Geophysical Research Research Articles

Theoretical foundations of point cloud coordinate system transformation

Purpose. To provide theoretical foundations and develop mathematical models for the efficient transformation of coordinate systems for point clouds in geophysical research; the scientific analysis is aimed at developing algorithms and establishing necessary dependencies for the reliable integration of data obtained at different time points into a unified coordinate system, opening up prospects for further study and analysis of processes in geophysical research. The methods.The calculation is carried out using the following steps. Determination of known coordinates of four points (x1', y1', z1'; x2', y2', z2'; x3', y3', z3'; x4', y4', z4') in a hypothetical coordinate system (X', Y', Z') and the coordinates of the same points (x1, y1, z1; x2, y2, z2; x3, y3, z3; x4, y4, z4) in the coordinate system (X, Y, Z) to which the point clouds need to be transformed. Determination of constants a1, a2, a3, d, b1, b2, b3, e, c1, c2, c3, f through a system of equations. After determining the constants, the coordinates of points (x', y', z') in the hypothetical coordinate system (X', Y', Z') are calculated using equations where each equation expresses the coordinates of points (x', y', z') in terms of coordinates of points (x, y, z) in the coordinate system (X, Y, Z) and the determined constants. After performing the calculations, point clouds can be merged into a single coordinate system using the computed coordinates (x', y', z'). This methodology allows for the successful transformation of coordinate systems for point clouds in geophysical research. Findings. Analytical regularities have been established based on known coordinates of four points in both coordinate systems, allowing for the efficient transformation of a point cloud from one coordinate system to another. The originality. For the first time, precise analytical dependencies have been established that enable the efficient transformation of point clouds from one coordinate system to another using known coordinates of four points in both systems. Practical implementation. The obtained dependencies enable the efficient transformation of point clouds from one coordinate system to another using known coordinates of four points in both systems.

REVIEW AND CRITICAL ANALYSIS OF THE CURRENT STATE AND WAYS OF DEVELOPING THE TECHNOLOGICAL PROCESS OF OIL PRODUCTION BY AN ELECTRIC DRIVE IN INTERMITTENT MODES OF OPERATION OF LOW- AND MEDIUM-RATE WELLS

Link for citation: Kladiev S.N. Review and critical analysis of the current state and ways of developing the technological process of oil production by an electric drive in intermittent modes of operation of low- and medium-rate wells. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 8, рр. 220-231. In Rus. Relevance. The Russian Federation is one of the world leaders among oil-producing countries in terms of proven oil reserves. Historically, industrial oil production in the Russian Empire began in the area of the Caspian Sea on the territory of modern Azerbaijan. The energy strategy of the Russian Federation for the period up to 2035, as one of the measures to ensure the energy security of the country, provides for the introduction into economic circulation of hard-to-recover oil reserves (including from the Bazhenov formation) based on innovative domestic technologies and equipment. The main problem of the oil industry in Russia, as well as throughout the world, is the decline in the quality of the resource base. In oil-producing regions, there is a depletion of active oil reserves. Significant residual reserves of developed fields are expected to be brought into active exploitation using new oil production technologies. Ways of growth in oil production are possible in accordance with three different scenarios: innovative – it is supposed to increase the contribution to the total indicators of Russian oil production from new provinces, such as Eastern Siberia, the Republic of Sakha (Yakutia), as well as new fields in Western Siberia and the Krasnoyarsk Territory and the development of the shelf northern seas; forced scenario – in case of more active introduction of new technologies and incentive measures that reduce the cost of the production process, it is possible to increase the efficiency of oil production in offshore and hard-to-recover fields; extensive scenario of oil production is possible only at high market prices for oil. The main volume of production is carried out and will continue to be exclusively electrically driven. The purpose: a review and critical analysis of the current state and ways of developing the technological process of oil production by an electric drive in intermittent modes of operation of low- and medium-rate wells. Object: theoretical substantiation of the introduction of cyclic or short-term operation of electric centrifugal pump installations with an electric drive method of downhole oil production into practice. Methods: geophysical research to develop a concept for the operation of a marginal well stock, ways to increase the profitability of oil production, methods for optimizing the stock of medium and marginal wells, putting them into economic circulation. Results. Based on a critical analysis of literary sources and a feasibility study, it is shown that the most promising way to extract hard-to-recover oil reserves on the example of the Bazhenov formation is the electric drive of a submersible centrifugal pump according to the scheme «ground power converter – submersible cable – submersible electric motor – electric centrifugal pump». The technology of cyclic operation of wells in oil production shown that it is economically feasible for low- and medium-rate wells and is widely implemented in wells that cannot be operated in a continuous mode.

