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Hydrocarbon Generation Histories (hydrocarbon_generation + history)
Selected AbstractsTHERMAL HISTORY RECONSTRUCTION IN THE SOROOSH AND NOWROOZ FIELDS, PERSIAN GULF, BASED ON APATITE FISSION TRACK ANALYSIS AND VITRINITE REFLECTANCE DATAJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2008A. Bashari The thermal history of the sedimentary successions at the Soroosh-17, Soroosh-02 and Nowrooz-16 wells in the northern Persian Gulf have been studied using apatite fission track analysis and vitrinite reflectance data. These data were used to identify and quantify episodes of heating and cooling which have affected the sections penetrated by these wells. This information was synthesised to provide a thermal history framework for the wells, within which the history of hydrocarbon generation, as well as regional structural development, can be understood. Preliminary hydrocarbon generation histories are presented for the Soroosh and Nowrooz oilfields and nearby areas. Modelling of hydrocarbon generation histories based on the AFTA- and VR-derived thermal histories, assuming a dominant Type III kerogen for possible Albian Kazhdumi Formation source rocks and a dominant Type II kerogen for possible Neocomian Fahliyan (Lower Ratawi) Formation source rock, suggest that local sourcing of oil from the Kazhdumi Formation is unlikely. The most likely source rock for oil in the Burgan Formation reservoir at Soroosh-17 and Nowrooz-16 is interpreted to be the Fahliyan Formation based on the available data. On the other hand, speculative modelling of the Hendijan-I well down-dip from the Nowrooz field does allow some oil to be generated from the Kazhdumi sequence at that location, and this might be available for migration to the Nowrooz field. [source] DISTRIBUTION OF SOURCE ROCKS AND MATURITY MODELLING IN THE NORTHERN CENOZOIC SONG HONG BASIN (GULF OF TONKIN), VIETNAMJOURNAL OF PETROLEUM GEOLOGY, Issue 2 2005C. Andersen The northern offshore part of the Cenozoic Song Hong Basin in the Gulf of Tonkin (East Vietnam Sea) is at an early stage of exploration with only a few wells drilled. Oil to source rock correlation indicates that coals are responsible for the sub-commercial oil and gas accumulations in sandstones in two of the four wells which have been drilled on faulted anticlines and flower structures. The wells are located in a narrow, structurally inverted zone with a thick predominantly deltaic Miocene succession between the Song Chay and Vinh Ninh/Song Lo fault zones. These faults are splays belonging to the offshore extension of the Red River Fault Zone. Access to a database of 3,500 km of 2D seismic data has allowed a detailed and consistent break-down of the geological record of the northern part of the basin into chronostratigraphic events which were used as inputs to model the hydrocarbon generation history. In addition, seismic facies mapping, using the internal reflection characteristics of selected seismic sequences, has been applied to predict the lateral distribution of source rock intervals. The results based on Yükler ID basin modelling are presented as profiles and maturity maps. The robustness of the results are analysed by testing different heat flow scenarios and by transfer of the model concept to IES Petromod software to obtain a more acceptable temperature history reconstruction using the Easy%R0 algorithm. Miocene coals in the wells located in the inverted zone between the fault splays are present in separate intervals. Seismic facies analysis suggests that the upper interval is of limited areal extent. The lower interval, of more widespread occurrence, is presently in the oil and condensate generating zones in deep synclines between inversion ridges. The Yükler modelling indicates, however, that the coaly source rock interval entered the main window prior to formation of traps as a result of Late Miocene inversion. Lacustrine mudstones, similar to the highly oil-prone Oligocene mudstones and coals which are exposed in the Dong Ho area at the northern margin of the Song Hong Basin and on Bach Long Vi Island in Gulf of Tonkin, are interpreted to be preserved in a system of undrilled NW,SE Paleogene half-grabens NE of the Song Lo Fault Zone. This is based on the presence of intervals with distinct, continuous, high reflection seismic amplitudes. Considerable overlap exists between the shale-prone seismic facies and the modelled extent of the present-day oil and condensate generating zones, suggesting that active source kitchens also exist in this part of the basin. Recently reported oil in a well located onshore (BIO-STB-IX) at the margin of the basin, which is sourced mainly from "Dong Ho type" lacustrine mudstones supports the presence of an additional Paleogene sourced petroleum system. [source] Mudstone compaction curves in basin modelling: a study of Mesozoic and Cenozoic Sediments in the northern North SeaBASIN RESEARCH, Issue 3 2010Ĝ. Marcussen ABSTRACT Basin modelling studies are carried out in order to understand the basin evolution and palaeotemperature history of sedimentary basins. The results of basin modelling are sensitive to changes in the physical properties of the rocks in the sedimentary sequences. The rate of basin subsidence depends, to a large extent, on the density of the sedimentary column, which is largely dependent on the porosity and therefore on the rate of compaction. This study has tested the sensitivity of varying porosity/depth curves and related thermal conductivities for the Cenozoic succession along a cross-section in the northern North Sea basin, offshore Norway. End-member porosity/depth curves, assuming clay with smectite and kaolinite properties, are compared with a standard compaction curve for shale normally applied to the North Sea. Using these alternate relationships, basin geometries of the Cenozoic succession may vary up to 15% from those predicted using the standard compaction curve. Isostatic subsidence along the cross-section varies 2.3,4.6% between the two end-member cases. This leads to a 3,8% difference in tectonic subsidence, with maximum values in the basin centre. Owing to this, the estimated stretching factors vary up to 7.8%, which further gives rise to a maximum difference in heat flow of more than 8.5% in the basin centre. The modelled temperatures for an Upper Jurassic source rock show a deviation of more than 20 °C at present dependent on the thermal conductivity properties in the post-rift succession. This will influence the modelled hydrocarbon generation history of the basin, which is an essential output from basin modelling analysis. Results from the northern North Sea have shown that varying compaction trends in sediments with varying thermal properties are important parameters to constrain when analysing sedimentary basins. [source] | ||||||||||