Abstract

In land seismic surveys placement of shot (blasting of explosive) in an appropriate near surface layer plays an important role in terms of transmission of shot generated energy. An optimally placed shot is expected to result in good energy transmission and better data quality. Normally a higher velocity layer is expected to give rise to better energy transmission and conversely in case of lower velocity. Results of the data analysis show that increased sand content in the shooting medium (the layer in which explosive is blasted), lowers the quality of recorded data in terms of energy (Signal to noise ratio, S/N) and frequency. In sandy formations, shot hole drilling is very challenging because of water loss as well as hole collapse. Use of bentonite clay mixed in mud while drilling shot holes prevents water loss and hole collapse.