Reducing the Exploratory Risk in Northern Tunisia: Integrating HRes Gravity, Magnetic and Seismic Data

The area of interest is located in northern offshore Tunisia which belongs to the Maghrebide-Apennine Fold-Thrust Belt. In this complex geological region, numerous 2D seismic surveys have been acquired showing a very poor data quality. The presence of residual noise, diffracted energy from steeply dipping faults and strata, and diapiric bodies are the main factors that degrade the seismic imaging. Repsol managed to increase the quality and quantity of data in the area by re-processing old seismic surveys, acquiring new 2D seismic data and high resolution bathymetry, and conducting detailed onshore geologic studies. Also, a high-resolution airborne gravity and magnetic survey was flown in order to obtain complementary geophysical data to provide important information about the structure of the basement, the location and size of evaporite or shale diapirs, and constraints on sedimentary section thickness. This study presents an integrated interpretation of the regional geology, seismic, gravity and magnetic data which allowed Repsol to substantially reduce the exploration uncertainty and identifying the most prospective areas.