Check Valve Plunger Prevents Borehole Contaminant Backflow
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Solution Overview
Problem
During horizontal directional drilling, the pressure differential between the drilling fluid system and the borehole causes contaminants to flow back into the drill string when the fluid delivery system is inactive, potentially damaging internal components.
Innovation Solution
A check valve system with a plunger and socket arrangement within the downhole tool assembly prevents backflow by allowing fluid communication when pressure is high and blocking it when pressure is low, using a plunger that moves between positions to control fluid flow between the central bore and external ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the fluid delivery system is inactive during drill string section changes, then system maintenance and assembly operations can be performed, but contaminants from the borehole flow back into the drill string causing damage to internal components
Solution Approach 1:
A check valve is introduced as an intermediary component between the borehole environment and the drill string internal components. The valve includes a body with a bore, a closure member that moves between open and closed positions, and a seal that prevents contaminant ingress when the fluid delivery system is inactive, thus protecting internal components during assembly operations
Solution Approach 2:
The check valve is pre-installed in the fluid delivery system to provide preliminary protection against contaminant backflow. The valve remains in a default closed or controlled position during drill string section changes, actively preventing contaminants from entering the drill string before any damage can occur
2Reliability
If a check valve system is added to prevent backflow, then internal components are protected from contaminants, but device complexity increases
Solution Approach 1:
The check valve is designed as a segmented, modular component that can be integrated into the existing fluid delivery system without redesigning the entire system. The valve body, closure member, and seal are separate可替换 components that maintain system reliability while minimizing overall complexity
Solution Approach 2:
The check valve is designed to operate automatically based on pressure differentials without requiring external control systems. The closure member responds to pressure changes from the fluid delivery system, opening or closing the bore automatically, which eliminates the need for complex control mechanisms and reduces overall 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
Effectively prevents contaminants from entering the drill string, reducing damage to internal components and maintaining system integrity during drill string section changes.
Implementation Method 1
discontinuizing fluid flow such that ambient pressure about the drilling tool is greater than the pressure within the central bore and moving the plunger to a second position within the socket due to the pressure differential
Data Source
AI summary
A check valve for a drill string fluid delivery system. The fluid delivery system allows for drilling mud to travel from a source up the drill string, through the drill string, through a downhole tool assembly, to a port located at a surface of a boring tool. The check valve rests in a socket within the downhole tool assembly, with a forward face extending into a gallery within the bit. When the ambient pressure within the fluid delivery system exceeds the ambient pressure in the borehole, mud flows through the system to the ports and into the borehole. When the ambient pressure within the borehole exceeds the ambient pressure in the fluid delivery system, the pressure is applied to the forward face, causing the check valve to close, preventing contaminants from the borehole from entering the fluid delivery system.