Application of Post-stack migration to seismicdata associated with fault structures

Abstract

Abstract In hydrocarbon exploration, wave-equation migrationtechniques play an important role in imaging thecomplex geological structures. Usually, post-stack migrationscheme is applied to the seismic data to improve theresolution with restoration of dipping reflectors to theirtrue position. As a result, the migrated time sections areinterpretable in terms of subsurface features. As a numericalstudy, three fault models are considered for the presentstudy. First of all, synthetic time sections are generatedcorresponding to three models. Later, post stack migrationschemes such as Gazdag(PS), Phase-shift with turningrays and reverse time migration (T-K) domain techniquesare applied in order to judge the imaging accuracy, preservationof true amplitude and computational speed. All thethree post stack time migrated sections delineate the structurewith their throw.However, the reverse time migrations(T-K) clearly delineate the reflectors in restoring the throwproperly with minimum computational time. In order totest the validity the numerical results, similar exercise hasbeen undertaken using field seismic data of KG basin, India.The results indicates that the field migrated sectionsare imaged. But, the reverse time migration (T-K ) providesthe best subsurface image with restoration of reflectorsand collapse of diffracted events with least computationaltime. Gazdag (PS) and Phase-Shift with turning migratedsection shows the reduction of amplitude whereas, the reversetime migration preserved the amplitude fully.