The comparison of removing plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging for near-well ultrasonic processing technology

Near-well ultrasonic processing technology is characterized by high adaptability, simple operation, low cost and zero pollution. The main plugs of oil production include paraffin deposition plug, polymer plug, and drilling fluid plug etc. Although some good results have been obtained through laboratory experiments and field tests, systematic and intensive studies are absent for certain major aspects, such as: effects of ultrasonic treatment for different kinds of plugs and whether effect of ultrasound-chemicals combination deplugging is better than that of ultrasonic deplugging. In this paper, the experiments of removing drilling fluid plug, paraffin deposition plug and polymer plug by ultrasonic wave, chemical deplugging agent and ultrasound-chemical combination deplugging respectively are carried out. Results show that the effect of ultrasound-chemical combination deplugging is clearly better than that of using ultrasonic wave and chemical deplugging agent separately, which indicates that ultrasonic deplugging and chemical deplugging can produce synergetic effects. On the one hand, ultrasonic treatment can boost the activity of chemical deplugging agent and turn chemical deplugging into dynamic chemical process, promoting chemical agent reaction speed and enhancing deplugging effect; on the other hand, chemical agent can reduce the adhesion strength of plugs so that ultrasonic deplugging effect can be improved significantly. Experimental results provide important reference for near-well ultrasonic processing technology.