Three-Point Contact Bottom Hole Assembly Steering
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Solution Overview
Problem
Existing directional drilling systems face challenges in achieving efficient and maneuverable drilling while maintaining large borehole sizes, particularly when resources are located such that drilling directly above is inconvenient.
Innovation Solution
A directional drilling system featuring a bottom hole assembly (BHA) with a rotary steerable system (RSS) and a reamer, which includes a drill bit for initial contact, a steering pad assembly for secondary contact, and a reamer for tertiary contact, allowing for agile steering and expansion of the pilot hole into a larger borehole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional directional drilling systems are used to drill curved trajectories, then the ability to reach laterally spaced resources is improved, but the maneuverability and efficiency of drilling tight arcs deteriorates
Solution Approach 1:
The bottom hole assembly is segmented into three distinct contact points: a drill bit at the leading end, a steering pad assembly at an intermediate position, and a reamer at the trailing end. This segmentation allows each component to independently interact with the borehole wall, enabling precise control over the curved trajectory by adjusting the relative positions and forces at each contact point, thereby improving maneuverability for tight arcs.
Solution Approach 2:
The steering pad assembly incorporates adjustable positioning mechanisms that allow dynamic modification of the second contact point's location along the axial direction during drilling operations. This dynamic adjustment capability enables the system to optimize its steering characteristics in real-time, improving ease of operation for drilling tight curved trajectories while maintaining the ability to reach laterally spaced resources.
2Productivity
If larger borehole sizes are maintained for resource extraction, then production capacity is improved, but the maneuverability and steering precision of the drill bit deteriorates
Solution Approach 1:
The system separates the functions of drilling, steering, and hole enlargement into three axially spaced components. The drill bit drills the pilot hole, the steering pad assembly provides steering control, and the reamer enlarges the hole. This segmentation allows the reamer to create a large final borehole while the smaller drill bit and steering pads maintain precise steering control during the drilling process, resolving the contradiction between borehole size and steering precision.
Solution Approach 2:
The drill bit first drills a small-diameter pilot hole that is easier to steer and control. Once the pilot hole is established, the reamer follows behind to enlarge it to the final large diameter required for production. This preliminary action of drilling a smaller guide hole first allows the system to achieve both steering precision and large final borehole size, as the steering control is exercised when the bit is smaller and more maneuverable.
Data Source
AI summary
A system includes a bottom hole assembly (BHA) that includes a drill bit configured to drill a pilot hole in a subterranean formation, such that the drill bit provides a first point of contact between the BHA and the subterranean formation. The BHA includes a steering pad assembly that includes one or more steering pads each configured to move over a path of travel between a retracted position and an extended position to provide a second point of contact between the BHA and the subterranean formation, and a reamer configured to expand the pilot hole into a borehole, such that the reamer provides a third point of contact between the BHA and the subterranean formation. The system includes a controller configured to steer the BHA via the first, second, and third points of contact and adjustments to the second point of contact via control of the steering pad assembly.