煤田三维地震综合解释技术在复杂地质条件下的应用

3D COALFIELD SEISMIC INTEGRATED INTERPRETATION TECHNIQUE IN COMPLEX GEOLOGICAL CONDITION

常规的煤田三维地震解释以时间域运动学信息为主,适用于地质条件不太复杂的情况。如果把这种方法应用于复杂的地下地质构造,则会因为信息量小降低解释的精度和可靠性。多信息、多学科相融合,即地震运动学和动力学相结合,地震与地质、测井多学科相结合,时间域和深度域相结合的综合解释技术是提高复杂地质条件解释精度的重要手段。地震属性技术、三维可视化技术、测井约束地震反演技术和基于空变速度场的时深转换技术是三维地震综合解释的关键技术。以淮南煤田为例,利用全三维可视化技术探测出煤层内的旋纽构造和新构造运动,利用地震属性中的运动学和动力学特征探测出煤系地层中的陷落柱,通过测井约束地震反演方法和基于空变速度场的时深转换技术实现煤系地层及煤层的空间预测,这些复杂地质构造的发现以及煤层的空间预测结果,对于重新评价煤田开采条件和储量具有重要意义。这项综合解释技术通过利用各种地质信息,有效地降低复杂地质条件下的勘探成本,因此,将成为今后解决煤田复杂构造和岩性勘探的主要手段。

General 3D coalfield seismic interpretation commonly uses kinematics information in time domain,and it is not suitable for complex geology condition. If it is applied to complex underground geological structure,the interpretation precision and reliability would be affected because of lack of information. It is an important measure to integrate more information and more subject to increase interpretation precision under complex geological condition. It means that seismic kinematics should combine with dynamics;seismic should combine with geology and well logging,and time domain should integrate with depth domain. The seismic attribute,3D visualization,log constrained seismic inversion,time-depth conversion based on space-varying velocity are the key techniques of 3D seismic integrated interpretation. Taking Huainan coalfield as a case,the torsional structure and neotectonic movement are discovered by 3D visualization technique;collapse column is detected by kinematics and dynamics feature of seismic attribute,and the space variety of coalseam and coal-bearing strata are predicted by logging constrained seismic inversion and space-varying velocity time-depth conversion. According to the discovery of the complex geological structure and the prediction result of coalseam,the coalfield mining condition and reserve can be reappraised. The integrated interpretation techniques use a lot of geological information,so the exploration cost can be reduced under the complex geological condition,and it will become the main technique to solve coalfield complex structure and lithology exploration.