Gap Sub Assembly for Dual Telemetry in Drill Strings

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Solution Overview

Problem

Current telemetry systems in drilling operations, such as mud-pulse telemetry, are limited by the need for continuous mud flow and are unreliable in geological formations like dry coal seams and salt domes, leading to downtime when switching between systems like EM and mud-pulse due to the requirement for tripping the drill string.

Innovation Solution

A gap sub-assembly with non-conductive isolation between drill string subs allows for dual telemetry capabilities using EM and mud-pulse systems without tripping the drill string, enabling continuous data transmission through electrical isolation and multiplexing schemes, allowing existing hardware to be used for both EM and pulse telemetry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mud-pulse telemetry is used, then data transmission is achieved during drilling, but the system becomes unreliable in geological formations like dry coal seams and salt domes requiring system switching

Engineering Contradiction:

Improvetelemetry reliabilityVSAvoidgeological formation adaptability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The drill string is designed with both EM telemetry and mud-pulse telemetry capabilities integrated into a single system. The gap sub assembly enables EM telemetry while the drill string maintains mud-pulse functionality, allowing the system to adapt to different geological formations by switching between telemetry methods without requiring separate drill strings or tripping operations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If telemetry systems are switched between EM and mud-pulse, then adaptability to different geological formations is achieved, but downtime occurs due to tripping the drill string

Engineering Contradiction:

Improvetelemetry system adaptabilityVSAvoiddrilling downtime

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

Both EM telemetry and mud-pulse telemetry systems are merged into a single drill string configuration. The gap sub assembly enables EM telemetry functionality while the same drill string maintains mud-pulse capabilities, allowing seamless switching between telemetry methods without tripping the drill string and eliminating associated downtime.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If electrical isolation is implemented between drill string subs, then EM telemetry capability is enabled, but the structural continuity of the drill string is disrupted

Engineering Contradiction:

Improvetelemetry capabilityVSAvoiddrill string structural continuity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

A gap sub assembly with non-conductive isolation serves as an intermediary element between drill string subs. This gap sub provides electrical isolation necessary for EM telemetry while maintaining mechanical connection and structural integrity through specialized coupling mechanisms that bridge the electrical gap while preserving drill string continuity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables uninterrupted data transmission during drilling operations by allowing simultaneous use of EM and mud-pulse telemetry without the need to trip the drill string, reducing downtime and enhancing operational efficiency.

Implementation Method 1

a non-conductive isolation between the first sub and the second sub, the non-conductive isolation being interposed between respective shoulders of the first sub and the second sub and being interposed between respective threads

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentUS10450858B2Gap sub assembly for a downhole telemetry system

Publication Date: 2019.10.22 MOSTAR DIRECTIONAL TECH

AI summary

There is provided a gap sub-assembly for electrically isolating an upstream portion of a drill string from a downstream portion of the drill string. The gap sub-assembly includes a first sub; a second sub; and a non-conductive isolation between the first sub and the second sub, the non-conductive isolation being interposed between respective shoulders of the first sub and the second sub and being interposed between respective threads of a male end of the first sub and a female end of the second sub, the non-conductive isolation comprising an insulative wrapping between at least the respective threads of the first and second subs, wherein connecting the female end of the second sub to the male end of the first sub over the insulative wrapping electrically isolates the respective threads of the first and second subs. A method for assembling such a gap sub-assembly is also provided.