Pressure-Activated Sliding Sleeve with Staged Shear Pin Activation
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Solution Overview
Problem
Existing downhole tools for hydraulic fracturing face challenges in reliably creating and controlling multiple fractures along a wellbore due to inconsistent shear pin activation pressures, leading to potential casing failure and premature tool activation.
Innovation Solution
A pressure-activated sliding sleeve mechanism with a shear pin assembly and locking mechanism that operates at distinct set points, allowing for controlled activation and locking to ensure accurate fracture creation and prevent casing pressure exceedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shear pins are used for sliding sleeve actuation, then the tool can be activated at a set pressure point, but the activation pressure becomes inconsistent and unreliable
Solution Approach 1:
The actuation system is divided into multiple independent shear pins (first shear pin and second shear pin) with different set points, allowing the sliding sleeve to be actuated in stages rather than all at once, improving reliability and control
Solution Approach 2:
The invention changes the pressure parameter by introducing multiple activation pressure thresholds (first set point and second set point), where the first set point is lower than the second set point, enabling staged actuation and more precise control over when the sliding sleeve opens
2Ease of operation
If shear pin set value is less than maximum operating pressure, then the tool can open at the set pressure, but casing pressure test at maximum operating pressure cannot be performed
Solution Approach 1:
The pressure testing capability is segmented into two stages: first, test at maximum operating pressure with the sliding sleeve closed (below the second set point); second, continue pressurizing above the second set point to shear the second shear pin and open the sliding sleeve, enabling both testing and activation
Solution Approach 2:
The first shear pin is designed to shear at a lower pressure threshold, allowing preliminary activation or testing to occur before the second shear pin activates the sliding sleeve, enabling staged operations including pressure testing at maximum operating pressure
3Reliability
If shear pin set value is greater than maximum operating pressure, then the tool remains closed during testing, but the operating pressure must exceed maximum operating pressure to open the tool
Solution Approach 1:
The activation process is segmented into two pressure thresholds: the first shear pin shears at or below maximum operating pressure, allowing the tool to activate reliably during normal operations, while the second shear pin provides a higher threshold for specialized applications
Solution Approach 2:
The first shear pin acts as an intermediary mechanism that can activate the sliding sleeve at lower pressures, providing a middle ground between maintaining closure during testing and enabling activation at reasonable operating pressures
4Force
If cement is present in the wellbore, then additional friction is created for the sliding sleeve, but cement also tends to collect in cavities and passages
Solution Approach 1:
The actuation system is segmented into multiple shear pins positioned at different locations, allowing staged activation that can work through cement obstructions more effectively than a single-point activation system
Solution Approach 2:
The invention changes the pressure parameter by establishing multiple activation thresholds, allowing the system to progressively overcome cement friction and accumulation effects through staged pressure increases rather than requiring a single high-pressure event
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 precise and reliable activation of the sliding sleeve at designed pressures, preventing premature opening and casing failure, while allowing for effective fluid communication and hydrocarbon production from multiple pay zones.
Implementation Method 1
A wellbore stimulation assembly includes a shear pin assembly and a sliding sleeve assembly. The sliding sleeve assembly is movable relative to the stimulation assembly between a closed position and an open position. The shear pin assembly is configured to shear the pins at an activation set point
Implementation Method 2
The pressure-activated sliding sleeve mechanism with a shear pin assembly and locking mechanism that operates at distinct set points, allowing for controlled activation and locking
Data Source
AI summary
A downhole tool and system for actuation of the tool. The tool includes a sliding sleeve assembly that is urged toward an opening position due to an interior pressure in the tool. A shear pin assembly hold the tool in the closed position. As pressure is increased to above a predetermined locking set point, a locking mechanism on the sliding sleeve radial engages the housing of the tool to lock the sliding sleeve to the housing. As pressure is further increased to a predetermined an activation set point, the shear pin assembly shears, but the sliding sleeve is maintained in the closed position by the locking mechanism. Only after the interior pressure is subsequently lowered to below a predetermined opening set point will the sliding sleeve shift to an open position.