Self-Adaptive Turbine Pulse Generator for Downhole Valve Erosion Control
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Solution Overview
Problem
Existing hydraulic oscillators in downhole drilling tools experience reduced service life due to continuous operation under composite drilling conditions, leading to increased erosion and limited friction-reducing and anti-backing pressure effects.
Innovation Solution
A turbine type pulse generator with an automatic control mechanism that switches between rotating and non-rotating states based on drilling conditions, ensuring the pulse generator operates only during sliding drilling, thereby extending the service life and enhancing friction-reducing and anti-backing pressure effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic oscillator is always in the working state during directional drilling, then the friction-reducing and anti-backing pressure effect is maintained, but the service life of the pulsing system is shortened due to aggravated erosion of the valve assembly
Solution Approach 1:
The patent applies the dynamics principle by making the turbine shaft's rotational state changeable based on drilling conditions. The turbine shaft can rotate during sliding drilling to generate pressure pulses for friction reduction, and remain stationary during composite drilling to prevent valve assembly erosion. This dynamic state adjustment resolves the contradiction between maintaining continuous friction-reducing effect and extending service life of the pulsing system.
Solution Approach 2:
The patent implements self-service through the automatic control mechanism that uses the rotational state of the drilling string itself to control the turbine shaft. The rotation of the drilling string during composite drilling automatically drives the turbine shaft to remain stationary, while during sliding drilling, the turbine shaft rotates to generate pulses. This self-controlled mechanism eliminates the need for external control systems while extending service life and maintaining effectiveness.
2Object-affected harmful factors
If the turbine type pulse generator operates continuously, then the friction-reducing effect is maintained, but the erosion of the valve assembly is aggravated
Solution Approach 1:
The patent applies periodic action by operating the turbine type pulse generator only during sliding drilling conditions rather than continuously. The pressure pulse generation occurs periodically when needed (during sliding drilling), allowing the valve assembly to rest during composite drilling when erosion would occur. This periodic operation maintains friction-reducing effectiveness while reducing erosion damage to the valve assembly.
3Force
If the pulse generating device is always active, then the backing pressure is eliminated, but the service life of the pulsing system is reduced
Solution Approach 1:
The patent implements feedback through the automatic control mechanism that responds to the rotational state of the drilling string to control the turbine shaft. The system detects whether the drilling string is rotating (composite drilling) or not rotating (sliding drilling) and automatically adjusts the turbine shaft state accordingly. This feedback control eliminates backing pressure during sliding drilling while extending service life by preventing operation during composite drilling when erosion would occur.
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
The turbine type pulse generator significantly extends the service life and enhances the friction-reducing and anti-backing pressure effects, improving the efficiency and safety of directional drilling operations in extended reach and horizontal wells.
Implementation Method 1
The turbine mechanism is configured to drive the turbine shaft to rotate relative to the turbine housing under an impact of drilling fluid
Data Source
AI summary
A turbine type pulse generator for downhole drilling tool has a pulse generating device (2), which has a turbine housing (21), a turbine shaft (22) concentrically arranged inside the turbine housing (21), a turbine mechanism arranged around the turbine shaft (22), and a valve disc mechanism provided at a lower end of the turbine shaft (22). The turbine mechanism is configured to drive the turbine shaft (22) to rotate under an impact of drilling fluid, so that a flow area of the valve disc mechanism is changed periodically to generate pressure pulses. The turbine type pulse generator also has an automatic control mechanism (1) configured to keep the turbine shaft (22) static relative to the turbine housing (21) in a circumferential direction during composite drilling, and to drive the turbine shaft (22) to rotate relative to the turbine housing (21) under an impact of the turbine mechanism during sliding drilling.