Hydraulic Position Indicator for Wellbore Back Pressure Monitoring
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Solution Overview
Problem
Existing back pressure control devices in drilling operations face challenges in monitoring and controlling back pressure effectively, particularly in harsh environments, where electronic indicators require special certifications and pneumatic indicators fail under lost air pressure, and local position indicators are hazardous and unreliable.
Innovation Solution
A hydraulically operated position indicator system is coupled to a choke assembly, using a cylinder with a piston to indicate changes in back pressure through fluid volume changes, allowing for remote monitoring and control without relying on air pressure or electronic systems, thus providing a reliable and hazardous environment-resistant solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic position indicators are used for remote monitoring, then measurement precision is improved, but reliability deteriorates due to requiring special certifications and electronic system failures in harsh environments
Solution Approach 1:
The patent replaces electronic position indication systems with a purely mechanical indicator mechanism. The indicator is directly driven by the choke valve stem through mechanical linkages, eliminating electronic components entirely. This mechanical substitution resolves the contradiction by providing reliable operation in harsh environments without requiring electronic certifications or power supplies, while maintaining adequate measurement precision for position indication.
Solution Approach 2:
The patent utilizes the existing hydraulic control fluid system to drive the position indicator mechanism. The hydraulic fluid that controls the choke valve also actuates the indicator through hydraulic linkages, eliminating the need for separate pneumatic or electronic indication systems. This approach improves reliability by using the already-proven hydraulic system in the harsh environment while providing sufficient measurement precision for position monitoring.
2Device complexity
If pneumatic position indicators are used for remote monitoring, then device complexity is reduced, but reliability deteriorates when system air pressure is lost
Solution Approach 1:
The patent switches from pneumatic indication to hydraulic indication by utilizing the existing hydraulic control fluid system. The position indicator is actuated by the same hydraulic fluid that controls the choke valve, ensuring that the indicator remains reliable even when pneumatic pressure is lost. This hydraulic approach reduces device complexity by eliminating separate pneumatic systems while maintaining reliability through integration with the proven hydraulic control system.
3Measurement precision
If local visual position indicators are placed between choke bonnet and actuator, then measurement precision is improved, but object-affected harmful factors increase due to placement in hazardous environment
Solution Approach 1:
The patent segments the position indication function from the hazardous choke valve environment. The indicator mechanism is mechanically linked to the valve stem but positioned in a separate, safer location away from the hazardous bonnet and actuator area. This segmentation allows the indicator to provide precise position measurement while being protected from direct exposure to harmful factors such as high pressure, temperature, and potential fluid injection hazards.
Solution Approach 2:
The patent introduces mechanical linkages and hydraulic fluid as intermediaries between the choke valve stem and the position indicator. These intermediaries transmit position information from the hazardous environment to the indicator without requiring the indicator itself to be placed in the hazardous area. This intermediary approach maintains measurement precision while reducing exposure to harmful factors by isolating the indicator in a safer location.
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 hydraulic position indicator system enables reliable monitoring and control of back pressure in drilling operations, improving operational safety and reducing the need for specialized utilities, while being more economical and suitable for harsh environments compared to traditional electronic or pneumatic systems.
Implementation Method 1
a first piston (36) disposed in the axial bore and separating the axial bore into a first chamber (33) and a second chamber (38)
Implementation Method 2
fluidly coupling the second chamber (38) to a position indicating device (39), wherein movement of the choke assembly causes a corresponding movement in the rod (60) and the first piston (36), resulting in a change in a volume of fluid in the second chamber (38)
Data Source
AI summary
A system useful for monitoring or controlling the back pressure of fluid in a wellbore is disclosed. The system may include: a choke assembly including: a housing having an inlet, an outlet, and a bore; a choke member disposed in the bore for controlling a flow of a fluid from the inlet to the outlet, and a rod coupled to the choke member and extending through the housing; a cylinder including: a housing having an axial bore; a piston, directly or indirectly coupled to the rod, disposed in the axial bore and separating the axial bore into a first chamber and a second chamber; a position indicating device fluidly coupled to the second chamber, wherein a change in volume of fluid in the second chamber causes a corresponding change in volume of fluid in the position indicating device, thereby indicating a change in the position of the choke member.