Abstract: Fractures are initiated or extended into fluid producing earth formations from a well by providing a reservoir of high pressure gas at the earth's surface together with a flow control valve or a frangible closure, such as a shear disk, interposed in a conduit connecting the reservoir to the well. The well is precharged with high pressure gas at a pressure less than or about the same as the reservoir gas pressure. Fracture initiation and/or extension may be carried out by firing the perforation gun and opening the flow control valve between the reservoir and the wellhead in timed relation or by allowing a pressure drop across a shear disk interposed between the reservoir and the wellhead to effect rupture of the shear disk to release the reservoir charge.

Abstract: Perforations and other openings in well casings, liners and other conduits may be substantially blocked or sealed to prevent fluid flow between the casing or liner interior and an earth formation by placing a radially expansible sleeve adjacent the perforations or openings and urging the sleeve into forcible engagement with the casing or inner wall using an explosive charge. An apparatus including a radially contracted sleeve formed by a coiled plate member or a tubular member having flutes defined by external and internal folds, may be deployed into a well casing or liner through a production or injection tubing string and on the end of a flexible cable or coilable tubing. An explosive charge disposed on the apparatus and within the sleeve may be detonated to urge the sleeve into forcible engagement with the casing inner wall.

Abstract: A downhole chemical cutting tool for cutting downhole tubular goods and supporting the tubular goods within the well through a load bearing hub section in the tool. The tool comprises an elongated tool body having a upper head section which is adapted to be connected to a running string such as a string of coiled tubing capable of supporting large loads. The tool body comprises a propellent section and a cutting section. A chemical section is interposed between the propellant section and the cutting section and contains at least one chamber adapted to contain a chemical cutting agent. The cutting section is adapted to receive the chemical cutting agent and has an outer wall section which contains a plurality of transverse cutting ports arranged circumferentially of the cutting section.

Abstract: Linear apertures are created in well casing through the use of linear charges lowered into the well casing in place; hydraulic fracturing conducted through the linear apertures achieves larger and less dissipated fractures than conventional small circular perforations which generate near well bore tortuosity. The linear charges can also be used in open bores and in overbalance perforating.

Abstract: A well, such as an oil or gas well, may be revived and or increase the flow of hydrocarbons from the well, by inserting a surfactant/chemical solution in solid stick form into the wellbore through the wellhead. The soap stick falls down the production tubing or casing due to gravitational pull and upon contacting the undesired well fluid(s) instantly reacts with the fluids to transform the fluids into foam, thus lightening the hydrostatic pressure being applied to the producing formation and increasing the flow of hydrocarbons. The sticks are manufactured by melting solid surfactants and or foamers to liquid form, then mixing the hydrogen gas producing chemicals and or acid solutions uniformly in the molten surfactants and or roamers, then pouring the molten mixture into various sized containers. When the mixture cools, it returns to solid form ready for use. The surfactant(s) are low moisture content foamers, the chemical(s) are hydrogen gas producing compounds which react violently with the downhole fluids.

Abstract: The present invention is a system for severing pipe. The system includes an explosively actuated pipe cutter, a pressure actuated initiator, and a means for suspending the cutter and the initiator inside the pipe and pressure sealing the interior of the pipe.In a particular embodiment of the invention, the initiator includes a time delay to enable reduction in pressure applied to the interior of the pipe for actuating the initiator.

Abstract: A method of and apparatus for severing multiple concentric casing strings in an abandoned oil or gas well allowing the upper portion of the casing strings to be removed comprising positioning a container holding a sealed cylinder full of air at atmospheric pressure that is surrounded by a high velocity explosive in the casing at the location of the desired cut. Igniting the explosive at one end of the container so that the mixture detonates producing a shock wave and gas bubbles that travel downwardly progressively, collapsing the sealed cylinder and increasing the pressure of the air in the cylinder until the cylinder fails whereby pressurized air forced from the cylinder causes the shock wave and gas bubbles from the TNT, RDX, and aluminum mixture to move laterally and sever the casing strings.

