Abstract: A “mini-severing and back-off” tool includes a tubular magazine for a column of explosive pellets that are sized in diameter to provide a predetermined weight of explosive per unit column length. The tubular wall is vented at prescribed intervals for fluid pressure equalization between the internal bore of the tubular and the fluid pressure around the outside of the tubular. A fluid barrier is positioned between one end of the explosive pellet tubular and a detonator or an explosive booster provided to detonate the explosive pellet tubular. The explosive pellet tubular is positioned within the flow bore of a pipe string and adjacent to an intended pipe joint, and the explosive pellet tubular is detonated simultaneously with an application of torque on the pipe string, wherein the torque is applied in the thread release direction to disassemble the intended pipe joint.

Abstract: A “back-off” tool comprises a magazine cylinder having one distal end of a long mast rod secured to the lower end-face of a magazine cylinder. The magazine cylinder is attached to an electrically detonated firing head. A first plurality of blind hole cavities penetrate the magazine cylinder end-face around the mast rod junction. A second plurality of elongated detonation cord ends are inserted into high temperature grease filled magazine cylinder cavities. From the cavities, the detonation cord lengths are bound to the rod surface along the rod length by non-metallic cord. The tool assembly is secured to the end of a wireline or tubing string for downhole placement and detonation.

Abstract: A “mini-severing and back-off” tool includes a tubular magazine for a column of explosive pellets that are sized in diameter to provide a predetermined weight of explosive per unit column length. The tubular wall is vented at prescribed intervals for fluid pressure equalization between the internal bore of the tubular and the fluid pressure around the outside of the tubular. A fluid barrier is positioned between one end of the explosive pellet tubular and a detonator or an explosive booster provided to detonate the explosive pellet tubular. The explosive pellet tubular is positioned within the flow bore of a pipe string and adjacent to an intended pipe joint, and the explosive pellet tubular is detonated simultaneously with an application of torque on the pipe string, wherein the torque is applied in the thread release direction to disassemble the intended pipe joint.

Abstract: An apparatus for, and method of, centering downhole well tools within the wellbore of a pipe comprises at least a pair of discs secured, respectively, to the distal end of a tool in a plane normal to a longitudinal tool axis, with an arc of each disc extended past the outer perimeter of the tool to at least an internal perimeter of an applied pipe bore and flexing to centralize the tool. In alternative embodiments, the discs are replaced by blades that are secured by a plurality of attachment points and fasteners, or by spring steel wires that are secured in radial apertures through an end boss by interference fit, soldering, swaging, or gluing.

Abstract: An apparatus and method, usable for centering downhole well tools within a pipe or wellbore, comprises a cylindrical end boss extension, from a distal end of a well tool housing, and a thin ring secured about said end boss comprising a plurality of radial apertures. Thin metallic wires, having distal ends secured within said apertures, extend radially from said ring into contact with the inside wall(s) of the pipe or wellbore. An alternative embodiment includes an annular extension from the distal end of said well tool that encloses a cavity within. A plurality of diametrically opposite apertures in said annular extension receives respective wires across a tool housing axis to project in opposite directions into contact with said inside wall of the pipe or wellbore. Said wires may be secured to said well tool by a potting compound, including a high temperature silica compound, an adhesive paste, or other compounds.

Abstract: A “back-off” tool comprises a magazine cylinder having one distal end of a long mast rod secured to the lower end-face of a magazine cylinder. The magazine cylinder is attached to an electrically detonated firing head. A first plurality of blind hole cavities penetrate the magazine cylinder end-face around the mast rod junction. A second plurality of elongated detonation cord ends are inserted into high temperature grease filled magazine cylinder cavities. From the cavities, the detonation cord lengths are bound to the rod surface along the rod length by non-metallic cord. The tool assembly is secured to the end of a wireline or tubing string for downhole placement and detonation.

Abstract: A shaped charge pipe cutter is constructed with the cutter explosive material packed intimately around an axially elongated void space that is continued through a heavy wall boss portion of the upper thrust disc. The boss wall is continued to within a critical initiation distance of a half-cuter junction plane. An explosive detonator is positioned along the void space axis proximate of the outer plane of the upper thrust disc. Geometric configurations of the charge thrust disc and end-plate concentrate the detonation energy at the critical initiation zone.

