Composite Choke Assembly for Downhole Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cylindrical chokes used in downhole flow control devices face limitations due to brittleness and high hoop stresses, which can lead to cracking and shattering under elevated vibrations and differential pressures, and have pre-defined flow characteristics that are not easily adjustable without disassembly.
Innovation Solution
A flow control assembly with a composite choke assembly, featuring an inner sleeve made of an erosion-resistant material and an outer sleeve made of a more ductile material, allowing for adjustable flow control and reduced hoop stress through alignment of choke and sleeve orifices, and a movable flow control device for open or closed positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cylindrical chokes are made from erosion-resistant materials like carbides or hard ceramics, then erosion resistance is improved, but the material becomes brittle and prone to cracking or shattering under elevated vibrations and high differential pressures
Solution Approach 1:
The patent employs composite materials combining hard erosion-resistant materials (carbides or hard ceramics) with softer, more ductile materials. This composite structure allows the choke to maintain erosion resistance while the ductile component absorbs vibrations and prevents catastrophic cracking, resolving the contradiction between erosion resistance and fracture resistance.
2Object-affected harmful factors
If cylindrical chokes are designed with symmetric orifices to cancel flow stream energy, then erosion from impinging jets is reduced, but circumferential hoop stresses increase due to differential pressure acting from inner to outer radial fibers
Solution Approach 1:
The patent segments the choke structure into multiple components including the choke body, inner sleeve, and outer sleeve. This segmentation allows the symmetric orifice configuration to continue providing erosion protection while the multi-layer structure distributes and manages hoop stresses across different material layers, preventing stress concentration in a single component.
3Ease of operation
If cylindrical chokes have pre-defined flow characteristics through in-built orifice design, then flow control is simplified, but the flow characteristics cannot be replaced or adjusted externally without disassembly of the flow control device
Solution Approach 1:
The patent implements a dynamic, replaceable inner sleeve containing the orifices that can be independently accessed and replaced through the flow control device without full disassembly. This allows flow characteristics to be adjusted or changed while maintaining operational simplicity, resolving the contradiction between ease of operation and adaptability.
Data Source
AI summary
A flow control assembly includes a cylindrical body defining an interior and one or more openings through a wall of the body, and a composite choke assembly positioned within the body. The composite choke assembly includes an inner sleeve made of a first material and defining choke orifices that coincide with the openings, and an outer sleeve sized to receive the inner sleeve within the outer sleeve and being made of a second material that is more ductile than the first material. The outer sleeve defines sleeve orifices alignable with the choke orifices to facilitate fluid communication through the composite choke assembly. A flow control device is movably disposed within the body between a fully open position, where the choke orifices and the sleeve orifices are exposed, and a fully closed position, where the choke orifices and the sleeve orifices are occluded by the flow control device.