Straddle Packer Auto-J Sleeve Automatic Stay-Set Mechanism
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Solution Overview
Problem
Existing straddle packers for wellbore pressure isolation are unreliable and lack the ability to automatically maintain a packer set condition after fluid pressure is terminated, hindering the monitoring of pressure drops for fracture closure analysis.
Innovation Solution
A straddle packer with a floating auto-J sleeve that rotates freely on a piston mandrel, featuring a continuous auto-J groove with run-in, pressure-set, stay-set, and shift slots, and auto-J pins that automatically shift between conditions using fluid pressure, allowing for reliable sealing and monitoring of pressure changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional straddle packer is used for pressure isolation, then the basic sealing function is achieved, but the packer cannot automatically maintain the set condition after fluid pressure is terminated
Solution Approach 1:
The packer system uses the pumped fluid itself to automatically set and maintain the packer elements through pressure-sensitive activation of the piston and packer element engagement, without requiring external control mechanisms or additional energy sources
Solution Approach 2:
The packer elements and piston are designed to dynamically respond to fluid pressure changes, automatically transitioning between set and unset states based on the presence or absence of pumped fluid pressure
2Reliability
If the packer remains set after pumping termination, then pressure monitoring for fracture closure analysis is enabled, but the packer cannot be easily moved or repositioned
Solution Approach 1:
The continuous circulation of fluid through the packer system automatically maintains the set condition during monitoring and enables self-unsetting when circulation stops, eliminating the need for manual intervention to change packer state
Solution Approach 2:
The packer is designed to be set and unset through periodic cycles of fluid pumping and circulation, allowing repeated positioning and monitoring operations
3Reliability
If a mechanical setting mechanism is used, then the packer can be set reliably, but the system becomes more complex and requires additional components
Solution Approach 1:
The packer setting mechanism uses hydraulic pressure from pumped fluid to activate the piston and engage the packer elements, replacing complex mechanical linkages with a simpler fluid-pressure-driven system
Solution Approach 2:
The system uses the pumped fluid itself as the setting mechanism, eliminating the need for separate setting wires, mechanical actuators, or additional control systems
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 reliable pressure isolation and automatic shifting between run-in, set, and stay-set conditions, facilitating precise well stimulation and remediation treatments while allowing for post-treatment pressure monitoring.
Implementation Method 1
the piston sleeve reciprocating, with respect to the piston mandrel in response to fluid pressure pumped into the straddle packer
Data Source
AI summary
A straddle packer has a floating auto-J sleeve that automatically shifts the straddle packer from a run-in condition to a stay-set condition after pumping of high-pressure fluid into the straddle packer in excess of a predetermined pump rate is terminated. In the stay set condition, packer elements of the straddle packer remain in sealing contact with a well casing or well bore into which the straddle packer has been run.