Other

Tomahawk Downhole, LLC

Team Engineering and Manufacturing, Inc.

Thomas E Falgout, Jr

Chad Daigle

William N Schoeffler

John W Hester

Toby S Baudoin

A down hole drilling motor shaft security apparatus is disclosed. The apparatus has a general body housing threadedly attached to a lower radial bearing housing and an output shaft extending from the lower radial bearing housing. Within the general body housing is a thrust bearing assembly that secures a portion of the output shaft within the general body housing and the lower radial bearing housing. An intermediate sleeve having a capture groove of an elongated predetermined width is threadedly attached to the output shaft. An interference structure that is secured to the general housing extends radially into the capture groove in a manner that prevents axial loads from being transmitted to the intermediate sleeve from the interference structure while the bearing assembly is intact. The interference structure is configured to secure the intermediate sleeve and the output shaft to the general housing by engagement with the capture groove of the intermediate sleeve in the event of axial movement of the intermediate sleeve a preselected amount.

Motor shaft security apparatus

Manipulation of the rate of drilling fluid flow down a drill string containing the apparatus causes a drilling fluid powered linear motor, preferably a piston, to move an output shaft, hingedly attached to the general body to laterally, and selectively, deflect the longitudinal axis of the apparatus with the effect of bending an associated drill string assembly just above the drill head.

Drill string deflecting apparatus

A bearing assembly is situated to conduct axial forces between the general housing and the output shaft by way of an intermediate sleeve that is secured to the output shaft outside the general housing and is axially confined by a bearing assembly secured to the general housing.

A general housing encloses a drilling motor that can be disabled to permit optimum rotary drilling practice. A mode selector responds to manipulation of the drilling fluid flow rate and permits activation of the drilling motor to drive a drill bit. The general housing is a two part arrangement that is connected by a deflection arrangement that is activated by start-up of the motor. A one-way clutch allows the lower housing to drive the drill bit when the motor is disabled and the clutch, with drill bit rotation resistance, changes the deflection arrangement for straight rotary drilling when the drill string is rotated.

Directional drilling apparatus

The drill string is fitted for drilling activity in the formation expected, including a jet nozzle equipped drill head, and a near bit kick sub. The drill string is deflected to change the progressing well bore to a preferred direction. After the change in well bore direction is accomplished by jetting, the kick sub is straightened and drilling proceeds along the new well bore center line. Ideally, the kick sub responds to direction from the surface and produces a change in drilling fluid pressure at the surface to indicate which mode, straight or deflected, is being carried out down hole.

Jet assisted drilling method

A drilling motor is housed in the upper portion of a housing, with a drive shaft extending through a lower portion of the housing. The two portions are coupled by bearing that has an axis of rotation that is tilted a small amount relative to the axes of both portions. The lower portion is rotationally coupled to the lower housing until a small amount of drilling fluid flow, or a preselected amount of motor torque, forces a clutch to disengage the motor, rotationally, from the lower housing. The lower portion is allowed limited rotation relative to the upper portion. At one rotational limit, the housing is in the straight configuration. At the other limit, the housing is in the deflected configuration. Conversion to the straight configuration is achieved, while drilling fluid flows, when the drill string is rotated, by formation drag, which rotates the lower portion to the straight configuration.

A drill string is fitted at the lower end with a drill string deflecting apparatus and a drill bit. The drill string deflecting apparatus is activated to deflect the drill bit from the general center line of the drill string. Drilling proceeds to enlarge a length of larger well bore. The drill bit is lifted to allow the lower end of the drill string to move, by gravity, to the low side of the enlarged well bore. The drill string deflecting apparatus is straightened and drilling bit load is applied to drill ahead along the extended center line of the lower end of the drill string.

Drilling method for enlarging a borehole using a kick sub

A hermetic seal functions as a closure between opposite ends of the coupling by combining a metal sleeve and an elastomer sleeve extension. The metal sleeve is sealingly attached to the outer surface of one end of the coupling and the elastomer sleeve, sealingly attached to the metal sleeve, is attached at the distal end to the other end of the coupling. As an alternative, the distal end may be bonded to a second metal sleeve sealingly attached to the other end of the coupling. The seal may be convoluted, with multiple convolutions.

Sealed flexible motor coupling

A timer is enclosed in a pressure tight enclosure which is attached to or is part of the motor rotor. Rotation of the rotor is sensed and the timer is turned on when the rotor is turning and is turned off when the rotor is idle. The version usable in motors of the progressing cavity type can power the timer, and provide timer control.

Motor run timer

As a serial element of a drill string, the drill string is adjustably bent by rotating one end of the sub relative to the other end. The opposite ends rotate about a tilted center line such that in one rotational position the sub is straight. One half turn of one end relative to the other bends the sub to the maximum angle. Between straight and maximum bend, any angle can be achieved by control of the amount of the relative rotation between the opposite ends of the sub.

Adjustable deflecting sub

Motor coupler

Between a drilling motor and the upwardly continuing drill string a housing contains a speed sensor rotationally connected to the motor rotor. Motor speed is sensed and if rotating at a rate less than a selected speed, a cooperating by-pass valve opens to shunt drilling fluid to the well annulus to prevent damage to the stalled motor.

Stalled motor by-pass valve

A by-pass valve is part of an apparatus arranged to function as a serial element of a drill string. An arbor is attached to the top end of a tubular motor rotor and extends some distance along the generally central opening of the housing which is attached to the top end of the motor housing. A head on the arbor comprises a normally closed valve which is capable of conducting fluid from inside the housing to the well annulus outside the drill string by way of the bore of the tubular rotor. The valve is opened by downward movement, in excess of a selected amount, of the rotor of the motor. The excessive downward movement of the rotor indicates problems in the motor bearing structure, or disruptive failure elsewhere in the bottom hole assembly. The opening of the by-pass valve reduces standpipe pressure which is a signal detectable at the surface. The signal indicates disruptive failure in the down hole assembly.

Motor by-pass valve

Opposite ends, or terminals, of the sub are connected by a tubular arbor with threaded pins on each end. The arbor is bent in the middle. A mating threaded box on the upper terminal is tilted an amount equal to the bend angle of the arbor and mates with the bent end of the arbor. If the arbor is rotated in the box, the centerline of the other threaded end describes a cone. One line on the cone is the axis of rotation of the upper terminal. If the lower terminal is locked in that position, the sub is in the straight configuration. Locked in any other rotational position, the sub is bent an angle that is a function of the amount of arbor rotation. To make the arbor adjustable from the outside, an indicator ring is mounted on splines on the arbor. The ring can slide axially on the arbor. The lower terminal can be tightened on the lower end of the arbor to jam the indicator against the upper arbor, locking the assembly for use. At least one pin is provided to reside in aligned holes in the mating faces of the upper terminal and the indicator ring.

Adjustable orienting sub

The apparatus has a housing arranged to function as a length of drill string, including a fluid tight fluid conducting bore, with means at each end for connecting to a continuing drill string. The housing has two principal portions bearingly connected for rotation and axial constraint. A spring loaded one way clutch connects the two portions such that torque can be conducted therethrough in only one rotational direction. The clutch has one, spring loaded, axially moving element to actuate the clutch unless locked by optional provisions. The axial movement, optionally, actuates a valve in the fluid conducting bore to create a pressure drop in the fluid stream when the clutch is disengaged to provide a pressure signal that can be detected at the surface to indicate that the clutch is disengaged.

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Lafayette, LA, United States of America

Thomas E Falgout, Jr