Shallow velocity model from the transient electromagnetic method data: results of application in Eastern and Western Siberia

The geological section of Eastern and Western Siberia is an extremely complex object for a seismic exploration. The reason for this is the extremely high variability of the upper part of the section lithology, rough terrain, and permafrost rocks. This paper delivers an alternative approach to predicting the velocity model of the upper part of the section. The approach based on the original method of restoring the elastic-velocity characteristics from the data of transient electromagnetic method (TEM) in the near field zone. Research devoted to test the methodology of the shallow section velocity model calculation based on TEM data in a number of fields in Eastern and Western Siberia. Derived results aimed to improve the accuracy of the geological model building and the reliability of the hydrocarbon plays prediction. Synthetic modeling and field data confirm the high level of the proposed methodology effectiveness. It was shown that for the Eastern Siberia settings, an improvement in the quality of processing of seismic data consists in a significant increase in the dynamics and coherence of seismic recordings. In Western Siberia, it is possible to take into account the velocity anomalies associated with the permafrost rocks and zones of transit from the onshore part of the survey area to the sea. The main features of the study are useful in oil & gas companies and scientific institutions dealing with seismic data processing and interpretation to optimize expenses and improve blocks geology understanding.

Использование геофизических методов для изучения криогенного состояния пород разрабатываемых золоторудных месторождений Магаданской области

The authors consider the problem of applicability and sensitivity of methods of ground geophysics for studying the state of rock massifs in the permafrost zone. Using the example of gold deposits in Magadan Oblast, they study and analize peculiarities of changes in the values of electrical resistivity and induced polarization of soils, depending on their cryogenic state. Sufficiently high efficiency of geophysical methods in distinguishing thawed, seasonally thawed, locally frozen, and permafrost rocks is substantiated. The research results are recommended for optimizing field development processes in various engineering and geological settings.

Scientific and technological aspects and prospects for application of cryogenic drilling technology

In the article, we analyze types of drilling mud, which are used to drilling intervals of permafrost rocks; the importance of wellbore stability is noted. Wedescribethemain technologies, which have been being applied in the north of Western Siberia; these technologies are aimed at minimizing the loss wellbore stability due to violation of the temperature conditions in the well. We also analyze hydrocarbon systems, taking into account foreign experience, which is based on prospecting and exploratory drilling of ice deposits in Greenland and Antarctica. The article draws your attention to using synthetic fluids, monoesters and chladones. The difficulties of the existing technology and the disadvantages of the hydrocarbon systems are highlighted. We propose to apply a new cryogenic drilling technology, which consists in the use of synthetic fluorine-containing agents as flushing fluid at low temperatures. The text gives valuable information on composition of the proposed flushing fluid and the prospects of using the technology to prevent complications. Much attention is given to issue of manufacturing the main chemical reagent with the reduction of the generalized production chain of its production from the starting material, it is fluorspar.

Cryogenic soils in the area of Batagaika crater in Northern Yakutia

The subject of this research is the soil and catena soils in the area of Batagaika crater located in Verkhoyansk District of Northern Yakutia. Soils are usually represented by Cryosols Gleyic and Podzols Entic, which are formed on eluvial and eluvial-deluvial deposits under larch forests. Exploration of soils was carried out in 2017, 2018 and 2019. On the slope to the Batagaika crater is the soil-geochemical catena, which included the ridge-top surface of the slope of Kirgilyah Mountain, the middle part of the slope, as well as levelled surfaces of Batagaika crater. Soil types are described in accordance with the classification of soils of Russia (2004) and the World Reference Base of Soil Resources (2014 WRB). The following conclusions were made: 1) The soil cover in the area Batagaika crater features various types of soils formed on the permafrost rocks, mainly Cryosols Gleyic, found in various landscape conditions, and Podzols Entic are also sporadically distributed in the area. On alluvial deposits in the valley of the Batagaika River may develop Podzols Haplic. Leptosols Lithic are confined to the elevation of the relief with bedrock located close to the surface; 2). The main processes typical for soils in the area of Batagaika crater are: cryogenic structuring, organic matter accumulation, coarse--humus accumulative processes, gleyification; 3) Nearby the horizon of permafrost rocks in the area of Batagaika crater is marked a local minimum of PH level in Podzols and Cryosols.