Core-Shell Self-Healing Composition for Well Cement Microfissure Repair
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Solution Overview
Problem
Existing well cementing technologies face challenges with high operation risks, low success rates, and high costs, and the self-healing agents used in oil and gas fields suffer from poor heat resistance and durability, limiting their effectiveness in maintaining long-term seal integrity.
Innovation Solution
A composition comprising hydrogenated styrenic thermoplastic elastomer, inorganic filler, and a hydrophilic polymer is used to create a self-healing agent with a core-shell structure, providing high oil and gas absorption, heat resistance, and durability, ensuring compatibility with cement slurry and enhancing bonding forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stimulus-responsive type polymer technology is used for self-healing, then self-healing effect is achieved, but heat resistance and durability are poor
Solution Approach 1:
The patent applies parameter changes by hydrogenating the styrenic thermoplastic elastomer to modify its chemical structure and properties. This hydrogenation process changes the physical and chemical parameters of the polymer, improving its heat resistance and durability while maintaining the self-healing function through oil and gas absorption expansion.
Solution Approach 2:
The patent uses composite materials by combining hydrogenated styrenic thermoplastic elastomer with inorganic filler and hydrophilic polymer in a core-shell structure. This composite structure integrates the self-healing capability of the elastomer with the heat resistance and durability provided by the inorganic filler and hydrophilic polymer coating.
2Ease of repair
If existing self-healing agents are used, then self-healing function is provided, but service life is limited due to poor durability
Solution Approach 1:
The patent changes the chemical parameters of the polymer through hydrogenation, which improves the molecular stability and resistance to degradation. This parameter change extends the service life of the self-healing agent by enhancing its durability against chemical erosion and thermal stress.
Solution Approach 2:
The patent employs composite materials with a core-shell structure where the hydrogenated styrenic thermoplastic elastomer core provides self-healing function and the hydrophilic polymer shell with inorganic filler provides durability and heat resistance. This composite structure simultaneously achieves long-term service life and effective self-healing.
3Quantity of substance
If polymer material is used for self-healing, then oil and gas absorption expansion occurs, but bonding force and heat resistance are insufficient
Solution Approach 1:
The patent uses composite materials with a core-shell structure where the hydrogenated styrenic thermoplastic elastomer core provides oil and gas absorption expansion and the hydrophilic polymer shell with inorganic filler enhances bonding force and heat resistance. The core-shell structure allows both functions to work together synergistically.
Solution Approach 2:
The patent applies local quality by having different regions of the self-healing agent perform different functions: the core region (hydrogenated styrenic thermoplastic elastomer) is optimized for oil and gas absorption, while the shell region (hydrophilic polymer with inorganic filler) is optimized for bonding force and heat resistance. This spatial differentiation of properties resolves the contradiction.
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 self-healing agent effectively expands upon oil and gas contact, uniformly dispersing in cement slurry to repair micro-fissures, improving long-lasting sealing and reducing elasticity modulus, thus enhancing the durability and self-healing capability of cement annulus.
Implementation Method 1
a composition having a density of 1.2-2 g/cm3, a water contact angle not more than 90°, preferably less than 85°, and a diesel oil and/or natural gas absorption expansion ratio of 5-15 times, preferably 8-12 times
Implementation Method 2
coating the pellets obtained in step (1) with a hydrophilic polymer to obtain a granular material
Data Source
AI summary
Described are a self-healing composition, and a preparation method for and an application of the composition. The composition is of a core-shell structure; the core contains a hydrogenated styrenic thermoplastic elastomer polymer and an inorganic filler; the shell contains a hydrophilic polymer; the composition has a density of 1.2-2 g/cm3, a water contact angle of no more than 90°, and a diesel oil and/or natural gas absorption expansion ratio of 5-15 times. By coating the hydrogenated styrenic thermoplastic elastomer and the inorganic filler with the hydrophilic (surface polarized) polymer, a core-shell structure is formed. When the composition is used for well cementing in an oil/gas field, the composition has a density and compatibility matching cement mortar and thus can form a uniform and stable cement slurry for well cementing in the oil/gas field, and has excellent oil/gas absorption expansion performance and thus can expand after absorbing oil/gas to perform self-healing.