Meltable Eutectic Alloy Wellbore Plugs for Milling-Free Zone Isolation
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Solution Overview
Problem
Current oil and gas extraction methods face challenges in isolating hydraulic fracturing zones without the need for milling operations, as conventional frac balls are often stuck, require acidic environments for degradation, and cause flow restrictions due to their design, leading to inefficiencies and increased costs.
Innovation Solution
The development of restriction plug elements made from meltable eutectic alloys that change phase or strength with wellbore temperature, allowing for selective isolation and removal without milling, using a wellbore setting tool to deploy these elements into a restriction sleeve member, enabling efficient hydraulic fracturing and production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional frac balls are used to isolate hydraulic fracturing zones, then zone isolation is achieved, but the balls become stuck and require milling operations for removal
Solution Approach 1:
The plug element's physical state is changed from solid to liquid through temperature parameter change. The plug is deployed as a solid that sets and isolates zones, then is heated to melt and flow through the casing for removal, eliminating the need for milling operations
Solution Approach 2:
The mechanical milling system is replaced with a thermal system. Instead of using mechanical cutting tools to remove stuck plugs, the invention uses heat to melt the plug material, allowing it to flow away naturally, thus substituting a complex mechanical removal system with a simpler thermal process
2Reliability
If conventional frac balls are used for zone isolation, then hydraulic fracturing can proceed, but acidic environments are required for degradation
Solution Approach 1:
The degradation mechanism is changed from chemical (acid dissolution) to physical (thermal melting). The plug material is selected to melt at temperatures achievable in the wellbore environment, eliminating the need for harmful acidic chemicals while maintaining effective zone isolation during the fracturing process
Solution Approach 2:
The plug element is designed as a temporary, disposable component that serves its isolation function during hydraulic fracturing and then naturally disappears through melting. This eliminates the need for complex chemical degradation processes and acidic environments, as the plug simply melts and flows away after completion
3Reliability
If conventional frac ball design is used, then zone plugging is achieved, but flow restrictions occur due to the ball design
Solution Approach 1:
The plug transitions from a static, rigid ball to a dynamic system that changes state. During installation and isolation, the plug is solid and provides effective sealing. During removal, the plug melts into a liquid that flows freely with the production fluids, eliminating flow restrictions that would occur with a permanent solid ball in the casing
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
This solution allows for the isolation of multiple hydraulic fracturing zones without milling, reduces cycle time, and ensures cost-effective and efficient well production by eliminating the need for acidic environments and minimizing flow restrictions, thereby enhancing overall extraction efficiency.
Implementation Method 1
restriction plug elements that are insoluble in well fluid but have properties such as phase or strength that vary with temperature so as to change shape to pass through restrictions during production
Implementation Method 2
restriction plug elements made from meltable eutectic alloys that change phase or strength with wellbore temperature
Data Source
AI summary
A wellbore plug isolation system and method for positioning plugs to isolate fracture zones in a horizontal, vertical, or deviated wellbore is disclosed. The system/method includes a wellbore casing laterally drilled into a hydrocarbon formation, a wellbore setting tool (WST) that sets a large inner diameter (ID) restriction sleeve member (RSM), and a restriction plug element (RPE). The RPE includes a first composition and a second composition that changes phase or strength under wellbore conditions. After a stage is perforated, RPEs are deployed to isolate toe ward pressure communication. The second composition changes phase to create flow channels in the RPE during production. In an alternate system/method, the second composition changes phase or strength thereby deforming the RPE to reduce size and pass through the RSM's. The RPEs are removed or left behind prior to initiating well production without the need for a milling procedure.