Source rock characterization and thermal history modelling of Upper Cretaceous organic matter rich carbonates of the eastern Mediterranean

Abstract

The east Mediterranean Levant Basin has in the last decade become a frontier hydrocarbon province. Several gas discoveries have been recorded in Miocene reservoirs offshore Israel and seismic data suggest promising prospective plays in deeper intervals throughout the basin. Source rock information and calibration points are hitherto scarce due to the lack of well data, especially in the offshore Lebanon part of the basin.

The first part of this work consists of geochemical data from several potential (immature) source rocks, specifically Upper Cretaceous (Campanian – lower Maastrichtian), outcropping along the eastern margin of the Levant Basin onshore Lebanon. The Upper Cretaceous rock succession has shown very good source rock properties of type II and type IIS kerogen. Biomarker, petrographic, and elemental data suggest deposition of these source rocks under a high productivity zone mostly restricted to the shelf area. This depositional model would imply a decrease in organic matter (OM) richness towards deeper and distal basinal areas, which in turn would be accompanied by a shift in bulk hydrocarbon generation kinetics to higher values due to oxidation of labile OM. A similar trend is observed in HI values and measured bulk hydrocarbon generation kinetics of Upper Cretaceous source rocks with various OM content onshore Lebanon.

In the second part we will present a large scale 3D petroleum system model integrating the produced geochemical and petrographic data with the available calibration data in order to provide an evaluation of the thermal history of the study area and assess the potential hydrocarbon plays. Preliminary modelling results suggest several potential plays, among which an Oligo-Miocene play in the deep basin, a Jurassic-Cretaceous play along the margin, and a Triassic play in the onshore. This model will also allow us to analyse the sensitivity of the system to the various poorly constrained parameters in frontier basins (e.g. crustal thickness, rifting phases, lithologies).

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015