Triaxial Induction Logging Calibration Without Ground Conductivity Knowledge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing induction logging tools face challenges in accurately calibrating conductivity measurements due to interference from environmental factors, requiring improved calibration methods to enhance sensitivity and precision in resistivity measurements of geologic formations.
Innovation Solution
A method involving multiple receiver coils with distinct orientations, where the tool is positioned at different heights to perform conductivity measurements, allowing for the determination of calibration factors that correct conductivity readings in a borehole by using a combination of measurements taken at these positions, and providing these factors as output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the induction logging tool is placed in a calibration area with unknown ground conductivity, then the calibration process becomes simpler and more adaptable, but the measurement precision deteriorates due to environmental interference
Solution Approach 1:
The patent changes the parameter of tool position by performing measurements at multiple distinct heights above the ground surface. By taking measurements at different vertical positions (first height and second height), the system can mathematically separate the ground conductivity effect from the tool calibration factors, enabling accurate calibration without requiring prior knowledge of ground conductivity.
Solution Approach 2:
The patent uses feedback by utilizing the measurements taken at multiple heights to iteratively solve for both the calibration factors and the ground conductivity simultaneously. The system processes the set of measurements from different positions to determine calibration factors that correct for environmental influences, creating a self-calibrating system that adapts to unknown ground conditions.
2Measurement precision
If the tool uses multiple receiver coils at different orientations and heights, then the calibration accuracy improves by accounting for environmental influences, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by using the same three receiver coils for multiple purposes: they measure both the calibration signals and the environmental ground conductivity effects. By performing measurements at multiple heights with the same coil configuration, the system universally handles both calibration factor determination and environmental characterization, improving accuracy without requiring additional specialized hardware.
3Measurement precision
If the induction logging tool requires prior knowledge of calibration area ground conductivity for accurate calibration, then the measurement precision improves, but the ease of operation deteriorates
Solution Approach 1:
The patent implements self-service by enabling the calibration system to automatically determine its own calibration factors without requiring external knowledge of ground conductivity. The system performs self-calibration by taking measurements at multiple heights and using these measurements to solve for both the calibration factors and the ground conductivity simultaneously, making the calibration process autonomous and easier to operate.
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 improves the calibration accuracy of induction logging tools by accounting for environmental influences, leading to more precise resistivity/conductivity measurements and enhanced imaging of geologic formations.
Implementation Method 1
the induction logging tool transmits electromagnetic waves into the formation using a transmitter coil
Implementation Method 2
The electromagnetic waves induce circulating currents in the formation. The circulating currents in turn emit electromagnetic waves that induce a signal in a receiver coil at the tool
Data Source
AI summary
Disclosed is a method for determining calibration factors of an induction tool that includes three receiver coils, each having a distinct orientation. The method includes: placing the induction logging tool in a first position at a first height above a surface of the earth; performing a first set of measurements of conductivity using the receiver coils with the induction logging tool in the first position at the first height; placing the induction logging tool in a second position at a second height above the surface of the earth; performing a second set of measurements of conductivity using the receiver coils with the induction logging tool in the second position at the second height; and determining the calibration factors that correct conductivity measurements performed by the induction logging tool in a borehole penetrating the earth using the first and second sets of measurements.