Gaina C.,University of Oslo |
Torsvik T.H.,University of Oslo |
Torsvik T.H.,Geological Survey of Norway |
Torsvik T.H.,University of Witwatersrand |
And 4 more authors.
Tectonophysics | Year: 2013
We present a model for the Jurassic to Present evolution of plate boundaries and oceanic crust of the African plate based on updated interpretation of magnetic, gravity and other geological and geophysical data sets. Location of continent ocean boundaries and age and geometry of old oceanic crust (Jurassic and Cretaceous) are updated in the light of new data and models of passive margin formation. A new set of oceanic palaeo-age grid models constitutes the basis for estimating the dynamics of oceanic crust through time and can be used as input for quantifying the plate boundary forces that contributed to the African plate palaeo-stresses and may have influenced the evolution of intracontinental sedimentary basins. As a case study, we compute a simple model of palaeo-stress for the Late Cretaceous time in order to assess how ridge push, slab pull and horizontal mantle drag might have influenced the continental African plate. We note that the changes in length of various plate boundaries (especially trenches) do not correlate well with absolute plate motion, but variations in the mean oceanic crust age seem to be reflected in acceleration or deceleration of the mean absolute plate velocity. © 2013 Elsevier B.V.
Deville E.,French Institute of Petroleum |
Guerlais S.,French Institute of Petroleum |
Lallemant S.,Cergy-Pontoise University |
Schneider F.,French Institute of Petroleum |
Schneider F.,Beicip Franlab
Basin Research | Year: 2010
This paper discusses the origin and the dynamics of subsurface sediment mobilization processes in tectonically mobile regions and shale-rich environment. This is illustrated by the example of Trinidad and the south of the Barbados prism. In this area of the southeast Caribbean, geophysical acquisitions have spectacularly shown the widespread development of sediment mobilization features in the interference area between the southern part of the Barbados prism and the active turbidite system of the Orinoco. Numerous mud volcanoes are especially developed along ramp anticline crests through hydraulic fracture systems. The area also exhibits trends of structures that correspond to massive uplifts of well-preserved turbidite and hemipelagic sediments that cut up the surrounding sediments. Some of these structures are complicated by the development of collapse structures, calderas and superimposed mud volcanoes. The mobilized sediments expelled by the mud volcanoes are not only liquefied argillaceous but also fine sandy material from deep horizons, and various shallower formations pierced by the mud conduits. Both in the Barbados prism and in Trinidad, the expelled mud is rich in thangular and mechanically damaged quartz grains, which are probably cataclastic flows issued from sheared and collapsed deep sandy reservoirs. The exotic clasts and breccias result mostly from hydraulic fracturing. In Trinidad, the gas phase is mainly deep thermogenic methane associated with hydrocarbon generation at depth. Subsurface sediment mobilization notably differs from salt mobilization by the role taken by the fluid dynamics that control overpressured shale mobilization and induce sediment liquefaction. A reaction chain of several deformation processes develops around the conduits. Massive sedimentary uplift corresponds to large movements of stratified solid levels, possibly due to the tectonic inversion of pre-existing mud volcano systems. All these phenomena are controlled by the development of overpressure at depth. No evidence for piercing shale diapirs has been observed in the area studied. © 2010 The Authors. Journal Compilation © Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.
Ma J.,Heriot - Watt University |
Sanchez J.P.,Heriot - Watt University |
Sanchez J.P.,Beicip Franlab |
Wu K.,Heriot - Watt University |
And 3 more authors.
