, in order to understand the geometry and propagation of fractures, the influence of the thermo-gas-chemical method was studied on core samples in a core holder, and then the cores were scanned using 4D tomography.
The results show that after the activator is introduced, a rapid increase in temperature and pressure are observed. The 4D tomography and experiments with core samples showed the emergence of new fractures and the propagation of existing ones.
The technology is economical and eco-friendly, which makes it promising for the extraction of viscous oils.