煤矿隐蔽致灾地质体地震绕射波探测方法

Seismic diffraction detection method for geological hidden disasters in coal mining

  • 摘要: 小尺度断层和陷落柱等隐蔽致灾地质体破坏煤层的连续性,易诱发瓦斯突出和采空区突水等事故,严重威胁煤矿生产安全。传统地震勘探方法以反射波为主,对隐蔽致灾地质体分辨率有限。本文提出基于曲波稀疏变换和平面波分解的多参数稀疏优化绕射波分离方法,能够解决在地震波场相交和相切情况下绕射波分离问题,并且分离的绕射波具有波形一致性和完整性。三维数值模拟测试结果表明,该方法能够有效消除强反射波对弱信号的屏蔽作用,分离出完整的绕射波/散射波,提高断层断点和散射点成像精度,其中极性反转成像特征可用于区分不同类型小尺度地质构造。山西阳泉煤业二矿九采扩区实际数据应用证实,本文提出的方法能够有效去除煤层强反射信息屏蔽作用,叠加剖面中绕射波的双曲形态可以质控绕射波分离可靠性。在利用绕射波成像资料解释时,结合反射波场成像结果提供的宏观地质背景,可更好揭示隐蔽致灾地质体,两者相辅相成。绕射波成像对陷落柱的边界形态和内部结构刻画更为清晰,对小尺度断裂的展布规律描述更准确,是一种高分辨率的地震波成像方法,在隐蔽致灾地质体探测上具有很大潜力,一定程度上为我国煤矿安全高效开采提供技术支撑。

     

    Abstract: The geological hidden disaster-causing bodies such as small-scale faults and collapsed columns may destroy the continuity of the coal seam, which will lead to accidents such as gas outburst and water outburst in the air mining area, and seriously threaten the coal mining safety.Traditional seismic exploration methods are mainly involved with reflected waves that have a limited resolution and cannot effectively identify them.A multi-parameter sparse optimization diffraction separation method in the shot domain is proposed that is based on curvelet sparse transformation and plane-wave decomposition.It can solve the problem of diffraction separation in the interfering or tangency cases and the separated diffractions have a waveform consistency and integrity.The 3D numerical modeling and simulation test results show that the proposed method can effectively eliminate the shielding effect of strong reflections, separate the complete diffracted/scattered wave, and improve the imaging accuracy of fault edges and scattering points, where the imaging features of polarity reversal can be used to distinguish different types of small-scale geological structures.The field data of Shanxi Yang Erkuang coal mine confirmed that the proposed method can effectively remove the shielding effect of strong reflections from coal seam, and the hyperbolic forms of diffractions in the stacked profile can qualitatively control its reliability.For seismic diffraction interpretation, full-wave field imaging results are generally required to provide a macroscopic geological background and the diffraction imaging results are combined to reveal hidden disaster-induced geological bodies.The diffraction image of collapsed column boundaries and their insider characterization is clearer, and the exhibition of small-scale fractures is more powerful.It is a high-resolution imaging method and has a great potential in detecting hidden disaster geological bodies, which can provide a technical guarantee for coal mine safety and efficient mining in China.

     

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