Innovative solutions to frontier exploration in Eastern Mediterranean salt basins

Abstract

The Eastern Mediterranean region is expected to hold large undiscovered natural gas resources that could address critical energy supply needs of the surrounding countries. However, exploration is challenged due to regional geologic complexities. The combination of Messinian salt structures and diapiric shales in offshore Cyprus and Egypt often causes strong attenuation of seismic energy and severe seismic imaging illumination shadows, which lead to large uncertainty regarding subsalt reservoir presence and the underlying petroleum system assessment. As part of the efforts to solve these imaging challenges, we present innovative seismic acquisition solutions to address key exploration risks such as reservoir presence. A one-sided wide-azimuth configuration consisting of one streamer vessel and one dedicated source vessel operating under the simultaneous-source mode was used to acquire data in a cost-effective way. An 8000 in3 low-frequency source was used on both vessels to provide higher energy output in the low-frequency bands of less than approximately 4 Hz. Our preliminary results show evidence of seismic image uplift due to enhanced acquisition and processing, leading to greater confidence in interpretation, which is critical for positioning wells in future drilling campaigns. This paper highlights seismic testing results undertaken to design a large exploration-scale seismic survey in the Eastern Mediterranean and early results from the execution of that program. This will help better refine optimal design criteria for future acquisition, signal processing, and imaging in order to unlock additional resources beneath complex salt provinces and identify where additional imaging needs still exist.