COMPARISON OF MULTI AZIMUTH 3D SURVEY WITH CONVENTIONAL SINGLE AZIMUTH SURVEY IN A COMPLEX GEOLOGICAL AREA

摘要

Multi-Azimuth (MAZ) seismic is a technique primarily used to improve the imaging of the subsurface in areas of complex structures. The Multi-Azimuth technique requires a given area of interest to be acquired several times with different acquisition azimuths over the same area. In the past few years the exploration industry has seen an increase in the use of this technique leading to impressive improvements over conventional single azimuth 3D surveys.In a MAZ survey, the same subsurface point is illuminated from many different angles. By processing the individual azimuth surveys separately and then combining the data, it is possible to improve the imaging quality and gain a better understanding of exploration targets located in areas of complex geology.The first MAZ survey acquired in Indonesia was carried out by Eni Indonesia in the Bukat PSC located offshore East Kalimantan. Traditionally, the quality of the seismic in this area is fairly poor, preventing seismic interpreters from positioning exploration and appraisal wells with confidence. The main geophysical challenges of the area include strong 3D multiples, poor illumination at target level and limited signal-to-noise ratio. By acquiring two new azimuths with a previous conventional 3D survey over the Aster structure, key aspects of MAZ processing were examined and by comparing the results with conventional techniques, it was found to greatly mitigate these limitations on exploration.