Abstract: The present apparatus and method utilizes a downhole electrolysis process implemented by means of an elongated gas generating apparatus containing an array of cascaded electrolysis cells distributed along all or part of the borehole length to be fractured. In one use of the present invention in a deep or a shallow drilled borehole, an electrical current delivered downhole converts an appropriate electrolyte to a stoichiometric mixture of combustible gases, such as, oxygen and hydrogen, which is ignited when sufficient gases have been collected to achieve the desired explosive force in the area surrounding the drilled borehole. In another use of the present invention, the gases are not ignited but rather at least one of the generated gases are delivered by pressure into the area surrounding the drilled borehole to enhance environmental remediation processes.

Abstract: Method and apparatus for plasma blasting comprises a capacitor bank for storing electrical charge to which is coupled an inductance which delivers the electric charge as a current through a switch to an explodable conductor comprising a portion of a probe. The explodable conductor is a ribbon helically wound on a cylindrical mandril, the ribbon having a given length to cross section ratio which is proportional to the square root of the ratio of the inductance to the capacitance in order to ensure efficient dissipation of an optimal amount of the electrical energy stored in the capacitance.

Abstract: A detonation system 10 particularly suitable for use in subterranean environments, for example in oil exploration and production, uses a detonating device 2 containing explosive material 3. The explosive material 3 is detonated by a pulse of laser light of a pre-determined frequency and power. The laser pulse is sent down a fiber optic line 5 from a laser 6 through an optical splitter 4 which is designed to reflect all frequencies apart from the above mentioned pre-determined frequency. To test the integrity of the fiber optic line a test signal from a second laser 11 is sent down the optical fiber line. The test signal has a different frequency and much lower power and is therefore reflected back along the fiber optic line by the optical splitter where it can be detected. This test signal allows testing while considerably reducing the chances of accidental damage.

Abstract: A wellbore tool is provided to perform work in a wellbore by converting a chemical pressure source into a force exerted over a distance. The wellbore tool includes a pressure chamber sealed by a firing head and containing a power charge which includes a plurality of chemical components which are burned in a combustion reaction to generate gas. The combustion reaction of the power charge is initiated by a resistance heater which directly initiates the combustion reaction by receiving electrical energy and generating heat. The combustion reaction generates gas within the pressure chamber, the gas having a pressure which pushes a pressure responsive member into movement relative to the pressure chamber for providing a force over a distance to operate a downhole tool.

Abstract: A method and an apparatus for use in a wellbore are provided to prevent an electrical current from passing between a power supply and an electrically operated downhole well tool until after the electrically operated downhole well tool is positioned downhole within the wellbore. A temperature sensitive member prevents a biased member from moving from a first position to a second position until after the temperature sensitive member has been heated to an activation temperature, at which the temperature sensitive member softens to allow the biased member to move through the temperature sensitive member and to the second position for electrically connecting between the power supply and the electrically operated downhole well tool.

Abstract: A system is provided for performing multiple operations on a well in response to multiple fluid pressure increases. The system includes first and second pressure actuated firing heads and a source of actuating fluid pressure for the firing heads. A first selective communication device is provided for isolating the second firing head from the source of actuating fluid pressure until after the first firing head has been actuated and for then communicating the second firing head with the source of actuating fluid pressure in response to actuation of the first firing head. This system is particularly adapted for allowing pressure testing of a well upon a first fluid pressure increase, followed by perforation of the well upon a second fluid pressure increase.

Abstract: Chemical cutting tool for use within a well bore for cutting very small diameter tubular goods. The tool has an elongated tool body having anchoring means for anchoring the tool within a conduit and a pressure generating section. A cutting section of the tool body has a longitudinal bore having at least one cutting port for expelling cutting agent. A chemical section in the tool body is between the pressure generating section and the cutting section. The chemical section includes a casing having a chamber containing a source of fluid cutting agent. The tool further comprises closure means at at least one end of the casing. The closure means comprises a diaphragm body which is inserted into one end of the casing by an interference fit and which has spaced transverse rupture diaphragms. One of the rupture diaphragms fits into the diaphragm body in an interference fit. The other rupture diaphragm may fit into the tool body in an interference fit, or may be formed integrally.

