Abstract: A shaped charge carrier tool is provided that has particular utility for perforating well casing as a preparation for cement placement. A plurality, four or more elongated shaped charge carrier ribs having a high bending modulus are secured for radially expanded displacement around a central framing tube or rod. Radius rods link the ends of the carrier ribs to top and bottom hinge carriers. The hinge carriers encircle the framing tube and are free for axial translation along the framing tube. Articulating hinges connect the radius rods to the carrier ribs and to the hinge carriers. Opposed compressed coil springs provide a resilient bias on the hinge carriers to translate the carrier ribs radially outward against the interior surface of a well casing as the tool passes from a riser tube into a larger inside diameter well casing.

Abstract: For a free falling well tool sub having one or more pipe bore centering cages, a collapsible material cone secured inside of the centering cage half length with the cone base opening in the downhole direction restricts the rate of pipe bore fluid flow past the cone and thereby restricts the descent rate of the tool. The rate of descent may be regulated with fluid flow by-pass apertures in the sub. A collapsible material cone in a bore centering cage having a base opening in the up-hole direction may be used as piston to drive the tool sub along horizontal segments of a deviated well bore. Both cones may be used separately or together.

Abstract: Downhole drill pipe cutting is achieved by a free-falling sub carrying a shaped charge cutter and an ablative fluid cutter. Upon seating on a drill string flow bore orifice, fluid pressure is raised to detonate the shaped charge cutter. In the event the shaped charge cutter fails, pressure is further raised to effect a cut by fluid ablation.

Abstract: Downhole drill pipe cutting is achieved by a free-falling sub carrying a shaped charge cutter and an ablative fluid cutter. Upon seating on a drill string flow bore orifice, fluid pressure is raised to detonate the shaped charge cutter. In the event the shaped charge cutter fails, pressure is further raised to effect a cut by fluid ablation.

Abstract: A shaped charge carrier tool is provided that has particular utility for perforating well casing as a preparation for cement placement. A plurality, four or more elongated shaped charge carrier ribs having a high bending modulus are secured for radially expanded displacement around a central framing tube or rod. Radius rods link the ends of the carrier ribs to top and bottom hinge carriers. The hinge carriers encircle the framing tube and are free for axial translation along the framing tube. Articulating hinges connect the radius rods to the carrier ribs and to the hinge carriers. Opposed compressed coil springs provide a resilient bias on the hinge carriers to translate the carrier ribs radially outward against the interior surface of a well casing as the tool passes from a riser tube into a larger inside diameter well casing.

Abstract: Detonation of a perforating gun is initiated by engagement of the lower distal end of the gun assembly against a bottom hole bore plug. A fluid pressure actuated firing head is initiated by well fluid that is pressurized by a free piston having an integral rod projecting from the distal end of the gun assembly. The piston is displaced against a closed fluid volume when the projecting rod engages the bore plug.

Abstract: Detonation of a perforating gun is initiated by engagement of the lower distal end of the gun assembly against a bottom hole bore plug. A fluid pressure actuated firing head is initiated by well fluid that is pressurized by a free piston having an integral rod projecting from the distal end of the gun assembly. The piston is displaced against a closed fluid volume when the projecting rod engages the bore plug.

Abstract: For a free falling well tool sub having one or more pipe bore centering cages, a collapsible material cone secured inside of the centering cage half length with the cone base opening in the downhole direction restricts the rate of pipe bore fluid flow past the cone and thereby restricts the descent rate of the tool. The rate of descent may be regulated with fluid flow by-pass apertures in the sub. A collapsible material cone in a bore centering cage having a base opening in the up-hole direction may be used as piston to drive the tool sub along horizontal segments of a deviated well bore. Both cones may be used separately or together.

Abstract: For a free falling well tool sub having one or more pipe bore centering cages, a collapsible material cone secured inside of the centering cage half length with the cone base opening in the downhole direction restricts the rate of pipe bore fluid flow past the cone and thereby restricts the descent rate of the tool. The rate of descent may be regulated with fluid flow by-pass apertures in the sub. A collapsible material cone in a bore centering cage having a base opening in the up-hole direction may be used as piston to drive the tool sub along horizontal segments of a deviated well bore. Both cones may be used separately or together.

Abstract: A perforating gun assembly comprises a drop sub linking the firing head to the gun tube or tubes. The drop sub includes a 360° perimeter shaped charge explosive for severing pipe having an axial bore to accommodate a pass-through of the perforation charge detonation chord. Consequently, the severing tool is detonated by the traverse of a detonation wave along the chord length to disconnect the perforating gun prior to detonation of the perforation charges.

