Mitigating perforating gun shock

A wellbore tool string, the tool string comprising:

• a perforating gun having a plurality of explosive perforating charges;
• and
• a shock mitigation tool comprising:
• a tubular body having a top end, a bottom end, and a chamber;
• a valve having a barrier disposed proximate the bottom end in communication with the chamber, wherein the barrier is operational between an open position and a blocking position;
• and
• at least one actuator connected with the tubular body proximate to the top end of the tubular body, the at least one actuator opening at least one port in the tubular body providing fluid communication with the chamber when the at least one actuator is activated, wherein the port is located a distance above the barrier such that when the barrier is in the blocking position a fluid entering the chamber through the port impacts the barrier with a force to cause a pressure wave to dampen the shock of the detonated explosive perforating charges.

A method for mitigating the shock from the detonation of a perforating charge in a subterranean wellbore, the method comprising the steps of:

• 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, wherein the barrier is a valve member moveable between an open position and a blocking position;
• 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;
• and
• impacting the wellbore liquid on the barrier positioned in the elongated chamber with a force creating a mitigating pressure wave in the wellbore, wherein the mitigating pressure wave dampens the detonation shock in the wellbore.