Identification of Repeating Earthquakes: Controversy and Rectification

Abstract Repeating earthquakes (repeaters) are events that recurrently rupture the same fault patch with nearly identical magnitudes. Although repeaters have been widely studied and utilized in many fields over the last four decades, there are no standard criteria for reliably identifying such events. The current criteria adopted in the geophysical research community are inconsistent and difficult to justify. Different criteria may inescapably incur inadequate hypotheses and lead to controversial interpretations, highlighting the urgent need for seeking a uniform approach to reliably identify repeaters. In this study, we address this long-standing issue by deriving the most logical criteria on the basis of theoretical calculation with simple yet reasonable assumptions. Quantitatively, we define a repeating pair if their interevent distance is ≤80% of the rupture area of the larger event and their magnitude difference is ≤0.3. We demonstrate the superiority of our proposed approach with challenging cases in California, and our results shed new insight into the hierarchical fault structures in the source areas. Although this study focuses on defining repeating earthquakes, the application to repeating seismic events in other planetary bodies such as moonquakes and marsquakes is straightforward, potentially help avoid misinterpretations of the physical processes in both Earth and planetary interiors.

Geophysics in Antarctic Research: A Bibliometric Analysis

Antarctica is of great importance in terms of global warming, the sustainability of resources, and the conservation of biodiversity. However, due to 99.66% of the continent being covered in ice and snow, geological research and geoscientific study in Antarctica face huge challenges. Geophysical surveys play a crucial role in enhancing comprehension of the fundamental structure of Antarctica. This study used bibliometric analysis to analyze citation data retrieved from the Web of Science for the period from 1982 to 2022 with geophysical research on Antarctica as the topic. According to the analysis results, the amount of Antarctic geophysical research has been steadily growing over the past four decades as related research countries/regions have become increasingly invested in issues pertaining to global warming and sustainability, and international cooperation is in sight. Moreover, based on keyword clustering and an analysis of highly cited papers, six popular research topics have been identified: Antarctic ice sheet instability and sea level change, Southern Ocean and Sea Ice, tectonic activity of the West Antarctic rift system, the paleocontinental rift and reorganization, magmatism and volcanism, and subglacial lakes and subglacial hydrology. This paper provides a detailed overview of these popular research topics and discusses the applications and advantages of the geophysical methods used in each field. Finally, based on keywords regarding abrupt changes, we identify and examine the thematic evolution of the nexus over three consecutive sub-periods (i.e., 1990–1995, 1996–2005, and 2006–2022). The relevance of using geophysics to support numerous and diverse scientific activities in Antarctica becomes very clear after analyzing this set of scientific publications, as is the importance of using multiple geophysical methods (satellite, airborne, surface, and borehole technology) to revolutionize the acquisition of new data in greater detail from inaccessible or hard-to-reach areas. Many of the advances that they have enabled be seen in the Antarctic terrestrial areas (detailed mapping of the geological structures of West and East Antarctica), ice, and snow (tracking glaciers and sea ice, along with the depth and features of ice sheets). These valuable results help identify potential future research opportunities in the field of Antarctic geophysical research and aid academic professionals in keeping up with recent advances.

Applying Map Filters and Inversion Model for Gravity Data in Matlab-based Application