Abstract: Detonation of a perforating gun is initiated by engagement of the lower distal end of the gun assembly against a bottom hole bore plug. A fluid pressure actuated firing head is initiated by well fluid that is pressurized by a free piston having an integral rod projecting from the distal end of the gun assembly. The piston is displaced against a closed fluid volume when the projecting rod engages the bore plug.

Abstract: Detonation of a perforating gun is initiated by engagement of the lower distal end of the gun assembly against a bottom hole bore plug. A fluid pressure actuated firing head is initiated by well fluid that is pressurized by a free piston having an integral rod projecting from the distal end of the gun assembly. The piston is displaced against a closed fluid volume when the projecting rod engages the bore plug.

Abstract: A perforating gun assembly comprises a drop sub linking the firing head to the gun tube or tubes. The drop sub includes a 360° perimeter shaped charge explosive for severing pipe having an axial bore to accommodate a pass-through of the perforation charge detonation chord. Consequently, the severing tool is detonated by the traverse of a detonation wave along the chord length to disconnect the perforating gun prior to detonation of the perforation charges.

Abstract: For a free falling well tool sub having one or more pipe bore centering cages, a collapsible material cone secured inside of the centering cage half length with the cone base opening in the downhole direction restricts the rate of pipe bore fluid flow past the cone and thereby restricts the descent rate of the tool. The rate of descent may be regulated with fluid flow by-pass apertures in the sub. A collapsible material cone in a bore centering cage having a base opening in the up-hole direction may be used as piston to drive the tool sub along horizontal segments of a deviated well bore. Both cones may be used separately or together.

Abstract: A free falling drop sub carries an explosive tool such as a shaped charge pipe cutter or well perforator. The drop sub includes an aperture plugging element to isolate an upper pipe string from a lower pipe string. An upper pipe string fluid pressure actuated valve element retained by shear pins is released to admit the upper string pressure against a pressure displaced firing pin. Displacement of the firing pin initiates detonation of the explosive tool.

Abstract: A string of drill pipe, for example, is assembled with a severing sub in anticipation of a possible need to cut the string at some point in the operation. The severing sub includes a thin wall tube that links opposite end tool joint bosses. The tin wall tube is easily cut by a shaped charge cutter. Rotary drive torque is transmitted between the sub tool join bosses by a concentric external torque tube having a torque transmitting assembly at each boss. The torque tube connection to the upper boss has an inseparable circumferential shoulder engagement with the boss. The lower boss engagement of the torque tube is axially separable. When the thin wall tube is cut, the upper boss and torque tube is withdrawn from the well with the upper pipe string.

Abstract: A free falling drop sub carries an explosive tool such as a shaped charge pipe cutter or well perforator. The drop sub includes an aperture plugging element to isolate an upper pipe string from a lower pipe string. An upper pipe string fluid pressure actuated valve element retained by shear pins is released to admit the upper string pressure against a pressure displaced firing pin. Displacement of the firing pin initiates detonation of the explosive tool.

Abstract: A system for positioning a downhole tool along a pipe string, the system having a series of seating subs inserted along the length of the pipe string wherein each seating sub has a seating aperture disposed around its internal periphery so as to form a bore plug seat of smaller diameter than the diameter of the pipe. The seating apertures are given distinctive diameters that are consecutively arranged along the pipe string length so that the aperture diameters decrease with increasing depth. A drop assembly having an aperture plugging diameter selected to pressure seal a selected aperture includes a bore pressure activated by-pass valve and firing head.

Abstract: A string of drill pipe, for example, is assembled with a severing sub in anticipation of a possible need to cut the string at some point in the operation. The severing sub includes a thin wall tube that links opposite end tool joint bosses. The tin wall tube is easily cut by a shaped charge cutter. Rotary drive torque is transmitted between the sub tool join bosses by a concentric external torque tube having a torque transmitting assembly at each boss. The torque tube connection to the upper boss has an inseparable circumferential shoulder engagement with the boss. The lower boss engagement of the torque tube is axially separable. When the thin wall tube is cut, the upper boss and torque tube is withdrawn from the well with the upper pipe string.

Abstract: A system for positioning a downhole tool along a pipe string, the system having a series of seating subs inserted along the length of the pipe string wherein each seating sub has a seating aperture disposed around its internal periphery so as to form a bore plug seat of smaller diameter than the diameter of the pipe. The seating apertures are given distinctive diameters that are consecutively arranged along the pipe string length so that the aperture diameters decrease with increasing depth. A drop assembly having an aperture plugging diameter selected to pressure seal a selected aperture includes a bore pressure activated by-pass valve and firing head.