Fluid Control Valve Spool for Rotary Steerable Piston Actuation
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Solution Overview
Problem
Existing rotary steerable tools face challenges in achieving high build rates at higher drilling string rotational speeds due to limitations in fluid control valve designs, which are prone to blockages, wear, and inability to adjust activation and deactivation phases effectively, leading to reduced performance and flexibility.
Innovation Solution
A fluid control valve with a spool mechanism that allows independent control of fluid flow into and out of piston galleries, featuring unrestricted exhaust galleries and adjustable spool positions to manage fluid flow paths, enabling precise control over piston actuation and deactivation phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If drilling mud is used to generate hydraulic power for pistons, then the system is simpler and uses available drilling fluid, but the mud contains abrasive elements and particles that cause blockages and wear in the rotary steerable tools
Solution Approach 1:
The system divides the fluid flow paths into separate segments: a first fluid passage for drilling mud containing abrasive particles, and a second fluid passage for filtered drilling fluid. This segmentation allows the abrasive mud to be routed away from sensitive piston components while still utilizing drilling fluid for hydraulic power generation.
Solution Approach 2:
A filtered drilling fluid acts as an intermediary medium between the abrasive drilling mud and the piston components. The filtering system removes abrasive particles from a portion of the drilling fluid, creating a cleaner intermediate fluid that can safely actuate the pistons without causing wear or blockages.
2Device complexity
If a fluid control valve with bleed nozzles is used to control piston actuation, then the valve structure is simple, but the bleed nozzles become blocked with lost circulation material or foreign debris
Solution Approach 1:
The fluid control valve is segmented into multiple independent passages: a first passage controlling fluid flow into the piston chamber, and a second passage controlling fluid flow out of the piston chamber. This eliminates the need for small bleed nozzles that are prone to blockage, as each passage can be designed with adequate flow dimensions.
Solution Approach 2:
The harmful bleed nozzle component is completely removed from the system. Instead of using a single valve with bleed nozzles, the invention extracts the bleed function entirely by providing a dedicated second passage for fluid exhaust, eliminating the blockage-prone small orifices.
3Ease of operation
If the spool is movable between actuation and discharge positions, then precise control of piston actuation and deactivation is achieved, but the valve structure becomes more complex
Solution Approach 1:
The movable spool performs multiple functions simultaneously: it controls fluid flow into the piston chamber through the first passage, controls fluid flow out of the piston chamber through the second passage, and provides sealing between the two fluid passages. This multi-functionality achieves precise piston control without requiring separate valves for each function.
Solution Approach 2:
The invention merges the inlet control and exhaust control functions into a single spool valve structure. The spool simultaneously manages both the first passage (inlet) and second passage (exhaust), combining multiple control functions into one integrated component that 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
Enhances drilling performance by allowing high build rates and flexibility in steering control, reducing piston wear, and minimizing pressure losses, thus improving the efficiency and adaptability of rotary steerable tools.
Implementation Method 1
The spool is movable to an actuation position in the inner chamber such that the first passage forms a fluid flow path between the piston gallery and the drilling inlet port, and also movable to a discharge position such that the second passage forms a fluid flow path between the piston gallery and the exhaust port
Data Source
Figure 1
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AI summary
A downhole tool control system for a drill string rotary steerable tool that includes a body having an inner chamber, a piston gallery extending between the inner chamber and a piston port, and an exhaust gallery extending between the inner chamber and an exhaust port. A spool in the inner chamber is movable into a plurality of positions to direct and control the timing and duration of the flow of drilling fluid to energize pistons of the rotary steerable tool, and to de-energize the pistons. The spool includes a first passage in fluid communication with a drilling fluid inlet port but not the exhaust port, and a second passage in fluid communication with the exhaust port but not the drilling fluid inlet port.