Increasing media permeability with acoustic vibrations

Abstract

A coalbed methane production method comprises acoustic radiators strategically placed within exhaust boreholes that sonically vibrate the immediate wall areas. The gas volume output that can be realized by an exhaust well is mainly determined by the penetrability of the inside faces of the borehole. Such inside faces behave like a filter matrix, and the important areas involved in restricting the gas flow the most are not more than a few diameters away from the exhaust well in the collector zone. Therefore, the more permeable that such immediate area around the exhaust borehole can be made, the higher will be the volume of gas produced. Strong sonic vibrations from the acoustic radiators positioned in a drillstring shake open spaces in the media for the gas to flow out and be collected. The media experiences a type of elastic collapse under the differential pressures that are exerted the strongest near the borehole opening.