天然源槽波勘探的可行性研究

常规炸药震源在高瓦斯矿井受到了十分严格的管制,迫切需要一种新型非炸药震源的槽波勘探方法作为替代。基于此,开展了矿井中天然源槽波勘探方法的可行性实验研究。通过理论分析和数值模拟实验,论证了煤层具备天然源槽波发育的地球物理基础。通过构建“三随机”天然源槽波模型,即震源的空间位置随机、震源初始激发时刻随机和震源的振幅随机,成功实现了天然源槽波的时间域数值模拟实验。采用相移法对天然源槽波数值模拟数据进行了频散谱计算,结果具有明显的频散特征。数值模拟实验结果证明了理论模型中天然源槽波的存在,且基阶和高阶形态均发育。在安徽淮南某煤矿工作面进行实测实验,成功采集到天然源槽波三分量数据,对实测数据进行频散谱计算,结果表明3个分量均具备频散特征,其中X分量频散曲线能量脊较为清晰,达到了验证天然源槽波存在的预期目标。总的来说,数值模拟结果表明天然源槽波的地球物理基础和形成机理是正确的,现场实验结果证明了天然源槽波在煤层中自然存在,该方法在矿井地质勘探中具有可行性和潜力。

Feasibility study of nature source in-Seam exploration

The conventional explosive seismic sources are very tightly controlled in high-gas mine, and a novel non-explosive channel wave method is urgently needed as an alternative. Therefore through the theoretical analysis and numerical simulation experiments, we demostrated that the coal seam satisfied the geophysical conditions to develop the nature source in-seam wave. The time-domain numerical simulation experiment of the passive source channel wave was successfully realized by constructing the nature source in-seam wave model with three stochastic terms, including the stochastic spatial position, stochastic initial excitation time and stochastic amplitude of seismic source. We performed frequency dispersion spectrum calculation on the numerical simulation data of nature source in-seam wave using the phase shift method, and the result shows the obvious frequency dispersion characteristics. Moreover, the numerical simulation results demonstrate the existence of nature source in-seam wave in theoretical models, and the development of both fundamental and higher order morphology. Specifically, a field experiment was conducted in the working face of a coal mine in Huainan, Anhui, to successfully collect the data of three components of the nature source in-seam wave, and frequency dispersion spectrum of the measured data was calculated. The calculation results indicate that the three components have the characteristics of frequency dispersion amony which the energy ridge of the frequency dispersion curve of X component is relatively clear. In general, the numerical simulation results show that the geophysical foundation and mechanism of development of nature source in-seam wave is correct. Moreover, the field experimental results confirm the natural existence of nature source in-seam wave in the coal seam, and this method has the feasibility and potential for mine geological exploration.