Unlocking the Exploration Potential of Challenging Seismic Acquisition Enviroments With 3D Geologic Modeling and Inversion of 2D Seismic and Nonseismic Data

N. Raterman¹, I. Hanbal¹, E. Janoubi¹, E. Muzaiyen¹, V. Celis franco¹, and R. Zayer¹

Abstract

Exploration of the remaining frontier basins requires geophysical data acquisition in complex and challenging environments that may make the cost of 3D seismic prohibitive. An example of such an area is the transition zone of the Saudi Arabian portion of the Red Sea, a late Oligocene to recent rift basin. The Red Sea transition zone is a 15 to 30 km wide zone of extreme bathymetric variation (0 - 500 meters) characterized by frequent, patchy pinnacle and platform reefs that lie immediately offshore. The dense, patchy nature of the reefs precludes the acquisition of marine streamer seismic over much of the area, requiring the use of marsh geophones and ocean-bottom cable nodes to acquire seismic data over, near and between the reefs. The use of these advanced acquisition devices, and the intense planning, surveying and man power needed to place them, increases the cost of seismic acquisition to the point where 3D seismic for exploration purposes is cost prohibitive. In the absence of 3D seismic data — an industry standard for exploration in most geologically complex basins — the exploration geologist or geophysicist must rely on more cost-effective data such as bathymetry, airborne gravity and magnetics, and 2D seismic, which do not yield a 3D image of the subsurface. Effective exploration of the Red Sea transition zone requires a 3D understanding of the geologically complex syn- and post- rift structures and stratigraphy present in the subsurface. We present an iterative interpretation workflow utilizing 3D numerical modeling and nonseismic forward modeling and inversion, to guide the integration of 2D/2.5D bathymetry, airborne gravity and magnetics, and seismic into a geologically consistent 3D interpretation of the subsurface. This methodology has resulted in exploration success in the Red Sea transition zone. We contend that a similar workflow could be easily adapted and employed in analogous frontier basins.

AAPG Search and Discovery Article #90188 ©GEO-2014, 11th Middle East Geosciences Conference and Exhibition, 10-12 March 2014, Manama, Bahrain