Real-time EM Ranging Calibration for Wellbore Drilling
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Solution Overview
Problem
Current ranging techniques, particularly active ranging, face challenges such as requiring access to both drilling and target wellbores, halting production, equipment intensity, and sensitivity to axial alignment, which can lead to misplacement and decreased well productivity, especially in deep wellbores.
Innovation Solution
A real-time calibration method using passive ranging that generates an electromagnetic field around the target wellbore through a surface power source, incorporating numerical simulations and real-time EM sensor measurements to improve accuracy, and accounts for noise to determine precise distance and direction between wellbores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active ranging is used to determine distance and direction between wellbores, then ranging capability is achieved, but the system requires access to both drilling and target wellbores, halts production, and uses extensive equipment
Solution Approach 1:
The patent extracts the EM source from the drilling wellbore and places it only in the target wellbore. This eliminates the need for equipment in both wellbores, allowing continuous production in the drilling well while maintaining ranging capability. The EM source is placed in the target wellbore and monitored via sensors on the drill string in the wellbore under construction.
Solution Approach 2:
The EM source in the target wellbore serves multiple functions: it enables ranging for multiple drilling wellbores simultaneously, maintains production continuity, and eliminates the need for separate equipment in each drilling wellbore. A single EM source can track multiple drilling operations.
2Measurement precision
If active ranging is used to determine wellbore position, then ranging data is obtained, but the system is sensitive to axial alignment between magnetic source and sensor, requiring labor and time intensive alignment procedures
Solution Approach 1:
The patent introduces a numerical simulation model as an intermediary that predicts the EM field signal based on wellbore geometry and formation properties. This simulation accounts for misalignment effects and allows the system to compensate for axial misalignment between the EM source and sensors, reducing the need for precise manual alignment.
Solution Approach 2:
The system uses real-time EM sensor measurements combined with numerical simulations to continuously update and calibrate the predicted signal. This feedback mechanism allows the system to detect and correct for alignment deviations, maintaining ranging accuracy without requiring precise initial alignment.
3Productivity
If passive ranging is used to avoid access requirements, then production continuity is maintained, but the predicted signal accuracy is reduced due to formation resistivity uncertainties and noise
Solution Approach 1:
The patent performs numerical simulations before drilling to predict the EM field signal based on formation resistivity data and wellbore geometry. This preliminary prediction allows the system to account for formation uncertainties and noise in advance, improving the accuracy of the passive ranging measurements taken during drilling operations.
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 accuracy of wellbore placement, reduces uncertainties, and allows for denser wellbore placement, minimizing environmental impact and optimizing space usage, while improving hydrocarbon recovery.
Implementation Method 1
A power source disposed at a surface location passes a current down a casing of the target wellbore to generate an electromagnetic field along the target wellbore
Implementation Method 2
An electromagnetic sensor disposed in a drill string used to drill the drilling wellbore receives the electromagnetic field signal
Data Source
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AI summary
A method includes generating a ranging model of a drilling wellbore to be drilled and generating a predicted signal along measured depths of the drilling wellbore based on the ranging model. The method includes performing the following operations until the drilling wellbore has been drilled to a defined depth. The following operations include drilling, with a drill string, the drilling wellbore to an increment of the defined depth and detecting, by a sensor positioned on the drill string, an electromagnetic field emanating from a target wellbore. The following operations include determining ranging measurements to the target wellbore at the increment based on the electromagnetic field and calibrating the predicted signal based on the ranging measurements. The following operations include determining ranging accuracy for all deeper depths in the wellbore and making drilling decisions or adjusting drilling operations based on the predicted ranging accuracy for deeper depths.