Self-Healing Wellbore Cement With Meltable Elastomer Crack Sealing
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Solution Overview
Problem
Wellbore cement sheaths are prone to mechanical failure due to cyclic stresses, leading to potential hazards and catastrophic accidents, and existing remedial operations are inadequate in sealing cracks or fissures.
Innovation Solution
Incorporating elastomer particles into cement slurries, which are heated above their melting point to infiltrate into defects and solidify within the cement structure, enhancing mechanical properties and sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement slurries are used for wellbore cementing, then zonal isolation and well stability are achieved, but the cement structures are vulnerable to mechanical failure due to cyclic stresses and temperature fluctuations
Solution Approach 1:
The patent incorporates elastomer particles (1-25% by weight of cement) into the cement slurry to create a composite material system. The elastomer particles act as flexible inclusions within the rigid cement matrix, providing crack-bridging and stress-distribution mechanisms that enhance mechanical strength while maintaining sealing integrity under cyclic stresses and temperature fluctuations.
2Reliability
If remedial operations like squeezing resin or micro-cement are performed to repair cracks, then sealing is improved, but the operation cost increases significantly
Solution Approach 1:
The elastomer particles are incorporated into the cement slurry during the initial cementing operation, providing preventive reinforcement before mechanical failures occur. This preliminary action eliminates the need for expensive remedial operations by ensuring the cement structure is inherently more resistant to cracking and mechanical failure from the start.
3Manufacturing precision
If elastomer particles are heated above melting point to infiltrate defects, then crack sealing is improved, but energy consumption increases
Solution Approach 1:
The repair method utilizes the phase transition of elastomer particles from solid to liquid state by heating them above their melting point. This allows the elastomer to flow into and infiltrate defects and cracks within the cement structure. After infiltration, cooling restores the elastomer to solid state, sealing the defects. The process leverages natural phase change properties to achieve precise defect filling with controlled energy input.
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
The repaired cement structures exhibit improved mechanical properties, such as low permeability and high compressive strength, effectively preventing further damage and ensuring wellbore integrity.
Implementation Method 1
applying heat to the cement structure to heat at least a portion of the elastomer particles above a melting point of an elastomer of the elastomer particles to cause at least a portion of the elastomer to melt and infiltrate into a defect in the cement structure
Implementation Method 2
allowing the elastomer to cool below the melting point of the elastomer to yield a repaired cement structure
Data Source
AI summary
A self-healing cement structure may be used for repairing defects. An example method of using such a cement structure includes: providing a cement structure in a wellbore, wherein the cement structure includes: a cement and elastomer particles at 1% by weight of the cement (bwoc) to 25% bwoc; applying heat to the cement structure to heat at least a portion of the elastomer particles above a melting point of an elastomer of the elastomer particles to cause at least a portion of the elastomer to melt and infiltrate into a defect in the cement structure; and allowing the elastomer to cool below the melting point of the elastomer to yield a repaired cement structure.