Rotary Pulser Axial Gap Adjustment for Bearing Load Reduction
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Solution Overview
Problem
Existing mud pulse telemetry systems face challenges in accommodating changes in data rate and drilling mud flow rate without the need for mechanical adjustments or removal of the pulser, leading to suboptimal pressure waveforms and increased load on thrust bearings.
Innovation Solution
A rotary pulser with a stator and rotor design that automatically adjusts the axial gap between the rotor and stator in response to changes in pressure drop, allowing for varying degrees of obstruction and pulse characteristics to maintain efficient data transmission across different data rates and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the axial gap between rotor and stator is increased to reduce pressure drop and load on thrust bearings, then the load on thrust bearings is reduced, but the pulse waveform slope decreases resulting in suboptimal pulse characteristics
Solution Approach 1:
The axial gap between the rotor and stator is made dynamically adjustable rather than fixed. The gap can be modified during operation to optimize the balance between pressure drop reduction and pulse waveform quality, allowing the system to adapt to varying operating conditions without sacrificing either bearing load reduction or pulse characteristics.
Solution Approach 2:
The physical parameter of the axial gap is changed during operation to resolve the contradiction. By adjusting the gap size, the system can reduce pressure drop and bearing load when needed while maintaining optimal pulse waveform slope through careful parameter selection and control.
2Shape
If mechanical adjustments are made to the pulser to accommodate changes in data rate and flow rate, then optimal pulse waveforms can be maintained, but the device complexity and operational complexity increase
Solution Approach 1:
The pulser system is designed to automatically adapt to changing operating conditions without requiring external mechanical adjustments. The system self-regulates by allowing the axial gap to vary naturally in response to pressure differential changes, eliminating the need for manual intervention to maintain optimal pulse waveforms across different data rates and flow rates.
Solution Approach 2:
The system incorporates implicit feedback mechanisms where the pressure differential across the rotor automatically influences the axial gap through the flexible diaphragm or elastic element, creating a self-regulating system that maintains optimal pulse characteristics without external control or adjustment.
3Shape
If the axial gap is decreased to improve pulse waveform slope, then pulse characteristics are optimized, but the pressure drop increases placing greater load on thrust bearings
Solution Approach 1:
The axial gap is designed as a dynamic parameter that can change during operation. This allows the system to decrease the gap when optimal pulse waveform slope is needed and increase it when bearing load reduction is prioritized, providing flexibility to resolve the contradiction based on actual operating requirements.
Solution Approach 2:
The physical dimension of the axial gap is made variable rather than fixed, enabling the system to optimize the trade-off between pulse waveform quality and bearing load by changing this critical parameter in response to varying operating conditions such as data rate and flow rate.
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
Enables flexible and efficient data transmission by automatically adjusting the pulser's operation to accommodate changes in data rate and flow rate, reducing the load on thrust bearings and maintaining optimal pulse waveforms without the need for mechanical adjustments.
Implementation Method 1
the rotor imparting a different degree of obstruction to the flow of drilling fluid flowing through the stator passage depending on the circumferential orientation of the rotor... drilling fluid flowing through the pulser experiences a pressure drop across the rotor
Implementation Method 2
means for automatically responding to a change in the pressure drop across the rotor so as to attenuate the change in the pressure drop... varying the gap in response to the change in pressure drop
Data Source
AI summary
A rotary pulser for transmitting information to the surface from down hole in a well by generating pressure pulses encoded to contain information. The pulser includes a rotor having blades that are capable of imparting a varying obstruction to the flow of drilling fluid through stator passages, depending on the circumferential orientation of the rotor, so that rotation of the rotor by a motor generates the encoded pressure pulses. A spring biases the rotor toward the stator so as to reduce the axial gap between the rotor and stator. When the pressure drop across the rotor becomes excessive, such as when increasing drilling fluid flow rate or switching from a high data rate to a low data rate transmission mode, the spring bias is overcome so as to increase the axial gap and reduce the pressure drop across the rotor, thereby automatically reducing the thrust load on the bearings.