In general, there are two types of processes using the gravity method, that is the basic processes and the advanced processes. The basic process includes Gravity Meter reading conversion until the gravity corrections process. While the advanced process is a process to put an edge on the geological appearance of the research area that is already in the form of a map. The advanced process includes map filtering and inversion modeling. This advanced processing of gravity data is very useful, one of which is to separate regional anomalies and local anomalies, while inversion modeling is useful for knowing the approximate location of the anomaly depth. What will be applied to the software is advanced processing, because in its application this processing is required in every geophysical research and requires data processing support tools. However, for now, gravity data processing software, especially for the filtering and data modeling process is available as a licensed software. Where not everyone can access it because of limited costs and those who are still in the learning stage in lectures need practicing to process the geophysical data. The purpose of implementing this filtering process and inversion modeling is to provide access to gravity data processing for free and open source so that it can make it easier for students to process the data while practicing in the field, and in the future this software can be the basis for learning and development in the field of geophysical computing. This research was made using a descriptive method with a complete step and explanation of the creating and applying of the geophysical data processing into a software, so the detail processes inside it can be known. A literature study was also conducted to determine the basic formula that will be used as a reference in calculating gravity data in order to obtain the expected processing and modeling results. After that, the final step is to apply all of the components in a program to create a software based on MATLAB for the final result of this research. This software will containing map filtering and inverse modeling for gravity data which can be used for data processing.

Multicopters for Geophysical Research

The current paper presents three multicopters developed at the Space Research and Technology Institute – Bulgarian Academy of Sciences. These unmanned aircraft designs are aimed at geophysical research and are particularly usable for detection of objects on ground surface and underground. The detection is realized by taking advantage of certain objects' properties. Metals and other conductors are identified by their electrical conductivity. Ferromagnetic objects are discovered by observing their magnetic permeability. Voids and other objects are localized utilizing the difference of the dielectric permittivity that is encountered on the boundary of the object and surrounding ground or rock.
 Some of the potential targets discoverable with the described geophysical drones are military land mines (including anti-personnel and anti-tank mines), ammunition depots, reservoirs, pipelines, underground galleries, voids, bunkers, tunnels, etc.
 All three developments are subject to patent protection.

20 Years of Biogeosciences Research: Looking Back to Forge Ahead

A new special collection invites review papers to mark the 20th anniversary of the Journal of Geophysical Research: Biogeosciences with a focus on what we have learned and what is still unknown.

Deep structure of the Rongcheng geothermal field, Xiongan New Area: Constraints from resistivity data and boreholes

The development of the Xiongan New Area is China's exploration into the future of urban design, with plentiful geothermal resources serving as a crucial component for building a green, ecological and habitable city. However, the region currently lacks high-precision geophysical exploration research. The boundaries of each sub-tectonic unit and the unclear distribution of deep strata impede further drilling and efficient geothermal resources development. Wide field electromagnetic method (WFEM) provides superior detection depth and high precision compared to the traditional electromagnetic methods. We obtained a high-precision resistivity model of Rongcheng geothermal field through two WFEM survey lines (343 stations) for the first time. This model distinctly illustrates the stratigraphic framework of the Quaternary-Neogene-Jixian system, and accurately reveals the spatial locations of the Rongcheng Bulge, Niutuozhen Bulge, Niubei Slope, and the Dahezhen Depression within the Xiongan New Area. Moreover, the model provided a more precise representation of the faults and strata structure, reinforced by two boreholes. The low resistivity area within the Rongcheng Bulge has a large potential for geothermal resources. Conversely, the low resistivity area at a depth of 4000 m in the Niubei Slope was formed by fractures and groundwater activities, and presumed to be a water-rich area, indicating a favorable area for future geothermal investigation. Thus, our study can provide fundamental data for the upcoming geological researches and geothermal development in the Xiongan New Area.

About the application of modern geophysical research methods and the problems solved Summary

The vast majority of oil and gas fields in Azerbaijan are at the final (late) stage of development, and therefore a natural decline in production is expected. Despite the long-term development of fields, their reserves are of great industrial importance for ensuring the stability of the energy balance of our country. Therefore, it became necessary to introduce new technologies in order to maintain or partially increase production at fields that are in long-term development. Before carrying out geological activities, it is necessary to apply a new type of more modern borehole geophysical research in order to involve in the processing of zones with residual resources of these depleted fields. From this point of view, the article considers the application and results of modern borehole geophysical surveys, and analyzes the possibilities for expansion. Keywords: Logging; Geophysical research; Reservoir; Formation; QUAD; Logging tool.

