Ranging Measurements Using Third Well Referencing
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Solution Overview
Problem
Existing methods for precise ranging measurements in well drilling, especially during blowouts, face challenges due to difficulty in accessing the target well and inaccuracies when relying solely on measurements from the relief well, often resulting in imprecise formation excitation and interference.
Innovation Solution
The method involves injecting an alternating current into a formation from a first borehole to induce an electromagnetic field, which is measured at a second borehole, allowing for the identification of a third borehole's location and adjustment of the drilling trajectory to intersect it, utilizing additional boreholes for increased accuracy and integrity of measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If formation excitation and measurements are performed solely at the relief well, then the measurement process is simplified, but the measurements become inaccurate or imprecise due to formation excitation interference
Solution Approach 1:
The measurement system is segmented into three separate boreholes: a first borehole for current injection, a second borehole for current reception, and a third borehole (target well) for trajectory identification. This segmentation separates the excitation source from the measurement location, eliminating interference while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an intermediary measurement approach where electromagnetic fields are measured at a drilling assembly in a third borehole rather than directly at the relief well. This intermediary measurement location avoids the interference zone created by formation excitation at the relief well while still providing accurate ranging data.
2Measurement precision
If multiple downhole measurements are taken to identify the precise location of the target well, then measurement accuracy is improved, but the difficulty of accessing the target well increases
Solution Approach 1:
The patent extracts the measurement function from the target well itself and performs it remotely using a drilling assembly in a third borehole. The electromagnetic field measurements are taken at the drilling assembly location rather than requiring direct access to or interaction with the target well, thereby maintaining precision while improving ease of operation.
Solution Approach 2:
The system uses the drilling assembly's own electromagnetic field measurements to identify its location relative to the target well, eliminating the need for separate measurement tools or direct interaction with the target well. The drilling assembly serves both as the drilling tool and the measurement instrument.
3Measurement precision
If current is injected into the formation from the target well, then the electromagnetic field measurement is obtained, but the current injection interferes with the measurements
Solution Approach 1:
The patent extracts the current injection function from the target well and relocates it to a first borehole. This separation removes the harmful interference effect from the measurement location while preserving the necessary electromagnetic field generation for accurate ranging measurements.
Solution Approach 2:
The system segments the electromagnetic measurement process into distinct functional components located in different boreholes: current injection in the first borehole, current reception in the second borehole, and field measurement at the drilling assembly in the third borehole. This spatial segmentation eliminates interference between excitation and measurement.
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 and depth of measurements by moving current injection and reception away from the target well, reducing interference and improving the precision of drilling trajectory adjustments, thereby facilitating more effective intersection of wells.
Implementation Method 1
injecting a current into a formation from a first borehole to induce an electromagnetic field in the formation
Implementation Method 2
receiving the current from the formation at a second borehole; measuring the electromagnetic field at a drilling assembly disposed within the formation
Data Source
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AI summary
A method for obtaining ranging measurements comprises: injecting a current (115) into a formation from a first borehole (102) to induce an electromagnetic field (120) in the formation; receiving the current (115) from the formation at a second borehole (107); measuring the electromagnetic field (120) at a drilling assembly (150) disposed within the formation; identifying the location of a third borehole (102) within the formation based, at least in part, on the measured electromagnetic field (120); and altering a drilling trajectory of the drilling assembly (150) disposed to intersect with the third borehole (102).