Customized Grounding for Electromagnetic Well Ranging

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Solution Overview

Problem

Current electromagnetic ranging techniques for guiding well placement in oilfield operations face challenges such as high costs, unreliable results due to current variations, and safety hazards from increased current levels needed to enhance signal strength, particularly in deep wells.

Innovation Solution

The implementation of a customized grounding arrangement at the earth's surface, which includes options like increased length or radius ground stakes, downhole casings, or elongated stakes, to manage impedance and improve signal-to-noise ratio, allowing for safer and more precise electromagnetic field sensing for directional drilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the current level is increased to improve EM field strength and signal-to-noise ratio for deep wells, then the ranging precision is improved, but the safety hazard to workers at earth's surface increases

Engineering Contradiction:

Improveranging precisionVSAvoidsafety hazard

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The grounding arrangement is customized with different configurations (increased length or radius ground stakes, downhole casings, or elongated stakes) to concentrate current intensity specifically in the subsurface region where the target well is located. This local concentration of current achieves the required EM field strength for deep well ranging while limiting current exposure at the surface, thereby resolving the contradiction between measurement precision and safety hazard.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If multiple wireline tools are deployed in existing wells with multiple teams, then the ranging coverage is improved, but the operation cost increases

Engineering Contradiction:

Improveranging coverageVSAvoidoperation cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention extracts the ranging functionality from complex multi-well EM ranging systems and implements it through a simplified single-well approach using surface excitation with customized grounding. This extraction eliminates the need for multiple wireline tools and teams, reducing operation cost while maintaining adequate ranging coverage for guiding new well drilling relative to the target well.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If larger inter-well spacings are employed to reduce short circuit effects, then the short circuit vulnerability is reduced, but the well placement precision worsens

Engineering Contradiction:

Improveshort circuit resistanceVSAvoidwell placement precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention replaces mechanical precision drilling (which requires tight inter-well spacing control) with electromagnetic field-based ranging guidance. By using surface excitation with customized grounding to generate strong, localized EM fields, the system provides precise distance and orientation measurements that enable accurate well placement even with larger inter-well spacings, thus resolving the contradiction between reliability and manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach enhances the safety and effectiveness of electromagnetic ranging by concentrating current intensity below the surface, reducing the risk of injury and improving signal strength, enabling more precise well placement and reducing short circuit vulnerabilities in steam-assisted gravity drainage processes.

Implementation Method 1

conveying an electrical current output from the power supply along a target well with a metal casing. The EM fields emitted from the target well due to the electrical current

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 2

sensing EM fields emitted from the target well due to the electrical current

Methodology Applied

Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Data Source

PatentUS10557342B2Surface excitation ranging methods and systems employing a customized grounding arrangement

Publication Date: 2020.02.11 HALLIBURTON ENERGY SERVICES INC

AI summary

A surface excitation ranging method includes installing a customized grounding arrangement for a power supply located at earth's surface, wherein the customized grounding arrangement fulfills an impedance criteria or ranging performance criteria. The method also includes conveying an electrical current output from the power supply along a target well with a metal casing. The method also includes sensing electromagnetic (EM) fields emitted from the target well due to the electrical current. The method also includes using distance or direction information obtained from the sensed EM fields to guide drilling of a new well relative to the target well.