Abstract

Ahmedabad south carpet 3D was planned in Nawagam Wasna area under four phases. Seismic data acquisition was completed on Phase-I & II. In Phase-I, land analog geophone was used as sensor whereas in Phase-II, digital sensor SVSM was used. Vector Seis (SVSM) is a 3-component digital sensor uses micro-mechanical as sensing element and provides an output proportional to the acceleration of ground movement whereas traditional seismic Geophone having moving coil sensor provides an output sensitive to velocity of the ground movement. The responses of these two sensors are different in amplitude and Phase from each other. The requirement of seamless merging of these two different data set producing gathers suitable for Pre stack inversion and other attribute studies warranted a new approach in processing. Emphasis was given on bringing the two dataset on same phase and amplitude level. Once the two data sets are on same level careful conditioning of the gathers, removal of noises was carried. Then higher order residual correction, close-grid RMS velocity analysis was done. The presence of thick coal layer present within Kalol formation resulted in the multiple reflections and attenuation of seismic energy. The multiples were attenuated using parabolic radon transform and the energy loss was taken care during preprocessing.