• OpenAccess
    • List of Articles کژدمی

      • Open Access Article

        1 - Geochemical characterization and oil family definition for the Azadegan reservoir in the Azadegan oil field
        سید حسین حسینی
        Abstract This study aims at geochemical investigation of the hydrocarbons contained within the Azadegan sandstone reservoir by using the GC and GC-MS techniques. The Azadegan reservoir contains paraffinic and paraffinic – naphthenic oils with an API of 30. The gas chro More
        Abstract This study aims at geochemical investigation of the hydrocarbons contained within the Azadegan sandstone reservoir by using the GC and GC-MS techniques. The Azadegan reservoir contains paraffinic and paraffinic – naphthenic oils with an API of 30. The gas chromatograms reveal that the source rocks responsible for these oils contains mainly type II kerogen deposited in a reducing environment. According to these data the studied oils have a relatively high level of thermal maturity. Ratios of C35S/C34S, C29/C30, C31R/C30 Hopane and Pr/Ph, Ph/nC18 show that the studied oil derived from carbonate source rock; which is also evident form Pr/Ph Vs. DBT/Phen diagrams. Diagrams of (20R) C29/C27 vs. Pr/Ph as well as the ratios of C21+/C21-, Pr/P, TAR are consistent with abundance of algal organic matter. Presence of Tricyclic terpanes, higher ETR ratios and diagrams of δ13C vs. Pr/P introduce a Jurassic aged source rock for the studied oils. Based on biomarker and isotopic data it could be concluded that oils within the Azadegan reservoir are mainly derived from carbonate source rocks of Mid-Upper Jurassic which are deposited in paralic/open marine environment with a predominance of algal organic matter. Manuscript profile
      • Open Access Article

        2 - An attempt to reservoir characterization of Burgan sand, in the northwest of the Persian Gulf toward Kuwait
        Ali reza Bashari
        The Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in More
        The Sand tongues of the Albian Kazhdumi Formation is a major prodactive reservoir in North West part of the Persian Gulf towards Kuwait . High porosity and high permeability of these sandstones together with existence of shale either as source rock or cap rock in this formation, have provided all conditions needed for hydrocarbon accumulation. A rapid sea level fall in ealry Albian initiated the deposition of Burgan clastic reservoirs over the Shuaiba Carbonates. The lower Burgan Formation was deposited in a lowstand systems tract represented by massive sandstone reservoirs. High frequency sealevel changes have resulted in deposition of shoreface sands and extensive marine shales within an overall fluvial setting. The middle part Burgan was deposited in a transgressive systems tract. The upper part witnessed a relative sealevel fall in a lowstand systems tract with deposition of sand prone facies in estuarine channels. The clastic cycle was terminated by initiation of Mauddud carbonate sedimentations in transgressive systems tract. A combined effect of allocyclic nesting of sequence stratigraphic packages and autocyclic ramp profile were the primary factors controlling the lithofacies association. This Formation has been informally subdivided into: Lower Interval (C) mainly shaly sands, middle Interval (B) clean sands “main reservoir” and upper Interval (A) interbedded shale & sands. Petrographic analysis shows that the reservoir consists of quartz-rich sands, (typically>70%) and feldspar poor (mainly <5%). Nine authigenetic minerals in the Burgan sands have been identified: quartz, calcite, siderite, pyrite, glauconite along with four groups of the clay minerals. XRD analysis of clay fraction indicates the presence of four clay mineral groups in the Burgan reservoirs : kaolin, illite , chlorite and expandible- lattice mixed –layer, illite/ smectite. Manuscript profile
      • Open Access Article

        3 - palaeoechology and taphonomy of Albian-Cenomanian Echinoids of Kazhdumi Formation in Firouzabad section, Zagros Basin
        Babak Sedghi Ali Bahrami Yazdi Yazdi
        Kazhdumi Formation deposits in Firouzabad section were investigated regarding the postmortem and burial events of echinoderms, from about 150 echinoderm fossils which include 10 genera and 13 species of Coenholectypus neocomiensis, Phymosoma binexilis, Dorocidaris taouz More
        Kazhdumi Formation deposits in Firouzabad section were investigated regarding the postmortem and burial events of echinoderms, from about 150 echinoderm fossils which include 10 genera and 13 species of Coenholectypus neocomiensis, Phymosoma binexilis, Dorocidaris taouzensis, Cottaldia aff. Benettiae, Leptosalenia sergipensis, Phymosoma baylei, Micropedina olisiponensis, Tetragramma deshayesi, Macraster douvillei, Mecaster batnensis, Macraster obtritus, Pliotoxaster comanchei, Macraster sp., Hemiaster sp. most part of them suffer from disarticulation and fragmentation, radial cracks and shell deformation (test outline distortion and radial cracking) and volume change and biological erosion (bioerosion) and perforation by living worms (microboring). Of course, after volume changes, fractures or taphonomic compression, the existing solutions (hydrocarbon and solutions rich in iron, manganese and sometimes silica) hydroxides have been replaced in the cracks. The test of these echinoderms has been used by symbiotic epifauna such as Osterids and Gryphaes as food and attachment points and shelter after their death and burial. It seems that the volume change, crushing, solution injection and fauna bending are influenced by the tectonic pressure of the salt domes of the region and the soft lithology (high plasticity) of the Kazhdami formation between the Darian and Sarvak formations. Manuscript profile