Abstract In fracturing an underground formation by burning a propellant in a confined space within a well bore, the packer is set by gas pressure originating from a level above the packer. The pressure generated by burning the main propellant charge below the packer frequently is sufficient to dislodge it from the formation. The present invention overcomes this problem by the use of a suitable check valve carried between the packer and the main propellant charge. The valve traps the gases in the upper assembly which seats the packer. If pressure develops below the packer exceeding the gas pressure used to hold it against the well wall, the check valve opens, allowing gases to enter the packer from the packed off zone so that the tool will remain set until the fracture treatment has been completed.
An apparatus for use in fracturing underground formations comprising an elongated tubular body having a lower disposable portion adapted to contain a propellant charge and an upper portion having means responsive to fluid pressure for setting said apparatus in a well, said apparatus having a combination a hollow pressure retainerelectrical connector sub joining said upper and lower portions, said sub comprising a pressure responsive valve located within said sub and fluidtight means in said sub for bypassing electrical conductor means around said valve.
Claim 2
Independent Claim
83 words
An apparatus for use in fracturing underground formations comprising an elongated tubular body having a lower disposable portion adapted to contain a propellant charge and an upper portion having means responsive to fluid pressure for setting said apparatus in a well, said apparatus having a combination a hollow pressure retainerelectrical connector sub joining said upper and lower portions, said sub comprising a pressure responsive valve located within said sub and fluidtight means in said sub for bypassing electrical conductor means around said valve.
Claim 3
Dependent Claim
17 words
The apparatus of claim 1 wherein said valve consists essentially of a ball and seat check valve.
Claim 4
Dependent Claim
42 words
The apparatus of claim 1 wherein the means for bypassing said valve comprises separate passageways above and below said valve and leading from the interior to the exterior of said sub, the uppermost of said passageways being provided with a fluidtight seal.
Claim 5
Dependent Claim
42 words
The apparatus of claim 1 wherein the means for bypassing said valve comprises separate passageways above and below said valve and leading from the interior to the exterior of said sub, the uppermost of said passageways being provided with a fluidtight seal.