Removable Mandrel Isolation Device for Frac Plug Flow
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Solution Overview
Problem
Traditional isolation devices in the oil and gas industry require a permanent inner mandrel for support, which cannot be removed after setting, limiting fluid flow and increasing the cost and time required for milling components for removal.
Innovation Solution
The novel isolation device features self-supporting slip props and a removable inner mandrel, allowing the packer element to engage directly with the tubing string without the mandrel, enabling larger fluid flow paths and reducing milling requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a permanent inner mandrel is used for support in traditional isolation devices, then structural support and stability are improved, but fluid flow capacity is limited and device removal complexity increases
Solution Approach 1:
The isolation device is divided into two functional phases: during setting, the inner mandrel provides structural support; after setting, the mandrel is removed to enable larger fluid flow. This segmentation of functional requirements resolves the contradiction between needing support during installation and needing maximum flow capacity during operation.
Solution Approach 2:
The inner mandrel transitions from a permanent structural component to a temporary setting aid. The device dynamically adapts its configuration - with mandrel during setting for stability, then without mandrel after setting for maximum fluid flow capacity. This dynamic reconfiguration resolves the contradiction between structural support and flow capacity.
2Strength
If a permanent inner mandrel is used for support, then structural integrity is improved, but the time and cost required for milling components for removal increases
Solution Approach 1:
The inner mandrel is extracted from the permanent structure and designed as a removable component. After the mandrel completes its function during setting, it is removed from the isolation device, eliminating the need for time-consuming milling operations to remove permanent mandrel components. This extraction resolves the contradiction between structural integrity during setting and removal time.
Solution Approach 2:
The inner mandrel is designed to be discarded after serving its temporary purpose during setting. The mandrel is not recovered or retained in the final isolation device configuration, allowing for rapid removal without requiring complex milling operations. This discarding approach resolves the contradiction between maintaining structural integrity and minimizing removal time.
3Ease of operation
If a setting sleeve with direct contact with top slips is used, then setting process is simplified, but the need for a permanent inner mandrel is eliminated
Solution Approach 1:
The slip props are designed to be self-supporting during the setting process, eliminating the need for a permanent inner mandrel. The setting sleeve provides temporary support during setting, then the slips self-support the structure after setting, allowing the mandrel to be removed. This self-service design resolves the contradiction between ease of setting and device complexity.
Data Source
AI summary
An isolation device can include a packer element that is actuated via a slip system to engage with an inner diameter of a tubing string to set the plug. The isolation device can be a frac plug. Top and bottom slip props of the slip system can be shaped such that the packer element is inhibited or prevented from engaging with an inner mandrel after the plug has been set within a wellbore. The slip props can be self-supporting; thus, the inner mandrel can be removed from the isolation device after setting and can be reused in other downhole tools. The isolation device can be used for zonal isolation to treat a zone of interest within a subterranean formation. The treatment can be a fracturing operation.