黄陇煤田厚层砂岩水害精准注浆防治水技术研究

Research on water control technology of precise grouting in thick sandstone water damage in Huanglong coalfield

近年来,随着我国西部侏罗纪煤炭资源的大规模开发利用,煤层顶板水害影响与威胁日益显现。为阻截煤层上覆含水层中水下泄,以实现井下目标区域内堵水、减水,提出了一种秉持“保水采煤”理念,以精细探查为基础,以精准注浆为主要工程手段的厚层砂岩水害顶板防治水技术方法,并在黄陇煤田高家堡煤矿进行了应用。首先,优选出了自然伽马曲线(GR)为能够区分研究区砂、泥岩的敏感曲线,利用波形指示反演精细解释了煤层上覆岩层的岩性展布形态。在岩性解释的基础上结合抽水试验结果,分析了研究区上覆地层不同含水层的响应特征,综合岩性、泥质含量(VSH)、自然电位(SP)以及孔隙度(POR)刻画了煤层上覆地层的富水性分布特征,解释成果表明对煤层开采隐患最大的为洛河组中段(K_(1)lm)上层,该区域岩层主要为中粗粒砂岩,为中等−强富水含水层。然后,利用多属性融合技术对煤层上覆岩层中原生裂隙进行了精细刻画,在纵向上的展布规律具有断续分布特点,且发育具有分段性特征,相对集中分布在洛河组中下段,在平面上,裂隙主要发育方向为NW-NWW,以井27-2为界限,上部裂隙较发育。最后,综合考虑煤层上覆岩层岩性、富水性和原生裂隙分布特征以及导水裂隙带发育高度预测结果,选择对洛河组中段底部通过水平孔进行注浆,加固薄弱地层,阻滞洛河组中、上段水量下泄。经过地面预注浆治理后,204工作面推采过程中涌水量减少超过1000 m^(3)/h。同时,改善了生产条件,比相邻工作面多回收35万t煤炭资源,为治理黄陇煤田厚层砂岩水害提供了一种可行的办法。

In recent years,with the large-scale development and utilization of Jurassic coal resources in western China,the impact and threat of water damage to the coal seam roof has become increasingly apparent.In order to stop the water leakage in the overlying aquifer of the coal seam and to reduce the water inflow in the target area,a technical method for preventing and controlling water in the roof of thick sandstone flood damage is proposed.This method adheres to the concept of“water-preserving coal mining”,is based on fine exploration,takes precise grouting as the main engineering method,and has been applied in Gaojiapu Coal Mine in Huanglong Coalfield.First,the natural gamma curve(GR)is selected as a sensitive curve that can distinguish sand and mudstone in the study area,and the lithological distribution pattern of the overlying strata of the coal seam is precisely interpretated by the waveform indication inversion.On the basis of lithologic interpretation and pumping test results,the response characteristics of different aquifers in the overlying strata in the study area are analyzed.The water-rich distribution of the overlying strata of the coal seam is characterized by combining lithology,shale content(VSH),spontaneous potential(SP),and porosity(POR).The interpretation results show that the most hidden danger to coal seam mining is the upper layer of the middle section of the Luohe Formation(K1lm).The rock formations in this area are mainly medium-coarse-grained sandstone,which is a medium-strong water-rich aquifer.Then,the primary fissures in the overlying strata of the coal seam are finely described by using the multi-attribute fusion technology.The distribution law in the longitudinal direction has the characteristics of intermittent distribution,and the development has the characteristics of segmentation,and it is relatively concentrated in the middle and lower members of the Luohe Formation.On the plane,the main development direction of fractures is NW-NWW.With the well 27-2 as the boundary,the upper fractures are relatively developed.Finally,considering the lithology,water-rich and primary fracture distribution characteristics of the overlying strata of the coal seam and the prediction results of the development height of the water-conducting fracture zone,the bottom of the middle section of the Luohe Formation is selected to be grouted through horizontal holes.The project can strengthen the weak stratum and block the water discharge in the middle and upper sections of the Luohe Formation.After surface pregrouting treatment,the mine water inflow is reduced by more than 1000 m^(3)/h during the mining process of the 204 working face.At the same time,the production conditions are improved and 350000 tons more coal resources are recovered than the adjacent working faces,which provides a feasible method for controlling the water damage of thick sandstone in Huanglong Coalfield.