Co-Located Tilted Coil Antennas for Compact Resistivity Logging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resistivity logging tools in subterranean wellbore operations have coil antennas that are axially separated, leading to increased tool length and costs, while also limiting the sensitivity and efficiency of the logging process.
Innovation Solution
The design incorporates co-located tilted coil antennas with stacked soft magnetic inserts and innovative antenna shields, which overlap each other to reduce axial length and enhance sensitivity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If coil antennas are axially separated in resistivity logging tools, then the tool length increases, but the sensitivity and efficiency of the logging process deteriorates
Solution Approach 1:
The patent combines multiple coil antennas into a co-located configuration where they occupy the same axial position on the logging tool. This merging approach reduces the overall tool length while maintaining or enhancing measurement sensitivity through the synergistic interaction of the combined antenna system.
Solution Approach 2:
The patent transitions from axial separation (one-dimensional arrangement) to co-located positioning with angular orientation (multi-dimensional arrangement). By orienting the coil antennas at different angles around the tool circumference, the system achieves compact axial length while preserving sensitivity through spatial distribution in the angular dimension.
2Device complexity
If coil antennas are axially separated, then the tool structure becomes simpler, but the efficiency of the logging process deteriorates
Solution Approach 1:
The patent merges multiple antenna functions into a compact co-located structure, reducing the axial space required while improving logging efficiency. The combined antenna system enables simultaneous or rapid sequential measurements, enhancing productivity without proportionally increasing structural complexity.
Solution Approach 2:
The patent changes the geometric parameters of the antenna arrangement from axial separation to co-located angular positioning. This parameter change optimizes the balance between structural simplicity and logging efficiency by achieving compact dimensions while maintaining effective measurement capabilities.
3Measurement precision
If co-located tilted coil antennas with stacked soft magnetic inserts are used, then gain and sensitivity are improved, but the device complexity increases
Solution Approach 1:
The patent implements a nested structure where soft magnetic inserts are stacked within the co-located coil antenna assembly. This nesting approach concentrates the magnetic enhancement components within the existing antenna footprint, improving gain and sensitivity without proportionally increasing the overall device complexity or external dimensions.
Solution Approach 2:
The patent employs composite construction by combining coil windings with stacked soft magnetic inserts in the antenna assembly. This composite structure leverages the electromagnetic properties of both components to achieve enhanced gain and sensitivity while managing the complexity through integrated design.
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 configuration results in a more compact and cost-effective wellbore logging tool with improved gain, sensitivity, and efficiency, allowing for more accurate resistivity measurements of subterranean formations.
Implementation Method 1
The soft magnetic material facilitates a higher magnetic permeability path (i.e., a flux conduit) for the magnetic field generated by the coil windings
Implementation Method 2
helps shield the coil windings from adjacent drill collars and associated losses (e.g., eddy currents generated on the drill collars)
Data Source
AI summary
An antenna assembly includes a tool mandrel having a tool axis; a first coil antenna including a first plurality of windings wrapped about the tool mandrel, wherein the first coil antenna is arranged in a first orientation and wherein portions of the first plurality of windings are wrapped about the tool mandrel at a first winding angle defined with respect to the tool axis; and a second coil antenna co-located with the first coil antenna and including a second plurality of windings wrapped about the tool mandrel, wherein the second coil antenna is arranged in a second orientation opposite the first orientation, wherein portions of the second plurality of windings are wrapped about the tool mandrel at a second winding angle defined with respect to the tool axis and wherein a difference between a loop area of the first coil antenna and a loop area of the second coil antenna is less than 25%.