Acoustic energy has the potential to stimulate wells by removing drilling and production damage from the formation near the wellbore, overcoming water block and breaking emulsions. All of these applications require high acoustic power and frequency. A fluid-powered turbo-acoustic source has been developed for operation on coiled tubing. This source generates a high-power, high-frequency resonant acoustic signal in the treatment fluid to ensure good acoustic coupling to the formation. The turbo-acoustic source incorporates a turbine, flow-splitter and resonant cavity to convert hydraulic power into an acoustic signal. A 1-11/16″ prototype generates 2 to 12 kW of acoustic power at 4 kHz. The source was used to recover permeability of sandstone that was damaged with guar gum in laboratory tests. Successful recovery of core permeability requires high-acoustic power levels and underbalanced flow conditions to flush the fines out. The turbo-acoustic source provides the ability to restore near-wellbore permeability using coiled tubing in a variety of well configurations. The tool can be operated with a gas separator for underbalanced operations in depleted wells.

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