Abstract: A process for the thermo-chemical cleaning of storage tanks which contain sludges from petroleum oil or related products. The process is carried out by the combined action of an organic solvent and the generation of nitrogen gas and heat, whereby produced heating in situ, agitation by turbulence and flotation of the fluidized sludge, which after being collected and transferred to tanks or desalting units can be reintroduced in the usual refining flow.

Abstract: A process, based on the Nitrogen Generating System/Emulsion in the presence of organic solvents, which is useful for the dewaxing of producing formations, is disclosed. The heat generation with the nitrogen reaction system and organic solvents gives rise to a thermo-chemical, synergistic system for long lasting removal of paraffinic damage, oil production rates being restored and even increased. The process is relatively easy to implement and of low cost.

Abstract: A continuous process of hydraulic fracturing of a well with in situ nitrogen foam generation, comprising the steps of:(a) preparing an aqueous solution of NH.sub.4 Cl having a concentration of from 2.0-6.0M;(b) preparing an aqueous solution of NaNO.sub.2 having a concentration of from 6.0-9.0 M;(c) preparing an aqueous solution of acetic acid having a concentration of about 40% v/v;(d) adding hydroxyethylcellulose (HEC) to said NH.sub.4 Cl solution at a concentration of from 0.3-1.2% w/v to form a viscosified NH.sub.4 Cl solution;(e) simultaneously pumping said viscosified NH.sub.4 Cl solution and said NaNO.sub.2 solution to form a mixture having a equimolar amounts of NH.sub.4 Cl and NaNO.sub.2 thereby initiating an equimolar reaction between the components of said mixture;(f) pumping the acetic acid solution into the equimolar mixture of NH.sub.4 Cl solution and NaNO.sub.2 solution, so as to initiate foam generation, while keeping the pH of the mixture between 4.75 and 5.