Books and research papers of our employees
Zorin N., Bobachev A.
The transfer impedance of capacitive electrodes and insulated wires on the ground surface // Moscow University Geology Bulletin, 2022, 77(5), p. 585-595
This article presents a formula for the capacitance of a thin disk over a conducting plane corrected for the edge effects and offers a number of generalized expressions for assessing the transfer impedance of capacitive electrodes over ground with finite conductivity. It is shown that the transfer impedance of an insulated wire on the ground in a wide frequency range is described by the Cole–Cole formula with an exponent parameter from 0.9 to 1.
Zorin N., Epishkin D.
Effect of electrode contact resistance on electrical field measurements // Izvestiya, Physics of the Solid Earth, 2022, 58(5), p. 727-733
Electrical exploration on frozen or stony soil is associated with high difficulties in achieving good quality of electrode grounding. In such conditions, the results of high-frequency electric field measurements are often biased due to capacitive leakages in the receiving dipole and voltage division in the measuring circuit. We provide a brief description of currently existing methods of solving the problem of poor grounding conditions, and offer a new method of full analytical correction of distorted data.
Kulikov V., Ionicheva A., Korolkova A., Pushkarev P., Sokolova E., Yakovlev A.
3D inversion of MT data in the Southern Ladoga region // Moscow University Geology Bulletin, 2022, 77(1), p. 138-146
Based on the results of MT data inversion in the ModEM program a 3D geoelectric model of the Earth’s crust in the Southern Ladoga region to a depth of 60 km has been constructed. Two anomalous zones of crustal electrical conductivity oriented SE and NE are distinguished in the geoelectric model; the first one is a continuation of the well-known Ladoga anomaly. The presence of the second conductive structure confirms the results of the single-site magnetovariational soundings performed by I.I. Rokityansky in the several segments of the East European Platform in the early 1980s.
Zorin N., Yakovlev A.
A hybrid receiving line for measuring the electric field in a wide frequency band
// Moscow University Geology Bulletin, 2021, 76(6), p. 639-645
High-frequency electric field measurements with a regular receiving dipole with poor electrode contact are greatly influenced by capacitive currents between the wires and the ground. At the same time, noncontact receiving dipoles are not generally suitable for low-frequency electric field measurements. We introduce a novel hybrid galvanic-capacitive receiving dipole, which could be used for broadband electric field measurement, even with high contact resistance of grounded electrodes.
Zorin N., Alekseev D., Epishkin D., Shimizu H., Yakovlev D., Zaytsev S.
The impedance tensor and tipper are shown to be non-causal in some classes of 2-D and 3-D magnetotelluric (MT) models, including those widely encountered of shore. At the same time, examination of a large database of onshore MT records yields only a handful of non-causal tensors, being non-causal due to the infuence of nearby artifcial conductors rather than some exotic geological conditions. This result implies that the actual chance to encounter a non-causal impedance tensor or tipper in terrestrial MT exploration is vanishingly small, thus securing the universal applicability of the dispersion relation technique for quality assessment of the mentioned transfer functions.
Zorin N., Aleksanova E., Shimizu H., Yakovlev D.
Application of the dispersion relations (DR) in magnetotellurics (MT) is an efcient tool of post-processing and quality assessment of broadband feld data. The main limitation of the approach is that it requires the observed transfer functions to be causal and minimum-phase (MP), which is formally secured only for 1-D and some types of 2-D impedances. As a consequence, many MT practitioners involuntarily restrict the DR application to apparent resistivity curves acquired in relatively simple geological conditions. In the present research, we show how an inherently non-MP or non-causal transfer function could be recognized, and propose a universal technique, which makes it possible to correctly apply the DR virtually to any set of feld MT data.
Palshin N., Giraudo R.E., Yakovlev D., Zaytsev S., Aleksanova E., Zaltsman R., Korbutiak S.
Detalied MT study of the northern part of Subandean fold belt, Bolivia // Journal of Applied Geophysics, 2020, vol. 181, 104136.
