The regeneration of water wells is an urgent problem nowadays, when drilling of new wells becomes more and more expensive. Formation damage leads to a reduction of the formation's permeability and/or pore volume which in turn inhibits the ability of the water to flow from the reservoir formation into the wellbore. A new technology that uses high-power ultrasound to remove formation damage of water wells has been developed. The effectiveness of regeneration of wells can be enhanced if ultrasound and shockwaves are used during the same treatment. It was shown by computer modelling, that the two methods have different depths of impact. Whereas the ultrasonic method has a strong impact on the area of the filter tube, the impact of the shock waves is focused on the gavel pack, the wall of the well and the adjacent aquifer. A shockwave treatment, which is normally more effective due to larger impact zone, needs to be followed by ultrasonic treatment in order to facilitate the removal of the detached deposits. These theoretical assumptions were confirmed by field tests on two wells. The use of the method leaded to an increase of the production by 40% and 109% respectively.
Keywords: Combined approach; Regeneration of wells; Shockwaves; Ultrasound.
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