Geoelectrical model of the Earth’s crust along the Shu-Sarysu geotraverse according to magnetotelluric soundings

Purpose. To study and assess the possibility of effective application of electrical prospecting by magnetotelluric sounding (MT-sounding) and to determine the range of geological problems to be solved in the geoelectric conditions of the Shu-Sarysu geotraverse. Methodology. The issues of methodology of modern technologies of field observations, peculiarities of processing and interpretation of MT-sounding data are considered, which showed that modern instrumental and methodical electrical survey technologies of MT-sounding allow obtaining results of field measurements of increased reliability, due to their accuracy, productivity, mobility, noise immunity, level of automation. To identify the main features of the geoelectric structure of the Earth’s crust and the upper mantle, the modern technique of interpreting MT data allows for 1, 2D inversion of the effective curves of apparent resistivity and impedance phase. Findings. Based on MT-sounding data, a geoelectric section of the Shu-Sarysu geotraverse was constructed, characterizing the position and morphology of five geoelectric boundaries in the crustal section in the 0–40 km depth interval. The identified five geoelectric horizons show good coincidence with the conventional seismic horizons and confidently correlate with the geological references established by GIS data. Originality. On the basis of MT-sounding studies, the geological interpretation of the structure of suprasalt and subsalt structural-formation complexes is presented; the geological efficiency of MT-sounding electrical prospecting in revealing the complex structures in the conditions of the Shu-Sarysu geotraverse is shown. On the basis of model constructions of the geoelectric section, new data on the deep geological structure of the Shu-Sarysu geotraverse were obtained: new data on the structure of Mesozoic terrigenous-sedimentary rock complexes and the Paleozoic part of the section with the allocation of the supposed faults; on the basis of MT-sounding results, recommendations for further detailed geological exploration work were given. Practical value. A comprehensive interpretation is recommended of the obtained MT-sounding data together with the results of geological and geophysical research on the regional profile in order to establish search criteria for the discovery of mineral deposits and the prospects of gas content in the area.

Применение химерных сеток для явного учета неоднородностей при моделировании распространения упругих волн

The method of chimeric meshes is applied to simulate the propagation of elastic perturbations in media containing porous and fractured inclusions. A model of a linearly elastic isotropic medium is considered, which describes the state of a geological rock. The grid-characteristic method with the third-order accurate Rusanov scheme is used for numerical modeling of the dynamic propagation of elastic disturbances. Special attention is paid to the presence of separate inclusions of pores or fractures, which introduce heterogeneity into the medium and can substantially influence the response of elastic disturbances. The use of the chimera grid method allows for both the position and shape of such inclusions to be described explicitly, taking into account their influence on the propagation of elastic disturbances. As a result of the conducted investigation, a methodology for numerical modeling of the propagation of elastic disturbances in media with porous and fractured inclusions was developed, which can be used to assess the influence of such inclusions on the dynamic response of elastic disturbances. The presented results can be applied in geophysical and seismic research related to modeling the dynamics of various processes in soils and rocks.

Main trends and results of 300-years anthropogenic impact on the geological environment and ecosystem of the Eastern Gulf of Finland

The seafloor of the eastern Gulf of Finland (the Baltic Sea), especially its easternmost part – Neva Bay – has experienced anthropogenic impacts since the beginning of the XVIII century. The aim of this paper is: i) to analyze results of different stages of anthropogenic impact on the geological environment and ecosystem, ii) to assess the influence of dredging, dumping, and aggregates (sand, gravel) and ferromanganese concretions extraction on bottom relief and sedimentation processes, and iii) to establish the major spatial and temporal trends of heavy metal accumulation in the soft bottom sediments. Since the establishment of St. Petersburg, and into the 1960s, there was a physical impact on the seabed through the construction of artificial islands, dredging, and dumping. From 1960s to the 1990s, these types of activity became even more intense, as nearshore submarine terraces were used for sand and gravel extraction, and sediment pollution (e.g., heavy metals) has become one of the main environmental problems of the region. Based on extensive geochemical data collected for the first time in the study area, we examined a vertical distribution of heavy metals in cores obtained from different sedimentary basins. Results demonstrate a trend of increasing concentration values from the 1940s to the 1990s. Background concentrations of heavy metals are based on the geochemistry of catchment areas, decreasing in concentrations from the northwest to the southeast, while the maximum concentrations of hazardous substances deposited from the 1970s to the 1990s were observed in the easternmost part of the gulf. Since the 1990s the heavy metal input to the Gulf of Finland has significantly decreased, so the concentration of these hazardous substances in the surface sediments dropped as well, demonstrating a spatial distribution corresponding more to background (natural, pre-industrial) values. On the other hand, big hydrotechnical projects, realized during the last 20 years – artificial territories and new harbors construction, accompanying with dredging and dumping, ferromanganese concretion extraction, etc. – led to resuspension and secondary pollution of water. The other problem is the expansion of anoxic areas, caused both by climate change and human-stimulated eutrophication. Near-bottom anoxic conditions stimulate heavy metal migration from bottom sediments into the water column. All these processes impacted benthic communities as our review of previously published studies reveals. Geological and geophysical research revealed that within some areas anthropogenic impact caused a complete change of the sedimentation processes such as direction and rates of transport, which led to the total transformation of bottom relief, surface sediment distribution, and the benthic communities.

