Abstract: A process and apparatus are provided to enhance the recovery of petroleum from onshore and offshore reservoirs. The process includes the simultaneous stimulation of the formation by elastic sound waves, created by a sonic source installed at the oil well so that the elastic sonic waves which are superimposed reduce the adherence forces in the layer between oil/water and the rock formation, and by the oscillating electrical stimulation of the same layer, as from the same wells subject to sonic treatment. The electricity heats the formation by using resistive heating, and thus increases the pressure, thus eliminating the surface tensions between the faces of the fluid as a consequence of the oscillatory action of the ions in the surfaces of the fluid and in addition, reducing the viscosity of the fluids.

Abstract: A process for the correction of oil well productivity, or injection profiles, or both, is disclosed. The process includes injecting a dilute solution of hydrochloric acid having a concentration less than 1% via an oil well into an adjacent subsurface formation, followed by injecting a solution of sodium silicate and hydrochloric acid into the formation, and then shutting in the well for several hours. The dilute hydrochloric acid solution and the sodium silicate-hydrochloric acid solution may each be displaced into the formation with injection water. Best results are achieved when systems based on sodium silicate and hydrochloric acid of long-curing time are injected, followed by systems based on sodium silicate and hydrochloric acid of short-curing time.