Fuel | Year: 2014
The capability to simulate real gas flow in porous materials with micro- and nano-meter-scale pores is of importance in many applications, such as gas extraction from shale reservoirs, and the design of gas-based fuel cells. A node-bond pore-network flow model (PNFM) has been developed for gas flow where it is the only fluid phase. The flow conductance equation includes the usual Darcy flow terms, and additional terms that capture the contributions from slip flow to Knudsen diffusion. With respect to the case for a non-ideal gas, the extra contributions, which are necessary, to the coefficients of the Darcy and Knudsen terms, are expressed in terms of reduced temperature and pressure, using van der Waals's two-parameter principle of corresponding states. Analysis on cylindrical pores shows that the coefficient deviates from that of the non-ideal gas case by more than 80% in the Darcy term, while between -80% and 150% in the Knudsen term, when the physical states approach to the critical state of the fluid. Although the deviations become smaller when the states are away from the critical state, they remain relatively large even at conditions relevant to practical applications. The model was applied to a pore network of a realistic 3D shale model to show slippage and Knudsen effects on the predicted permeability and the sensitivity to pore sizes. Simulations were carried out for methane under the operational conditions of typical shale-gas reservoirs, and nitrogen under the conditions of laboratory experiments. The results show that the ratio of gas and Darcy permeability correlates positively and strongly with the pore size but inversely with the gas pressure and Tangential Momentum Accommodation Coefficient (TMAC) in the slip term, which can impact gas permeability disproportionally. The results are in favour of controlling the rate of gas depressurisation to avoid early depletion in shale gas production. The methane permeability is shown to be 30% greater, relatively, than that when the ideal gas law is applied, even under normal field operational conditions, while the nitrogen permeability can only approximate the methane permeability within a certain range of field operational conditions when the slip flow is not dominating. © 2013 Elsevier Ltd. All rights reserved.
Haeseler F.,French Institute of Petroleum |
Behar F.,French Institute of Petroleum |
Garnier D.,French Institute of Petroleum |
Chenet P.-Y.,Beicip Franlab
Organic Geochemistry | Year: 2010
The objective of the work is to develop a conceptual model (BioClass) for predicting both the biodegradation level and the corresponding chemical changes (FR. Patents No. 2.934.605 and No. 2.934.606). This model comprises two parts: a 0D compositional and quantitative simulator and the dynamic coupling of this 0D simulator with a basin model that considers the petroleum system history (e.g., time, temperature, fluid dynamics). The 0D model computes the hydrocarbon losses from the different chemical classes. It is based on four global stoichiometric equations that describe hydrocarbon biodegradation under aerobic, denitrifying, sulfate reducing and methanogenic conditions. These equations are applied on model compounds representing the main chemical classes of oils: C6-C14 saturates, C6-C14 aromatics, C14+ n+iso-alkanes, C14+ cycloalkanes and C14+ aromatics. Each chemical class is defined by a relative biodegradation coefficient (Kbio), which takes into account both the accessibility of the hydrocarbons to microbes and their intrinsic susceptibility to biodegradation. These coefficients were first optimised using a natural series of biodegraded oils from the Potiguar Basin (Brasil). The estimated total hydrocarbon loss (58-73%) was in excellent agreement with that from literature using metal concentration, such as Ni (Magnier et al., 2001). Then, BioClass 0D was applied successfully to a series of oil samples from the Williston Basin (Canada) for which the predicted loss ranged from 11-54%. This validated the basic concepts of the model to predict oil composition changes during biodegradation and the resulting hydrocarbon losses. Consequently, BioClass 0D provides a new biodegradation ranking based on the determination of the total hydrocarbon loss calculated from the residual oil composition. In parallel, BioClass 0D, which is totally independent of any geological parameter, will be coupled to transport of the oil and water in a basin simulator in order to predict the biodegradation rates of different chemical classes in oil samples. It will integrate critical factors that control hydrocarbon biodegradation, such as residence time and temperature. © 2010 Elsevier Ltd.
