Processing Ultra–High Density 3D Seismic Surveys: An Abu Dhabi Case Study

Abstract

Abstract A new land ‘nimble node’ acquisition system was developed to deliver economical high-quality seismic data with the lightest and lowest-cost seismic channel system in the seismic industry. Besides the advantages in terms of environmental impact and operational safety, the design goal of the system is improvement of data quality by reducing the cost barriers to acquiring high-density seismic surveys. The present case study examines deployment of the nimble node system in Abu Dhabi, United Arab Emirates. ADNOC conducted a pilot survey in 2019 that involved approximately 50,000 single-sensor nodes laid-out on a 12.5 m × 12.5 m grid combined with source point interval of 12.5 m × 100 m source line interval. The acquisition of 81 sq km was completed ahead of planned schedule and field data quality met expectation. To accelerate acquisition turnaround, sources were vibrated simultaneously where only a minimal ‘no offset/time limiting’ rule was applied. While this approach had the advantage of greatly reducing cost and turnaround time for the field operations, it requires an efficient separation algorithm that identifies and removes the simultaneous-source interference while leaving the prime shot energy intact. We provide a summary of the processing efforts required to exploit the high-density data set in full, focusing on noise attenuation, surface consistent processes, and the improvements achieved in the final imaging over that of the legacy survey.