顺煤层钻孔约束的采煤工作面煤层迭代高精度建模方法研究

Iterative refined model of coal seam in longwall panel with constraints of in-seam boreholes

针对地表勘探钻孔水平间距大、采煤工作面中部缺乏地面钻孔控制、煤层建模精度低等问题,提出了一种顺煤层钻孔约束下的采煤工作面煤层迭代高精度建模方法,并开展了现场实证实验。该方法采用“测斜-自然伽马-钻孔电视”一体化测井仪测量顺煤层钻孔轨迹、探测煤层顶底板点;基于巷道测量、煤层厚度反演成果及地面钻孔等数据插值构建初始煤层顶底板模型,检测顺煤层钻孔煤、岩孔段与顶底板模型之间的“非逻辑交点”,并据此动态引入“虚拟顶底板点”,迭代更新顶底板模型。当顺煤层钻孔与迭代模型之间不存在“非逻辑交点”时,所构建的煤层模型严格满足各类地质数据的空间约束。模拟实验结果表明:参数z坐标调整量取平均煤层厚度的1/3~2/3时,顶底板建模精度最高;随着顺煤层钻孔密度的降低,建模精度降低,且下降速率逐渐减小。黄陵某煤矿810工作面现场实验表明:相较于以巷道测量为主要数据所构建的工作面模型,迭代构建的煤层模型实现了煤层厚度、顺煤层钻孔轨迹、地面钻孔和巷道测量等数据的深度融合,模型精度大幅度提升。迭代建模方法充分利用工作面数量众多的顺层瓦斯抽采钻孔,对工作面中部煤层起伏形态进行约束,提升了工作面煤层建模精度,是一种构建高精度采煤工作面煤层模型的潜在方法。

Currently,the coal seam model is in low accuracy due to the large horizontal spacing of surface exploration boreholes and the lack of surface borehole in the middle of longwall panel.Therefore,an iterative refined model of coal seam with the constraint of in-seam boreholes was proposed,and the field test was carried out.First of all,the borehole trace,and coal seam roof and floor points are surveyed using“inclination-gamma-TV”integrated logger.Then,an initial coal seam model is constructed based on the roadway surveying,coal seam thickness of in-seam seismic survey(ISS),and surface boreholes.Subsequently,the abnormal intersections between the coal seam floor and roof models and the coal and rock borehole segments are detected.Finally,the virtual roof and floor points are introduced dynamically and the coal seam model are updated iteratively.The coal seam model strictly satisfies the spatial constraints of various geological data when there is no abnormal intersection between the in-seam borehole and the iterative model.The simulation test shows that the roof and floor modelling accuracy is in highest when the parameter z-coordinate adjustment is 1/3~2/3 of the average thickness of coal seam.In addition,the modeling accuracy decreases and the rate decreases gradually with the decrease of logged in-seam boreholes.The field test in a coal mine located in Huangling shows that the coal seam modelling accuracy of the proposed iterative modelling method increases dramatically compared to the model mainly constructed with the roadway surveying.The iterative coal seam model realizes the deep fusion of various geological data,including the ISS coal seam thickness,in-seam borehole traces,surface boreholes,and roadway surveying.The proposed iterative modeling method makes full use of numerous gas drainage in-seam boreholes to predict the fluctuation form of coal seam in the middle of longwall panel.It could be a method for constructing high-precision coal seam model of longwall panel.