高密度三维地震勘探在四川复杂山区的应用效果

勘探区位于四川盆地与云贵高原的过渡地带,地形高差大、地层倾角陡、煤层薄、地质情况复杂,浅表层地震地质条件较差。通过实验,采用端点下倾方向激发的观测方法。在资料处理中,采用了多种静校正方法与去噪处理技术;在资料解释时,利用三维地震数据体等时水平切片、均方根振幅属性等多种方法对断层、陷落柱及采空区进行解释,其中解释溶洞2个,陷落柱1个,断层38条,并圈定了C13、C19、C25三层煤的采空范围。实践证明:若满足地形高差不超过500m、地层倾角不能大于45°、煤系地层上覆灰岩厚度不大于200m等条件,在四川山区开展煤田地震工作具有可行性。

Application Effect of High Density 3D Seismic Prospecting in Sichuan Complex Mountainous Areas

The prospecting area is situated at the transition belt of Sichuan Basin and Yunnan-Guizhou Plateau.It has large topographic height difference,steep strata dips,thin coal seams,complex geological configuration,thus caused poor near-surface seismic-geologic condition.Through experiments,observation method of down-dip direction end-on has adopted.In data processing,multiple statics and noise reduction processing technologies have adopted.During data interpretation,multiple methods of 3D seismic data volume horizontal section,mean square root amplitude attribute etc.have used to interpret fault,subsided column and gob area,finally 2 karst caves,1 subsided column,38 faults and cycled out C13,C19 and C25 three coal seams＇ gob area limits have interpreted.Practices have demonstrated that： If conditions of topographic height difference not more than 500m,strata dip less than 45o,thickness of coal measures overlying limestone less than 500m are satisfied,coalfield seismic prospecting is feasible in the Sichuan mountainous areas.