Deschamps R.,French Institute of Petroleum |
Eschard R.,Total S.A. |
Rousse S.,Beicip Franlab
Sedimentary Geology | Year: 2013
The architecture of three Late Ordovician glacial valleys was studied in detail in the Tassili N'Ajjer (SE Algeria) outcrops. The valleys are oriented south-north, 2 to 5. km wide, and up to 250. m deep. The valley-fills revealed a very complex sedimentary architecture with significant lateral facies changes. Several glacial cycles induced the formation of Glacial Erosion Surfaces (GES) at the base and within the glacial valleys.The first type of GES shows a sharp and steep-angled contact without striations or associated syn-sedimentary deformation, suggesting that subglacial meltwater was the dominant erosive agent. A second type associated with the deformation of pre-glacial and syn-glacial sediment, suggests that ice was in contact with the valley floor. Four facies associations are proposed: FA1: subglacial tillite; FA2: Sub-to pro-glacial ice contact fans; FA3: Proglacial sub-aqueous gravity flows; and FA4: outwash fans.The stratigraphic architecture of three of the main valleys reveals a complex polyphase infill. At least two main cycles of ice-sheet advance and retreat can be interpreted from the sedimentary succession of each valley. Minor glacial cycles by ice oscillations also occur locally. GES morphology and the facies sequence suggest that the Iherir valleys were initiated by meltwater erosion in subglacial channels, whereas the Dider and Ouarsissen valleys were part of a large ice stream pathway. Above the valley-fill and the interfluves, a sand-rich unit of stacked lobes and channels is interpreted as submarine outwash fans deposited during final ice retreat.A glacial sequence found between two GES comprises fluvio-glacial or ice-contact fan deposits, fluvio-glacial eskers and tills. These sediments were deposited subglacially or at the glacier front during the ice maximum phase and/or the early ice retreat phase. During the ice retreat, interbedded subaqueous gravity flow deposits and diamictites filled the glacially cut topography as the sea invaded the valleys. Maximum ice retreat was associated with high water fluxes and sediment discharge, causing a sand-dominated outwash fan to prograde out over the valleys and interfluves. This outwash fan was supplied mainly by flood activity at the ice front, involving high-density sustained flows. The dominant facies consists of giant aggrading climbing dunes filling channels or constructing sandy lobes downstream. © 2013 Elsevier B.V.
Lecante G.,Beicip Franlab
1st EAGE/ACGGP Latin American Geophysics Workshop | Year: 2012
Multi-attribute seismic analysis has been widely applied to characterize the large scale fracture corridors (close to seismic resolution) affecting Cretaceous and Jurassic carbonate formations in the Middle East region, where a number of reservoirs comprise tight carbonate lithology with bulk of the production from fractures. In such context, fracture swarms/corridors correspond to seismic and sub-seismic faults which extend to tens or hundreds of meters. The method applied for fracture delineation is based on combined use attributes sensitive to discontinuities. Deliverables are fracture index maps/volumes which are calibrated against fracture characteristics observed at wells. These results can be used further as initialization maps for the Discrete Fracture Network. Multi-attribute analysis appears to be an efficient approach for detecting and characterizing fractured zones, even in absence of azimuthal attributes.
Fazelipour W.,Beicip Franlab
Proceedings - SPE International Symposium on Oilfield Chemistry | Year: 2011
Asphaltene precipitation is a sophisticated issue in the upstream oil industry, worldwide, and has detrimental effects on a variety of production processes in oilfields; it damages the properties of the reservoir and causes an unfavorable and significant decrease in oil production. It is very desirable for oil companies to investigate/predict the precipitation behavior of asphaltene in their subsurface reservoirs before it occurs. This allows them to optimize field development plans and review remedial solutions, in advance. To achieve this objective, complex compositional reservoir simulation technology was studied and utilized which is capable of simulating/predicting the dynamic aspects of this unwanted phenomenon. Compositional reservoir simulation technology along with advanced phase behavior and fluid characterization, offer reservoir engineers, the best means to study the issue of asphaltene precipitation, throughout the life of reservoirs. Multiphase flash calculation procedures empower users to predict the onset point and help monitor the amount of precipitation in reservoirs as a function of time, pressure, and composition of the reservoir fluid under investigation. The detrimental effects of the issue on important reservoir properties such as reduction of porosity and permeability; and alteration of wettability can be predicted, as well. A number of complex reservoir simulation cases representing various oilfield-production scenarios were carried out to study the issue of asphaltene precipitation. Results indicate that asphaltene precipitation severely damages the productivity of wells and reduces oil production. A key conclusion of achievements is the capability to predict the detrimental effects of asphaltene precipitation in oilfields without the need for data generation from expensive downhole samples. This research presents a leading-edge technology that can be utilized by oil companies to help with the design of more accurate and reliable primary/secondary/tertiary processes (i.e. EOR) such that asphaltene precipitation in subsurface reservoirs could be predicted and avoided beforehand, in order to help resolve the challenges the E&P industry is facing in this area. Copyright 2011, Society of Petroleum Engineers.
