Compact LWD Antenna Subassembly for Look-Ahead Formation Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Long logging tools with large spacing between antennas face communication issues and mechanical variance, leading to unreliable real-time operations and a lack of fine-scale anisotropy and formation dip angle measurements, which limits the 'look ahead' capability during drilling.
Innovation Solution
A compact sub assembly design brings transmitter and receiver antennas closer together, stabilizing communication and enabling fine-scale anisotropy and formation dip measurements by using a deep triad receiver and dual-collocated receivers, allowing for accurate inversion of component signals and improved formation property determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the logging tool is made longer to include more antennas for deeper formation measurements, then the measurement capability is improved, but the communication reliability between transmitter subs and receiver subs deteriorates
Solution Approach 1:
The logging tool is divided into multiple sub-assemblies (subs), with transmitters and receivers distributed across different subs. This segmentation allows the tool to achieve long measurement reach while maintaining manageable communication distances between individual subs, as each sub communicates with its nearest neighbors rather than across the entire tool length.
Solution Approach 2:
The patent arranges antennas in a three-dimensional configuration within compact sub-assemblies, using spatial dimensionality to achieve deep formation measurements without requiring long linear spacing between transmitters and receivers. This 3D arrangement allows electromagnetic fields to penetrate deeper into the formation while keeping physical communication paths short.
2Ease of manufacture
If the spacing between antennas is increased to reduce mechanical variance, then the manufacturing complexity is reduced, but the measurement precision of anisotropy and formation dip angle deteriorates
Solution Approach 1:
Multiple antennas (transmitters and receivers) are merged into compact sub-assemblies with precise relative positioning. This merging approach maintains tight spacing between antennas within each sub for high measurement precision, while the modular sub-assembly structure simplifies manufacturing by pre-configuring antenna groups as integrated units.
Solution Approach 2:
The patent changes the spacing parameter from large distances between distributed antennas to small distances within compact sub-assemblies. This parameter change enables fine-scale measurements of anisotropy and formation dip angle while the modular design absorbs manufacturing tolerances at the sub-assembly level rather than across the entire tool.
3Length of stationary object
If the logging tool is made longer to achieve deeper formation measurements, then the depth of investigation is improved, but the device complexity and cost increase
Solution Approach 1:
The patent employs a nested arrangement where multiple antennas are positioned within compact sub-assemblies that are themselves nested within the drill string. This nesting allows deep formation measurements to be achieved through the 3D spatial arrangement of antennas within compact volumes, rather than requiring long linear tool configurations, thereby reducing overall device complexity.
4Manufacturing precision
If the spacing between transmitter and receiver is increased to reduce mechanical variance, then the manufacturing precision requirement is reduced, but the look ahead capability deteriorates
Solution Approach 1:
The logging tool is segmented into multiple sub-assemblies with transmitters and receivers distributed across them. This segmentation enables the creation of multiple transmitter-receiver pairs with tight spacing, preserving look-ahead capability through fine-scale measurements while distributing the manufacturing precision requirements across multiple manageable sub-assemblies rather than requiring high precision across the entire tool length.
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
The compact sub assembly enhances the 'look ahead' capability, providing stable and accurate measurements for steering the drill string, enabling refined resolution and reliable real-time operation during drilling.
Implementation Method 1
Measurements by antennas on the logging tool may provide information that may allow an operator to determine wellbore and/or formation properties
Data Source
AI summary
A compact sub assembly and well measurement system. The compact sub assembly may comprise a deep transmitter disposed about one end of the compact sub assembly, a shallow dual transmitter disposed on the compact sub assembly between the deep transmitter and a second end of the compact sub assembly, a shallow dual-collocated receiver disposed on the compact sub assembly between the deep transmitter and a second end of the compact sub assembly, and a deep receiver disposed about the second end of the compact sub assembly. A well measurement system for decoupling a component signal may comprise a logging tool. The logging tool may comprise a first sub assembly and a conveyance attached to the logging tool. In examples the first sub assembly is a compact sub assembly comprising a deep transmitter, a shallow dual transmitter, a shallow dual-collocated receiver, and a deep receiver.