A detailed magnetotelluric survey was carried out in the northern part of Subandean fold belt, Bolivia, with the main goal of better understanding of the geological structure of the sedimentary basin and petroleum system in the study area. An improvement of magnetotelluric technology was developed aimed at better imaging of resistivity structures in fold belt. A new static shift correction procedure and a new multistage unconstrained and constrained 2D inversion workflow was suggested and successfully implemented. In addition, the original 3D inversion approach was developed and its efficiency for fold belt geological settings was shown.
Kulikov V.A., Anoshina S.A., Bobachev A.A., Solovieva A.V., Turchkov A.M., Yakovlev A.G.
Integrated Geophysical Studies of an Esker in the Kaluga Region // Moscow University Geology Bulltin, 2019, vol. 74, № 4, p. 422-428.
This paper discusses integrated geophysical studies of an esker body in the Kaluga Region. An apparent polarizability anomaly was investigated. Integrated interpretation of geophysical data, drilling results, and core analysis made it possible to clarify the nature of the anomaly and confirm that the sand–gravel deposits contain zones with a high percentage of gravel of a magmatic origin, which are characterized by higher electrical polarizability.
Zaytsev S., Kulikov V., Yakovlev A., Yakovelv D.
In this paper we will discuss a few examples of 3D inversion of EM geophysical field data with the usage of Lomonosov supercomputer and show its effectiveness on several geological objects. Each object is associated with a variety of problems: from search for shallow ore to regional hydrocarbon exploration. But all these objects contain a large volume of measurements obtaining qualitative results for which requires a huge amount of time. So that the use of 3D inversion with a high-performance computational complex makes it possible to obtain a qualitative result of solving a wide range of problems.
Zorin N.I, Alekseev D.A.
Causality and dispersion relations in electrical prospecting // Russian Geology & Geophysics, 2018, vol. 59, p. 313-323.
The problem of causality in low-frequency electrical prospecting with artificial and natural sources is considered. We present numerical examples of the application of dispersion relations to transfer function spectra used in the induced polarization and controlled-source electromagnetic methods and to the components of telluric, horizontal magnetic, and other magnetotelluric tensors. Approaches to the processing and interpretation of spectra with violated dispersion relations are proposed.
Piskunova E. A., Palshin N.A., Yakovlev D.V.
Electrical conductivity features of the Arctic shelf permafrost and EM technologies for their studies // Russian Journal of Earth Sciences, 2018, vol. 18, ES5001.
The change in the ice conditions in the Arctic made it possible to study vast areas of the shelf by geophysical methods, including electromagnetic ones. The structure of the Arctic shelf subsea permafrost differs from the well-studied continental permafrost due to its accelerating degradation caused by the action of near-bottom waters. The features of the subsea permafrost are reflcted in the electrical conductivity of rocks, since this property is sensitive to parameters such as the pore fluid salinity and pore ice/gas hydrate content. The capabilities and resolution of various marine electromagnetic technologies are analyzed, especially in application to the Arctic shelf exploration, an area with the sea depths of up to 100 m, where relict permafrost may exist.
Afanasenkov A.P., Yakovlev D.V.
Application of electrical prospecting methods to petroleum exploration on the northern margin of the Siberian Platform // Russian Geology & Geophysics, 2018, vol. 59, p. 827-845.
This paper considers the potential of modern electrical prospecting methods for evaluating oil and gas occurrence on the northern margin of the Siberian Platform—a vast region from the Gydan Peninsula to the mouth of the Lena River. Results of regional electrical surveyes over the past 12 years in this region are generalized. The capabilities of electrical prospecting for solving the following four problems are defined: survey, in conjunction with seismics and drilling, in the Jurassic–Cretaceous part of the section; study of the structure of the Paleozoic sequence; study of the junction zones of large geoblocks and deep structure of the Earth’s crust and upper mantle; and study of the permafrost.
Kulikov V.A., Kaminskii A.E., Yakovlev A.G.
