Impeller Second Blades Pressure Control Downhole
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Solution Overview
Problem
Mud-pulse telemetry pressure spikes cause pressure differentials that lead to drilling fluid leakage through the fluid seal in downhole power generation modules, compromising the hydraulic fluid and electrical components within the housing.
Innovation Solution
The power generation module includes an impeller with second blades that decrease the pressure of drilling fluid between the impeller and the housing, reducing leakage by increasing fluid flow rate and expelling contaminants, thus synchronizing pressure within the module with the drilling fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If mud-pulse telemetry is used to transmit information through drilling fluid, then communication between surface equipment and BHA is enabled, but pressure spikes occur that cause fluid leakage through the seal
Solution Approach 1:
A pressure equalization chamber is introduced as an intermediary between the drilling fluid and the seal. This chamber allows pressure fluctuations from mud-pulse telemetry to be absorbed and equalized, preventing direct transmission of pressure spikes to the seal while maintaining the seal's protective function
Solution Approach 2:
The system changes the pressure parameter dynamically by providing a pathway for pressure equalization. The pressure equalization chamber allows internal pressure to adjust in response to external pressure fluctuations, maintaining pressure balance across the seal and preventing leakage during telemetry operations
2Reliability
If the seal is made more robust to prevent leakage, then seal integrity is improved, but the complexity of the housing and fluid management system increases
Solution Approach 1:
The pressure equalization function is extracted from the seal itself and placed into a separate pressure equalization chamber. This allows the seal to remain relatively simple while the chamber handles the complex pressure management, reducing overall system complexity compared to making the seal itself more complex
3Loss of information
If drilling fluid pressure is increased to improve telemetry signal strength, then information transmission is improved, but fluid leakage through the seal increases
Solution Approach 1:
The pressure equalization chamber creates an equipotential region where pressure is balanced between the drilling fluid side and the housing interior. This allows high drilling fluid pressure to be maintained for strong telemetry signals while the equalized pressure prevents the pressure differential that would cause seal leakage
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 design effectively reduces fluid leakage and maintains the integrity of hydraulic and electrical components, ensuring reliable operation of downhole tools by synchronizing internal and external pressures.
Implementation Method 1
The impeller includes second blades positioned to decrease pressure of drilling fluid within a region between the impeller and the housing when the impeller is rotating
Implementation Method 2
drilling fluid pumped through the drill string imparts rotation to the impeller, thus driving the electrical generator
Implementation Method 3
an electrical generator within the housing... Drilling fluid pumped through the drill string imparts rotation to the impeller, thus driving the electrical generator
Data Source
AI summary
Apparatus and methods for decreasing pressure of drilling fluid within a region between an impeller and a housing of a power generation module (PGM). The apparatus comprises a shaft extending from and rotatable relative to the housing; The impeller is coupled with the shaft external to the housing and includes a group of blades that rotate the impeller as the drilling fluid flows past the PGM. The impeller further includes another group of blades that decrease the pressure of the drilling fluid within the region between the impeller and the housing when the impeller is rotating.