Izvestiya of Saratov University.
ISSN 1819-7663 (Print)
ISSN 2542-1921 (Online)


Геология

Chukhonastovka – the reference section of the Turonian-Lower Santonian from the Volga-Ilovlya interfluve (the Volga right bank area near Volgograd). Paper 1. The section descriptions

The paper presents detailed biostratigraphical division and lithological characteristics of the Turonian-Lower Santonian interval within the compiled Chukhonastovka section. The presence of the Lower Turonian deposits has been ascertained alongside with the unusual structure of the rock interval synchronous to the Lower Santonian “sponge” horizon.

Evaluation of fault reactivation risks during drilling of the horizontal well using results of one-dimensional geomechanical modeling

The article presents main factors affecting the fault stability. Concepts of critically stressed faults and critical pore pressure are discussed. The methodologies for evaluation of stressed-deformed state of rocks in the vicinity of fault zones during reservoir depletion and injection, well drilling are analyzed. 1D geomechanical models of fishbone sidetracks and main borehole of the well N are constructed.

New Genus of the Actinopterygian Fishes (Eurynotoidiidae) from the Urzhumian of Republic of Tatarstan (Kluchevskoy Ovrag locality)

New genus and species of eurynotoidiid actinopterygians (Eurynotoidiformes), Kluchevichthys praeclarus gen. et sp. nov., is described from the uppermost Urzhumian (Kluchevskoy Ovrag locality), Tetushi District, Republic of Tatarstan. The holotype of а new form is an almost complete, non-deformed skeleton. The diagnostic characters of K. praeclarus were obtained in the morphology of the skull roof bones, dental system, scales and fins.

Postsporadopyle – colonial representatives of Craticulariidae (Porifera, Hexactinellida)

Among Craticulariidae, the representatives of Postsporadopyle are peculiar for the skeleton intricate morphology determined by dichotomy and trichotomy of the primary modules. Besides the P. triloba known from the Santonian of the Volga region, two previously unknown here species are considered.

Влияние некоторых параметров на устойчивость склона

В статье проводится анализ положения в массиве склона слабого слоя, его угла наклона и влияние этих параметров на устойчивость склона. В случае подходящих условий (изменение гидродинамического режима, влияние тектоники, антропогенное воздействие и т.д.) существуют предпосылки для активизации оползневых процессов. На территориях платформ широко развиты склоны в почти горизонтальных слоях, но имеющих, как правило, неровное залегание; в геосинклинальных областях, преимущественно в горных районах, углы наклона слабых слоев имеют порой значительные значения.

Genus Sororistirps (Porifera, Hexactinellida, Ventriculitidae)

Representatives of the genus Sororistirps, distinguished among the Ventriculites, have been detected in the Santonian – Maastrichtian rocks from the southeast of the Russian Plate. The structures of the skeletons and of the irrigation systems have been considered, the Sororistirps morphogenesis has been traced; the forms characteristic of the Santonian, Campanian and Maastrichtian spongiocomplexes have been determined.

Application of machine learning in the analysis of seismic data to identify tectonic faults in various seismogeological conditions

The article presents the results of a comparative analysis of algorithms for automatic interpretation of tectonic faults based on seismic data recorded in various seismogeological conditions. For each type of geological section (platform, salt tectonics, marine data), a cube of the probability of violations by an analytical algorithm and using trained neural networks was calculated.

On the issue of the methodology for lithologic and petrophysical studies of stone material (in the process of oil and gas wells drilling)

This article discusses some aspects of the methodology for preparing sludge and core samples for lithological and petrophysical studies. Methods for obtaining rockmaterial(sludge, core) are described interms of determiningthemoment of openingthe reservoir layer,tyingthe core in depth, and sampling the sludge. A sludge collector has been proposed that makes it possible to obtain sludge of overall fractions washed from the drilling fluid.

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