Abstract A method of fracturing a geological formation adjacent a well bore is described, comprising injecting a free-flowing explosive slurry, which is nondispersible in well fluids over a time period required to fracture the formation and thus retains its initial density until fracturing and which contains a granular explosive which is nonhygroscopic and insoluble in the dispersive medium of the slurry, into the well bore directly adjacent the formation to be fractured, so that the slurry cannot contact fluids in the well bore before reaching the formation, then placing a detonating device in the slurry and detonating it to explode the slurry. The explosive slurry used in the method is an even dispersion in an inert fluid dispersive medium of a granular solid explosive, which is an organic nitro compound of high explosive power and which is insoluble in the dispersive medium, to which is added a gelling agent for maintaining the solid explosive evenly dispersed throughout the fluid medium under conditions of temperature and pressure encountered in well fracturing.
A method as defined in claim 1 wherein the detonating device includes a timer for detonating the high explosive charge after a preset interval, and detonation of the high explosive charge is initiated by said timer.
Claim 2
Independent Claim
180 words
A method of fracturing a formation adjacent a well bore with a slurry explosive consisting essentially of a fluid dispersive medium capable of desensitizing a granular explosive dispersed therein; one or more granular solid explosives which are organic nitro compounds of high explosive power and which are nonhygroscopic and insoluble in the dispersive medium, evenly dispersed throughout the dispersive medium; and a gelling agent for maintaining the granular solid explosive evenly dispersed throughout the dispersive medium under conditions of pressure and temperature existing in well fracturing, said slurry explosive being nondispersible in well fluids over a time period required to fracture such formation, said method comprising: injecting said slurry explosive into the well bore directly adjacent said formation through a tube extending from the surface through the well bore to a level adjacent the formation, such that the slurry cannot contact fluids in the well bore before reaching the formation; placing a detonating device containing a high explosive charge within the slurry in the well bore; and detonating said high explosive charge to explode the slurry, thereby fracturing said formation.
Claim 3
Dependent Claim
43 words
A method as defined in claim 3 wherein said granular solid explosive is one or more organic nitro compounds selected from the group consisting of RDX, HMX, PETN and TNT, and constitutes about between 35 and 70 percent by weight of the slurry.
Claim 4
Dependent Claim
23 words
A method as defined in claim 4 wherein said dispersive medium is selected from the group consisting of water, alcohol, kerosene and hexane.
Claim 5
Dependent Claim
28 words
A method as defined in claim 4 wherein said dispersive medium is water and said explosives constitute about between 45 and 70 percent by weight of the slurry.
Claim 6
Dependent Claim
24 words
A method as defined in claim 6 wherein said gelling agent is Carbopol 941 and constitutes about 0.5 percent by weight of the slurry.
Claim 7
Dependent Claim
23 words
A method as defined in claim 3 wherein said dispersive medium constitutes about between 55 and 65 percent by weight of the slurry.