Seismic Imaging of Small Faults in Coal Seams by Prestack Time Migration

In order to improve imaging precision of small structures and small fault blocks of coal seams, the prestack time migration method is used for imaging. Preserved amplitude processing (PAP) is applied to prestack gather firstly after geological data and original seismic data of the exploration area are fully understood. Initial root mean square velocity field is established through the method of picking up root mean square velocity on CRP gather. Then, a precise root mean square velocity model is created after continuous iteration and modification. Meanwhile, appropriate algorithm and migration parameters are selected during the migration process. Finally, the imaging of small fault blocks and small faults in the prestack time migration section is clear and migration is highly coinciding with the case disclosed by boreholes. It’s proved that prestack time migration is especially suitable for processing 3D seismic data of small faults and small fault blocks in coal seams with complicated geological conditions.