Drill String Signal Coupling for Noise-Resilient Downhole Communication
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Solution Overview
Problem
Existing measurement while drilling (MWD) systems face challenges with noise and distortion in data transmission through electrically conductive drill strings, necessitating improvements for effective communication between drill rigs and inground tools.
Innovation Solution
A drill string communication system utilizing an uphole transceiver and downhole transceiver to transmit signals through the drill string, with adaptive power and frequency adjustments to compensate for signal degradation and loss, and incorporating a walkover locator for electromagnetic locating signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data signals are transmitted through the electrically conductive drill string using the surrounding earth as a signal return path, then communication between the drill rig and inground tool is enabled, but noise and distortion effects degrade signal quality
Solution Approach 1:
An isolated signal return path is introduced as an intermediary between the signal source and the earth. This dedicated return path is electrically isolated from the drill string and surrounding earth, preventing noise and distortion from coupling into the signal while still enabling complete data transmission from the inground tool to the drill rig.
Solution Approach 2:
The conventional electrical signal transmission system is replaced with an optical signal transmission system. Optical signals are coupled onto the drill string and detected at the drill rig, eliminating the noise and distortion problems associated with electrical signals transmitted through the earth as a return path.
2Loss of information
If the drill string serves as an electrical conductor for data transmission, then communication functionality is achieved, but signal degradation occurs over distance
Solution Approach 1:
The electrical signal transmission system is replaced with an optical signal transmission system. Optical signals experience minimal attenuation and interference when transmitted through the drill string, enabling reliable data transmission over long distances from the inground tool to the drill rig without significant signal degradation.
3Reliability
If electromagnetic locating signals are transmitted through the drill string, then walkover locator communication is enabled, but signal strength decreases with distance
Solution Approach 1:
Electromagnetic locating signals are replaced with optical signals for transmission through the drill string. Optical signals maintain their strength over longer distances and are less susceptible to attenuation, enabling reliable walkover locator communication and location tracking even when the drill string is extended to great depths.
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 communication reliability and accuracy by dynamically adjusting transmission parameters and detecting signal degradation, ensuring uninterrupted data transfer and precise location tracking during inground operations.
Implementation Method 1
utilizes a drill string, extending from a drill rig to an inground tool, as an electrical conductor to provide communication between the drill rig and the inground tool
Implementation Method 2
An uphole transceiver is located at the drill rig including an uphole transmitter that couples an uphole signal onto the drill string
Implementation Method 3
A downhole transceiver is located downhole proximate to the inground tool including a downhole receiver that detects the uphole signal from the drill string
Implementation Method 4
a downhole transmitter that couples a downhole signal onto the drill string at a downhole transmit power that is selectable within a downhole power transmit range for transmission to the drill rig
Implementation Method 5
with adaptive power and frequency adjustments to compensate for signal degradation and loss
Data Source
AI summary
A drill string communication system is described. An uphole transceiver can couple a signal onto the drill string at a power that is always greater that a selectable power for a downhole signal. Communication from a drill rig to an inground tool can be re-initiated using a maximum uphole transmit power of an uphole transceiver. A procedure can establish a new set of transmission parameters for a drill string signal to establish communication between the drill rig and the inground tool. The system can include a walkover locator that receives an active/inactive status-controlled electromagnetic locating signal. Responsive to a locating signal degradation, a reconfiguration command can modify the locating signal. The uphole transceiver and a downhole transceiver can automatically modify at least one parameter of a downhole signal. An uphole receiver can apply a compensation response to a transferred signal to compensate for a drill string channel transfer function.