基于蠕变变形的顺煤层钻孔筛管封孔技术研究

针对顺煤层抽采钻孔在抽采过程中由于钻孔断面变形缩小导致抽采流量和浓度低下的问题,采用FLAC^3D软件构建基于蠕变规律的钻孔煤体形变模型,对比分析常规和预置筛管钻孔周围煤体的蠕变位移和塑形区变化情况;提出预置筛管抽采封孔技术以提高孔壁支护力、改善钻孔抽采断面,并进行工业验证。研究表明:顺层抽采钻孔完孔后,孔壁受环向压力的影响,钻孔周围煤体呈现出向钻孔方向蠕变挤压特性,而且筛管钻孔相较常规钻孔形变量明显变小;现场采用预置筛管抽采封孔技术后,相较常规封孔技术,抽采65天时钻孔抽采量提高191%,抽采浓度提高137%,抽采效率提高显著。

Research on sealing technology of screen pipe based on creep deformation

In order to solve the problem of low extraction flow rate and concentration caused by borehole deformation in the process of extraction, the FLAC^3Dsoftware was used to build a deformation model of coal body around the borehole based on creep law, and the creep displacements and plastic-zone shape change of coal body around conventional and preset screen pipe were compared and analyzed. The technology of sealing hole inner screen extraction was put forward to improve the borehole support force and ensure the borehole extraction section, and the industrial test was carried out. The results show that after the completion of the borehole, the hole wall is affected by the circumambient pressure, and the coal body presents the creep pressing characteristics towards the direction of borehole, that compared with conventional borehole, the shape variable of sieve tube drilling is obviously smaller, and that after adopting the sealing technology of preset screen pipe extraction, on the 65 day of extraction, the volume of extraction increases by 191% and concentration increases by 137% compared with the conventional sealing technology, and the extraction efficiency is significantly improved.