Abstract: A production valve includes an outer housing having a production port, a piston disposed within the outer housing and adapted to move from one position to another position, a frangible breakup element supporting the piston in the one position, and a detonating cord adapted for propagating a detonation wave passing through the center of the piston and the breakup element. The detonation wave shatters the frangible breakup element when the detonation wave, propagating within the detonating cord, passes through the breakup element. When the breakup element shatters, the support provided to the piston by the breakup element is removed. When the support provided to the piston by the breakup element is removed, the piston moves from the one position to the other position in response to either tubing pressure or rathole pressure or both, and the production port of the production valve opens when the piston moves to the other position.

Abstract: A downhole tool apparatus for use in a well includes a housing having a cylindrical chamber defined therein. A power piston is slidably disposed in the cylindrical chamber and divides the cylindrical chamber into first and second chamber portions on opposite sides of the power piston. First and second explosive charges are contained within the housing and communicated with the first and second chamber portions on opposite sides of the power piston. Firing of the first explosive charge moves the power piston in a first direction. Firing of the second explosive charge moves the power piston back in a second direction opposite the first direction. Thus, the operating power for a downhole tool is provided by selective firing of explosive charges which provide the operating pressure to move the power piston of the tool.

Abstract: A method and apparatus for stimulating the production zone of an oil well having a high pressure gas gun and a coil tubing conduit to deliver cleaning, stimulating, and cooling liquid to the zone while firing the gun. The coil tubing conduit has discharge ports positioned to allow discharge of the liquid at or near the gun to provide cooling of the gun's electrical transmission line and the gun's moving parts. The gun may be gradually withdrawn from the production zone while continuing to fire the gun to stimulate the production zone.

Abstract: A downhole chemical cutting tool for use in a well bore to cut large diameter conduits including an elongated tool body having a chemical section adapted to contain a chemical cutting agent and a cutting section adapted to receive the cutting agent from the chemical section. The cutting section has a plurality of externally upset cutting heads extending circumferentially outwardly from the cutting section and terminating in outer cutting surfaces. Each of the cutting heads has a plurality of cutting ports extending radially inwardly from the outer cutting surface and in fluid communication with an internal chamber within the cutting section. The tool further comprises expansible slip and bow spring means in the elongated tool body for centering and anchoring the tool during cutting. The cutting heads are of a configuration having an inner spoke section which has a central bore opening into the interior chamber of the cutting section and a disk section secured to the outer portion of the spoke section.

Abstract: A system is provided for selectively perforating multiple zones in a well on a single trip into the well. The system includes a tubing string which carries at least a first and a second perforating gun. At least a first and a second pressure actuated firing head are associated with the first and second perforating guns, respectively. A source of actuating fluid pressure for the firing head is provided, which may be the bore of the tubing string. A first selective communication device is provided for isolating the second firing head from the source of actuating fluid pressure until after the first perforating gun has been fired, and for then communicating the second firing head with the source of actuating fluid pressure in response to firing of the first perforating gun. The first firing head provides a time delay during which the actuating fluid pressure may be bled off prior to the firing of the first perforating gun.

Abstract: The preferred firing mechanism of the present invention includes a number of components which cooperate together to actuate an electrically-actuable wellbore tool, which is operable in a plurality of operating modes, and which is carried within the wellbore by a selected one of a plurality of concentrically-nested wellbore tubular members. Viewed broadly, the apparatus includes an electromagnetic sensor means for detecting electromagnetic fields and providing an actuation signal to the electrically-actuable wellbore tool, when an electromagnetic field is detected. The electromagnetic sensor means is carried by the first selected one of the plurality of concentrically nested wellbore tubular members. The apparatus further includes means for selectively generating an electromagnetic field in the wellbore, which is carried by a second selected one of a plurality of concentrically nested wellbore tubular members.

