Dual Drill String Valve Actuator with Backup Flow Control
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Solution Overview
Problem
Current valve systems for concentric drill strings lack a reliable backup flow control mechanism, which is essential for preventing gas-kicks and blow-outs during drilling operations.
Innovation Solution
A dual drill string valve system featuring a biasing device, such as a spring, that urges a piston to move toward the upper inner conduit, along with a rotary valve mechanism comprising a rotatable valve disc and a rotationally fixed plunger, which closes fluid passages to provide a backup flow control when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single valve system is used in concentric drill strings, then the device complexity is reduced, but the reliability of flow control is insufficient due to lack of backup mechanism
Solution Approach 1:
The patent implements nested valve assemblies where an inner valve is positioned within an outer valve housing. The inner valve assembly (including piston, valve disc, and plunger) is contained within the outer valve housing, creating a compact dual-barrier system. This nesting arrangement provides redundant flow control capability while maintaining a space-efficient design suitable for drill string applications.
Solution Approach 2:
The valve system is divided into functionally independent segments: an outer valve assembly with its own sealing mechanism and an inner valve assembly with separate piston-driven valve disc and plunger. This segmentation allows each valve to operate independently as a backup, enhancing reliability while maintaining manageable system complexity through modular design.
2Reliability
If a backup valve mechanism is added to the concentric drill string system, then the reliability of flow control is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple valve functions into a single integrated assembly. The outer valve and inner valve are merged into one housing structure, sharing common components such as the piston, seals, and control mechanisms. This merging reduces the overall number of separate assemblies needed while providing dual-barrier backup flow control capability.
Solution Approach 2:
The valve assembly is designed with multi-functional components that serve multiple purposes. For example, the piston serves both as a sealing element and as a actuator for the valve disc. The same housing accommodates both the outer valve sealing surface and the inner valve mechanism. This multi-functionality reduces the number of dedicated components needed, thereby reducing overall system complexity while maintaining backup reliability.
3Adaptability or versatility
If a rotary valve mechanism with multiple components is used, then the flow control capability is enhanced, but the ease of manufacture decreases
Solution Approach 1:
The valve components are designed to be pre-assembled as modular units before installation in the drill string. The inner valve assembly with its rotatable disc and plunger can be manufactured and tested as a complete sub-assembly, allowing for quality control and simplification of the final assembly process. This preliminary action reduces manufacturing complexity by breaking down the complex rotary valve into manageable pre-fabricated modules.
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 dual drill string valve system effectively controls fluid flow, providing a double barrier system for both supply and return flows, enhancing wellbore pressure management and emergency shut-off capabilities, thus preventing uncontrolled fluid movements.
Implementation Method 1
a biasing device arranged to urge the piston to move toward the upper inner conduit. In one or more embodiments, the biasing device comprises a spring.
Implementation Method 2
The seal may be in a sealed position, preventing uncontrolled fluid flow from a high pressure side to a low pressure side.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A dual drill string valve includes an actuator (100) including a piston (114) disposed in a housing (110), which is configured to couple at its ends to an end of a nested dual drill string segment. An upper inner conduit (112) and a lower inner conduit (115) are mounted in the housing, proximate to the longitudinal ends thereof. The piston is slidably, sealingly engaged between the upper and lower inner conduits and defines a fluid flow passage therethrough. The upper inner conduit, the piston and the lower inner conduit define another flow passage between respective exterior surfaces thereof and an interior of the housing such that application of fluid pressure to the external flow passage causes movement of the piston away from the upper inner conduit. A rotary valve is coupled to the actuator whereby longitudinal movement thereof rotates the rotary valve.