This study deals with the East Beni Suef Basin (Eastern Desert, Egypt) and aims to evaluate the source-generative potential, reconstruct the burial and thermal history, examine the most influential parameters on thermal maturity modeling, and improve on the models already published for the West Beni Suef to ultimately formulate a complete picture of the whole basin evolution. Source rock evaluation was carried out based on TOC, Rock-Eval pyrolysis, and visual kerogen petrography analyses. Three kerogen types (II, II/III, and III) are distinguished in the East Beni Suef Basin, where the Abu Roash "F" Member acts as the main source rock with good to excellent source potential, oil-prone mainly type II kerogen, and immature to marginal maturity levels. The burial history shows four depositional and erosional phases linked with the tectonic evolution of the basin. A hiatus (due to erosion or non-deposition) has occurred during the Late Eocene-Oligocene in the East Beni Suef Basin, while the West Beni Suef Basin has continued subsiding. Sedimentation began later (Middle to Late Albian) with lower rates in the East Beni Suef Basin compared with the West Beni Suef Basin (Early Albian). The Abu Roash "F" source rock exists in the early oil window with a present-day transformation ratio of about 19% and 21% in the East and West Beni Suef Basin, respectively, while the Lower Kharita source rock, which is only recorded in the West Beni Suef Basin, has reached the late oil window with a present-day transformation ratio of about 70%. The magnitude of erosion and heat flow have proportional and mutual effects on thermal maturity. We present three possible scenarios of basin modeling in the East Beni Suef Basin concerning the erosion from the Apollonia and Dabaa formations. Results of this work can serve as a basis for subsequent 2D and/or 3D basin modeling, which are highly recommended to further investigate the petroleum system evolution of the Beni Suef Basin.

Sandstone channels are one of the best stratigraphic traps for hydrocarbon accumulation, and their depositional and composition make them difficult to detect on ordinary seismic data, especially in structurally affected onshore areas like the Western Desert of Egypt. The Western Desert of Egypt has many hydrocarbon-bearing reservoirs of various compositions like carbonates and sandstones with high production rates, and thus the Western Desert of Egypt is recognized as a hot spot for oil and gas exploration. One of the important reservoirs in the Lower Cretaceous “the Aptian sand” produced around 285 MBBLS cumulative oil of 22° API and still produces 102 BOPD. This reservoir has a channel-type depositional environment, and the dimensions of this channel could be resolved by good quality 3D seismic data in the moderately deep basins as the basins become deeper, the detection of the channel becomes increasingly challenging. This study aims to delineate the geometry of this reservoir and reveal the exposure from the Aptian sand channel in the Alamein area using the seismic attributes analogy on the re-processed 3D seismic data to determine the best drilling location for increasing the production from this reservoir. In this context, the relative acoustic impedance (RAI), iso-frequency components, and sweetness stratigraphic attribute analyses were conducted on the optimized seismic data and attested as important as they resolved the stratigraphic geological mystery in the structurally affected study area. These attribute analyses revealed the exposure from the distinctive meander channel of the Aptian sand for the first time in the study area nearby the producing Alamein field, where this channel was hard to be distinguished by the ordinary seismic interpretation methods and there is no drilled well penetrated the detected channel’s body. Upon the results, the conclusion and recommendation summaries to intensify the efforts to test the productivity of the detected channel to increase the production from this motivating reservoir by drilling a new well targeting the best structural locations of the channel body.

The Mesozoic Cameros Basin, northern Spain, was inverted during the Cenozoic Alpine orogeny when the Tithonian – Upper Cretaceous sedimentary fill was uplifted and partially eroded. Tar sandstones outcropping in the southern part of the basin and pyrobitumen particles trapped in potential source rocks suggest that hydrocarbons have been generated in the basin and subsequently migrated. However, no economic accumulations of oil or gas have yet been found. This study reconstructs the evolution of possible petroleum systems in the basin from initial extension through to the inversion phase, and is based on structural, stratigraphic and sedimentological data integrated with petrographic and geochemical observations. Petroleum systems modelling was used to investigate the timing of source rock maturation and hydrocarbon generation, and to reconstruct possible hydrocarbon migration pathways and accumulations. In the northern part of the basin, modelling results indicate that the generation of hydrocarbons began in the Early Berriasian and reached a peak in the Late Barremian – Early Albian. The absence of traps during peak generation prevented the formation of significant hydrocarbon accumulations. Some accumulations formed after the deposition of post‐extensional units (Late Cretaceous in age) which acted as seals. However, during subsequent inversion, these reservoir units were uplifted and eroded. In the southern sector of the basin, hydrocarbon generation did not begin until the Late Cretaceous due to the lower rates of subsidence and burial, and migration and accumulation may have taken place until the initial phases of inversion. Sandstones impregnated with bitumen (tar sandstones) observed at the present day in the crests of surface anticlines in the south of the basin are interpreted to represent the relics of these palaeo‐accumulations. Despite a number of uncertainties which are inherent to modelling the petroleum systems evolution of an inverted and overmature basin, this study demonstrates the importance of integrating multidisciplinary and multi‐scale data to the resource assessment of a complex fold‐and‐thrust belt.

