Latex Cement Additives with Dual Elastomer Phases for Downhole Stress Resistance
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Solution Overview
Problem
Current cement compositions used in downhole environments are inadequate in resisting cyclic stresses and sudden impacts, and lack effective self-healing properties, leading to cracks and fractures that compromise zonal isolation and require costly remedial operations.
Innovation Solution
The development of latex cement additives comprising an aqueous latex with a solid elastomer and a liquid elastomer of specific viscosity, along with a surfactant, which enhances the mechanical properties of cement by reducing brittleness, providing stress-resistant and self-sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cement compositions are used, then the cement setting and zonal isolation are achieved, but the cement lacks resistance to cyclic stresses and sudden impacts, leading to cracks and fractures
Solution Approach 1:
The patent applies composite materials by incorporating both solid elastomer particles (0.1-5 wt%) and liquid elastomer (5-20 wt%) into the cement composition. The solid elastomer particles provide structural reinforcement and stress distribution, while the liquid elastomer provides flexibility and stress absorption. This dual-phase elastomer composite structure enables the cement to resist cyclic stresses and sudden impacts, directly resolving the contradiction between reliability under stress and overall strength.
Solution Approach 2:
The patent changes the physical and chemical parameters of the cement composition by introducing elastomers with specific properties: solid elastomer particle size (0.1-5 wt%), liquid elastomer viscosity (50,000-300,000 cP), and surfactant concentration (0.1-5 wt%). These parameter modifications transform the cement from a brittle material to a ductile composite that can accommodate cyclic loading and impact events without cracking, thereby improving both strength and stress resistance.
2Reliability
If particulate elastomers are included to improve cyclic stress resistance, then the solution is simpler, but poor adhesion between cement and liquid elastomer occurs
Solution Approach 1:
The patent uses surfactants as intermediary agents to bridge the cement matrix and liquid elastomer phase. The surfactants (0.1-5 wt%) reduce interfacial tension and improve wetting between the hydrophilic cement and hydrophobic elastomer, ensuring stable adhesion. This intermediary mechanism prevents phase separation and maintains compositional stability while preserving the cyclic stress resistance benefits of the elastomer addition.
Solution Approach 2:
The patent optimizes the concentration parameters of surfactants (0.1-5 wt%) and liquid elastomer (5-20 wt%) to achieve optimal adhesion. By adjusting these parameters, the patent ensures sufficient surfactant coverage at the cement-elastomer interface to maintain stable bonding, preventing the poor adhesion issue while preserving the mechanical performance benefits.
3Reliability
If foamed cement slurries are used to improve cyclic stress resistance, then the resistance is enhanced, but highly specialized equipment such as cryogenic equipment is required
Solution Approach 1:
The patent replaces expensive, specialized cryogenic equipment with conventional mixing and delivery equipment. The elastomer-based cement composition can be mixed and pumped using standard wellsite equipment, eliminating the need for complex cryogenic systems. This approach achieves cyclic stress resistance through material composition rather than complex equipment, significantly reducing device complexity while maintaining reliability.
Solution Approach 2:
The patent changes the physical state and composition parameters of the cement by incorporating liquid elastomer (50,000-300,000 cP) and solid elastomer particles, creating a ductile composite that resists cyclic stresses. This material-based solution achieves the same protective function as foamed cement but without requiring specialized equipment, thereby reducing device complexity while maintaining the desired mechanical performance.
4Reliability
If cement compositions are modified to be more ductile and less brittle, then stress resistance is improved, but the cement may exhibit phase separation in the slurry
Solution Approach 1:
The patent employs surfactants as intermediary agents to stabilize the slurry composition and prevent phase separation. The surfactants (0.1-5 wt%) form a protective interface between the liquid elastomer and aqueous cement phases, maintaining homogeneous distribution during mixing and pumping. This intermediary mechanism ensures stress resistance through elastomer incorporation while preventing the harmful effect of phase separation.
Solution Approach 2:
The patent optimizes the concentration parameters of surfactants (0.1-5 wt%) and elastomers to achieve the right balance between stress resistance and slurry stability. By carefully controlling these parameters, the patent ensures sufficient elastomer content for mechanical performance while maintaining surfactant levels that prevent phase separation, achieving both goals simultaneously.
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 latex cement additives improve the tensile and compressive strength of cement, reduce brittleness, and enable self-healing, thereby enhancing the durability and zonal isolation of cemented zones under downhole conditions, reducing the need for frequent remedial operations.
Implementation Method 1
a surfactant operable to facilitate incorporation of the liquid elastomer into the aqueous latex
Implementation Method 2
The cement slurry upon setting can isolate the cemented formation zones and can prevent fluid communication... the cement may develop cracks and fractures... the latex cement additives improve the tensile and compressive strength of cement, reduce brittleness, and enable self-healing
Data Source
AI summary
A composition for use as a latex cement additive, the composition comprising an aqueous latex, the aqueous latex comprising an aqueous fluid and a solid elastomer, where the solid elastomer is dispersed in the aqueous fluid; a liquid elastomer, the liquid elastomer having a viscosity between 50,000 cP and 300,000 cP at room temperature; and a surfactant, the surfactant operable to facilitate incorporation of the liquid elastomer into the aqueous latex.