Abstract: A method and apparatus adapted to disable the actuation assembly for a perforating gun or any other detonation device used in subterranean wells to prevent premature surface detonation of the device. An apparatus is provided which can be quickly and easily connected in a tubing string intermediate the firing head and the perforating gun or other detonation device. In a preferred embodiment, the invention comprises a cylinder and firing piston combination wherein a chamber is provided between the cylinder wall and the firing piston. The chamber contains a transition material, such as an eutectic alloy. The transition material changes state from a solid to a fluid when the temperature of the material is increased above the material's "melting temperature." The transition material changes back from a fluid to a solid when the temperature of the material is decreased below the material's "melting temperature.

Abstract: An annular shaped gas generating power charge is shown of the type which can be used in a downhole tool in a well. The charge is provided in the form of a longitudinal strip of solid propellant having a length and a width, a leading end which defines a burn area, a trailing end and opposing side edges. The strip is helically wrapped in at least one spiral turn about a central axis so that the opposing edges of the strip abut one another to form an annular shape. The annular shape provides a controlled gas generation rate and can be installed in the setting chamber of a downhole tool to provide a controlled setting action of the elastomeric components of the downhole tool.

Abstract: A pneumatic well tool for fracturing or enlarging perforations in a subsurface formation so that the petroleum in the formation more freely flows. The tool takes the form of an elongate tool body or sonde which is lowered by a wireline into the well bore to a desired depth adjacent the formation of interest. A fluid chamber in the sonde in fluid communication with the fluid in the well bore is filled with a quantity of well bore fluid. Periodically, a pneumatic pressure source in the sonde exerts pressure on the fluid chamber to force fluid from the chamber into the well bore, thus creating a sudden pressure surge which increases the ability of fluid to flow from the perforated formation.

Abstract: A differential firing head for a tubing conveyed perforation assembly includes a pressure-balanced firing pin propelled by a separate actuator assembly into a detonator to ignite charges in the gun. The actuator assembly includes a shock absorber which functions to keep fluid pressure momentum forces from being transmitted to the firing pin during movement of the tubing string, but which allows differential fluid pressure forces of a preselected magnitude to be applied to the firing pin for detonation of the gun.

Abstract: An apparatus attenuates a shock, such as an impact load from an explosion, by undergoing plastic deformation and by serially dissipating energy from a plurality of surfaces. In a particular embodiment, the plastic deformation and serial energy dissipation occur in and from a hollow unitary body having a cylindrical wall in which are defined a plurality of longitudinally spaced circumferential grooves. A method of attenuating shock from an explosion in an oil gas well comprises: lowering into the well an explosive connected to a shock attenuating member; detonating the explosive whereby an impact load with a shock wave is generated; and collapsing without severing the member in response to the impact load and dissipating energy of the shock wave from a plurality of surfaces of the member so that the shock wave is attenuated along the member.

Abstract: A blasting method which comprises delivering electrical energy at a rate of at least 100 megawatts per microsecond until a peak power of at least 3 gigawatts is reached across the gap of two poles of a coaxial electrode assembly immersed in an electrolyte within a confined area of a substance to be blasted. A dielectric break-down of the electrolyte in the confined area is produced resulting in the formation of plasma within the confined area which creates a pressure sufficient to blast the substance in the manner of a high explosive charge.

Abstract: In a gas-generating chemical reaction carried out in a borehole that is largely filled with water, substantial pressure increases can be generated. This pressure can be used to fracture rocks around the borehole and, hence, stimulate water, oil or gas wells in tight rock formations. This pressure increase can also be used to fracture coal seams for enhanced in-situ gasification or methane recovery. This invention discloses the use of a new, novel system, based on the homogeneous reaction of aluminum alkyls with water, to create a controlled pressure increase. The most appropriate reaction mixture, as characterized by the rise of time of the generated pressure pulse and the energy content per unit length of borehole charge, is disclosed in this new invention.

