Dip Azimuth Angle Estimation via Least Squares
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Solution Overview
Problem
Existing downhole electromagnetic logging methods face challenges in obtaining a reliable and accurate dip azimuth angle due to noise and phase wrapping issues, which affect the precision of hydrocarbon detection and pay-zone steering in subterranean formations.
Innovation Solution
A method involving least squares estimation of dip azimuth angle from downhole electromagnetic measurements, using a weighted sum of squared residuals to process voltage data from measurement arrays, which reduces noise and avoids phase wrapping by computing the arctangent function only once.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art methods are used to obtain dip azimuth angle from electromagnetic measurements, then the measurement process is straightforward, but the results are noisy and susceptible to phase wrapping issues
Solution Approach 1:
The patent transforms the measurement parameters by working with squared voltage components and their sums/differences rather than raw voltages. This parameter transformation eliminates phase wrapping issues and reduces noise in the dip azimuth angle calculation, directly resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The patent introduces intermediate calculated parameters (sum and difference of squared voltage components) as mediators between the raw electromagnetic measurements and the final dip azimuth angle. These intermediaries filter out noise and phase wrapping effects, improving both measurement accuracy and stability
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 provides a more accurate and less noisy estimation of the dip azimuth angle, enhancing the precision of hydrocarbon detection and pay-zone steering by stabilizing the measurement results and reducing statistical bias.
Implementation Method 1
electromagnetic measurement data acquired in a subterranean borehole from an electromagnetic measurement tool array
Data Source
AI summary
An electromagnetic method for obtaining a dip azimuth angle from downhole electromagnetic measurements includes acquiring electromagnetic measurement data in a subterranean borehole from at least one measurement array. The electromagnetic measurement data is processed by a least squares method to obtain the dip azimuth angle. Related systems and apparatuses are also disclosed herein.