Combined 2D inversion of ERT and AMT data to solve mining problems // Journal of Mining Institute, 2017, vol. 223, p. 9-19.
Electrical methods of exploration are widely applied in prospecting and estimation of ore mineral resources. It is not always that geoelectrical models obtained in the course of interpretation of different types of electric and electromagnetic sounding are in line with each other. This leads to difficulties in geological interpretation of electrical exploration results. In single cases a geological model can be built that with great precision satisfies data from different electrical explorations, for instance, results of geometric and inductive electromagnetic soundings. For this purpose an algorithm of combined inversion of electrotomographic and audio-megnetotellurgic sounding data has been developed and implemented by A.E.Kaminskii in software ZondRes2D. Advantage of combined inversion has been shown for investigation of sections up till 400-500 m deep on synthetic models and actual field data.
Zorin N., Ageev D.
Electrical properties of two-component mixtures and their application to HFIP exploration of permafrost // Near Surface Geophysics, 2017, vol. 15, p. 603-613.
We investigate the problem of determination of the volumetric ratio between the two components of a heterogeneous mixture with unknown internal structure. If both resistivity and permittivity of one component are known to be much higher than those of the other within a sufficiently wide frequency range, the volumetric ratio may be roughly estimated from measured electromagnetic response of the mixture by making use of the variational approach. Otherwise, such estimation requires the exact knowledge of the inherent electrical properties of the mixed materials and application of some universal mixing model, such as the weighted power mean formula.
Palshin N.A., Aleksanova E.D., Yakovlev A.G., Yakovlev D.V., Breves Vianna V.
Over the past fifteen years the number of MT surveys increased manifold, which prompted the development of MT data acquisition technology, inversion and interpretation methods and the efficiency of the method achieved a new level. MT sounding method have become in high demand in the market of geophysical services. The application of MT sounding is especially effective in the regions with basalt traps, salt tectonics and folded belts, i.e. in the areas where seismic methods are confronted with certain difficulties.
Epishkin D.V.
A magnetotelluric (MT) data processing algorithm that demonstrates high robustness to intense electromagnetic noise that occurs in measured MT data has been developed. The key features of the algorithm are a specific approach to estimating different transfer functions and the ability to utilize all four channels acquired at remote reference stations. The code utilizes various techniques to reduce the estimation errors, including the robust Huber estimator, jack-knife approach, improved remote reference technique, and compensating for overestimation of power spectra.
Zorin N., Epishkin D., Yakovlev A.
Natural field induced polarization (NFIP) is a branch of low-frequency electromagnetics designed for detection of buried polarizable objects from magnetotelluric (MT) data. The conventional approach to the method deals with normalized MT apparent resistivity. We show that it is more favorable to extract the IP effect from solely electric (telluric) transfer functions instead.
Davydcheva S, Kaminsky A, Rykhlinski N, Yakovlev A
A large-scale field study in eastern Siberia using novel TDEM technology // Interpretation, 2015, v. 3, №2, p. T109-T120.
We evaluated the results of a large-scale commercial project that illustrated the capabilities of advanced timedomain electromagnetic (TDEM) technologies powered with integrated interpretation of geologic and geophysical data. To study the hydrocarbon prospectivity of a field in Eastern Siberia, we developed a survey design, and then acquired, processed, and interpreted the TDEM data from 30 profiles (total length 772 km) covering an area of approximately 1000 km2. The data were acquired using the conventional TDEM and a novel high-resolution version of TDEM, the focused-source electromagnetic method.
Sobornov K.O.
Russian fold belts: the next hot play? // Report made at GeoExPro, 2015.
Three successful cycles of petroleum reserve build-up can be recognised in the history of Russian petroleum exploration. Could the fold belts be the basis of the next cycle?
Alekseev D., Kuvshinov A., Palshin N.