GEOPHYSICAL INDICATORS OF AUFEIS IN THE ANMANGYNDA RIVER (MAGADAN REGION)

Giant aufeis fields are the indicators of water exchange processes in the permafrost zone. The study of aufeis dynamics is relevant to assessing the state of the cryosphere in a changing climate. The Anmangynda aufeis which forms upstream of the Kolyma River basin, was as large as 6.8 km2in the last century and is considered representative of the mountainous territories in the northeast Russia. In recent decades, there have been significant changes in the aufeis formation regime that require updating the understanding of the cryosphere processes. The historical observational data obtained in 1962-1990 for the Anmangynda aufeis allows using it as the present-day object of research.The main goal of geophysical research in 2021-2022 was to study the structure of the Anmangynda aufeis and aufeis glade to determine its genesis and development processes. The main tasks were to identify the boundary between frozen and unfrozen rocks, to reveal groundwater discharge channels, and to assess the aufeis thickness distribution. There were carried out georadar survey using an antenna unit with central frequency of 250 MHz and ground-based capacitively coupled electrical resistivity tomography. It was found that by April 5, 2021, the maximum ice thickness was 4.35 m with an average value of 1.35 m, and the volume of aufeis was 3.56 million m3. By means of georadar, there were performed identification and drilling verification of the groundwater discharge channels from alluvium to aufeis surface, located in the stream beds. There is geophysical evidence of deep bedrock groundwater sources. Based on the electrical resistivity tomography data, there were identified large and locally freezing river taliks, from which the water is squeezed onto the ice surface. It is recommended to conduct further interdisciplinary research to clarify the geophysical results obtained.

The role of the structural-tectonic characteristics of Caspian-Guba oil-gas bearing region in formation of underground water reserves

The article is devoted to the analysis of the impact of structural-tectonic characteristics of the Caspian-Guba oil- gas bearing region on the formation conditions of underground water resources. Based on the analysis of the short chronological sequence of geophysical research carried out by various organizations from the beginning of the last century to the modern era, the author came to the conclusion that geographically the area is a complex structural-tectonic formation, and in this view, it is necessary to conduct new research surveys to study the underground water resources. Particularly, highly accurate geophysical surveys should be carried out in this direction to specify the perspectives of the underground water.

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GEOPHYSICAL STUDIES OF ROCK DISTORTION IN MINING OPERATIONS IN COMPLEX GEOLOGICAL CONDITIONS

Abstract. Geophysical methods of rock mass survey are one of the most effective ways of solving various problems in mining and are widely used in mining, gas and oil industries, as well as in science. They allow carrying out prospecting and evaluation works remotely, to reveal structural heterogeneities, cavities, contact zones of different media in rock mass with rather high accuracy. At the stage of designing a mining enterprise and making major decisions, it is necessary to have reliable information about the tectonic structure of the undermined and adjacent massif and parameters of its geodynamic activity. For this purpose, special studies of the tectonic structure of the rock massif must be carried out and the parameters of modern geodynamic movements must be determined. The most complete information about tectonic disturbances, identification of gliding surfaces, zones of macrofracturing are provided by geophysical methods of rock mass survey.In the article analysis of study of structural-tectonic structure of ore areas, separation and specification of ore-controlling structures, detection and depth mapping of ore-controlling faults, volume mapping of intrusive massifs based on previously conducted geophysical research in Zhezkazgan syncline area carried out. Geological and geophysical conditions of the central ore field (presence of rich bodies with high electric conductivity, considerable thicknesses of ore bodies, etc.) were favorable for application of various geophysical methods to search and trace rich ore bodies occurring at low depths.Moreover, possibilities of application of seismic works are considered at the solution of problems of ore geology in difficult mining-geological conditions of Kazakhstan.

