Schlumberger Technology Corporation

Schlumberger Technology Corportion

Antoni K Miszewski

Klaus B Huber

A Glen Edwards

William M Hill

Joe C Hromas

An automatic tubing release mechanism is adapted to be disposed in a wellbore between a tubing, on one end, and a perforating gun, on the other end. The release mechanism includes a frangible breakup tube, firing head positioned above the breakup tube, and the perforating gun positioned below the breakup tube when the release mechanism is disposed in the wellbore. A detonating cord is interconnected between the firing head and the perforating gun via the breakup tube. When the firing head detonates the perforating gun, the breakup tube shatters. When the breakup tube shatters: in accordance with one embodiment, a release piston, previously resting on the breakup tube, moves downwardly in response to hydrostatic pressure of wellbore fluid and releases a collet arm which rests against a threaded connection of a housing, the release of the collet arm disconnecting the perforating gun from the tubing, the perforating gun falling to a bottom of the wellbore; or, in accordance with another embodiment, wellbore fluid at hydrostatic pressure enters a plurality of fluid ports and exerts a pressure on an underside of a release piston causing the piston to move upwardly thereby releasing a collet arm which rests against a threaded connection of a housing, the release of the collet arm disconnecting the perforating gun from the tubing, the perforating gun falling to a bottom of the wellbore.

Automatic tubing release

An explosive diode transfer system is interconnected between adjacent perforating guns of a modular perforating apparatus. The explosive diode transfer system includes a downwardly directed shaped charge, a booster, and a multi-density barrier interposed between the shaped charge and the booster. The multi-density barrier includes a first metal layer and a second metal layer spaced from the first metal layer thereby defining a sealed air-space between the first and second metal layers. The first metal layer, air space, second metal layer combination represents a plurality of different density barriers or layers which are collectively designed to prevent a first detonation wave, propagating from the booster to the shaped charge, from propagating therethrough, but nevertheless to allow a jet, propagating from the shaped charge to the booster, to propagate therethrough. The multi-density character of the barrier and the air space reflect and therefore completely attenuate the first detonation wave as it propagates from the booster to the shaped charge, but does not significantly attenuate the jet propagating from the shaped charge to the booster. Therefore, the explosive diode transfer system functions like a diode, allowing propagation in one direction, but not allowing propagation in the opposite direction. Consequently, the multi-density barrier of the explosive diode transfer system prevents a back fired detonation wave originating from a lower oriented perforating gun from detonating a higher oriented perforating gun in the modular perforating apparatus.

Explosive diode transfer system for a modular perforating apparatus

In the representative embodiment of the method and apparatus of the invention which are disclosed herein, a well tool arranged for suspension in a well bore from a cable includes a mandrel that is telescopically arranged on the tool body and is operable after the tool is stationed in a well bore to be shifted upwardly and downwardly by the cable. A pressure-responsive actuator is arranged on the tool for being released in response to an initial downward movement of the suspension cable for rapidly extending an anchor on the tool body into engagement with the well casing. Thereafter, a successive upward movement of the suspension cable is effective for releasing the pressure-responsive actuator for slowly traveling to a position in the tool body where a firing pin on the body is released for detonating an impact-actuated explosive device on the tool only after a predetermined time delay following the upward cable movement. Subsequent cable movements are operative for thereafter disengaging the anchor to enable the tool to be recovered from a well bore wall.

Method and apparatus for controlling a well tool suspended by a cable in

A well apparatus adapted to be disposed in a wellbore includes a perforating apparatus and a packer adapted to set and isolate an annulus above the packer from a rathole annulus below the packer, the perforating apparatus including a new and novel rathole differential pressure balanced firing system where the firing system includes a ball release sleeve holding a firing piston, means for initially opening a top end and a bottom end of the ball release sleeve to the rathole annulus below the packer; and a plurality of sequentially operable hydraulic systems, the top end of the ball release sleeve being initially open to the rathole annulus below the packer but being subsequently closed to the rathole annulus below the packer and then reopened to the annulus above the packer when the packer is set. When the top end of the ball release sleeve is opened relative to the annulus above the packer and the significant pressure is applied to the annulus above the packer, the ball release sleeve releases the firing piston; as a result, since the firing piston is released, the firing piston drops and impacts a primer, the impact of the firing piston on the primer detonating the perforating apparatus.