Lericolais G.,French Research Institute for Exploitation of the Sea |
Bourget J.,University of Western Australia |
Popescu I.,GeoEcoMar |
Jermannaud P.,Beicip Franlab |
And 3 more authors.
Global and Planetary Change | Year: 2013
The Danube River Basin-Black Sea area represents a unique natural laboratory for studying the interplay between lithosphere and surface as well as source to sink relationships and their impact on global change. This paper addresses some information on the "active sink" of the system; i.e. the Danube deep sea fan and the Black Sea basin. The present study focuses on the distal sedimentary processes and the evolution of sedimentation since the Last Glacial Maximum. This is investigated through recently acquired long piston coring and shallow seismic data recovered at the boundary of influence of the distal part of the Danube turbidite system (to the north-west) and the Turkish margin (to the south). This dataset provides a good record of the recent changes in the sedimentary supply and climato-eustasy in the Black Sea region during the last 25. ka. This study demonstrates that the deep basin deposits bear the record of the Late Quaternary paleoenvironmental changes and that the western Black Sea constitutes an asymmetric subsident basin bordered by a northern passive margin with confined, mid-size, mud-rich turbidite systems mainly controlled by sea-level, and a southern turbidite ramp margin, tectonically active. © 2012 Elsevier B.V.
Montadert L.S.,Beicip Franlab
EAGE/SPE Subsalt Imaging Workshop 2014: Challenges of Subsalt Exploration and Imaging in the Middle East and North Africa Deep Water | Year: 2014
The Messinian (Latest Miocene) salinity crisis in the Mediterranean, only 700 000 years long, resulted in the widespread deposition of 1000-2500 m thick evaporites comprising mobile salt layers. Due to a 1500m sea level drop, these evaporites covered all the deepest areas at that time in the western and eastern Mediterranean whatever the local sedimentary and tectonic setting and pinch-out on the margins. Below the Messinian Evaporites, very thick (about 12km) Mesozoic sedimentary basins exist in the eastern Mediterranean: the Levant, Herodotus and Ionian basins. On the contrary, in the Western Mediterranean, the sedimentary basins are much younger: Lower Miocene like the Liguro- Provençal Basin.
Gorini C.,CNRS Paris Institute of Earth Sciences |
Montadert L.,Beicip Franlab |
Rabineau M.,CNRS Oceanic Domains Laboratory
Marine and Petroleum Geology | Year: 2015
Through several examples we show that following sea-level fall and marginal erosion during the Messinian salinity crisis (MSC), clastic inputs into the eastern and western Mediterranean Sea are not distributed evenly in space and time but are mainly limited to the lower section of the Messinian salinity crisis depositional megasequence. Significant similarities around the basin allow us to propose a Mediterranean Messinian salinity crisis depositional episode that can be divided into two seismic megasequences: the Messinian lower megasequence (MLM) and the Messinian upper megasequence (MUM). Their distinctive seismic facies correspond to systems tracts deposited during three main stages that represent a complete sea level cycle. (1) A falling stage systems tract including mass transport deposits and forced regressive clinoforms deposited in the early part of the falling stage, and related to the increasing rate of relative sea level fall. This stage is characterized by a marked shift in the depocenter towards the deep basins. (2) An early lowstand characterized by massive clastic inputs from major Messinian rivers (the Rhone, Nile, and Antalya Gulf rivers) or smaller river systems (offshore south Lebanon). These clastics were deposited in an oversaturated basin, as evidenced by the interfingering chaotic and transparent seismic facies of the Messinian lower megasequence (MLM). (3) A late lowstand, starting with rapid deposition of massive halite, with no detrital inputs into the deep basin. The upper part of the evaporites clearly onlaps the Messinian erosional surface at the margins and is evidence for a transition between a late lowstand stage and an early transgressive stage. These deposits belong to the Messinian upper megasequence (MUM). We interpret the transition between the two megasequences as the peak of the "salinity" crisis, the end of the relative sea level fall, and the maximum dispersal of sands into the deep Mediterranean basins. © 2015 .