LITOPHYSICAL STRUCTURE OF MIDDLE DEVONIAN DEPOSITS OF THE DOBRUDJA FOREDEEP IN THE CONTEXT OF THE THREE-LAYER RESERVOIR MODEL

• Дата: 2026
• Автори: Григорчук, К.Г., Гнідець, В.П., Кошіль, Л.Б., Яковенко, М.Б.
• Формат: Стаття
• Мова: Українська
• Опубліковано: Institute of Geological Sciences, NAS of Ukraine 2026
• Теми: Dobrudja Foredeep; Middle Devonian; lithophysical structure
• Онлайн доступ: http://geojournal.igs-nas.org.ua/article/view/343948
• Назва журналу: Geological journal

In the work, for the first time, models of a three-layer lithophysical structure were developed for the Middle Devonian sediments of the Dobrudja Foredeep, which showed a rather complex picture of the spatial and age development of fluid-resistant packs and reservoir rocks, which is most clearly observed on the Skhidnosaratska structure, and is recorded by the lateral variability of the thicknesses of true fluid-resistant packs, reservoir horizons, as well as wedging or stratification of false fluid-resistant packs. In the area of the Yaroslavskaya, Saratskaya and Rozovskaya structures, the lithophysical structure of the stratum is more stable and homogeneous. For the Skhidnosaratskastructure, arched hydrocarbon traps are outlined, which in most productive horizons are composed not only of reservoir rocks, but also of false fluid-resistant packs, which often form the main volume of the reservoir. In the area of the Yaroslavska structure, the presence of partially tectonically shielded traps (horizons e-1–e-3, g-2–g-4) is predicted, which are also of interest due to the increased thickness of the reservoir rock horizons and the relatively insignificant development of false fluid-resistant packs. Local or zonal natural reservoirs were discovered in the latter units, which include sulfate-carbonate reservoir rocks. This, as well as the heterogeneous mosaic structure of carbonate reservoir rocks and the specific properties of the “Saratskaya” oil, require special technological approaches when testing wells. Instead, the latter were carried out using traditional methods, which is one of the reasons for obtaining small and unstable hydrocarbon inflows. Failure to take into account the lithofacies and lithophysical features of the Middle Devonian deposits did not allow for the application of the optimal regime of reservoir opening and well development and, accordingly, obtaining significant oil inflows. In addition, the test intervals usually covered several productive horizons, probably with different energies, which could cause fluid interflow and negatively affect the results of oil field tests. The regional nature of the distribution of various signs of oil content probably records the migration paths of hydrocarbons at different stages of catagenesis. In this regard, it is planned to reconstruct the history of postdiagenesis in the future, including in the context of its influence on the formation of false fluid-resistant packs.