Search results for "Source rock"
showing 10 items of 12 documents
Some sedimentological and geochemical characters of the late Triassic Noto formation, source rock in the Ragusa basin (Sicily)
1990
URA 724 du CNRS a intégré UMR 6113 - ISTO CNRS Université d'Orléans; In the Ragusa basin (southeastern Sicily), the late Triassic Noto formation is considered as the main oil source rock. We provide a detailed description of the sedimentary facies determined from core samples, and discuss geochemical results, obtained for both kerogens and chloroform extractable hydrocarbons from samples where sedimentary organic matter is immature. Two main sedimentary sequences were encountered: (i) layers of limestones and of marls (or shales) alternating at a metric scale, and (ii) laminites having various types and carbonate contents. The high petroleum potentials (S2 up to 100 kg HC/t rock) are relate…
Conjunctive use of spectral gamma-ray logs and clay mineralogy in defining late Jurassic-early Cretaceous palaeoclimate change (Dorset, U.K.).
2006
Abstract Detrital clay mineralogy is controlled by weathered source rock, climate, transport and deposition that in turn influence the spectral gamma-ray (SGR) response of resultant sediments. Whilst a palaeoclimate signal in clay mineralogy has been established in some ancient successions, the SGR response remains contentious, largely because the data sets have yet to be collected at the same or appropriate vertical scales to allow comparison. In addition, the influence of organic matter on SGR is not always considered. Here, we present clay mineralogical, total organic carbon (TOC) and SGR analyses from the late Jurassic and early Cretaceous of the Wessex Basin, a period of previously doc…
Fracture stratigraphy and oil first migration in Triassic shales, Favignana Island, western Sicily, Italy
2021
This study aims at evaluating the control exerted by fracture stratigraphy and diagenetic processes on oil first migration through an outcropping, mixed carbonate-siliciclastic succession. The present work included results of sedimentological, paleontological, mineralogical, petrographic, structural, and microstructural analyses carried out on organic-rich shales exposed at the Favignana Island of Sicily, Italy. The analyses focus on Upper Triassic yellowish siltstones and greyish laminated dolomitic limestones, which form a 10's of m-thick succession exposed along the westernmost portion of the Sicilian fold-and-thrust belt. The studied succession deposited in a coastal lagoon associated t…
Coupled petrological-geodynamical modeling of a compositionally heterogeneous mantle plume
2018
Abstract Self-consistent geodynamic modeling that includes melting is challenging as the chemistry of the source rocks continuously changes as a result of melt extraction. Here, we describe a new method to study the interaction between physical and chemical processes in an uprising heterogeneous mantle plume by combining a geodynamic code with a thermodynamic modeling approach for magma generation and evolution. We pre-computed hundreds of phase diagrams, each of them for a different chemical system. After melt is extracted, the phase diagram with the closest bulk rock chemistry to the depleted source rock is updated locally. The petrological evolution of rocks is tracked via evolving chemi…
Paleoenvironmental evolution of the Pliocene Villarroya Lake, northern Spain. A multidisciplinary approach
2002
The Pliocene Villarroya basin fill consists of lacustrine and alluvial deposits over 100 m thick. The lacustrine deposits, up to 30 m thick, comprise three sequences. The two lower sequences consist of profundal, laminated deposits formed by mostly terrigenous facies that are overlain by charophytic carbonates and varves. The uppermost, third sequence made up of massive bioturbated mudstones corresponds to a very shallow lacustrine-palustrine environment. Bulk mineralogy comprises carbonates, clay minerals, quartz and feldspars. The carbonates are: exogenic, biogenic calcite and biogenic aragonite. Biogenic calcite constitutes ostracod shells and charophyte stem encrustations, whereas arago…
Characterization of a fractured basement reservoir using high-resolution 3D seismic and logging datasets: A case study of the Sab'atayn Basin, Yemen.
2018
The Sab'atayn Basin is one of the most prolific Mesozoic hydrocarbon basins located in central Yemen. It has many oil producing fields including the Habban Field with oil occurrences in fractured basement rocks. A comprehensive seismic analysis of fractured basement reservoirs was performed to identify the structural pattern and mechanism of hydrocarbon entrapment and reservoir characteristics. A 3D post-stack time migration seismic cube and logging data of 20 wells were used and several 2D seismic sections were constructed and interpreted. Depth structure maps were generated for the basement reservoir and overlying formations. The top of the basement reservoir is dissected by a set of NW-S…
Importance des variations latérales discrètes dans les apports détritiques, observées dans des faciès de rampe sédimentaire riches en matière organiq…
2017
17 pages; International audience; We studied a potential petroleum source rock deposited in a clastic-dominated ramp environment: the Argiles de Châtillon Formation (Kimmeridgian-Tithonian, Boulonnais area, northern France). The formation was deposited along a proximal-distal gradient on this ramp affected by synsedimentary fault movements. A sedimentological, mineralogical and geochemical study was conducted to decipher the distribution patterns of sedimentary parameters along such a depth increase over the ramp. It comes out that smectite distribution unexpectedly mimics the lateral depth evolution despite the good floatability of the mineral. It is also observed that the Argiles de Châti…
Melt production, redistribution and accumulation in mid-crustal source rocks, with implications for crustal-scale melt transfer
2014
Abstract Ascent of granitic melt initiates under suprasolidus conditions in the mid- to lower crust before continuing through subsolidus rocks to higher crustal levels. Whereas migration of melt in suprasolidus rocks can occur in pervasive net-like structures and involve relatively small melt volumes, ascent through the subsolidus crust requires more focused, dyke-like structures and larger volumes to prevent freezing. Migmatites in the Aus granulite terrain, southern Namibia, preserve evidence that large-scale melt redistribution and accumulation occurred in the near-source region under suprasolidus conditions. Melt that was mainly produced in metapelitic rocks utilised pervasive small-sca…
Melting and dynamic metasomatism of mixed harzburgite + glimmerite mantle source: Implications for the genesis of orogenic potassic magmas
2017
Abstract Tectonically young, orogenic settings are commonly the sites of post-collisional silica-rich ultrapotassic magmas with extreme K2O-contents of up to 9 wt% and K2O/Na2O > 2. Many experimental studies investigating the generation of these melts have concentrated on melting of homogenous phlogopite bearing peridotites, whereas geochemical signatures indicate the involvement of at least two types of source rocks: ultra-depleted and K and trace elements-enriched ones. We report the results of melting experiments at 1–2 GPa of mixed glimmerite and harzburgite, in which these rock types make up two halves each capsule. Melting begins in the glimmerite, and its metasomatic effects on the h…
New experiment to model self-organized critical transport and accumulation of melt and hydrocarbons from their source rocks
2001
A new, simple, and easily reproducible experiment was designed to simulate the production, accumulation, and transport of melt within rock. The transport was found to be of the self-organized critical type. The emergence of self-organized criticality is explained by the availability of hydrofracture propagation as a rapid or ballistic transport mechanism. This mechanism also serves as a mechanism for stepwise accumulation. These findings are confirmed by a numerical model, which shows the emergence of self-organized critical behavior when Darcian transport cannot accommodate transport and the dormant transport mechanism of hydrofracture propagation is activated. Ballistic and self-organized…