Abstract: A high energy pipe severing tool is arranged to align a plurality of pressure balanced explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The explosive pellets are loaded serially in a column and in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: A pipe severing tool is arranged to align a plurality of high explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The pellets are loaded serially in a column in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: A high energy pipe severing tool is arranged to align a plurality of pressure balanced explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The explosive pellets are loaded serially in a column and in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: An apparatus and method, usable for centering downhole well tools within a pipe or wellbore, comprises a cylindrical end boss extension, from a distal end of a well tool housing, and a thin ring secured about said end boss comprising a plurality of radial apertures. Thin metallic wires, having distal ends secured within said apertures, extend radially from said ring into contact with the inside wall(s) of the pipe or wellbore. An alternative embodiment includes an annular extension from the distal end of said well tool that encloses a cavity within. A plurality of diametrically opposite apertures in said annular extension receives respective wires across a tool housing axis to project in opposite directions into contact with said inside wall of the pipe or wellbore. Said wires may be secured to said well tool by a potting compound, including a high temperature silica compound, an adhesive paste, or other compounds.

Abstract: An apparatus for, and method of, centering downhole well tools within the wellbore of a pipe comprises at least a pair of discs secured, respectively, to the distal end of a tool in a plane normal to a longitudinal tool axis, with an arc of each disc extended past the outer perimeter of the tool to at least an internal perimeter of an applied pipe bore and flexing to centralize the tool. In alternative embodiments, the discs are replaced by blades that are secured by a plurality of attachment points and fasteners, or by spring steel wires that are secured in radial apertures through an end boss by interference fit, soldering, swaging, or gluing.

Abstract: A high energy pipe severing tool is arranged to align a plurality of pressure balanced explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The explosive pellets are loaded serially in a column and in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: A shaped charge casing cutter is constructed with the cutter explosive formed into radial section modules aligned in a toroidal cavity between a pair of housing plates. The center sections of the housing plates are contiguously aligned with opposite parallel surfaces of a center disc. The housing plates comprise annular edges or rims, and the rims can be offset from respective center disc planes in opposite directions from each other to form a toroidal cavity. The toroidal cavity is enclosed by a circumferential belt secured to said housing plate rims. V-grooved shaped charge explosive in the form of multiple pi sections is distributed about the cavity to intimately contact a pair of frusto-conical liners. Assembly tolerance space between the pi sections is filled by dense paper card stock.

Abstract: A high energy pipe severing tool is arranged to align a plurality of pressure balanced explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The explosive pellets are loaded serially in a column and in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: A shaped charge casing cutter is constructed with the cutter explosive formed into radial section modules aligned in a toroidal cavity between a pair of housing plates. The center sections of the housing plates are contiguously aligned with opposite parallel surfaces of a center disc. The housing plates comprise annular edges or rims, and the rims can be offset from respective center disc planes in opposite directions from each other to form a toroidal cavity. The toroidal cavity is enclosed by a circumferential belt secured to said housing plate rims. V-grooved shaped charge explosive in the form of multiple pi sections is distributed about the cavity to intimately contact a pair of frusto-conical liners. Assembly tolerance space between the pi sections is filled by dense paper card stock.

Abstract: A shaped charge pipe cutter is constructed with the cutter explosive material packed intimately around an axially elongated void space that is continued through a heavy wall boss portion of the upper thrust disc. The boss wall is continued to within a critical initiation distance of a half-cuter junction plane. An explosive detonator is positioned along the void space axis proximate of the outer plane of the upper thrust disc. Geometric configurations of the charge thrust disc and end-plate concentrate the detonation energy at the critical initiation zone.

Abstract: A pipe severing tool is arranged to align a plurality of high explosive pellets along a unitizing central tube that is selectively separable from a tubular external housing. The pellets are loaded serially in a column in full view along the entire column as a final charging task. Detonation boosters are pre-positioned and connected to detonation cord for simultaneous detonation at opposite ends of the explosive column. Devoid of high explosive pellets during transport, the assembly may be transported with all boosters and detonation cord connected.

Abstract: A shaped charge casing cutter is constructed with the cutter explosive formed into radial section modules aligned in a toroidal cavity between a pair of housing plates. The center sections of the plates are contiguously aligned with opposite parallel surfaces of a center disc. The plate rims are offset from respective center disc planes in opposite directions from each other to form a toroidal cavity. The toroidal cavity is enclosed by a circumferential belt secured to said plate rims. V-grooved shaped charge explosive in the form of multiple pi sections is distributed about the cavity to intimately contact a pair of frusto-conical liners.

Abstract: A shaped charge pipe cutter is constructed with the cutter explosive material packed intimately around an axially elongated void space that is continued through a heavy wall boss portion of the upper thrust disc. The boss wall is continued to within a critical initiation distance of a half-cuter junction plane. An explosive detonator is positioned along the void space axis proximate of the outer plane of the upper thrust disc. Geometric configurations of the charge thrust disc and end-plate concentrate the detonation energy at the critical initiation zone.