Downhole adjustable bent housing for directional drilling

Abstract

The present invention provides a hydraulically actuated downhole adjustable bent housing for use in directional drilling of bore holes and wells that allows adjustment of the housing from aligned to a bent configuration without raising or lowering the drillstring. The present invention also provides a method of directionally drilling a bore hole or a well using an downhole adjustable bent housing that can be operated without raising or lowering the drillstring.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention provides a downhole adjustable bent housing for use in directional drilling of wells used to recover oil and gas, and a method for directionally drilling a well to recover oil and gas.[0003]2. Background of the Related Art[0004]Wells are generally drilled to recover natural deposits of hydrocarbons and other desirable, naturally occurring materials trapped in geological formations in the earth's crust. A slender well is drilled into the ground and directed to the targeted geological location from a drilling rig at the surface. In conventional “rotary drilling” operations, the drilling rig rotates a drillstring comprised of tubular joints of drill pipe connected together to turn a bottom hole assembly (BHA) and a drill bit that are connected to the lower end of the drillstring. The BHA typically comprises a number of downhole tools including adjustable bent housings, drill collars and mud motors, an...

AI Technical Summary

Benefits of technology

[0013]The above-described objects of the present invention, as well as other objects and advantages, are achieved by a downhole adjustable bent housing that is deployed and retracted by the driller by using the mud pumps located at the surface and used to circulate drilling mud in the well during the drilling process. The present invention does not require wires, cables or cumbersome reciprocation of the entire drillstring to deploy, lock or re-align the downhole adjustable bent housing, and the downhole adjustable bent housing is controllably deployed and realigned without a trip using hydraulic pressure provided by the mud pumps. The present invention provides the driller with readily available information regarding the status of the tool (aligned or deployed, and to what extent), utilizes existing mud pumps as its source of control, and is compatible with existing mud motors and other downhole equipment. The present invention provides reliable deployment and re-alignment of the downhole adjustable bent housing without interfering, with the mechanical transfer of transmission shaft power from a mud motor connected above the tool to a drill bit connected below the tool.

[0014]The present invention provides a surface-operated downhole adjustable bent housing with a bendable housing and a hydraulically actuated, tubular mandrel that engages and displaces an articulating member which, when actuated by the mandrel, sets or deploys the downhole adjustable bent housing, into its bent, or non-aligned configuration. The downhole adjustable bent housing comprises a mandrel housing 33 and a member housing 34 joined at a knuckle or joint to form a bendable housing. The housings and the knuckle provide a common center passage accommodating a transmission shaft providing power from the mud motor to the drill bit, and provide substantial rigidity to the bendable housing structure in its inactive and deployed configurations. Under the bending force provided by mechanical interaction of the mandrel and the articulating member, the joined sections of the housing are made to angularly deviate one relative to the other to form a slight angle in the downhole adjustable bent housing.

[0017]With a first actuation, the mandrel is displaced to its intermediate position by mud pressure axially displacing the mandrel and an attached rotating position control collar, such as a “J-slot” collar. The reciprocation of the mandrel is controlled by interaction of the control collar and the housing. The leading end, or nose, of the mandrel enters the receiving port of the articulating member and engages the passage therein without rotation of the articulating member or laterally displacing the articulating member. In this intermediate position, the contact between the nose of the mandrel and the articulating member provides additional rigidity to the downhole adjustable bent housing while drilling in a path defined by the tool in its undeployed configuration. The mandrel is unlocked from its intermediate position by reducing the pressure in the drillstring to below the threshold pressure and allowing the force of the return spring to stroke the mandrel back to its original, inactive position.

Problems solved by technology

These tools require complex schemes for controlling rotational positions of each housing.

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