Abstract: The device of the present invention comprises first means for initiating a first combustive reaction which is actuated in response to a first pressure condition in at least a portion of the well bore, means to initiate any desired number of additional combustive reactions, and means for actuation an explosive charge to actuate perforating guns, or the like, in the well bore.

Abstract: Device for extracting a liquid out of a tube of great length closed at one of its ends in case a communication between the closed end and a source of a substitution fluid should be difficult to establish, the device includes a mobile member provided with a body connected to a supporting surface apparatus, a piston whose cross-section is adapted to the inner cross-section of the tube controlled valve means allowing for the running of the mobile member along the tube and means in the body for providing a substitution fluid such as liquified gas bottles or substances which provide a great volume of gas when combusted. Such a device is useful for example for emptying tube when production tests are conducted in oil wells,.

Abstract: A method and apparatus for achieving adiabatic heat ignition of combustible material, particularly explosive compositions which involves entrapping a quantity of gas in a chamber which is in communication with the combustible material and suddenly compressing the gas to the extent that the temperature thereof is increased adiabatically to the ignition temperature of the combustible material. The apparatus is particularly adaptable for use as an adiabatic ignition device for detonating cord and shaped charges of perforating guns for completion of wells. A quantity of high explosive within an explosive barrel is in detonating proximity with the detonating cord. A cylinder forms an air chamber which is in communication with the explosive composition and is provided with a piston for compression of the gas. One or more shear pins or other locking devices are provided to secure the piston in immovable relation with the cylinder.

Abstract: A well sealing device using an internal propellant charge to drive slip segments outwardly against a well casing. A pin shears, releasing the device from its wire line prior to final setting of the slip segments.

Abstract: A method of charging waterlogged boreholes with water-resistant particulate explosive material, comprises inserting a pneumatic line with upwardly directed nozzles at the lower end thereof and a material supply line into a borehole, blowing compressed air through the pneumatic line such that at least a portion thereof is directed through the nozzles to form a substantially water-free air pocket around the lower end of the supply line, supplying particulate explosive material through the supply line to a charging zone in the vicinity of the lower end thereof, and gradually withdrawing said line as the borehole fills up with explosive material.

Abstract: A gas generating type tool includes a propellant charge having an axially extending passage receiving therein an ignition tube containing a quantity of easily ignited, fast burning powder. The propellant and ignition tube are separately handled and/or transported until ready to run into the well. The tube slides easily into the propellant passage. The propellant passage is at least about 12% larger in cross-section than the ignition tube and not more than about 55% larger in cross-section. In circular cross-sections, the propellant passage is at least about 6% greater in diameter and not more than about 25% greater in diameter.

Abstract: Apparatus for electrically generating hydraulic shock waves in a fluid bearing formation (14) of a bore hole (10) including a tool (16) having an upper electrode (42) and a lower electrode (46) forming a spark gap therebetween. The tool (16) has an upper end portion (40) comprised of a plurality of sections (40A-40E) threaded to each other in end to end relation and an armored electrical cable (18) having an outer metal sheath (34) is anchored to the uppermost section (40A). The tool (16) is particularly adapted for fitting within a casing having a four inch diameter and the electrodes (42,46) have diverging planar end surface portions (84) coated with tungsten carbide to provide wear resistant surfaces.

Abstract: A gas generating type fracturing tool is designed to work on long productive intervals and includes a series of separate propellant charges, an igniter for initiating combustion of one of the charges and means for transferring combustion from one charge to the next. In one embodiment, combustion of the charges occurs one after another with little or no delay between successive charges. In other embodiments, a delay is incorporated in the combustion train between successive charges. Some embodiments are specifically designed to unplug uncemented slotted liners and have very small gas generation capability.

