Tunable Dipole Moment for Resistivity Logging
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Solution Overview
Problem
Conventional electromagnetic logging tools face limitations in measuring subterranean formation resistivity due to noise introduced by tool rotation and limited measurement capabilities to lateral and angular orientations of antennas, restricting comprehensive formation evaluation.
Innovation Solution
A tunable dipole moment system is implemented using non-parallel and skewedly oriented receiver antennas, allowing for the creation of a pseudo antenna with adjustable orientation and position, enabling comprehensive resistivity logging by combining measurements from multiple antennas to simulate a pseudo antenna at various orientations and locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the tool is rotated to measure the entire formation around the borehole, then the measurement coverage is improved, but noise is introduced into the measurements
Solution Approach 1:
The patent creates a pseudo antenna through mathematical combination of signals from multiple physical antennas. This virtual copy of an antenna allows the system to achieve measurements equivalent to having a physically rotated antenna without actually rotating the tool, thereby eliminating rotation-induced noise while maintaining comprehensive formation coverage
Solution Approach 2:
The patent combines signals from multiple receiver antennas with different orientations and positions to create a synthesized pseudo antenna. By merging the measurement capabilities of multiple fixed antennas, the system achieves the functionality of a single rotated antenna without the associated noise problems
2Quantity of substance
If multiple transmitter antennas or receiver antennas are laid over each other, then the measurement locations are expanded, but the measurements remain limited to the lateral location of the antennas within the wellbore
Solution Approach 1:
The patent extends measurements beyond the lateral dimension by using the vertical separation between antennas at different depths. The pseudo antenna concept allows calculation of formation properties at locations not directly occupied by physical antennas, effectively adding a depth dimension to the measurement capability
Solution Approach 2:
The system makes a single set of physical antennas perform multiple functions by mathematically synthesizing pseudo antennas at various orientations and positions. This universal approach allows one physical configuration to provide measurements equivalent to multiple different antenna placements
3Measurement precision
If the receivers are tilted to focus measurements in the azimuthal direction, then the measurement precision in that direction is improved, but the measurements are limited to the angular orientation of the receivers
Solution Approach 1:
The patent creates a dynamic virtual antenna system where the pseudo antenna's orientation can be mathematically adjusted to any azimuthal angle. Instead of physically reorienting receivers, the system dynamically computes measurements for any desired angular orientation by combining signals from fixed tilted receivers, providing both precision and angular versatility
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 completeness of resistivity measurements by reducing noise and expanding measurement capabilities beyond the physical antenna's limitations, allowing for more precise characterization of subterranean formations.
Implementation Method 1
a transmitter of the induction logging tool transmits an electromagnetic signal that passes through the geological formation around the borehole and induces a signal in one or more receivers
Data Source
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Figure 3A~4
AI summary
In accordance with presently disclosed embodiments, a system and method for determining a measurement for a pseudo receiver antenna with a different lateral position and a different azimuthal direction than at least two receiver antennas disposed on one or more wellbore tools is provided. The method involves transmitting an electromagnetic signal into a subterranean formation surrounding a borehole, and measuring one or more responses of the subterranean formation to the electromagnetic signal using at least two receiver antennas. The two receiver antennas are oriented in differing azimuthal directions relative to one or more tools to which the receiver are coupled, and arranged in a non-parallel angular orientation with respect to each other. The method then includes determining a response measured by a pseudo receiver antenna with a desired angular orientation and a desired azimuthal direction with respect to the one or more tools.