High-Power/High-Frequency Acoustic Stimulation: A Novel and Effective Wellbore Stimulation Technology

摘要

Local impairment of formation permeability often causes reduced production because of the interaction of the reservoir with drilling and completion fluids. The problem may be further compounded by impairment caused by fines migration during production. High-frequency sonic and ultrasonic waves have been used in many industrial applications to remove contaminants, such as dirt, oil, and grease from parts that are immersed in fluids. An obvious extension of this application is the removal of wellbore impairment by exposing it to high-frequency acoustic waves. The influence of high-frequency waves is limited to the near-wellbore environment because of high attenuation. Dedicated experiments under realistic downhole conditions have been carried out in both linear and radial configurations. We have examined the acoustic power needed to remove near-wellbore formation damage caused by fines and particles plugging pores as well as drilling-induced damage. Specific issues related to well completion and the envelope of acoustic stimulation are presented. The laboratory results have led to the design and construction of a slim, high-power, and high-frequency (above 10 kHz) downhole acoustic tool for field deployment. This paper outlines the concept and presents key experimental results to support the claim. Key features of a prototype downhole tool are also described.