Electromagnetic Tool Calibration for Tilted Antennas
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Solution Overview
Problem
Existing wellbore logging tools require prior knowledge of antenna tilt angles to convert raw measurements into a multi-component tensor for 3D inversion processes, which complicates the mechanical design and restricts antenna orientation to specific angles like 45 degrees.
Innovation Solution
The logging tool decouples multi-component tensor measurements from antenna tilt angles through an air-hang calibration process, allowing signal information to be utilized independently of tilt angles, enabling flexible antenna design and reducing pre-deployment calibration efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior knowledge of antenna tilt angles is required to convert raw measurements into multi-component tensor, then measurement precision can be maintained, but device complexity and design restrictions increase
Solution Approach 1:
The patent applies preliminary action by performing air-hang calibration measurements before actual wellbore logging operations. During this preliminary phase, the tool characterizes its own antenna tilt angles and orientation in a known reference environment (air), storing these calibration parameters for later use. This pre-characterization eliminates the need for complex real-time tilt angle determination during logging operations, thereby reducing device complexity while maintaining measurement precision through the use of pre-determined calibration factors.
Solution Approach 2:
The patent implements self-service by enabling the logging tool to automatically determine and calibrate its own antenna orientation parameters without requiring external intervention or complex mechanical sensors. The tool uses its electromagnetic measurements in a known environment (air-hang calibration) to self-characterize its antenna tilt angles and orientation, storing these parameters for subsequent logging operations. This self-calibration capability reduces device complexity by eliminating the need for additional mechanical tilt sensors or complex orientation determination systems.
2Manufacturing precision
If antenna orientation is restricted to specific angles like 45 degrees, then manufacturing precision can be controlled, but adaptability and design flexibility decrease
Solution Approach 1:
The patent applies parameter changes by transitioning from fixed, pre-determined antenna tilt angles to variable, measurable, and calibratable orientation parameters. Instead of manufacturing antennas at precise fixed angles (e.g., exactly 45 degrees), the system allows antennas to have variable tilt angles that are subsequently measured and characterized through air-hang calibration. This approach changes the parameter from a fixed manufacturing specification to a variable parameter determined through operational calibration, thereby increasing design flexibility and adaptability while maintaining measurement accuracy through the calibration process.
Solution Approach 2:
The patent uses preliminary air-hang calibration to characterize antenna orientation parameters before deployment. This preliminary measurement phase allows the system to determine the actual tilt angles and orientation of antennas regardless of their specific manufacturing angles. By performing this characterization in advance in a known environment, the system can accommodate various antenna orientations (including non-standard angles) while maintaining measurement precision, thus enhancing adaptability without sacrificing manufacturing precision requirements.
3Measurement precision
If complex calibration processes are required to determine tilt angles, then measurement accuracy can be maintained, but ease of operation and deployment time increase
Solution Approach 1:
The patent implements self-service by enabling the logging tool to automatically perform air-hang calibration and determine its own antenna orientation parameters without requiring complex external calibration equipment or procedures. The tool uses its built-in electromagnetic measurements in an air environment to self-characterize its antenna tilt angles and orientation, storing these parameters for subsequent logging operations. This automated self-calibration process maintains measurement accuracy while significantly simplifying the calibration procedure and reducing deployment complexity.
Solution Approach 2:
The patent uses air-hang calibration as an intermediary reference environment that simplifies the determination of antenna orientation parameters. Instead of requiring complex mechanical tilt sensors or elaborate calibration procedures in the wellbore environment, the system uses the known, controlled air environment as an intermediary medium to characterize antenna orientation. This intermediary calibration phase provides a simple, repeatable reference measurement that maintains accuracy while greatly simplifying the overall calibration process and ease of 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 approach allows for accurate signal processing without prior knowledge of tilt angles, simplifying the design and operation of wellbore logging tools, enabling them to function effectively across various antenna orientations and reducing the complexity of determining tilt angles in laboratory settings.
Implementation Method 1
A method includes detecting, via a first receiver of a tool, a first measurement of a first signal transmitted by a transmitter of the tool into a substantially non-conductive material
Data Source
AI summary
A method includes detecting, via first and second receivers of a tool that are oriented at a first and a third tilt angle, respectively, a first and second measurement of a first signal transmitted by a transmitter of the tool that is oriented at a second tilt angle into a substantially non-conductive material. The method includes determining, based on the first and second measurements, a first tensor and conveying the tool into a first wellbore formed in a subsurface formation. The method includes detecting, via the first receiver and the second receiver, a third and fourth measurement, respectively, of a second signal transmitted by the transmitter and determining, based on the third and fourth measurements, a second tensor and determining a third tensor (having values independent of the first, second, and third tilt angles) based on a relationship between the first and second tensors.