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

Abstract

Abstract:In hydrocarbon exploration, wave-equation migration techniques play an important role in imaging the complex geological structures. Usually, post-stack migration scheme is applied to the seismic data to improve the resolution with restoration of dipping reflectors to their true position. As a result, the migrated time sections are interpretable in terms of subsurface features. As a numerical study, three fault models are considered for the present study. First of all, synthetic time sections are generated corresponding to three models. Later, post stack migration schemes such as Gazdag(PS), Phase-shift with turning rays and reverse time migration (T-K) domain techniques are applied in order to judge the imaging accuracy, preservation of true amplitude and computational speed. All the three post stack time migrated sections delineate the structure with their throw. However, the reverse time migrations (T-K) clearly delineate the reflectors in restoring the throw properly with minimum computational time. In order to test the validity the numerical results, similar exercise has been undertaken using field seismic data of KG basin, India. The results indicates that the field migrated sections are imaged. But, the reverse time migration (T-K ) provides the best subsurface image with restoration of reflectors and collapse of diffracted events with least computational time. Gazdag (PS) and Phase-Shift with turning migrated section shows the reduction of amplitude whereas, the reverse time migration preserved the amplitude fully.

Geometry, kinematics and dynamic characteristics of a compound transfer zone: the Dongying anticline, Bohai Bay Basin, eastern China

“…The time-domain 3D seismic dataset was used to interpret the T1, T2, T4 and T6 by tracing the peak of corresponding seismic reflections, and then the faults were interpreted in detail by interrupts or disturbances on these seismic reflections and seismic slices guided by geological concepts. Although the vertical resolution of seismic dataset is about 20 m [28], but for the study area is very small (12 sq Km), we used the 3D velocity field which provided by Shengli Oilfield to change the time-domain information to depth-domain information. The results are credible, and can interpret the changes of throw inside and outside the Dongying transfer zone.…”