Wellbore apparatus including a rathole pressure balanced-differential

A tension actuated device is adapted to be connected between a pipe string and an object stuck downhole in a wellbore and does not disconnect the pipe string from the object in response to a transient or temporary shock load that is temporarily applied to the pipe string. Rather, the tension actuated device selectively disconnects the pipe string from the object stuck downhole by continuously applying a pulling force of a predetermined magnitude to the device via the pipe string for a predetermined period of time. The tension actuated device includes an inner member adapted to be connected to an object stuck downhole, an outer member connected to the inner member and adapted to be connected to the pipe string, and a compressible material disposed between the inner and outer members, the compressible material being compressed and the inner member being disconnected from the outer member when a pulling force of predetermined magnitude is continuously applied to the outer member via the pipe string for a predetermined period of time. Transient loads cannot release the inner member from the outer member of the device because typical transient loads do not apply a force, of the predetermined magnitude, to the pipe string for a long enough period of time.

Apparatus for releasing a pipe string from an object stuck downhole by

A shock absorber is adapted to be disposed within a perforating gun string or within the tubing string above the perforating gun and includes an energy absorbing element adapted to absorb and store mechanical energy during detonation of the perforating gun and to permanently deform in response to the storage of the mechanical energy, the stored energy being released in the form of heat, and not in the form of kinetic energy. Therefore, following absorption of the mechanical energy by the shock absorber, no further expansion of the shock absorber is experienced. The shock absorber includes an inner housing, an outer hosuing, a connection for interconnecting the inner and outer housing, and a break up charge for breaking the connection and releasing the inner housing from the outer housing when the perforating gun is detonated whereby the shock absorber is as strong as the tubing string before the connection is broken and is flexible after the connection is broken. The energy absorbing element may be a damping coil or it may be a honeycomb. The damping coil and honeycomb energy absorbing elements permanently deform when mechanical energy is absorbed; therefore, the stored mechanical energy is subsequently released in the form of heat and not in the form of kinetic energy.

Shock energy absorber including collapsible energy absorbing element and

A perforating gun having no firing head and no primary explosives is attached to a tubing string and the tubing string is run into a borehole. A new pump apparatus, having a firing head, is run into the tubing string until the pump firing head is adjacent the perforating gun. The firing head in the pump apparatus detonates, firing the perforating gun. If the firing head fails to detonate, one need only remove the pump apparatus from the tubing string in order to gain access to the firing head, for repair and replacement thereof. One need not remove the tubing string to gain access to the firing head.

Method of detonating a perforating apparatus on a tubing including

Pump apparatus including a firing head for use with a perforating gun on

A perforating gun having no firing head and no primary explosives is attached to a tubing string and the tubing string is run into a borehole. A new well apparatus, having a firing head, is run into the tubing string until the firing head is adjacent the perforating gun. The firing head in the well apparatus detonates, firing the perforating gun. If the firing head fails to detonate, one need only remove the well apparatus from the tubing string in order to gain access to the firing head, for repair and replacement thereof. One need not remove the tubing string to gain access to the firing head.

Well apparatus including a pump and a firing head adapted to be inserted

A perforating gun, adapted to be disposed in a deviated borehole, includes an intra-gun swivel located between a first plurality of charges and a second plurality of charges of the perforating gun. The swivel includes a first housing, a second housing, and thrust and radial bearings disposed between the surfaces of the first and second housing for allowing the first housing to rotate with respect to the second housing and therefore the first plurality of charges to rotate with respect to the second plurality of charges of the perforating gun.

Growing community of inventors

Missouri City, TX, United States of America

Antoni K Miszewski