基于堵漏风测试系统的凝胶颗粒封堵性能实验研究

Experimental Study on Plugging Performance of Gel Particles Based on Air Plugging and Leakage Testing System

摘要: 本文通过自构建的堵漏风测试系统，聚焦凝胶颗粒在煤体裂缝封堵方面的性能展开深入研究。主要分析了凝胶颗粒的封堵机理，通过自制的堵漏风测试系统对凝胶颗粒的封堵特性和颗粒粒径与孔喉之间的匹配关系进行研究，从而得到凝胶颗粒粒径与孔喉直径的最佳封堵匹配关系。通过单、多凝胶颗粒的封堵作用力分析，总结了凝胶颗粒封堵机理并点出相应的注意点，同时对凝胶颗粒的封堵性能进行了研究，明确凝胶颗粒的封堵过程就是凝胶颗粒在煤体的裂缝、孔喉中不断滞留、挤压突破、堆积、架桥、沉降聚集、挤压填充、封堵成墙的过程。由此可以通过分析得知封堵墙是由单个或多个凝胶在孔喉位置的一种堵塞形式，封堵位置可能位于孔喉前端或孔喉处。当凝胶颗粒在孔喉前端进行封堵时，会减弱浆液–颗粒流作用力、颗粒之间作用力和自身重力等作用力的突破效果，从而减少封堵墙因作用力太大导致其变形失稳甚至崩塌现象的出现。由于凝胶颗粒并非刚性颗粒，所以当其受力形变后会导致力的矢量位移，进而导致封堵失效，但是若凝胶颗粒具有很高的形变能力就可以顺利通过孔喉，从而到达下一处裂缝或孔喉进行有效封堵。通过实验反复论证得出结论：可以通过提高凝胶颗粒的堆积度来避免封堵墙失稳甚至崩塌现象的发生，进而实现对煤体裂缝、孔喉的有效封堵。

Abstract: This paper focuses on the performance of gel particles in the sealing of coal fractures through the self built air leakage test system. This paper mainly analyzes the plugging mechanism of gel particles, and studies the plugging characteristics of gel particles and the matching relationship between particle size and pore throat diameter through a self-made plugging and leakage test system, so as to obtain the optimal plugging matching relationship between gel particle size and pore throat diameter. Through the analysis of the plugging force of single and multiple gel particles, the plugging mechanism of gel particles is summarized and the corresponding points for attention are pointed out. At the same time, the plugging performance of gel particles is studied. It is clear that the plugging process of gel particles is the process of continuous retention of gel particles in the cracks and pore throats of coal, extrusion breakthrough, accumulation, bridging, settlement accumulation, extrusion filling and plugging into walls. From this, it can be known through analysis that the plugging wall is a form of plugging by single or multiple gels at the pore throat, and the plugging position may be located at the front end of the pore throat or at the pore throat. When the gel particles are plugged at the front of the pore throat, the breakthrough effect of the forces such as the force of slurry particle flow, the force between particles and their own gravity will be weakened, so as to reduce the deformation, instability and even collapse of the plugging wall caused by too large force. Because the gel particles are not rigid particles, the force vector displacement will be caused when they are deformed by force, which will lead to plugging failure. However, if the gel particles have high deformation ability, they can smoothly pass through the pore throat, so as to reach the next crack or pore throat for effective plugging. Through repeated experiments, it is concluded that the instability and even collapse of the sealing wall can be avoided by increasing the stacking degree of gel particles, so as to realize the effective sealing of coal cracks and pore throats.