Earth's largest reactive carbon pool, marine sedimentary organic matter, becomes increasingly recalcitrant during burial, making it almost inaccessible as a substrate for microorganisms, and thereby limiting metabolic activity in the deep biosphere. Because elevated temperature acting over geological time leads to the massive thermal breakdown of the organic matter into volatiles, including petroleum, the question arises whether microorganisms can directly utilize these maturation products as a substrate. While migrated thermogenic fluids are known to sustain microbial consortia in shallow sediments, an in situ coupling of abiotic generation and microbial utilization has not been demonstrated. Here we show, using a combination of basin modelling, kinetic modelling, geomicrobiology and biogeochemistry, that microorganisms inhabit the active generation zone in the Nankai Trough, offshore Japan. Three sites from ODP Leg 190 have been evaluated, namely 1173, 1174 and 1177, drilled in nearly undeformed Quaternary and Tertiary sedimentary sequences seaward of the Nankai Trough itself. Paleotemperatures were reconstructed based on subsidence profiles, compaction modelling, present-day heat flow, downhole temperature measurements and organic maturity parameters. Today's heat flow distribution can be considered mainly conductive, and is extremely high in places, reaching 180 mW/m(2). The kinetic parameters describing total hydrocarbon generation, determined by laboratory pyrolysis experiments, were utilized by the model in order to predict the timing of generation in time and space. The model predicts that the onset of present day generation lies between 300 and 500 m below sea floor (5100-5300 m below mean sea level), depending on well location. In the case of Site 1174, 5-10% conversion has taken place by a present day temperature of ca. 85 degrees C. Predictions were largely validated by on-site hydrocarbon gas measurements. Viable organisms in the same depth range have been proven using C-14-radiolabelled substrates for methanogenesis, bacterial cell counts and intact phospholipids. Altogether, these results point to an overlap of abiotic thermal degradation reactions going on in the same part of the sedimentary column as where a deep biosphere exists. The organic matter preserved in Nankai Trough sediments is of the type that generates putative feedstocks for microbial activity, namely oxygenated compounds and hydrocarbons. Furthermore, the rates of thermal degradation calculated from the kinetic model closely resemble rates of respiration and electron donor consumption independently measured in other deep biosphere environments. We deduce that abiotically driven degradation reactions have provided substrates for microbial activity in deep sediments at this convergent continental margin. (c) 2006 Elsevier B.V. All rights reserved.

The formation and origin of high-maturity gas from Tertiary sediments in the Mackenzie Delta have been studied using programmed-temperature closed-system pyrolysis (MSSV), different open-system devices and numerical models for geological predictions. A sample from the type III Taglu Sequence was selected as being representative for one of the major hydrocarbon-prone deltaic sediments in this area. Artificial maturation under closed-system conditions was carried out at three different heating rates: 0.2, 0.7 and 5.0K/min. The gas composition as well as carbon isotopes of formed methane were analysed using GC-FID and GCIRMS. Structural characteristics of the residual macromolecules formed during these experiments were studied at different levels of thermal stress (immature, 360, 412 and 470°C).Under closed-system conditions, the Taglu Sequence forms unusually high amounts of gas at extreme levels of thermal stress. The recombination of previously formed hydrocarbons with residual kerogen/coal through aromatisation/polycondensation reactions is the best explanation for these high temperature features, a feature previoulsy reported for the Heather Formation, North Sea. When the neoformed material becomes active and forms gas at high levels of maturity, carbon isotopes measured on methane fall to values that are 10‰ lighter than those from open-system gas formation networks. A kinetic model for hydrocarbon formation from this neoformed organic matter has been developed. This predicts, that the initial phase of the neoformation processes shift from post-oil formation conditions at laboratory heating rates to peri-oil formation conditions when it comes to geological heating rates. This may indicate that recombination reactions through aromatisation/polycondensation processes partly influence the major phase of petroleum formation in nature and also justifies an enhancement of gas prospectivity at great depths, especially in deep basins where source rock maturities exceed 2.5%Ro.

