AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
An Integrated Approach to Salt Basin Evaluation
(1) Geology, RWTH Aachen University, Aachen, Germany.
Salt basins play a major role in the hydrocarbon industry but also are increasingly important as oil and gas storage sites. They display a complex geodynamic evolution characterized by several phases of halokinesis and associated sedimentation. Our approach to salt basins combines seismic, structural and sedimentary studies with analysis of rheological properties, and geomechanic modelling. High resolution reservoir quality studies in prospective salt basin sequences and new advances in micro-scale porosity and permeability analytical techniques can now be taken to a predictive level for exploration and serve to optimize production in existing fields. We illustrate these concepts with case studies from Europe and the Middle East.
One classic area of salt tectonics is the Central European Basin System (CEBS). Here, the mobile Permian Zechstein salt formed a large number of salt structures such as anticlines, diapirs, pillows, sheets, stocks, and walls during an extended period of salt tectonic activity in Mesozoic and Cenozoic times. Salt-influenced sedimentary responses to renewed phases of tectonism can be clearly discerned from detailed sequence analysis based on seismic and log data combined with retrodeformation modelling studies. High quality 3-D seismic data integrated with structural modelling improves the definition of salt structure and associated sediment architecture in salt-controlled sequences.
The improved understanding of the tectonic and sedimentary evolution of salt structures and detailed knowledge of the dynamics of subsurface salt has significant effects on seismic modelling, depth conversion and interpretation of complex structures. Integrated analysis advances the prediction of potential hydrocarbon reservoirs. Salt wedges which have formed by lateral extrusions during periods of diapir emergence and reduced sediment accumulation as well as isolated carbonate “rafts” and “stringers” can form potential hydrocarbon traps and thus represent an alternative exploration target in most salt-rich hydrocarbon provinces. Knowledge of the geometry and properties of salt as well as the surrounding host rocks significantly improves the prediction of seals and their capacity and helps in planning drilling operations.