Effects of reservoir rock pore geometries and ultrasonic parameters on the removal of asphaltene deposition under ultrasonic waves

Asphaltene deposition around the wellbore is a major cause of formation damage, especially in heavy oil reservoirs Ultrasonic stimulation, rather than chemical injection, is thought to be a more cost-effective and environmentally friendly means of removing asphaltene deposition. However, it seems to be unclear how crucial features like reservoir pore geometries and ultrasonic parameters affect this ultrasound treatment.In this work, five two-dimensional glass micromodels with different pore geometries were designed to assess the impact of pore geometries on the ultrasonic removal of asphaltene deposition. Experiments were undertaken in an ultrasound bath at a set frequency (20 kHz) and adjustable powers (100-1000 W). Direct image analysis before, during and after sonication was used to assess the impact of pore geometry and a change in ultrasonic parameter on the removal of asphaltene deposition. The effectiveness of ultrasound treatment at various sonication periods were found to be reliant on the pore geometries of the individual micromodels. For micromodels with throat sizes 300 mu m and pore shapes as circle, square and triangle, an increase in ultrasonic power from 400 to 1000 W resulted in an increase in the percentage of removed asphaltene deposition after 2 h from 12.6 to 14.7, 11.5 to 14.63, and 5.8 to 7.1 percent, respectively.

Automated summary

Asphaltene deposition around the wellbore is a common problem in heavy oil reservoirs and can cause formation damage. Ultrasonic stimulation is considered to be a cost-effective and environmentally friendly method for removing asphaltene deposition. This study aimed to investigate the impact of reservoir pore geometries and ultrasonic parameters on the effectiveness of ultrasound treatment. Five two-dimensional glass micromodels with different pore geometries were designed and experiments were conducted using an ultrasound bath at a set frequency (20 kHz) and adjustable powers (100-1000 W). The results showed that the efficiency of ultrasound treatment varied depending on the pore geometries of the micromodels, with an increase in ultrasonic power resulting in a higher percentage of removed asphaltene deposition.