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U.S. Department of Energy
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Method and apparatus for fracturing oil and gas strata

Patent ·
OSTI ID:5172841
A method and apparatus are described for fracturing hydrocarbon-bearing formations. A high pressure pipe has its lower end sealed in a well bore, and dispersed outlets are formed explosively through the pipe and seal at a fuel-producing stratum of the well. A mechanically driven hydraulic pump connected to the top of the pipe fills the pipe and exposed surfaces of the stratum to be fractured with fracturing liquid at an intermediate pressure. A first valve in the pipe between the pump and downwardly extending pipe is then closed. A second valve connecting the upper end of the pipe with an explosion chamber is closed while an explosive charge in the nature of a blank artillery shell is locked in the explosion chamber. The second valve is opened and the charge is exploded to create a very high over-pressure in the pipe. The over-pressure transmitted through the liquid creates multiple radiating fractures in the stratum. The valves are then reversed and the pump is again operated to force more fluid plus a quantity of a granular proppant such as fine sand into the newly created fractures. The explosive step may be repeated with the same or progressively stronger explosive charges. (12 claims)
Assignee:
A.M.S. McColl
Patent Number(s):
US 3848674
OSTI ID:
5172841
Country of Publication:
United States
Language:
English