Modeling of microbial gas generation: application to the eastern Mediterranean “Biogenic Play”

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

Modeling of microbial gas generation : application to the eastern Mediterranean "Biogenic Play"

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 syste

The Calabrian Arc subduction complex in the Ionian Sea: Regional architecture, active deformation, and seismic hazard

We analyzed the structure and evolution of the external Calabrian Arc (CA) subduction complex through an integrated geophysical approach involving multichannel and single‐channel seismic data at different scales. Pre‐stack depth migrated crustal‐scale seismic profiles have been used to reconstruct the overall geometry of the subduction complex, i.e., depth of the basal detachment, geometry and structural style of different tectonic domains, and location and geometry of major faults. High‐resolution multichannel seismic (MCS) and sub‐bottom CHIRP profiles acquired in key areas during a recent cruise, as well as multibeam data, integrate deep data and constrain the fine structure of the accretionary wedge as well as the activity of individual fault strands. We identified four main morpho‐structural domains in the subduction complex: 1) the post‐Messinian accretionary wedge; 2) a slope terrace; 3) the pre‐Messinian accretionary wedge and 4) the inner plateau. Variation of structural style and seafloor morphology in these domains are related to different tectonic processes, such as frontal accretion, out‐of-sequence thrusting, underplating and complex faulting. The CA subduction complex is segmented longitudinally into two different lobes characterized by different structural style, deformation rates and basal detachment depths. They are delimited by a NW/SE deformation zone that accommodates differential movements of the Calabrian and the Peloritan portions of CA and represent a recent phase of plate re‐organization in the central Mediterranean. Although shallow thrust‐type seismicity along the CA is lacking, we identified active deformation of the shallowest sedimentary units at the wedge front and in the inner portions of the subduction complex. This implies that subduction could be active but aseismic or with a locked fault plane. On the other hand, if underthrusting of the African plate has stopped recently, active shortening may be accommodated through more distributed deformation. Our findings have consequences on seismic hazard, since we identified tectonic structures likely to have caused large earthquakes in the past and to be the source regions for future events

From the Field to the Model Bernard Tissot's Path

This short article is not aimed to comment the long career of B. Tissot, but to single out certain periods of his professional life that were probably decisive. Of particular interest are the years in which he practiced the profession of oil explorer, and the transition period between these years and his entry into the profession of researcher into the scientific problems associated with the genesis and migration of oil

Ressources pétrolières pour le XXe siecle : quel avenir ?

Les réserves prouvées d'hydrocarbures liquides sont aujourd'hui évaluées, suivant les sources, entre 950 et 1 000 milliards de barils. Leur durée de vie, au rythme actuel de la production mondiale, est d'environ 41 à 45 ans, soit bien supérieure à celles qui étaient couramment données en 1970 et 1980. Toutefois, cette abondance des ressources ne garantit pas obligatoirement la sécurité des approvisionnements pétroliers pour tous les pays. Il importe de souligner que les réserves pétrolières sont géographiquement inégalement réparties et que réserves et productions sont actuellement le fait des champs géants (champs ayant plus de 500 millions de barils de réserves initiales). Si l'approvisionnement pétrolier semble assuré pour les trente à quarante années à venir, quelles sont les perspectives au-delà de 2020-2030 ? L'augmentation des réserves prouvées au cours des dix à vingt années qui viennent de s'écouler n'est qu'apparente. Cet accroissement, après 1986, est essentiellement dû à des révisions et à des extensions plutôt qu'à de nouvelles découvertes. L'article, présenté ici, s'efforce d'inventorier et d'évaluer quelles pourraient être les nouvelles sources de pétrole : bruts conventionnels (brut récupérable compte tenu d'un prix au baril de l'ordre de 20 US$ et d'un taux de récupération voisin de 30 %) restant à découvrir, ressources en huile issues d'une amélioration du taux de récupération, ressources résultant de l'exploitation de zones nouvelles (l'offshore profond), bruts de types non conventionnels tels que bruts extra-lourds, sables asphaltiques, huiles de schiste, et hydrocarbures liquides obtenus grâce aux méthodes de récupération assistée par voie chimique

Ressources pétrolières pour le XXe siecle : quel avenir ? Oil Ressources for the 21st Century: Constraints and Outlook

Les réserves prouvées d'hydrocarbures liquides sont aujourd'hui évaluées, suivant les sources, entre 950 et 1 000 milliards de barils. Leur durée de vie, au rythme actuel de la production mondiale, est d'environ 41 à 45 ans, soit bien supérieure à celles qui étaient couramment données en 1970 et 1980. Toutefois, cette abondance des ressources ne garantit pas obligatoirement la sécurité des approvisionnements pétroliers pour tous les pays. Il importe de souligner que les réserves pétrolières sont géographiquement inégalement réparties et que réserves et productions sont actuellement le fait des champs géants (champs ayant plus de 500 millions de barils de réserves initiales). Si l'approvisionnement pétrolier semble assuré pour les trente à quarante années à venir, quelles sont les perspectives au-delà de 2020-2030 ? L'augmentation des réserves prouvées au cours des dix à vingt années qui viennent de s'écouler n'est qu'apparente. Cet accroissement, après 1986, est essentiellement dû à des révisions et à des extensions plutôt qu'à de nouvelles découvertes. L'article, présenté ici, s'efforce d'inventorier et d'évaluer quelles pourraient être les nouvelles sources de pétrole : bruts conventionnels (brut récupérable compte tenu d'un prix au baril de l'ordre de 20 US$et d'un taux de récupération voisin de 30$20 and a recovery rate in the vicinity of 30%) remaining to be discovered; oil resources stemming from an improvement in the recovery rate; resources resulting from production from new zone, e. g. fields in the deep seas; unconventional crudes such as extra-heavy crudes, tar sands, shale oil and liquid hydrocarbons obtained by enhanced recovery by chemical methods

The Main Types of Passive Margins: An Introduction

Recent results indicate that the margins often exhibit complex structural patterns revealing a great variety in structural style as well as depositional regime. Thus, at the present state of the art it appears difficult to synthesize the available information into one or a few type sections. Some of the fundamental questions relate to how the change from continental to oceanic crust takes place along the margin

Modeling of microbial gas generation : application to the eastern Mediterranean "Biogenic Play"

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 syste