Scour-Resistant Interface Enhancer for Coalbed Methane Well Cementing
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Solution Overview
Problem
The poor cementing quality between coalbed methane wells and inorganic cement slurry due to the contradiction between the lipophilicity of coalbed surfaces and hydrophilicity of cement slurry leads to gas accidents, well collapse, leakage, low extraction volume, and pollution, necessitating improved wettability modification and scour resistance.
Innovation Solution
A scour-resistant interface enhancer composed of 0.1% surfactant CAEO-15 and 0.3% silane coupling agent in a clear water and absolute ethanol solution, which modifies the coal rock surface from oil-wet to completely water-wet and enhances scour resistance, maintaining water-wet characteristics even after cement slurry contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wettability modification is applied to coal bed surface, then cementing quality between coal bed and cement slurry is improved, but scour resistance of the modified surface deteriorates
Solution Approach 1:
The invention uses a composite interface enhancer containing both surfactant (for wettability modification) and silane coupling agent (for scour resistance). This composite approach allows the surfactant to modify the coal bed surface wettability while the silane coupling agent forms a protective layer that resists scouring by cement slurry, thereby simultaneously achieving both improved cementing quality and maintained scour resistance
Solution Approach 2:
The invention changes the chemical parameters of the interface enhancer by incorporating silane coupling agent alongside surfactant. The silane coupling agent undergoes hydrolysis and condensation reactions to form a cross-linked protective layer on the coal bed surface, fundamentally altering the surface properties to provide both water-wetness and scour resistance
2Reliability
If surfactant is used to modify wettability, then water-wet characteristics are achieved, but scour resistance against cement slurry is reduced
Solution Approach 1:
The silane coupling agent acts as an intermediary substance between the surfactant-modified coal bed surface and the cement slurry. It forms a protective intermediate layer that preserves the water-wet characteristics created by the surfactant while providing resistance against the harmful scouring action of the cement slurry
3Reliability
If pre-flush is applied for wettability modification, then cementing quality is improved, but secondary impact of cement slurry displacement and scouring reduces the effectiveness
Solution Approach 1:
The invention applies preliminary action by incorporating the silane coupling agent into the interface enhancer before cementing operations. The silane coupling agent pre-forms a protective layer on the coal bed surface that anticipates and prepares the surface against the upcoming scouring action of cement slurry displacement, thereby extending the duration of effective wettability modification
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
Significantly improves cementing quality, shear strength, and air tightness between coalbed interfaces, demonstrating good compatibility with cement slurry and sustained wettability modification and scour resistance.
Implementation Method 1
the surfactant CAEO-15 increases the wettability modification effect on the coal rock surface and allows the coal rock surface to be completely water-wet
Implementation Method 2
the addition of appropriate ethanol to water can ensure the effective hydrolysis of the silane coupling agent to produce silanol
Implementation Method 3
The silane coupling agent increases the scour-resistance effect of the coal rock surface so that the coal rock surface can stay water-wet after being scoured by cement slurry
Implementation Method 4
Absolute ethanol provides a stable environment for the silane coupling agent, and the addition of appropriate ethanol to water can ensure the effective hydrolysis of the silane coupling agent to produce silanol and prevent the reverse reaction of the generated silanol
Data Source
AI summary
A scour-resistant interface enhancer, a preparation method, and an application thereof are provided. The scour-resistant interface enhancer is a compound solution prepared by using a 0.1% surfactant CAEO-15 and a 0.3% silane coupling agent as solutes and using clear water and absolute ethanol as solvents, where the mass ratio of clear water to absolute ethanol is 9:1. The scour-resistant interface enhancer of the present invention used as pre-flush for well cementing of coalbed methane wells has good wettability modification effect, shows scour-resistant effect against cement slurry, exhibits good compatibility with cement slurry system, and can significantly improve the cementing strength and air tightness of two interfaces of coal bed and effectively enhance the cementing quality of coalbed methane wells.