Dynamic Sealing Arrangement for Drill Stem Pressure Support
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Solution Overview
Problem
Current dynamic sealing systems for drill stems in wells are hindered by their large physical size and complexity, inability to provide internal pressure support, and inefficiency in managing pressure differences, particularly in high-pressure and high-temperature reservoirs, limiting drilling operations in wells with loss of pressure.
Innovation Solution
A sealing arrangement with a receiver unit placed between the drill deck and the well, utilizing a series of elastomeric gasket elements and a lubricant/liquid with high viscosity to provide internal pressure support, reduce friction, and maintain sealing effectiveness, allowing the drill stem to operate at maximum well pressure while enabling movement compensation and pressure equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dynamic sealing systems are used for drill stems in wells, then sealing function is provided, but the system requires large physical size and has high complexity with many moving parts
Solution Approach 1:
The sealing system is divided into multiple independent sealing elements (first sealing element, second sealing element, third sealing element) that can be separately installed and function independently. Each sealing element is a discrete component that can be replaced or maintained separately, reducing the complexity of the overall system while maintaining reliable sealing functionality.
Solution Approach 2:
The sealing elements are nested within the drill stem structure, with each sealing element positioned concentrically around the drill stem. The first sealing element is outermost, followed by the second sealing element, and the third sealing element is innermost, creating a nested configuration that reduces spatial requirements and simplifies the overall system architecture.
2Reliability
If conventional dynamic sealing systems are used, then sealing is provided, but the systems cannot provide internal pressure support corresponding to surrounding pressure
Solution Approach 1:
A lubricant is introduced as an intermediary substance between the sealing elements and the drill stem. This lubricant provides internal pressure support by filling the annular space between the sealing elements and the drill stem, allowing the sealing system to withstand surrounding pressure without requiring the sealing elements themselves to bear the full pressure load.
Solution Approach 2:
The system uses a fluid (lubricant) under pressure to provide structural support and pressure balancing. The lubricant is pumped into the annular space between the sealing elements and drill stem, creating a hydraulic pressure distribution that supports the surrounding formation pressure and reduces the mechanical stress on the sealing elements.
3Stress or pressure
If drilling fluid with greater specific density is used to maintain pressure, then pressure control is improved, but the opportunity to drill wells with loss of pressure is reduced
Solution Approach 1:
The system changes the parameter of pressure support from relying on drilling fluid density to using an independently controllable lubricant injection system. This allows pressure to be maintained through controlled lubricant injection rather than requiring high-density drilling fluid, enabling flexible adaptation to different well conditions including wells with pressure loss where lighter drilling fluids can be used.
4Stress or pressure
If sealing between drill stem and riser is implemented for high pressure reservoirs, then pressure maintenance is improved, but friction and resistance to drill stem movement increase
Solution Approach 1:
The lubricant serves as a mediator between the sealing elements and the drill stem, reducing direct contact and friction. By filling the annular space and providing a lubricating film, it allows the drill stem to move freely while maintaining the sealing function and pressure support, thereby reducing the force required to move the drill stem.
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
Enables safer, less expensive well interventions and drilling operations by effectively sealing the annular space between the drill stem and riser, allowing drilling in previously inaccessible wells with reduced formation damage risk and maintaining pressure in high-pressure formations.
Implementation Method 1
an internal pressure support is provided in the sealing arrangement, at least corresponding to the surrounding pressure
Implementation Method 2
utilizing a series of elastomeric gasket elements and a lubricant/liquid with high viscosity to provide internal pressure support, reduce friction
Implementation Method 3
utilizing a series of elastomeric gasket elements and a lubricant/liquid with high viscosity to provide internal pressure support
Data Source
AI summary
A sealing arrangement and method for dynamic sealing around a drill stem (50) in water-carrying, drilling fluid-carrying or hydrocarbon-carrying wells, comprising at least one dynamic sealing (35a) which is arranged to envelop the drill stem (50), and a receiver unit (30) arranged to receive the at least one sealing (35a), with the dynamic sealing being arranged to be driven into the receiver unit (30) with the help of the drill stem, and to be securely locked in the receiver unit, and also that internal pressure support in the sealing arrangement is provided corresponding to at least the surrounding pressure. The receiver unit (30) is arranged in an area in or near the drill deck of a drilling rig or vessel and in a riser, landing string or in another connection between drill deck and a well to close the return side of the drilling fluid between the drill stem and upper part of the riser, with the receiver unit (30), in connection with a floating rig or drilling ship, being arranged below the compensating unit (21) of the riser to make movement compensation possible between riser (20) and surface vessel (10), or that the receiver unit (30) in connection with a fixed installation, is arranged as a part of the riser connection (20).