Downhole Tool Sliding Sleeve Isolation and Lubrication
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Solution Overview
Problem
Current well-bore treatment systems face challenges in selectively isolating and communicating fluids between the inner and outer surfaces of downhole tools, particularly in hydraulic fracturing and fluid disposal applications, due to limitations in sealing and port management.
Innovation Solution
A downhole tool system featuring a sliding sleeve with a collet mechanism for maintaining open or closed positions, combined with seal systems and lubrication ports, ensures selective isolation and communication through treatment ports, while a dissolvable treatment port cover facilitates fluid delivery and debris exclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sliding sleeve is used to selectively isolate the inner bore from the outer surface, then fluid isolation control is improved, but device complexity increases due to additional sealing and positioning components
Solution Approach 1:
The sliding sleeve is disposed within the inner bore of the body, creating a nested configuration where the sleeve is contained within the bore. This nesting arrangement allows the sliding sleeve to provide selective isolation functionality while minimizing the overall device footprint and reducing the complexity of external sealing components.
Solution Approach 2:
A collet mechanism is introduced as an intermediary component to maintain the sliding sleeve in the open position. The collet engages with the inner surface of the body to provide positive positioning, eliminating the need for more complex locking mechanisms while ensuring reliable isolation control.
2Productivity
If treatment ports are disposed on the outer surface for fluid delivery, then fluid communication capability is improved, but debris exclusion becomes more difficult
Solution Approach 1:
A dissolvable cover is disposed over the treatment port before the treatment operation begins. This preliminary protective action prevents debris from entering the port during tool deployment and wellbore conditions, while the cover is designed to dissolve during the treatment phase to enable fluid delivery without interfering with the treatment process.
3Reliability
If seals are disposed in fixed positions on the inner surface, then isolation reliability is improved, but lubrication access becomes more difficult
Solution Approach 1:
The inner surface of the body is segmented into distinct zones: seal locations in fixed positions for reliable isolation, and lubrication ports positioned separately for accessible lubrication. This segmentation allows seals and lubrication features to be independently optimized for their respective functions without compromising either isolation reliability or lubrication accessibility.
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 system enables precise control over fluid communication and treatment in well-bores, enhancing the efficiency and reliability of hydraulic fracturing and disposal operations by maintaining isolation and facilitating fluid delivery.
Implementation Method 1
a compression spring disposed in an inner wall formed by the inner bore, and a locking pin urged against the compression spring and protruding into the inner bore
Implementation Method 2
means for lubricating the sliding engagement of the outer surface of the inner sleeve with the inner surface of the body
Data Source
AI summary
A down-hole treatment tool including a tool body having a bore therethrough, a treatment port orifice disposed on the body, a sliding sleeve within the bore of the body. A constant-volume annular chamber, in isolation from the inner bore and the environment outside the body, provides a debris-free environment for locking the sleeve. A dissolvable treatment port cover provides protection of the treatment port until operation of the treatment port is needed. The treatment port cover and lubrication ports enable lubrication of the sleeve and inner bore of the body without risk of contamination by debris.