Abstract

Tomography is a method for refining the velocity /depth model when Pre Stack Depth Migration is performed with an improper velocity model. The degree of non-flatness of the resulting depth gathers determines the measure of error in the model. Tomography uses these measures of non-flatness as input, and attempts to find an alternate model to minimize the errors. The area under study belongs to south western offshore basin of India where potential exploration targets of Mesozoic sediments are overlain by Early Paleocene Deccan basalts. The rough and uneven nature of these basalts deteriorates seismic imaging of underlying Mesozoic sediments. Seismic expression of sub basalt section is of very poor quality data infested with multiples, high velocity diffractions and other noises making it very difficult to pick the horizons.