Effects Of Ultrasound On Bottom Hole Of Reservior
During the influence of ultrasonic wave bombardment, there is a set of the complex, interconnected processes leading to waves of compression - cyclically loading the porous environment after repeatedly reflected, are transformed to waves of pressure- stretching creating conditions for the development of a network of cracks and micro cracks, both in walls of punched channels and in breed of a layer adjoining to them. With the interaction of the acoustic field with phases of rocks, one finds:
- Increase in their permeability owing to changes in the structure of porous space.
- Removal of mineral salt deposits in the capillaries.
- Acoustic decontamination and decrease in viscosity of oil.
- The ultrasonic modulated frequencies, passing through a productive layer are capable to put into operation - both separate sub colmataged and low permeable interlayer and all productive part of a layer.
- Ultrasonic vibrations of high power can ensure effective clearing of the critical area of formation of a layer irrespective of the nature of colmotants.
- Ultrasonic vibrations effectively clear the capillaries of the close zones to the layer.
- Ultrasonic vibrations reduce the surface tension in capillaries.
- Ultrasonic vibrations effectively destroy the salt formation in the capillaries.
- Ultrasonic vibrations effectively destroy colloid formations.
Restoration of potential productivity of extracting and pumping wells is achieved due to destruction of colloid-disperse systems; colmatage bore hole part of a collector. The ultimate goal of application of ultrasonic technologies in the process of oil extraction is the increase in the efficiency of oil deposits operations.
This technology allows achieving, without damage to oil reservoir an efficient restoration of filtering characteristics of productive formations with minimal time and material inputs. Acoustic stimulation case history analysis shows that all the technology may be conditionally divided into 3 categories:
- Compensative (designed for wells that work tolerably well, but below their capability) that can be called "anticipatory" or preventive.
- Stimulating (designed for wells whose production rate has considerably decreased compared to initial one).
- TReviving (designed for the wells that are practically not working).
The share of Stimulating technologies is the biggest in the total statistics and the share and experience of the other two is extremely insignificant and at the same time their success ratio is lower. The field effect becomes statistically significant when maximal numbers of wells are treated. Therefore, it is time to transfer from individual wells stimulation to systemic effect on wells (especially taking into account possible reaction of neighbor wells on acoustic stimulation), which can ensure high probability of incremental oil production as a whole over a short period of time, as well as ultimate oil recovery increase.