P043 MODELING BURIAL HISTORY AND FLUID- ROCK-INTERACTIONS OF DEEP OVERPRESSURED RESERVOIRS IN THE CENTRAL GRABEN NORTH SEA Abstract 1 We study temperature and pressure-controlled inorganic and organic diagenetic processes in a study area of the Central Graben North Sea containing clastic Mesozoic reservoirs situated at depths of 4.5-5 km and temperatures of 170-192°C. The reservoirs are highly overpressured due to rapid burial during the last 2 Ma. We present first results of a basin modeling study focusing on the burial and temperature history of these HPHT-reservoirs. Furthermore we concentrate on organic-inorganic interactions enhancing mineral solubility and increasing porosity. This is

Numerical modeling of coupled heat and mass transport is applied to simulate the temporal and spatial evolution of temperature and quartz precipitation in a hydrothermal vein system. In detail, the computer model simulates the time-dependent temperature evolution of a shear zone and its vicinity by convective and conductive heat transport. A reaction term allows calculation of precipitation and dissolution of vein minerals, here quartz, due to flow-controlled mass transport. Assuming different flow scenarios, examples for the probable evolution of temperature and mineralization of hydrothermal systems are presented. The concept for the model is given by the geological, geochemical, and isotopic studies of hydrothermal vein systems of the Upper Harz Mountains. The suggested scenarios seek to approximate conditions typical for veins showing repeated opening and sealing.

Geothermal modeling is an important part of large-scale basin studies. Based on a new 3D structural model of the Northeast German basin, the present day regional geothermal field is modeled. Range and regional trend of the modeled temperature values are in agreement with the published data. Due to the high spatial resolution, the calculated temperature distribution provides additional information with respect to areas where no measured data is available. The results are used as input and boundary parameters for small-scale models of geothermal energy production. In general, in many regions not enough data is available to define all necessary physical or chemical parameters for modeling. In this context, data obtained from the large-scale model help to constrain unknown parameters. Subsequently, the small-scale model is used to simulate various production schemes focusing on enhanced predictions with respect to the possible lifetime of such installations. The simulation results also show the need for elaborated models if reliable predictions of the temperature evolution are required.

A 1D-modelling program has been applied to reconstruct the burial and thermal histories of two exploration boreholes, KB172 and KB174, located in the Campine Basin. The results show differences in geological histories. The coalification of the Westphalian A and B strata in KB174 (0.66–0.98% Ro) was pre-Permian. Calculated maximum temperatures, based on borehole data and vitrinite reflectance, regional thicknesses and a heat flow of 84 mW/m2 during the Late Westphalian, range from 110 °C at the top to 175 °C at the bottom of the Westphalian cored in this borehole. The high coalification (0.85–1.30% Ro) of the Westphalian C and D strata in KB172 could be the result of the deposition of ∼2500 m of Upper Permian to Middle Jurassic sediments in combination with elevated heat flows (71–80 mW/m2). Two coalification periods, i.e. Late Westphalian and Middle Jurassic, are suggested for this borehole. The simulated maximum temperatures range from 130 °C at the top to 175 °C at the bottom of the investigated Westphalian C and D. The differences in the burial and thermal histories of both boreholes can be related to the activity of the transversal Donderslag Fault, a major structural element in the Campine coalfield, and the Roer Valley Graben.

A three-dimensional computer model is presented for studying the interaction of heat and mass transport regarding the temporal and spatial evolution of sandstones. The model simulates coupled heat and reactive mass transport in porous rocks. In general, mineral solubilities in water are low. Therefore, large fluid volumes are required to flow through the rock to explain observed mineral cements in sandstones. Besides mass transport, pore fluids transport heat which modifies rock temperatures. Very high flow rates result in strong temperature modifications and, therefore, enhance diagenesis. Low flow rates often cannot account for observed cementation. The model results show the effect of advective, convective and conductive heat transport on temperature and diagenetic evolution of sandstones for two different flow systems in a simple geological environment.