Method and apparatus for perforating subsurface earth formations
AssigneeDresser Industries, Inc.
InventorsGerald B. McClure, William A. McPhee
Life of this patent
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Abstract
A perforating system for completing subsurface formations transversed by a borehole. A sub with a plurality of closed vent ports and a perforating gun are run into a borehole on the end of a tubing string. To initiate the perforating system an impact member is dropped through the tubing string. The impact member strikes a percussion firing head which initiates a detonation wave in a detonator cord. The detonation wave detonates an explosive pellet within the sub, the resulting explosion initiating a pressure wave which forcibly opens the vent ports and fluidly communicates the well bore to the tubing annulus. The detonation wave continues on in the detonator cord to actuate the perforating gun.
Claims19
A method of establishing fluid communications between a well bore annulus and a tubing annulus, comprising the steps of:
- positioning on the end of a tubing string below a packer assembly within said well bore annulus a sub having a plurality of vent ports closed by rupture discs, said tubing string having a tubing annulus fluidly isolated from said well bore annulus;
- and
- initiating a shock pressure wave originating within said sub, said pressure wave forcibly opening said vent ports by rupturing said rupture discs, thereby fluidly communicating said well bore annulus to said tubing annulus.
Apparatus for fluidly communicating a well bore to a tubing annulus, including a sub having a plurality of closed vent ports, said sub further comprising:
- explosive means for initiating a pressure wave originating within said sub for forcibly opening said closed vent ports for fluidly communicating said well bore to said tubing annulus;
- means for detonating said explosive means;
- and
- housing means for housing said explosive means and said detonating means.
A perforating apparatus for perforating subsurface earth formations surrounding a borehole and establishing fluid communications between said borehole and a tubing string annulus including a perforating gun adapted to be conveyed into a borehole at the end of a length of tubing string and having a sub with a plurality of closed vent ports for isolating the borehole from the tubing string annulus interposed therebetween, said sub further comprising:
- explosive means for initiating a shock pressure wave originating within said sub for forcibly opening said closed vent ports;
- detonating means for detonating explosive means;
- housing means for housing said explosive means and said detonating means;
- and
- firing means attached to said housing means for activating said detonating means.
Dependencies are inferred from the claim text.