Compilation of 3-D global conductivity model of the Earth for space weather applications // Earth, Planets and Space, 2015, 67:108.

We have compiled a global 3D conductivity model of the Earth with an ultimate goal to be used for realistic simulation of geomagnetically induced currents (GIC), posing a potential threat to man-made electric systems. The compiled 3D model represents the structure in depth range of 0–100 km, including seawater, sediments, earth crust, and partly the lithosphere/asthenosphere.
Zorin N

Spectral IP of low and moderately polarizable objects // Geophysics, 2015, v. 20, №5, p. E267-E276.

We have derived a reasonably accurate expression for the apparent spectral induced polarization (SIP) response of an arbitrary number of polarizable objects. The expression set a logical ground to the recently popularized Debye decomposition technique and provided a physical basis to phenomenological induced polarization models, such as Cole-Cole and others.
Berdichevsky M.N., Bubnov V., Aleksanova E., Alekseev D., Yakovlev A., Yakovlev D.

MT studies in Russia: regional-scale surveys and hydrocarbon exploration / in: Spichak V.V. (Ed.) Methods in geochemistry and geophysics, vol. 40: Electromagnetic sounding of the Earth's interior. - Elsevier B.V., 2015, 2nd edition. - pp. 379-401.

This book chapter represents an essential revision of the material published by Bubnov et al. (2007). In this text we briefly cover some results of recent regional-scale surveys, with primary target being Earth crust largescale structure, and then consider a number of case studies, aimed at hydrocarbon prospecting.
Kaufman A.A., Alekseev D., Oristaglio M.

Principles of EM methods in surface geophysics / in: Methods in Geochemistry and Geophysics, v. 45, 2014. - 770 p.

The book is devoted to the theory of electromagnetic methods of applied geophysics. It is intended for students and lecturers in geophysical departments, as well as for engineers and scientists involved in the use of electromagnetic fields in resource exploration and crustal geophysics.
Pankratov O.V., Geraskin A.I.

On processing of controlled-source EM data // Geologica Acta, 2010, v. 8, №1, p. 31-49.

In this paper, we present a fast and robust scheme of controlled-source EM data processing. We specify in detail various types of noise that affect measurements and show how these noise components can be uppressed. We promote an improved algorithm to process noisy data. We demonstrate that our method can recover response functions from extremely noisy field data. The proposed software can be adapted to new data sets and noisy environments. We apply our processing method to field data from Kola Peninsula, Norilsk region and Pechora province (Russia).
Aleksanova E.D., Alekseev D.A., Suleimanov A.K., Yakovlev A.G.

MT studies in salt-dome tectonic settings in the Pre-Caspian depression // First Break, 2009, v. 27, p. 105-109.

Seismic is often inefficient for imaging of the subsalt strata. This problem arises because of the strong velocity variations within the salt strata. Application of the MT methos in such conditions can provide more reliable information on the properties of subsalt sediments. The experience of mathematical modelling shows that MT is able to map relatively low-contrast anomalies with lateral size of 10 km and thickness of 1 km. In conditions typical for the Pre-Caspian depression, characterized by high content of clay minerals in Jurassic and Cretacous-Neogene rocks, MT is able to distinguish less conductive sandy layers from highly conductive clays.
Bubnov V.P., Yakovlev A.G., Aleksanova E.D., Yakovlev D.V., Berdichevsky M.N., Pushkarev P.Yu.

MT studies of the East-European Craton and adjacent territories // Acta Geophysica, 2007, vol. 55, №2, p. 154-168.

Magnetotelluric method is widely applied to study the Russian part of the East-European Craton, as well as the Caucasus and the Urals: several thousand soundings were performed during the last few years. Their periods range is approximately from 0.003 to 3000 seconds, which allows to study the sedimentary cover and the consolidated crust. MT investigations provided important information about the structure and reservoir properties of sedimentary complexes, the state of active geodynamic regions, the graphitization and fluid regime of the consolidated crust, and the permeable and fluid-saturated crustal zones.
Bubnov V.P., Yakovlev A.G., Aleksanova E.D., Yakovlev D.V., Berdichevsky M.N., Pushkarev P.Yu.

Regional MT explorations in Russia / in: Spichak V.V. (Ed), Methods in Geochemistry and Geophysics, vol. 40: Electromagnetic sounding of the Earth's interior. - Elsevier B.V, 2007. - pp. 351-367.

The book chapter provides a short review of the MT method application in several regional geophysical projects carried out in 1990s-2000s in the territory of Russia.