Patent ID: 8136608
Filing Date: 2012-03-20
Classification: E21B

Abstract:
1. A method for mitigating the shock from the detonation of a perforating charge in a subterranean wellbore, the method comprising: disposing a mitigation tool in the wellbore and within the wellbore liquid, the mitigation tool comprising a tubular body forming a chamber empty of liquid and a barrier disposed in the chamber proximate the bottom end of the mitigation tool; detonating the perforating charge in the wellbore; activating the mitigation tool to dampen the detonation shock in the wellbore, comprising opening a port between the wellbore liquid and the chamber a distance above the barrier; selecting the distance between the port and the barrier to achieve an impacting force sufficient to create a desired mitigating pressure wave; and impacting the wellbore liquid on the barrier positioned in the elongated chamber with the impacting force creating the mitigating pressure wave in the wellbore, wherein the mitigating pressure wave dampens the detonation shock in the wellbore, wherein the barrier is a valve member moveable between an open position and a blocking position.