Rotary Drill Bit Curved Gauge for Steerable Drilling

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Solution Overview

Problem

Conventional steerable drilling systems with conventional drill bits face issues of increased effort and potential for oversize boreholes when changing drilling direction, due to bit tilting causing fouling against adjacent formation material.

Innovation Solution

A rotary drill bit with a part-spherical leading face and frusto-conical gauge region, designed to minimize fouling by allowing tilting without additional formation removal, with a tapered gauge profile that matches the maximum tilt angle, ensuring efficient directional changes without enlarging the borehole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional drill bit is used in a steerable drilling system, then the bit can be tilted to change drilling direction, but the bit fouls against the adjacent formation requiring additional formation removal

Engineering Contradiction:

Improvedirectional controlVSAvoidformation removal

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The drill bit incorporates a curved gauge region with a radius of curvature substantially equal to one-half the diameter, and a leading face section blended with the curved region. This curved geometry allows the bit to tilt without the gauge region contacting the formation, eliminating fouling and the need for additional formation removal while maintaining directional control capability

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the drill bit is tilted to change drilling direction, then directional control is achieved, but increased bit wear occurs

Engineering Contradiction:

Improvesteering capabilityVSAvoidbit wear

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The curved gauge region design prevents contact between the bit and formation during tilting operations. By eliminating this contact, the invention prevents the additional wear that would otherwise occur on the bit components during directional changes, thereby extending bit life and improving reliability

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If the drill bit is tilted to change drilling direction, then directional control is achieved, but steering accuracy is negatively impacted

Engineering Contradiction:

Improvedirectional controlVSAvoidsteering accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The curved gauge region prevents fouling contact that would otherwise interfere with the intended drilling direction. By eliminating this parasitic contact, the bit can tilt precisely to the desired angle without deviation caused by formation interference, thereby maintaining or improving steering accuracy

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Adaptability or versatility

If the drill bit is tilted to change drilling direction, then directional control is achieved, but an oversize borehole is drilled

Engineering Contradiction:

Improvesteering capabilityVSAvoidborehole size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The curved gauge region with its specific radius of curvature prevents contact with the formation during tilting. This ensures that the borehole diameter remains consistent with the intended size, preventing the creation of an oversize borehole that would occur with conventional bits that foul against the formation

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS7318492B2Rotary drill bit

Publication Date: 2008.01.15 REEDHYCALOG (UK) LIMITED

AI summary

A drill bit for drilling a borehole with a steerable drilling system, the drill bit comprising a longitudinal axis, and a cutting profile with a leading face section blended with a curved region into a tapered gauge region having a tapered gauge profile. The tapered gauge region being tapered with respect to the longitudinal axis determined by the steerable drilling system. The cutting profile and the gauge profile lie wholly within a bit profile envelope made up of a three dimensional surface of two complimentary conical sections set at the tilt angle and separated by and blended with a rounded section which forms an outermost diameter of the bit profile envelope. The rounded section has a diameter substantially equal to a maximum allowable API diameter for the drill bit, and further has a radius of curvature substantially equal to one-half the diameter.