Well Location Determination Using Electromagnetic Casing Signals
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Solution Overview
Problem
Steering a drill bit through a crowded field of oil wells without interrupting production of existing wells is challenging due to the difficulty in detecting magnetic casing signals until close proximity, often requiring costly trajectory modifications.
Innovation Solution
The use of low-frequency electromagnetic signals launched on neighboring well casings, detected by magnetometers in the drillstring, allows for determining the relative position of the drill bit by monitoring changes in magnetic fields, enabling accurate steering between existing wells without production interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic detection methods are used to detect well casing signals, then the drill bit can be steered between existing wells, but the detection is only possible at close proximity requiring costly trajectory modifications
Solution Approach 1:
The patent applies parameter changes by transforming the magnetic field detection approach from passive detection of static casing magnetization to active detection of time-varying electromagnetic fields. By injecting alternating current at specific frequencies into neighboring well casings and detecting the resulting time-varying magnetic fields with magnetometers, the system achieves detection at greater distances without requiring trajectory modifications. This parameter transformation from static to dynamic field detection resolves the contradiction between detection distance and operational cost.
2Ease of operation
If active steering using rotary magnetic steering tools is used, then the drill bit can be steered through crowded well fields, but production of nearby wells must be shut down to detect signals
Solution Approach 1:
The patent applies self-service by enabling the existing well casings to serve dual purposes: maintaining hydrocarbon production while simultaneously acting as signal sources for navigation. By injecting low-power alternating current into the producing well casings, they generate detectable electromagnetic fields without requiring production shutdown. The producing wells essentially service their own navigation function, eliminating the need to interrupt hydrocarbon flow while providing steering signals to the drilling operation.
Solution Approach 2:
The system applies preliminary action by pre-establishing electromagnetic signal sources in neighboring wells before the drilling operation begins. By injecting alternating current into the casings of existing wells ahead of time, the navigation system is prepared and can immediately guide the drill bit through crowded fields without interrupting production. This preliminary setup of signal sources enables continuous operation of both drilling and production simultaneously.
3Productivity
If passive steering through magnetically polarized casing is used, then existing well production can be maintained, but the magnetic casing signals are extremely difficult to detect until imminent collision
Solution Approach 1:
The patent applies periodic action by transforming static magnetic polarization into time-varying electromagnetic signals. By injecting alternating current at specific frequencies into the well casings, the system creates periodic magnetic field variations that are easily detectable by magnetometers. This periodic excitation converts the invisible static magnetic field into a detectable oscillating signal, extending the detection range well before imminent collision and maintaining production continuity throughout the drilling operation.
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 method effectively navigates the drill bit through a crowded field by determining the distance and position relative to neighboring wells, reducing the risk of collision and maintaining production continuity, while improving operational efficiency and reducing costs.
Implementation Method 1
detected by magnetometers in the drillstring, allows for determining the relative position of the drill bit by monitoring changes in magnetic fields
Data Source
AI summary
In some embodiments, apparatus and systems, as well as methods, may operate to launch a set of currents into a corresponding set of existing well casings; monitor, in a well under construction, changes in at least one of a magnetic field or an electric field perturbed by the set of currents after each one of the set is launched; and determine a location of the well under construction in relation to the set of existing well casings. In some embodiments, the activities include inducing current into a drillstring located in a well under construction; monitoring, at a set of existing well casings, changes in at least one of a magnetic field or an electric field perturbed by the current after the current is induced; and determining a location of the well under construction in relation to the set of existing well casings. Additional apparatus, systems, and methods are disclosed.