Adria Mega 3D Seismic Project: Advanced Merge and Modern Processing Techniques to Revamp Near Field Exploration Opportunities in Northern Adriatic Sea

ABSTRACT

Since new seismic acquisitions are not planned in the Italian Adriatic Sea in the near future, the reprocessing and merge of available datasets is the only solution to appraise the true potential of new and existing near field opportunities. Leveraging on integrated G&G workflows, modern processing techniques and HPC capabilities, a large re-processing campaign in the Northern Adriatic Sea was carried out by Eni. It consisted of an 11,000 sqkm mega-merge of 10 different seismic surveys acquired during the last 25 years.

This paper illustrates strategies, methodologies and results of a 2-year seismic project, aimed to improve the imaging of the data, especially over the surveys overlapping areas, while preserving amplitude integrity.

The major challenges were the differences in the acquisition configurations, wavelets, amplitudes and geometries, time shift alignments, acquisition footprints and high amount of multiples' energy. Thanks to enhanced denoise techniques, 4D interpolation, smart regularization and advanced imaging capabilities, it was possible to deliver high quality homogenous volumes of the area.

For the first time, in addition to the PSTM product, a True Amplitude PSDM well calibrated volume was also produced, leading to a better understanding of the real geometries of the targets and their correct depth positioning. State-of-the-art tomographic technologies, together with a huge amount of well information, were used to create a geologically consistent velocity model of the whole area down to a maximum depth of 10 km.

The strong integration between geologists, geophysicists and explorationists, exploiting all the huge technical know-how built up in Eni during decades of activities in the area, was a key factor for the success of the project.

INTRODUCTION

The first offshore gas discovery in Adriatic Sea was Ravenna Mare in 1960. It was followed by a peak in exploration activity followed by substantial discoveries since the 70's. From the early 80's, the seismic DHI technologies became a key support for successful exploration and the 3D seismic surveys acquired in 1992 gave a strong impulse to the exploration activity. Today the exploration of biogenic gas plays in the Adriatic Sea is mature and the investigation of the residual potential, located in the more complex area, require an improvement in the quality of the available data.