MWD Signal Modulation via Friction Reducing Device
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Solution Overview
Problem
Wireless borehole telemetry systems face challenges in transmitting data from Measurement While Drilling (MWD) systems to the surface due to signal attenuation, noise, and distortion caused by down-hole and up-hole noise sources, as well as friction reducing devices, which reduce the signal-to-noise ratio and telemetry reliability.
Innovation Solution
The method involves generating a MWD signal and modulating it onto a pressure pulse carrier signal using a mud pulser, with a downhole friction reducing device generating a carrier signal that reduces propagation attenuation and noise, allowing for demodulation of the signal at the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a MWD signal is transmitted through drilling fluids to the surface, then data transmission is achieved, but signal attenuation and noise reduce the signal-to-noise ratio
Solution Approach 1:
The patent uses a friction reducing device as an intermediary component that generates carrier signals to modulate the MWD data. This mediator converts the weak MWD signal into a stronger modulated signal that can traverse the noisy drilling fluid environment more effectively, thereby improving telemetry reliability while overcoming signal attenuation and noise.
Solution Approach 2:
The friction reducing device generates mechanical vibrations that create carrier signals in the drilling fluids. These vibrations modulate the MWD data and propagate as acoustic signals through the fluid column to the surface, enabling reliable data transmission despite attenuation and noise interference.
2Productivity
If friction reducing devices are used to reduce drag, then drilling efficiency is improved, but they generate noise that degrades signal quality
Solution Approach 1:
The patent converts the harmful noise generated by the friction reducing device into a beneficial carrier signal. The device's mechanical vibrations, which originally caused noise interference, are harnessed to modulate and transmit MWD data to the surface, transforming a detrimental effect into a useful communication mechanism.
3Loss of information
If signal modulation is used to improve data transmission, then information fidelity is enhanced, but system complexity increases
Solution Approach 1:
The friction reducing device performs multiple functions: it reduces drilling friction and simultaneously generates carrier signals for data modulation and transmission. This multi-functionality eliminates the need for separate dedicated transmission equipment, thereby enhancing information fidelity while avoiding additional system complexity.
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 reliability of telemetry by reducing signal attenuation and noise, improving the signal-to-noise ratio and enabling effective data transmission from the MWD system to the surface.
Implementation Method 1
The mud pulser might, for example be configured to generate patterns of pressure fluctuations in the mud stream that correspond to the sensed data
Implementation Method 2
a downhole friction reducing device generating a carrier signal that reduces propagation attenuation
Data Source
AI summary
A method for transmitting data from a MWD system at the BHA of a drill string may include transmitting the data in a MWD signal from the MWD system. The MWD signal may be modulated at a position closer to the surface onto a mud pulse modulated signal. The mud pulse modulated signal may be generated by a downhole friction reducing device. The downhole friction reducing device may include a mud motor. The mud motor may create pressure pulses based on its speed of rotation. The downhole friction reducing device may include a modulating valve. The modulating valve may be electromechanically or mechanically operated. The modulated signal may be detected at the surface by a receiver using one or more pressure or flow sensors. The receiver may use one or more harmonics of the modulated signal to receive the data.