Pressure Balanced Drilling Choke for Wear Reduction
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Solution Overview
Problem
Current drilling choke configurations face challenges such as elevated pressure differentials, increased wear and erosion, and difficulty in inspection, service, and replacement due to harsh downhole environments and extreme drilling pressures, leading to higher maintenance and downtime costs.
Innovation Solution
A drilling choke design featuring a choke body with an adjustable plug and seat system, where the plug is pressure-balanced by fluid communication through a stem, allowing for reversible operation and reduced turbulence, facilitating easier maintenance and improved operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the drilling choke is designed to handle extreme drilling pressures, then the backpressure control capability is improved, but the pressure differential across the choke increases causing difficulty in unseating the choke
Solution Approach 1:
The choke assembly is divided into separable components including the choke body, plug, and actuator system. This segmentation allows the choke to be disassembled for maintenance and enables the unseating mechanism to function independently from the main choke body, resolving the contradiction between pressure handling capability and ease of unseating.
Solution Approach 2:
An unseating mechanism acts as an intermediary system between the high-pressure environment and the choke plug. This mechanism includes features such as unseating ports and pressure balancing channels that mediate the force required to overcome the pressure differential and release the plug from its seated position, making unseating feasible despite extreme operating pressures.
2Reliability
If the drilling choke operates in harsh downhole environments, then the backpressure control is maintained, but wear and erosion to components increases
Solution Approach 1:
The design incorporates wear-resistant materials and protective features in advance to cushion against the harmful effects of wear and erosion. This includes using hardened surfaces, erosion-resistant coatings, and redundant components that can withstand the harsh downhole environment while maintaining reliable backpressure control over extended periods.
Solution Approach 2:
The choke design allows for parameter changes in material properties and geometric features to resist wear and erosion. This includes selecting materials with appropriate hardness and erosion resistance, designing surface geometries that minimize turbulent flow and particle impact, and enabling parameter adjustments during operation to optimize performance under varying downhole conditions.
3Stress or pressure
If the drilling choke configuration is optimized for pressure control, then the backpressure management is improved, but inspection, service, and repair become difficult
Solution Approach 1:
The choke assembly is segmented into modular components that can be independently accessed, inspected, and serviced. The plug, actuator, and choke body are designed as separate units that can be disassembled without requiring complete system shutdown or complex disassembly procedures, enabling easy inspection and repair while maintaining effective backpressure management.
Solution Approach 2:
The design inverts the traditional approach by making the high-pressure sealing and control features accessible from the high-pressure side rather than requiring disassembly from the low-pressure side. This includes positioning inspection ports, maintenance access points, and service interfaces on the high-pressure side of the choke assembly, facilitating easier inspection and repair while maintaining effective backpressure control.
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 efficiency, reduces wear and erosion, and simplifies maintenance by allowing easier inspection and replacement, while maintaining precise control over backpressure in wellbores.
Implementation Method 1
the stem defining an internal passage; wherein, when the plug engages the seat, the recessed region of the nose is in fluid communication with the outlet passage of the choke body via the internal passage of the stem to thereby pressure balance the plug
Data Source
AI summary
A drilling choke including a choke body defining an internal region, an inlet passage, and an outlet passage, a seat extending within the outlet passage, a nose extending within the internal region and defining a recessed region, a plug extending within the recessed region, and a stem connected to the plug and extending axially therethrough, the stem defining an internal passage. The plug can be engaged with the seat to at least partially restrict fluid flow from the inlet passage to the outlet passage via the internal region. The stem and the plug are together axially moveable in opposing directions relative to the seat to thereby control a backpressure of the fluid flow. In some embodiments, the recessed region of the nose is in fluid communication with the outlet passage of the choke body via the internal passage of the stem to thereby pressure balance the plug.