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深部煤层群井上下联合逐级递进防突方法与关键技术

Method and key technologies of underground and surface combined stepwise progressive anti-outburst for deep coal seam groups

  • 摘要: 现代化高产高效矿井仍面临抽掘采接替紧张的局面,对防突技术治理的区域范围、超前时间提出更高要求,为突破现有瓦斯治理技术体系在近/远距离煤层群协同抽采、井上下逐级防突方面的瓶颈,系统阐述了井上下联合“时空抽采、逐级递进”防突原理,构建了“地面超前预抽降突–井下强化抽采消突–多煤层协同治理”的立体防控方法,融合地面井时空超前优势与井下作业精准控制能力,形成矿井级区域预控、采区级协同治理、工作面级精准消突的3级递进防控体系,针对近、远距离煤层群不同特征,分别提出“地面井广覆盖、井下高效抽”和“井下强化卸压、地面井多源抽”防突模式。综合运用数值模拟、理论分析和现场试验方法,系统构建了以主井与分支井夹角、分支井数量等为关键要素的多分支水平井参数优化技术,形成了融合水平井钻头空间磁场感应模型与高精度传感器数据的地面多分支井与井下定向钻孔对精准对接技术,分析了应力场–裂隙场–瓦斯渗流场3场耦合演化规律,揭示了深部煤层瓦斯富集靶区分布特征,结合地质条件与抽采时空衔接需求,提出了“单井区域最大化”与“全区密集型”多源井群协同布置模式。近距离煤层群高效抽采技术在沙曲一号煤矿应用,实现SQN–0501三口多分支水平井抽采1 a总产气量7 273 175.4 m3,日均产气量约2万m3;远距离煤层群卸压抽采关键技术在朱集西煤矿的应用表明,地面井累计抽采13–1煤层卸压瓦斯728.3万m3,抽采率高达81.4%,瓦斯含量显著降低。近、远距离煤层群井上下联合防突技术体系的成功应用验证了该技术体系在提升瓦斯抽采效率、降低突出风险方面的有效性,为深部煤层群安全开采提供了重要技术支撑。

     

    Abstract: Modern high-yield and high-efficiency mines still face the situation of tight replacement among roadway driving, mining and extraction, and put forward higher requirements for the regional scope and advanced time of outburst prevention and control technology. In order to break through the bottlenecks of the existing gas control technology system in the coordinated extraction of near/far coal seam groups and the step-by-step outburst prevention both on the surface and underground, the principle of “spatiotemporal extraction and step-by-step progression” for outburst prevention with the combination of surface and underground operations is systematically expounded. A three-dimensional prevention and control method of “surface advanced pre-extraction for outburst reduction – underground enhanced extraction for outburst elimination – coordinated governance of multiple coal seams” is constructed. By integrating the advantages of spatiotemporal advance of surface wells and the precise control ability of underground operations, a three-level progressive prevention and control system of mine-level regional pre-control, mining area-level coordinated governance and working face-level precise outburst elimination is formed. According to the different characteristics of near and far coal seam groups, the outburst prevention modes of “wide coverage by surface wells and efficient extraction underground” and “enhanced pressure relief underground and multi-source extraction by surface wells” are respectively proposed. By comprehensively using numerical simulation, theoretical analysis and field test methods, a parameter optimization technology for multi-branch horizontal wells with key elements such as the angle between the main well and branch wells and the number of branch wells is systematically constructed. A precise docking technology between surface multi-branch wells and underground directional boreholes is formed by integrating the spatial magnetic field induction model of horizontal well bits and the data of high-precision sensors. The coupling evolution law of the stress field, fracture field and gas seepage field is analyzed, and the distribution characteristics of gas enrichment target areas in deep coal seams are revealed. Combined with the geological conditions and the requirements of the spatiotemporal connection of extraction, the collaborative layout modes of “maximization of a single well area” and “intensive layout in the whole area” for multi-source well groups are proposed. The high-efficiency extraction technology for near coal seam groups is applied in Shaqu No.1 Coal Mine. The total gas production of three multi-branch horizontal wells SQN–0501 after one-year extraction is 7 273 175.4 m3, with an average daily gas production of about 20 000 m3. The key technology of pressure relief extraction for far coal seam groups is applied in Zhuji West Coal Mine. The surface wells have cumulatively extracted 7.283 million m3 of gas from the No.13–1 coal seam, with an extraction rate as high as 81.4%, and the residual gas content is significantly reduced. The effectiveness of this technical system in improving gas extraction efficiency and reducing outburst risks is verified, providing important technical support for the safe mining of deep coal seam groups.

     

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