Identification of Iron Ore Deposit in Sub-Surface using Resistivity and Induced Polarization Methods at Sarakaman, Sebuku Island, South Kalimantan

Iron is the second most abundant metal on earth. Sebuku Island is one of the areas in Indonesia that has potential for laterite iron ore. This study aims to detect the presence of mineralized zones and estimate the volume of iron ore. Therefore, geophysical research was carried out using the resistivity method and the Induced Polarization methods with the Wenner-Schlumberger configuration. The research was carried out in 4 paths along 475 m with a space between the electrodes of 5 meters. Based on modeling, 20 iron ore deposits were found in the study area on all trajectories characterized by high chargeability values ranging from 251,55 – 810,55 ms which correlated with low resistivity values of 4,02 – 124,41 m. Then it was found that the direction of the distribution of iron ore deposits in the study area was north-south and there was no continuous zone of iron ore deposits due to the long distance of the path. The volume of iron ore deposits in the study area in an area of ±39 hectares is estimated to be around 1.807.614 m3 with total reserves of iron ore deposits of 7.230.456 tons.

General order kinetics model for OSL rock surface exposure dating

Dating of rock surface using optically stimulated luminescence (OSL) is an emerging tool to estimate exposure age and post exposure erosion rates. The present study points out the lacuna in the mathematical model that is used for this method. So far, all existing research, use first order kinetics (FOK) model. The FOK model predicts an exponential decay of OSL signal of polymineral rock with sunlight exposure, which is contrary to the observation. The non-exponential decay of OSL signal, more precisely infrared stimulated luminescence (IRSL) of feldspar, can be better explained by general order kinetics (GOK). Thus, we propose a new GOK model for OSL surface exposure dating. Present theoretical study shows, for FOK model the OSL (IRSL) depth profile propagates faster with time of light exposure than actual. Consequently, the FOK model predicts lower exposure age. The propagation of OSL profile with time depends on order of kinetics of the GOK model. We demonstrate how the order of kinetics can be constrained through laboratory bleaching experiment. The impact of the GOK model on exposure age and upper age limit, for different order of kinetics are presented. We apply this new GOK model on experimental data, available in the literature (Luo et al. in Geophysical Research Letter 49: e2022GL099526, 2022), of OSL depth profile on exposed fault scarp and reevaluate the exposure ages for different order of kinetics to validate the GOK model. We conclude that the GOK model better explains the IRSL of feldspar than the FOK model and should be preferred for OSL rock surface dating.

Thank You to Our 2022 Peer Reviewers

AbstractMembers of the editorial board of the Journal of Geophysical Research—Earth Surface express their appreciation to those who served as peer reviewers for this journal in 2022.

How reproducible and reliable is geophysical research?

Geophysical research frequently makes use of agreed-upon methodologies, formally published software, and bespoke code to process and analyse data. The reliability and repeatability of these methods is vital in maintaining the integrity of research findings and thereby avoiding the dissemination of unreliable results. In recent years there has been increased attention on aspects of reproducibility, which includes data availability, across scientific disciplines. This review considers aspects of reproducibility of geophysical studies relating to their publication in peer reviewed journals. For 100 geophysics journals it considers the extent to which reproducibility in geophysics is the focus of published literature. For 20 geophysical journals it considers a) journal policies on the requirements for providing code, software, and data for submission; and b) the availability of data and software associated for 200 published journal articles. The findings show that: 1) between 1991 and 2021 there were 72 articles with reproducibility in the title and 417 with reliability, with an overall increase in the number of articles with reproducibility or reliability as the subject over the same period; 2) while 60% of journals have a definition of research data, only 20% of journals have a requirement for a data availability statement; and 3) despite ~86% of sampled journal articles including a data availability statement, only 54% of articles have the original data accessible via data repositories or web servers, and only 49% of articles name software used. It is suggested that despite journals and authors working towards improving the availability of data and software, frequently they are not identified, or easily accessible, therefore limiting the possibility of reproducing studies.