Structural Style in the Levant Basin: Implication on Hydrocarbon Trapping Mechanism

Abstract

The Levant Basin offshore Lebanon contains a series of anticlines, forming classical 4-way dip closed structural traps, and thus possessing an economic value. The main challenge in these anticlines, however, is associated with imaging in seismic data which – even if of high quality – prohibits to clearly observe their internal geometries, understand their tectonic evolution, and assess the mechanical-stratigraphic controls over trap formation. In addition, such data does not allow alone to identify and derisk the reservoir intervals. This leads to an inadequate judgment over the anticlines’ trapping potential and may result in improperly chosen well location during exploratory drilling. An integrated structural workflow has been used to assess the geological evolution of anticlines in block 4 in order to better understand their structural style, evaluate trap integrity and analyze the mechanical/stratigraphic relationship. First, restoration has been performed in order to validate seismic interpretation, reconstruct internal geometries and accurately determine the evolution of the structures through time. Second, forward structural modelling gave insight in terms of the nature of the anticlines and confirmed the restoration results. Third, the models have been compared with nearby, similar structures onshore Lebanon in order to create analogues that can be further studied with more detail and ease. Fourth, the reconstructed structures have been correlated with play fairway and reservoir distribution maps, which further decreased the reservoir presence risk and allowed to highlight potential sweet spots. The proposed workflow proves that robust structural interpretation and modelling could be a quick and efficient way to derisk traps and assess their integrity. This workflow has been applied to all the prospects offshore Lebanon and yielded accurate trap geometries and a detailed understanding their hydrocarbon potential. It can be applied to any other structural trap in which there are difficulties in mapping internal architecture elsewhere in typical frontier hydrocarbon provinces.

AAPG Datapages/Search and Discovery Article #90355 © 2019 AAPG Africa Region, The Eastern Mediterranean Mega-Basin: New Data, New Ideas and New Opportunities, Alexandra, Egypt, September 6-7, 2019