Drill String Signal Coupling for Cross-Bore Detection
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Solution Overview
Problem
Horizontal directional drilling (HDD) techniques face challenges in detecting pre-existing utilities and preventing frac-outs and key-holing during trenchless utility installations, as existing methods require prior knowledge of utility locations and are not effective in all soil conditions.
Innovation Solution
A system utilizing signal coupling through the drill string for cross-bore detection, which includes a coupling adapter with a current transformer and high-pressure electrical connections, and advanced monitoring of drilling parameters to detect potential cross-bore and frac-out conditions, and an integrated depth technique for precise steering and navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If acoustic and seismic information are used to detect pre-existing utilities, then detection capability is improved, but the method requires prior knowledge of utility locations and physical access
Solution Approach 1:
The patent replaces acoustic and seismic detection methods with electromagnetic field-based detection. The system uses a transmitter to generate electromagnetic fields and sensors to detect changes in these fields caused by proximity to utilities, eliminating the need for physical access to utilities while maintaining detection capability
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the detection system and the utilities. The transmitter generates electromagnetic fields that interact with utilities, and sensors detect these interactions, allowing indirect detection of utility locations without direct contact or prior knowledge
2Reliability
If thrust force monitoring is used to detect utility encounters, then real-time detection is improved, but thrust force changes may not indicate utility contact depending on material properties
Solution Approach 1:
The patent replaces mechanical thrust force monitoring with electromagnetic field-based detection. The system measures changes in electromagnetic field properties (conductivity, permittivity) rather than mechanical forces, providing more consistent and material-independent detection signals
Solution Approach 2:
The patent changes the detection parameter from mechanical thrust force to electromagnetic field properties. By monitoring changes in electrical conductivity and permittivity of the soil and utilities, the system achieves more reliable and material-independent detection of utility encounters
3Difficulty of detecting and measuring
If signal coupling through drill string is used for cross-bore detection, then detection of unknown utilities is improved, but system complexity increases
Solution Approach 1:
The patent makes the drill string serve multiple functions: it acts as both the drilling tool and the signal transmission medium. The existing electrically conductive drill string is used to couple electromagnetic signals to the boring tool, eliminating the need for separate signaling infrastructure and reducing overall system complexity
Solution Approach 2:
The system uses the drill string's inherent electrical conductivity for signal transmission without requiring additional components. The drill string serves itself by providing both the mechanical drilling function and the electrical signal coupling function, reducing system complexity while enabling cross-bore detection
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
Enhances the ability to detect and avoid pre-existing utilities, reduces the risk of frac-outs, and improves steering accuracy, enabling safer and more precise HDD operations.
Implementation Method 1
a current transformer configured for coupling a data signal onto the drill string for transmission to the inground tool
Data Source
AI summary
Systems, apparatus and methods are described for purposes of initiating a response to detection of an adverse operational condition involving a system including a drill rig and an inground tool. The response can be based on an uphole sensed parameter in combination with a downhole sensed parameter. The adverse operational condition can involve cross-bore detection, frac-out detection, excessive downhole pressure, a plugged jet indication and drill string key-holing detection. A communication system includes an inground communication link that allows bidirectional communication between a walkover detector and the drill rig via the inground tool. Monitoring of inground tool depth and/or lateral movement can be performed using techniques that approach integrated values. Bit force based auto-carving is described in the context of an automated procedure.