Force Balanced Asymmetric Drilling Reamer

Solution Overview

Problem

Existing downhole drilling tools face challenges in addressing constrictions caused by swelling formations, cuttings settlement, and sloughing, which lead to drilling inefficiencies and potential damage to borehole walls, as they lack effective force balancing and asymmetrical designs to minimize lateral movement and torque.

Innovation Solution

A force balanced asymmetric drilling reamer with curved blades, cutter sections, and gage inserts that are asymmetrically arranged to reduce lobed pattern movement, allowing for effective cutting and reaming while minimizing damage to the borehole walls, and featuring nitriding treatment for improved cutting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If symmetrical reamers with evenly spaced rollers or reaming blades are used, then the tool structure is simple and easy to manufacture, but the tool develops lobe patterned lateral movement that damages the tool and borehole wall

Engineering Contradiction:

Improvetool structure simplicityVSAvoidlobe patterned lateral movement damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by configuring reaming blades at non-uniform angular intervals around the reamer body, specifically with different spacings between adjacent blades. This asymmetric arrangement disrupts the formation of lobe patterns during rotation, eliminating the harmful lateral movement cycle that occurs with symmetrical blade configurations. The asymmetric blade spacing ensures that cutting forces are distributed more uniformly, preventing the development of resonant vibrations that damage both the tool and borehole wall.

Inventive Principle:

Principle #4Asymmetry

2Productivity

If active cutting gage sections with rollers or tungsten carbide cutting structures are used, then the reaming capability is improved, but the tool complexity increases and lateral oscillations are not controlled

Engineering Contradiction:

Improvereaming capabilityVSAvoidtool complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing cutting elements only at specific localized positions rather than uniformly across the entire reamer periphery. The reaming blades are positioned at selected angular locations to provide cutting action where needed, while other portions of the reamer body remain smooth or have different surface characteristics. This localized cutting approach maintains effective reaming capability while simplifying the overall tool structure and reducing the complexity associated with uniformly distributed cutting structures.

Inventive Principle:

Principle #3Local quality

3Productivity

If the reamer rotates through constricted wellbores, then the borehole can be opened, but radial forces cause lateral oscillations that damage the tool and borehole wall

Engineering Contradiction:

Improveborehole opening capabilityVSAvoidradial force induced lateral oscillations

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by configuring reaming blades at non-uniform angular intervals around the reamer body, specifically with different spacings between adjacent blades. This asymmetric arrangement disrupts the formation of lobe patterns during rotation, eliminating the harmful lateral movement cycle that occurs with symmetrical blade configurations. The asymmetric blade spacing ensures that cutting forces are distributed more uniformly, preventing the development of resonant vibrations that damage both the tool and borehole wall.

Inventive Principle:

Principle #4Asymmetry

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The tool effectively addresses constrictions by reducing radial forces and minimizing damage to the borehole walls, enhancing drilling efficiency and reducing downtime by maintaining a stable drilling process through swelling, sloughing, and cuttings settlement conditions.

Implementation Method 1

featuring nitriding treatment for improved cutting efficiency

Methodology Applied

Scientific EffectNitriding: Nitriding

Data Source

PatentUS8162081B2Force balanced asymmetric drilling reamer and methods for force balancing

Publication Date: 2012.04.24 VAREL INT IND LP

AI summary

A force balanced asymmetric drilling reamer comprising a plurality of blades, each blade having at least one cutter section and a gage section. The cutter section is designed to have a plurality of cutting devices for cutting through swelling formations and cutting free sloughing formations. The gage section has a full bore diameter with gage elements flushly coupled to gage section's outer surface. The blades may be curve/concave shaped or boomerang/chevron shaped, which thereby agitate the cutting beds. At least a portion of the drilling reamer's diameter is incrementally force balanced, starting from the outermost diameter, so that the net radial force is less than 10% of weight on bit with respect to the center of rotation. This balancing allows a greater cutter longevity and provides for a better wellbore condition. Optionally, at least a portion of the drilling reamer's surface may be treated by nitriding for repelling the cuttings.