Abstract: A downhole chemical cutting tool having an anchoring system employing interchangeable slip arrays of progressively larger outside diameters that can be used economically to adjust the range of the anchoring system. The range can be further adjusted by utilizing interchangeable slip expansion mandrels. This anchoring system both anchors and centralizes the chemical cutting tool. The cutting tool includes a slip shaft that provides fluid communication between the propellant section and chemical section, thence to the slip piston that receives the interchangeable slip arrays. The slip shaft and slip piston are threadably connected to a set coiled tension spring. Interchangeable slip expansion mandrels connected to the slip shaft below the slip arrays are constructed with ball bearings on the surface that receives the slip arrays expanding the slip segments into a gripping engagement an usually large angle as the slip piston is actuated by the application of fluid pressure during the cutting operation.

Abstract: There is disclosed an improved process and apparatus for generating a gaseous media for stimulating and/or fracturing a hydrocarbon bearing well formation comprised of a substantially horizontally-disposed gas generator having a first catalyst reaction bed, an expansion chamber, a second catalyst reaction bed, a venturi chamber for forming a gaseous stream to be introduced into the hydrocarbon bearing well formation.

Abstract: An improvement in chemical cutting apparatus for use down within a well bore comprising improved means of discharging a cutting agent in conjunction with an automatic means of pressure relief. The relief also includes an expendable plug and an "O" ring assembly, which acts to prevent clogging of the relief port prior to firing of the cutting apparatus. The pressure relief is made small enough and is so located to prevent it from interfering with the normal operation of the cutting tool, but nonetheless is effective in relieving the built-up high internal pressure when the tool malfunctions. The improved means of application of cutting fluid includes a discharge/containment sub assembly which contains means of driving the cutting agent from the assembly via a piston actuation arrangement.

Abstract: An active combustion zone is established in situ within a permeable hydrocarbon formation. The permeable formation is periodically charged with a combustible gas, and is thereafter subjected to a high pressure pulse produced by detonation of the combustible gas within an injection well. The periodic pressure pulses drive the combustible gas into the in situ combustion zone. Combustion is sustained by injection of an oxidant. The injection of oxidant is terminated periodically, and the injection well along with the surrounding formation is pressurized and saturated with the combustible gas mixture. The combustible gas mixture is displaced through the permeable formation in advance of the combustion flame front in response to a high pressure pulse produced by detonation of the pressurized combustible gas within the injection well. In the preferred embodiment, the combustible injection gas is a mixture of hydrogen gas and chlorine gas.

Abstract: A gas generating type fracturing tool includes a propellant charge and an ignitor for initiating combustion of the propellant. When combustion starts, a pressure buildup inside the tool manipulates a brake or drag acting against the inner casing wall to retard upward movement of the tool. A shear pin fails allowing a spring to move an element into frictional engagement with the casing string.

Abstract: An inflatable borehole plug is disclosed, the inflation of which is achieved by chemical reaction of two co-reagents disposed therein which results in evolution of a gas. The borehole plug can be dropped or lowered down a borehole to a preselected position since the extent of gas-producing chemical reaction is able to be delayed following initiation of mixing of co-reagents, by delay means in the borehole plug, for sufficient time to enable placement of the borehole plug.

Abstract: A device for fracturing a subterranean formation includes a propellant charge which generates, during combustion, a large quantity of high pressure combustion products. A drogue is provided on the device to prevent or minimize rapid upward movement of the device during combustion. This obviates "bird nesting" of the wire line, wire line damage and the like.

Abstract: Subterranean oil and gas producing formations are fractured in a first embodiment by providing one or more combustion gas generating units using rocket fuel type propellants disposed in a well casing at preselected depths. The well casing is filled with a compressible hydraulic fracturing fluid comprising a mixture of liquid, compressed gas, and propant material and precompressed to a pressure of about 1,000 psi or more greater than the fracture extension pressure at the depth of the zone to be fractured. At least one of the gas generating units is equipped with perforating shaped charges to form fluid exit perforations at the selected depth of the fracture zone. The gas generating units are simultaneously ignited to generate combustion gasses and perforate the well casing.

