Over-molded Composite Mandrel for Downhole Zonal Isolation
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Solution Overview
Problem
The high cost and complexity of manufacturing composite mandrels for downhole zonal isolation tools, particularly due to the expensive filament winding process and costly components, hinder their economical production and efficient deployment in well casings.
Innovation Solution
The use of over-molded composite structures fabricated from engineered structural composite molding sheet compound, featuring chopped fibers randomly oriented in layers, replaces the filament winding process, reducing manufacturing costs by 30-40% and allowing for quicker production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If filament winding process is used to manufacture composite mandrels, then manufacturing precision and structural strength are improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent changes the manufacturing parameters by switching from filament winding to molded composite construction. The molded composite mandrel uses random fiber orientation with a resin matrix, eliminating the need for complex filament winding equipment and multi-layer diagonal/circumferential winding processes, thereby reducing manufacturing cost while maintaining sufficient strength through the molded composite structure
Solution Approach 2:
The patent employs composite materials by using molded composite construction with random fiber reinforcement embedded in a resin matrix. This composite structure provides the necessary strength and mechanical properties while simplifying the manufacturing process compared to traditional filament winding methods, thus resolving the contradiction between strength requirements and manufacturing cost
2Manufacturing precision
If filament winding process is used to manufacture composite mandrels, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent changes the manufacturing parameters by adopting molded composite construction instead of filament winding. The molded process allows for faster production cycles and higher productivity while maintaining manufacturing precision through controlled fiber randomization and resin matrix formation, eliminating the time-consuming multi-layer winding and grinding operations
3Ease of manufacture
If molded composite construction is used, then ease of manufacture is improved, but manufacturing precision may deteriorate
Solution Approach 1:
The patent controls the manufacturing precision of molded composite mandrels by optimizing parameters such as fiber length distribution, resin matrix composition, molding pressure, and temperature. These controlled parameters ensure that the random fiber orientation achieves the required mechanical properties and dimensional accuracy, maintaining manufacturing precision while simplifying the manufacturing process
Solution Approach 2:
The patent achieves manufacturing precision by ensuring homogeneity in the distribution of random fibers throughout the resin matrix during the molding process. This uniform fiber-resin composite structure provides consistent mechanical properties and dimensional stability, maintaining precision requirements while enabling easier manufacture compared to filament winding
Data Source
AI summary
A composite mandrel includes a filament-wound composite tube, and composite material molded over the filament-wound composite tube. For example, the composite material includes chopped fibers and a matrix of thermoset resin. The chopped fibers are arranged in layers upon the filament-wound composite tube, and the chopped fibers in each of the layers are randomly oriented along first and second orthogonal directions in each of the layers. The composite material includes at least one sheet of the composite material wound over the filament-wound tube, and at least one strip of the composite material wound over the sheet of the composite material and forming a head on the composite mandrel. An internal cavity of the filament-wound composite tube may provide a lumen for the composite mandrel. The internal cavity may be threaded to receive a removable bridge plug.