نوع مقاله : مقاله پژوهشی
نویسنده
گروه زمین شناسی، شرکت ملی مناطق نفت خیز جنوب، اهواز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
This research was conducted with the aim of analyzing the role of the Bala Rud Fault in controlling sedimentary geometry, the evolution of the carbonate platform, and the reservoir quality of the Taleh Zang Formation at the boundary between the Lorestan sub-basin and the Dezful Embayment. The study employed a combination of surface data from the Chenareh section with a thickness of 140 meters, 320 thin sections, and subsurface data from three wells in the Lab Sefid oil field, including petrography of drill cuttings, petrophysical logs, and daily drilling reports, along with microfacies analysis, biostratigraphy based on large benthic foraminifera, and petrophysical evaluation such as porosity, water saturation, and mud loss. The activity of the Bala Rud Fault has caused severe structural subsidence in the southern block. In the northern block, the carbonate platform is of the homoclinal ramp type with tidal flat, lagoon, nummulitic shoal, and open marine facies, whereas in the southern block it was of the distally steepened ramp type, and slide facies containing fragmented foraminifera along with planktonic foraminifera indicate a deep basin and open marine environment. Overall, the Bala Rud Fault was likely the main factor causing intra-basin changes, and the mechanical response of the basin led to a fundamental change in sedimentary geometry and the creation of deep slide environments. The most important finding is the identification of dolomitic-sandstone layers with a thickness of 4 meters and an average porosity of 20% and significant hydrocarbon saturation in the southern block. The analysis of severe drilling fluid loss also indicates the development of fault-related fractures and increased secondary permeability. These hydrocarbon-bearing horizons, which are trapped in stratigraphic traps, can be considered as new and independent exploration targets in the development plans of the fields in the northern Dezful Embayment.
کلیدواژهها [English]
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