Abstract: An improvement in chemical cutting apparatus for use down within a well bore comprising an automatic means of pressure relief, whereby the anchoring mechanism of the apparatus is disengaged automatically when a clogging of the chemical discharge ports or other malfunction occurs, which pressure relief prevents the cutting tool from becoming stuck down in the hole. The automatic means includes a pressure relief port in the form of an axial bore from the exterior of the assembly to the anchor slip chamber, situated in such a manner that the inside pressure of the cutting apparatus does not communicate with the exterior, until the anchor slip becomes erect. The relief also includes an expendable plug and "O" ring assembly, which acts to prevent clogging of the relief port prior to firing of the cutting apparatus.

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.

Abstract: Apparatus is disclosed for connecting the firing head of a downhole tool to a set of jars to allow the jars to jar up and jar down. The apparatus includes a firing head housing, a hammer located in the housing, and a spring urging the hammer toward a firing pin. A mandrel extends into the housing. It has one end connected to a jar and the other end connected to the hammer by a shear pin. The mandrel also has longitudinally spaced oppositely facing shoulders and one or more lock segments around the mandrel between the shoulders. The movement of the lock segments along the axis of the housing is limited and the lock segments engage the oppositely facing shoulders to limit axial movement of the mandrel relative to the housing in either direction when the pin is sheared and the hammer released to strike the firing pin.

Abstract: An improved, simplified and less expensive apparatus and method for cleaning wells embodies an elongated tube of combustible material, sealed at its ends, that is ignited at one end to generate a pressure wave that travels along the length of the tube. Outwardly directed pressure generated within the well casing by the deflagration is periodically attenuated at spaced locations along the length of the tube by a plurality of spaced short, steel sleeves circumscribing the tube and secured thereto. Three such tube sections are provided, each with its spaced, short circumscribing steel sleeves and each ignited in a selected chronological and positional sequence by three individual simultaneously electrically activated detonator caps which are provided with mutually different delay times.

Abstract: An improved wireline operated oil well dump bailer includes an elongated tool body having a longitudinal bore that extends through the tool body, the bore including a chamber section for carrying cement. A port through the tool body provides fluid communication between the tool bore and the oil well bore. A piston is slidably movable within the tool body between a first position in which the piston seals the port and a second position in which the piston is spaced from the port so that well bore fluid pressure can enter the tool body through the port and communicate with the piston. A trigger carried by the tool body, preferably in the form of an explosive charge which can be activated using the wireline moves the piston away from the first position to the second position so that the well fluid pressure enters the bore and powers the piston to dispense cement from the cement carrying chamber section.

Abstract: Subterranean oil and gas producing formations are fractured by filling a well casing with a compressible hydraulic fracturing fluid comprising a mixture of liquid, compressed gas, and propant material and precompressed to a pressure of about 1,000 psi or more greater than the fracture extension pressure at the depth of the zone to be fractured. A perforator is provided in the casing to form fluid exit perforations at the selected depth of the fracture zone. Following perforation the perforated zone is fractured by the precompressed fracturing fluid laden with propant material that is discharged into the formation until the hydraulic extension pressure is reached and the perforations are eventually sanded off. Optionally, filling of the well bore is maintained continuously through the filling and perforation of the casing until after decompression of the fracturing fluid is completed.

Abstract: A subterranean formation is fractured by burning a quantity of fuel in an uncased bore hole to generate a large quantity of high pressure combustion products. These gases rapidly flow into the formation creating the fractures. The device is assembled in the well by placing a thermal ignitor in the well and delivering a quantity of fuel and oxidizer around the ignitor. The fuel and oxidizer comprise a flowable material and are either pumped or poured into the well.