Meltable Eutectic Alloy Frac Plugs for Milling-Free Wellbore 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 inefficient and costly production processes.
Innovation Solution
The development of restriction plug elements made from meltable eutectic alloys that change phase or strength with wellbore temperature, allowing for the creation of flow passages and deformation to pass through restriction sleeve members without milling, and are designed to be cost-effective and independent of wellbore fluid composition.
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 milling operations are required and cycle time increases
Solution Approach 1:
The frac ball is made from a material whose physical properties change in response to wellbore temperature. The material transitions from a solid state that can be set and isolated zones effectively to a state (liquid, gas, or degraded solid) that allows easy removal without milling, thereby reducing cycle time while maintaining reliable zone isolation
Solution Approach 2:
The invention uses a disposable frac ball made from cost-effective materials that degrade or transform under wellbore conditions. Instead of requiring expensive milling operations for removal, the frac ball is designed to naturally degrade or transform into removable states, reducing both operational cost and time
2Reliability
If conventional frac balls are used, then zone isolation is achieved, but acidic environments are required for degradation
Solution Approach 1:
The frac ball material is designed to respond to temperature parameters rather than chemical acidity. The material undergoes phase change or degradation based on wellbore temperature, eliminating the need for acidic environments and associated harmful effects on wellbore casing
Solution Approach 2:
Instead of requiring acidic chemicals that can harm wellbore casing, the invention converts the naturally occurring thermal energy in the wellbore into the mechanism for frac ball degradation. The wellbore's own temperature becomes the beneficial trigger for material transformation, eliminating the need for harmful chemical agents
3Reliability
If conventional frac balls are used, then zone isolation is achieved, but flow restrictions occur due to design
Solution Approach 1:
The frac ball material changes its physical state in response to temperature, transitioning from a flow-restricting solid configuration to a flow-friendly liquid, gas, or degraded state. This parameter change eliminates flow restrictions while maintaining the isolation function during the fracturing operation
Solution Approach 2:
The frac ball is designed with dynamic properties that allow it to adapt its state based on environmental conditions. The material dynamically transitions from a rigid isolation structure to a flexible or fluid state that accommodates production flow, thereby maintaining both isolation reliability and fluid flow productivity
4Loss of time
If meltable materials are used for frac balls, then milling is eliminated and cycle time is reduced, but material strength at wellbore temperature must be maintained
Solution Approach 1:
The material is engineered with a specific phase transition temperature that is lower than wellbore temperature but higher than surface temperature. During the fracturing operation, the material maintains solid strength for effective isolation, then transitions to a removable state when exposed to wellbore heat, achieving both strength and ease of removal
Solution Approach 2:
The frac ball is designed to undergo preliminary degradation or phase change in response to wellbore temperature exposure. This preliminary action weakens the material structure in advance, making subsequent removal easy without requiring milling operations, thereby reducing cycle time while maintaining initial strength
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 efficient and timely isolation of hydraulic fracturing zones without milling, reduces cycle time for stage fracturing, and ensures unrestricted well production fluid flow by using meltable materials that adapt to wellbore conditions, eliminating the need for acidic environments and preventing wellbore casing erosion.
Implementation Method 1
restriction plug elements made from meltable eutectic alloys that change phase or strength with wellbore temperature
Implementation Method 2
meltable materials that adapt to wellbore conditions
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.