Annular Sealing Device Pressure Drop for Wear Reduction
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Solution Overview
Problem
Existing wellbore drilling technologies face challenges in effectively managing pressure and reducing wear on sealing elements in rotating control devices during closed mud circulation processes, particularly in Managed Pressure Drilling, due to uneven pressure distribution and fluid circulation inefficiencies.
Innovation Solution
The introduction of a high viscosity liquid circulation system with vertically offset inlet and outlet and narrow annular gap defining members creates a pressure drop that assists the lower chamber end member in absorbing wellbore fluid pressure, reducing wear and maintaining a balanced vertical load, while allowing ambient pressure in the discharge zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If liquid is circulated through the chamber to transfer pressure to upper sealing elements, then load sharing between lower and upper end members is achieved, but the upper chamber end member still experiences significant pressure load
Solution Approach 1:
The chamber is segmented into a feed zone adjacent to the lower chamber end member and a discharge zone adjacent to the upper chamber end member, with narrow annular gap defining members creating separate flow paths. This segmentation allows the high viscosity liquid to generate pressure drop specifically in the feed zone to support the lower sealing element, while the discharge zone maintains ambient pressure to reduce load on the upper sealing element.
Solution Approach 2:
Different zones within the chamber are given different pressure characteristics: the feed zone is designed to generate high pressure through narrow gap flow to support the lower chamber end member, while the discharge zone is designed to vent to ambient pressure. This local differentiation of pressure quality allows each sealing element to operate under optimized pressure conditions, reducing overall wear.
2Force
If high viscosity liquid is circulated through narrow annular gap, then pressure drop is induced to assist lower chamber end member, but fluid circulation efficiency is reduced
Solution Approach 1:
The patent changes the viscosity parameter of the circulating liquid to a high viscosity state, which enables the liquid to generate sufficient pressure drop through the narrow annular gap to support the lower chamber end member. Although high viscosity reduces circulation efficiency, the pressure support function is achieved, and the system accepts this trade-off to protect the sealing elements.
3Force
If narrow annular gap is used to create pressure drop, then vertical load balancing is achieved, but sensitivity to imperfections and misalignment increases
Solution Approach 1:
The narrow annular gap defining members are designed to be movable or adjustable, allowing them to dynamically adapt to variations in drilling tubular string position and imperfections in the annular gap geometry. This dynamic capability enables the system to maintain effective pressure drop and vertical load balancing despite manufacturing tolerances and operational variations, reducing sensitivity to precision requirements.
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
This approach significantly reduces wear on sealing elements by effectively balancing vertical loads and maintaining desired pressure in the feed zone, allowing for efficient fluid pressure management and reduced fluid entry into the sealing device, even with imperfections in the annular gap around the drilling tubular string.
Implementation Method 1
the circulation of said high viscosity liquid and the narrow annular gap are such that shear of the high viscosity liquid is induced in said elongated and radially narrow annular gap, resulting in a pressure drop between said feed zone and said discharge zone
Data Source
AI summary
In a method for sealing and controlling fluid pressure in an annular fluid passageway in a wellbore related process, use is made of an annular fluid passageway sealing device, which includes a chamber delimited by chamber end members each provided with an opening therein so that the drilling tubulars string passes through said chamber and said chamber end members. The lower chamber end member is exposed, at least partially, to wellbore related fluid pressure in the annular fluid passageway. The housing is provided with an inlet and an outlet in communication with said chamber. Use is made of a pump that circulates a high viscosity liquid. The inlet and the outlet are vertically offset from each other and the chamber is provided with one or more narrow annular gap defining members that are arranged between vertically spaced apart feed and discharge zones. The circulation of liquid and the narrow annular gap are such that shear of the high viscosity liquid is induced resulting in a pressure drop between the discharge zones such that high viscosity liquid pressure in the feed zone assists the lower chamber end member in absorbing the wellbore related fluid pressure.