Rotary Steerable Fluid Control Valve With Dual Flow Paths
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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 issues with fluid control valve designs, including blockages from abrasive drilling mud and inefficient fluid flow management, which limits flexibility and performance in directional drilling.
Innovation Solution
A fluid control valve design featuring a spool with distinct passages for fluid communication, allowing for adjustable flow paths between drilling fluid inlet and piston galleries, and exhaust ports, enabling improved fluid flow management and piston actuation control, even at high rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional 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 abrasive drilling mud and foreign debris, and energy is consumed forcing the piston back into its inner position
Solution Approach 1:
The valve body is segmented into multiple independent flow paths: a first flow path for fluid entry and piston actuation, and a second flow path for fluid exit. This segmentation eliminates the need for small bleed nozzles that are prone to blockage, as each path can be designed with adequate flow dimensions.
Solution Approach 2:
The harmful function of bleed nozzles that force the piston back into its inner position is extracted and eliminated. The invention allows the piston to remain in its actuated position without automatic reset, removing the energy-consuming reverse forcing mechanism entirely.
2Power
If drilling mud is used as the fluid medium to power pistons, then hydraulic power is generated by large motors and pumps at the rig site, but abrasive elements such as sand rapidly wear the rotary steerable tools and particles can cause blockages within the tools
Solution Approach 1:
The flow paths are designed with locally optimized characteristics: the first flow path has sufficient cross-sectional area and smooth surfaces to handle abrasive drilling mud without excessive wear, while the second flow path is designed to efficiently discharge fluid. Each path's geometry is tailored to its specific function, reducing overall susceptibility to abrasive damage.
3Ease of operation
If a fluid control valve restricts exhaust flow from the piston chamber to maintain control, then fluid flow into the piston is controlled, but the restriction causes energy loss and reduces achievable build rates at higher drilling string rotational speeds
Solution Approach 1:
The valve system dynamically adapts to different operating conditions through its spool mechanism, which can be positioned to optimize flow characteristics. The flow paths allow dynamic adjustment of fluid delivery to the piston, enabling high build rates at higher rotational speeds without restrictive exhaust flow limitations.
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 design enhances drilling performance by maintaining effective fluid tight seals, accommodating large pressure differentials, and allowing for adjustable timing and duration of piston activation, thereby improving build rates and flexibility in directional control.
Implementation Method 1
The spool is movable to block fluid communication between the drilling fluid inlet port and the exhaust port
Implementation Method 2
the first passage forms a fluid flow path between the piston gallery and the drilling inlet port
Implementation Method 3
the second passage forms a fluid flow path between the piston gallery and the exhaust port
Data Source
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.