基于颗粒级配的密封黏液制备及应用

Preparation and application of sealing mucus based on particle gradation

为了解决瓦斯抽采钻孔围岩次生裂隙漏风而引起抽采后期瓦斯浓度急剧降低的难题,现场实测了钻孔周边煤岩裂隙及其尺度的分布特征,提出了裂隙封堵的颗粒级配黏液封堵材料制备方法。通过优选固相颗粒,同时以羧甲基纤维素钠为主料,以聚丙烯酸钠、明胶等为辅料制备了内掺级配颗粒的封堵黏液,测定了新型封堵材料的黏度、保水率、膨胀性等特性参数,并在现场进行了应用验证。结果表明,该新型内掺级配颗粒的黏液封孔材料稳定性好、黏性适中易注浆、膨胀率大,且与煤壁润湿接触性好。现场应用显示,相较于水泥基封孔材料可将钻孔平均瓦斯抽采浓度提高近40%。以此为基础,探讨了级配黏液对裂隙的封堵机理主要在于颗粒的桥堵堆积、支撑作用、膨胀堵塞及黏液滞留效应。

To solve the problem of the sharp reduction of gas concentration in the later stage of gas drainage caused by air leakage from the secondary fissures in the surrounding rock of gas drainage boreholes.The distribution characteristics of coal-rock fissures and their scales around the borehole were measured on site.And a preparation method of particle graded mucus sealing materials for fissure sealing were proposed.By optimize selecting solid phase particles and using sodium carboxymethyl cellulose as main material,sodium polyacrylate and gelatin as auxiliary materials,the sealing mucus with mixed graded particles was prepared.The viscosity,water retention and expansibility of the new sealing material were measured,and its application was verified in the field.The results show that the new type of viscous sealing material with mixed graded particles present good stability,moderate viscosity,easy grouting,large expansion rate,and good wettability with coal wall.The field application shows that the average gas drainage concentration of boreholes using this material can be increased by about 40%compared with cement-based sealing materials.Based on these results,the sealing mechanism of mucus with graded particles on the fissures is mainly due to the bridging accumulation of particles,supporting effect,swelling plugging and mucus retention effects.