Bidirectional Dual Eccentric Reamer Drift Enlargement

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Solution Overview

Problem

Existing wellbore reaming technologies face challenges in enlarging the drift diameter without increasing the entire wellbore diameter, while also reducing torque and drag on the drill string, especially when dealing with dogleg, spiraled, or tortuous paths, and in situations where casing is run into a wellbore.

Innovation Solution

A bidirectional dual eccentric reamer with a shaft having an annulus and outer diameters ranging from 4 to 26 inches, featuring helical blades with polycrystalline diamond compacts and tungsten carbide inserts, allowing for eccentric rotation to increase wellbore diameter and fluid flow while minimizing trips and maintaining casing integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional reamer is used to enlarge the drift diameter, then the wellbore diameter increases, but the torque and drag on the drill string increases

Engineering Contradiction:

Improvedrift diameterVSAvoidtorque and drag

Core Design Contradiction:

Volume of moving objectVSForce

Solution Approach 1:

The reamer employs an asymmetric single-eccentric design where the reamer body is offset from the drill string centerline, creating an elliptical reaming path. This asymmetric configuration allows the reamer to contact and enlarge only the high-side wellbore wall (the side with greater radius), thereby enlarging the drift diameter while minimizing contact with the low-side wall, which reduces the torque and drag forces acting on the drill string.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The reamer applies reaming action locally to specific regions of the wellbore rather than uniformly around the entire circumference. By positioning the reamer body eccentrically, the cutting elements concentrate their action on the high-side wellbore wall where enlargement is needed, while leaving the low-side wall relatively untouched. This localized reaming approach achieves drift diameter enlargement without the full circumferential contact that would generate high torque and drag.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the wellbore diameter is enlarged to improve passage, then the casing integrity may be compromised

Engineering Contradiction:

Improvepassage through wellboreVSAvoidcasing integrity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The reamer enlarges only the drift portion of the wellbore (the unobstructed passageway formed by wellbore surfaces) while leaving the overall wellbore diameter and casing dimensions unchanged. The single-eccentric design concentrates reaming action on the high-side wall where the drift diameter is smallest, thereby improving passage through the wellbore without compromising casing integrity elsewhere in the system.

Inventive Principle:

Principle #3Local quality

3Volume of moving object

If multiple trips are made to solve drift diameter issues, then wellbore fluid loss increases and safety decreases

Engineering Contradiction:

Improvedrift diameterVSAvoidfluid loss

Core Design Contradiction:

Volume of moving objectVSLoss of substance

Solution Approach 1:

The bidirectional dual eccentric reamer performs drift diameter enlargement in a single continuous operation during the primary drilling trip. By equipping the reamer with cutting elements on both the upper and lower sides of the eccentric body, it can ream in two directions (clockwise and counter-clockwise rotation) without requiring the drill string to be pulled out and re-run. This preliminary action approach resolves drift diameter issues during the initial trip, preventing the need for additional trips that would cause fluid loss and safety concerns.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If a single-eccentric reamer is used, then the reaming path is asymmetric, but the ability to ream bidirectionally is limited

Engineering Contradiction:

Improvereaming efficiencyVSAvoidbidirectional reaming capability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The reamer design combines a static single-eccentric body with dynamic bidirectional rotation capability. The asymmetric reamer body creates different reaming paths for clockwise and counter-clockwise rotation, but both directions are functional and productive. This dynamic adaptability allows the system to switch between rotation directions as needed, providing versatility while maintaining the productivity benefits of the eccentric design. The reamer can engage the wellbore wall effectively in both rotational directions, unlike a conventional symmetric reamer that would require optimal orientation for each direction.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9151119B1Bidirectional dual eccentric reamer

Publication Date: 2015.10.06 FRANKS INT

AI summary

A bidirectional dual eccentric reamer which can form a larger wellbore than originally drilled and a wellbore larger than the drill bit diameter. The bidirectional dual eccentric reamer can have a shaft with a longitudinal axis supporting a plurality of reamer portions. The reamer portions have a plurality of helical blades of varying thicknesses. The plurality of helical blades can have a plurality of cutting nodes and cutting inserts. The plurality of helical blades can have a center of eccentric rotation which is offset from the longitudinal axis, thereby creating an eccentric rotation. This allows for the formation of a larger wellbore than originally drilled and a wellbore larger than the drill bit diameter.