Improving the efficiency of processing the bottomhole zone of oil formations: chemical treatment in conjunction with ultrasonic exposure

Advantages of combined exposure

• Increased impact efficiency during well treatment by reducing surface tension at the oil-water and oil-rock boundaries;
• Improving the efficiency of chemical treatment due to acoustic effects;
• Increased processing area due to the connection of low-permeability interlayers;
• Controlled activation of chemical processes in the acoustic impact zone;
• Increased oil recovery in difficult geological and physical conditions of facilities operation, as well as in the development of hard-to-recover reserves.

Distinctive features of ultrasonic equipment

The power of the device in the well – 4 kW;
The device is lowered into the well using a geophysical cable in the tubing;
The possibility of interval treatment of the reservoir;
Control of the parameters of the ultrasonic drilling tool (power, frequency).

Filtration studies to determine changes in the permeability of a linear bulk reservoir model for oil before and after treatment with an acid composition of the SNPH grade with and without ultrasonic exposure

Summary results of the conducted research

Based on the results, it is established:

1. Acid composition. An increase in the permeability of the reservoir model for oil by 1.9 times.
2. Acid composition in combination with ultrasound exposure. An increase in oil permeability by 3.3 times.
3. Acidic and ultrasonic effects contribute to the decalmatation of the porous medium and increase oil permeability by 2 times compared to acid composition treatment.

Laboratory and field tests have shown an increase in the efficiency of chemical treatment due to acoustic effects

1. Increasing the processing area and joining the development of new interlayers;
2. Increasing the oil permeability of the reservoir;
3. Decalmatation of the porous medium in the bottomhole zone;
4. Increasing the injection rate of chemical reagent;
5. Reduction of work time during the development of low-permeability, colmatated, difficult-to-recover productive formations;
6. The combined use of solvent with ultrasonic treatment can increase the efficiency of the method by ~20%;
7. Ultrasonic effect enhances the strength characteristics of cement stone by 1.5-2 times.

In 2019, pilot field tests were conducted on chemical treatment technology in conjunction with ultrasound exposure (acid injection and ultrasound treatment) at 2 wells of the Vereiskiy horizon (C2ver).