Novel perforating tool with dynamic underbalance mitigation and related methods

Abstract

A perforating tool for perforating a subterranean formation intersected by a wellbore includes a carrier having an interior in which are disposed at least one shaped charge and a pressure applicator. The pressure applicator may be configured to release a gas simultaneous with detonation of the at least one shaped charge.

It is claimed: 
     
         1 . A perforating tool for perforating a subterranean formation intersected by a wellbore, the perforating tool comprising:
 a carrier having an interior;   at least one shaped charge disposed in the interior; and   a pressure applicator disposed in the interior, wherein the pressure applicator is configured to release a gas simultaneous with detonation of the at least one shaped charge.   
     
     
         2 . The perforating tool of  claim 1 , wherein the detonation of the at least one shaped charge creates a dynamic underbalance wherein pressure within the interior of the carrier is below hydrostatic pressure in the wellbore. 
     
     
         3 . The perforating tool of  claim 2 , wherein the gas is configured to mitigate the dynamic underbalance by generating a gas pressure that increases the pressure within the interior of the carrier. 
     
     
         4 . The perforating tool of  claim 3 , wherein the gas pressure is below an anticipated fracture threshold for the subterranean formation. 
     
     
         5 . The perforating tool of  claim 3 , wherein the detonation of the at least one shaped charge further creates an overbalanced pressure difference between the hydrostatic pressure in the wellbore and formation fluid pressure in the subterranean formation. 
     
     
         6 . The perforating tool of  claim 5 , wherein the gas pressure is between 10% and 120% of the overbalanced pressure difference. 
     
     
         7 . The perforating tool of  claim 1 , wherein the pressure applicator is configured to release the gas in accordance with a predetermined gas parameter selected from the group consisting of pre-specified gas pressure, release volume, flow rate, and combinations of the same. 
     
     
         8 . The perforating tool of  claim 7 , wherein the pre-specified gas pressure is between 250 psi and 5,000 psi. 
     
     
         9 . The perforating tool of  claim 7 , wherein the release volume is between 50 in 3  and 1,000 in 3 . 
     
     
         10 . The perforating tool of  claim 7 , wherein the flow rate is between 0.1 m 3 /s and 10 m 3 /s. 
     
     
         11 . The perforating tool of  claim 1 , wherein the pressure applicator is configured to release the gas for a pressure application interval between 0.01 seconds and 2 seconds. 
     
     
         12 . The perforating tool of  claim 1 , wherein the pressure applicator comprises a gas-generating material that is configured to generate the gas when initiated. 
     
     
         13 . The perforating tool of  claim 12 , wherein the gas-generating material is selected from the group consisting of nitro compounds, nitramines, nitrates, tetrazoles, tetrazines, perchlorates, thermites, black powder, synthetic polymers, metals, and metalloids. 
     
     
         14 . The perforating tool of  claim 12 , further comprising an initiator that is configured to apply kinetic energy, thermal energy, electrical energy, or a combination of the same to initiate the gas-generating material. 
     
     
         15 . A method for perforating a subterranean formation intersected by a wellbore, the method comprising the steps of:
 positioning a perforating tool within the wellbore, wherein the perforating tool comprises:
 a carrier having an interior, 
 at least one shaped charge disposed in the interior, and 
 a pressure applicator disposed in the interior, wherein the pressure applicator is configured to release a gas; 
   detonating the at least one shaped charge; and   releasing the gas simultaneous with the step of detonating the at least one shaped charge.   
     
     
         16 . The method of  claim 15 , wherein the step of releasing the gas further comprises the step of releasing the gas in accordance with a predetermined gas parameter selected from the group consisting of pre-specified gas pressure, release volume, flow rate, and combinations of the same. 
     
     
         17 . The method of  claim 15 , wherein the step of releasing the gas further comprises initiating a gas-generating material in the pressure applicator. 
     
     
         18 . A method for perforating a subterranean formation intersected by a wellbore, the method comprising the steps of:
 positioning a perforating tool within the wellbore, wherein the perforating tool comprises:
 a carrier having an interior, 
 a shaped charge disposed in the interior, and 
 a pressure applicator disposed in the interior, wherein the pressure applicator is configured to release a gas; 
   detonating the shaped charge, wherein the detonation creates an overbalanced pressure difference between hydrostatic pressure in the wellbore and formation fluid pressure in the subterranean formation; and   releasing the gas to generate a gas pressure simultaneous with the step of detonating the shaped charge.   
     
     
         19 . The method of  claim 18 , further comprising the steps of:
 estimating the overbalanced pressure difference that will be created by detonating the shaped charge; and   determining a quantity for the gas pressure that is between 10% and 120% of the overbalanced pressure difference.   
     
     
         20 . The method of  claim 18 , further comprising the step of determining an anticipated fracture threshold of the subterranean formation, wherein the step of releasing the gas further comprising generating a gas pressure that does not exceed the anticipated fracture threshold.