Schlumberger Technology Corporation

Anadrill, Inc.

Alan M Eddison

Warren E Askew

Lawrence James Leising

Charles Ingold

Spryo J Kotsonis

Bernhard Prevedel

An articulated directional drilling tool assembly for use in drilling a borehole having a short radius of curvature includes a mud motor having an upper housing that is pivotally connected to a lower housing having upper and lower sections. Such sections are joined together in a manner to define a bend angle. The drill bit box carries a stabilizer that centers it in the borehole. The upper housing section carries an eccentric stabilizer assembly which tilts it toward the low side of the borehole to increase the effectiveness of the bend angle. A hydraulic piston also can be used to increase the side loading on the bit and cause it to drill a sharply curving borehole. The upper housing of the motor is connected to the lower housing by an articulative, torque transmitting coupling, and the upper motor housing is connected to an orientation measuring sub thereabove in the same manner.

Articulated directional drilling motor assembly

A steerable rotary drilling tool includes a drill bit mounted on the lower end of a housing by a drive shaft having an articulative coupling that allows the bit's rotation axis to be inclined relative to the rotation axis of the housing, an eccentric weight in the housing that maintains the bit axis pointed in only one direction in space as the bit is turned by the housing, and a clutch system that allows such direction to be changed downhole. A measuring-while-drilling tool is included to allow the progress of the drilling to be monitored at the surface, and to allow changing the bit axis or toolface by a selected amount.

Steerable drilling tool and system

An articulated directional drilling tool assembly for use in drilling a borehole having a short radius of curvature includes a mud motor whose housing is pivotally connected to a lower housing having upper and lower sections that are joined together in a manner to define a bend angle. The drill bit box carries a stabilizer that centers it in the borehole. The upper housing section carries pads which are forced against the low side of the borehole by a hydraulic piston to increase the side loading on the bit and cause it to drill a sharply curving borehole. The motor housing is connected to the lower housing by an articulative, torque transmitting coupling, and the motor housing is connected to an orientation measuring sub thereabove in the same manner.

An articulated directional drilling tool assembly for use in drilling a borehole having a short radius of curvature includes a mud motor whose housing is pivotally connected to a lower housing having upper and lower sections that are joined together in a manner to define a bend angle. The lower housing section carries a full gage stabilizer that centers its lower end in the borehole. The upper housing section carries pads which are forced against the low side of the borehole by a hydraulic piston to increase the side loading on the bit below the lower housing section and cause it to drill a sharply curving borehole. The motor housing is connected to the lower housing by an articulative, torque transmitting coupling, and the motor housing is connected to an orientation measuring sub thereabove in the same manner.

A downhole adjustable orienting sub is included in a directional drilling tool string that is run into the borehole on coiled tubing. The bent housing of the tool string defines a bend angle and a bend point, and the bend point is oriented about the center of the bore by operating the orienting sub. The level of the reactive torque applied to the bent housing as the bit drills on bottom is controlled by selecting the amount of the weight of the coiled tubing that is applied to the bit. The orienting sub can be indexed downhole to provide different orientations of the bend point by temporarily reducing and then increasing the mud flow rate.

Apparatus and method for directional drilling with downhole motor on

In accordance with illustrative embodiments of this invention, a downhole adjustable stabilizer includes a sleeve having outwardly extending blades and mounted for limited rotation on a mandrel, vertically aligned sets of radially movable buttons mounted in bores in the blades, and longitudinal flats on the outer periphery of the mandrel that when radially aligned with the respective sets of buttons allows them to shift inward to positions where the stabilizer becomes undergage and can be tilted in the borehole. Some spring loaded buttons drag against the borehole wall to provide frictional restraint against rotation of the housing. The blades can each have an inclined side surface that causes the sleeve to be rotated to its position relative to the mandrel where the sets of buttons are retracted as the stabilizer slides downward in the borehole. In another embodiment a hydraulic delay is provided which restrains relative rotation in the direction which cause the buttons to extend to their full gauge diameter.

Downhole adjustable stabilizer

Methods are provided for controlling the direction of a borehole drilled by a downhole motor, including the steps of positioning downhole adjustable bent housing and near-bit stabilizer in the drill string, adjusting the bent housing from its normally straight condition to its bent condition to effect borehole curvature, and using the stabilizer in its undergage condition to enhance the inclination. The Measurements are made from which the inclination with respect to the vertical and the azimuth can be determined and telemetered uphole for processing, display, and recording. Preferably the directional measurements are made at two locations, one below the bent point and one above it. These two sets of measurements can be compared to confirm the bend angle and to obtain a definition of the orientation of the plane of the bend angle so that the drilling path can be accurately controlled. Use of the present invention eliminates having to superimpose rotation of the deflected drill string in order to drill straight ahead because the bend angle can be eliminated by downhole adjustment.

Growing community of inventors

Houston, TX, United States of America

Alan M Eddison