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[en] Biogenic gas is becoming increasingly important as an exploration target in the petroleum industry because it occurs in geologically predictable circumstances and in large quantities at shallow depths as free gas or gas hydrates. As accumulations of biogenic gas result in a subtle synchronization between early generation and early trapping, we integrated a macroscopic model of microbial gas generation within a 3D basin and petroleum system forward simulator. The macroscopic model is based on a microscopic model, which consists in a 1D sedimentary column that accounts for sedimentation, compaction, Darcy flow and Diffusion flow. The organic carbon is the only non-soluble element considered in this version of the model. The dissolved elements are O2, SO4 2-, H2, CH3COOH, and CH4. Methane is dissolved in water or present as a free phase if its concentration exceeds its solubility at given pressure and temperature. In this microscopic model, the transformation of substrate into biomass is described through a set of logistic equations coupled with the transport equations (advection and diffusion). Based on the microscopic considerations we developed the macroscopic model of low maturity/biogenic gas generation in which hydrocarbons are generated through first order kinetic reactions at low maturity. This macroscopic model is adapted to petroleum system modeling at basin scale with TemisFlow®, which aims to understand and predict hydrocarbon generation, migration, and accumulation. It is composed of: i) A source rock criteria which allow defining the biogenic gas source rocks potential and ii) A kinetic model of methane generation. The previous model has been successfully applied on different basins such as the Carupano Basin from the offshore Venezuela, the Magdalena Delta (offshore Colombia) and the offshore Vietnam where direct observations of low-maturity gas were available. Furthermore, it has been applied in the offshore Lebanon in order to check the viability of a biogenic gas system. (Author)
[en] Oil spill models are combined with bathymetric, meteorological, oceanographic, and geomorphological data to model a series of oil spill accidents in the Eastern Mediterranean Sea. A total of 104 oil spill simulations, computed for 11 different locations in the Levantine Basin, show that oil slicks will reach the coast of Cyprus in four (4) to seven (7) days in summer conditions. Oil slick trajectories are controlled by prevailing winds and current eddies. Based on these results, we support the use of chemical dispersants in the very few hours after large accidental oil spills. As a corollary, we show shoreline susceptibility to vary depending on: a) differences in coastline morphology and exposure to wave action, b) the existence of uplifted wave-cut platforms, coastal lagoons and pools, and c) the presence of tourist and protected environmental areas. Mitigation work should take into account the relatively high susceptibility of parts of the Eastern Mediterranean. - Highlights: • Oil spill simulations show oil slicks will spread in four (4) to seven (7) days in the Eastern Mediterranean during summer. • Oil slick trajectories are controlled by prevailing winds and current eddies. • Chemical dispersants should be used in the very few hours after large accidental oil spills. • Mitigation work should take into account the high susceptibility of parts of the coastline. - Simulations for eleven locations in the Eastern Mediterranean Sea show that oil slicks will spread to the coast in four (4) to seven (7) days, justifying the early use of oil dispersants to mitigate them.
[en] A key for the identification of Tintinnoinea is presented. The key's main aplication will be in the fields of production studies, species succession and alteration of the species composition caused by pollution of various origin. Each species described is accompanied by an appropriate drawing either an original or from published source, arranged in 45 plates. The key consists of two parts. One is a key to genera and the other a key to the species of mediterranean pelagic Tintinnoinea. The key is preceeded by an introduction into the general morphology of Tintinnoinea and of their principle morphological feature. This introduction is accompanied by 1 plate