Piston Initiator for Sidetrack Assembly Activation Control
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Solution Overview
Problem
Existing sidetrack assembly activation devices can unintentionally activate or cause the packer to set prematurely during fluid loss conditions, leading to improper orientation of the sidetrack assembly in wellbore operations.
Innovation Solution
A sidetrack assembly with a milling tool, piston, and releasable connection that controls fluid flow to prevent premature activation of the downhole tool, using a piston that moves from an uphole to a downhole position to communicate pressure to the downhole tool only when a predetermined force is reached, ensuring controlled activation of the packer and anchor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluid flow is communicated to the downhole tool during run-in, then the downhole tool can be activated, but premature activation occurs leading to improper orientation
Solution Approach 1:
The piston is pre-positioned in the bore to close the port before the tool is activated. This preliminary action prevents fluid flow from reaching the downhole tool during run-in and orientation, ensuring the tool remains inactive until the piston moves to expose the port.
Solution Approach 2:
The piston acts as an intermediary component between the fluid flow path and the downhole tool. It controls whether fluid flow is communicated to the tool by moving between two positions: closed (blocking the port) and open (exposing the port), thereby mediating the activation process.
2Reliability
If the piston is held in position by a releasable connection, then premature activation is prevented, but the connection must be designed to fail at a predetermined force
Solution Approach 1:
The releasable connection is designed with specific mechanical properties (shear strength, tensile strength) that correspond to a predetermined force threshold. When the applied force exceeds this threshold, the connection fails and releases the piston, allowing it to move and activate the downhole tool.
3Reliability
If fluid flow is restricted through the piston, then pressure differential is created to move the piston, but flow restriction must be precise
Solution Approach 1:
The piston includes a specific restriction feature (such as an orifice or constricted passage) with precisely controlled geometry at a localized position. This restriction creates the necessary pressure differential to actuate the piston while maintaining adequate flow rates elsewhere in the system.
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
Prevents premature activation of the downhole tool during run-in and orientation, ensuring accurate placement and activation of the packer and anchor, even in conditions of total fluid loss, thereby enhancing the reliability of sidetrack operations.
Implementation Method 1
In response to a predetermined downhole force from fluid flow in a downhole direction against the exposed surface area of the piston, the releasable connection is in the engaged state with the piston and is configured to release the piston to move from the uphole position toward the downhole position
Implementation Method 2
The piston in the uphole position closes the port from the bore, whereas the piston moved from the uphole position toward the downhole position exposes the port to the fluid flow in the bore
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A piston initiator is used on an assembly having a milling tool (60) and a whipstock (70) for creating a sidetrack in a wellbore. A piston (120) disposed in an uphole position in a bore (112) of the milling tool seals the bore from communicating with a side port (118). A line (155) from the port can communicate pressure to components on the whipstock for initiating their activation. The piston is movable from the uphole position, but is held by a releasable connection (141) configured to release the piston in response to a predetermined force from fluid flow in a downhole direction against an exposed surface area of the piston. An uphole shoulder (114) in the milling tool prevents movement of the piston in an uphole direction in response to reverse fluid flow through the milling tool.