Integrated Analysis of Borehole and Surface Seismic Data to Resolve Seismic Uncertainties in the Gulf of Suez

Seismic imaging in the Gulf of Suez is severely affected by salt plays, strong multiple contamination and raypath distortion etc. Consequently, geophysicists face challenges while interpreting the existing surface seismic and planning new wells, both in time as well as depth domain, and encounter surpirses while drilling. Borehole seismic is commonly used to address some of the seismic issues, which could also result in big uncertainties if not planned properly in challenging environment. In this paper, we present case studies from two areas in the Gulf of Suez where borehole seismic surveys were conducted in different configurations in wellbores with different geometries. Logging programs were defined after pre-survey ray trace modeling simulating different scenarios and careful planning considering the operational and geological challenges and logistics. Full waveform processing of well data resulted in much higher resolution 1D to 2D images in time and depth. Borehole seismic images were integrated with the existing surface seismic. In the first area, integrated analysis helped in horizon and structural interpretation revealing features not seen on low resolution surface seismic time and depth cubes. Seismic uncertainties for shallow as well as deep targets were resolved and fault interpretation was refined. Additionally, integrated analysis helped to detect new faults successfully, indicating new promising area for future development drilling. In the second area, integrated analysis confirmed presence of multiples in the surface seismic resulting in the target horizon deeper than expected, which was interpreted shallower all over the area. Analysis also confirmed change in the depositional environment in the area indicating a new block to be studied and estimated.