Simulation of long-term influence from technical systems on permafrost with various short-scale and hourly operation modes in Arctic region

Technogenic and climatic influences have a significant impact on the degradation of permafrost. Long-term forecasts of such changes during long-time periods have to be taken into account in the oil and gas and construction industries in view to development the Arctic and Subarctic regions. There are considered constantly operating technical systems (for example, oil and gas wells) that affect changes in permafrost, as well as the technical systems that have a short-term impact on permafrost (for example, flare systems for emergency flaring of associated gas). The second type of technical systems is rather complex for simulation, since it is required to reserve both short and long-scales in computations with variable time steps describing the complex technological processes. The main attention is paid to the simulation of long-term influence on the permafrost from the second type of the technical systems. © 2017 Author(s).The work was supported by Russian Foundation for Basic Research 16–01–00401 and program of scientific research UrB RAS 15–16–1–10

Computer simulation of operation of an open geothermal system consisting of multiple wells

The diffculties related to open loop geothermal systems using includes, in particular, the fact that there is a reverse injection of the cold water through an injection well into an underground aquifer from which hot water is extracted. This necessity for an injection well presence is caused the thermal water from an underground reservoir possible to be high mineralize and to contain toxic compounds and metals, and in most cases one have to avoid to discharge these waters into ground surface natural water systems. An open loop geothermal system of three wells is considered, which can be both productive and injection wells. The developed algorithms and programs allow to select an optimal system configuration of three wells for a specific geothermal deposit. The results of numerical calculations for various variants of the geothermal system are presented. © 2018 Author(s).The work was supported by Russian Foundation for Basic Research 16–01–00401 and program of scientific research UrB RAS 18–1–1–8

Simulation of thermal stabilization of bases under engineering structures in permafrost zone

Constructions on permafrost have to be ensured with reliability of the foundation, which, under the influence of various heat fluxes and annual freezing (thawing) of the soil, may get stressed, that leads to destruction of the foundation and the engineering structure itself. To assess the thermal impact of engineering structures on the ground, a computer simulation of the construction pads is used. Thermal stabilization of the soil is considered to be carried out due to freezing with the help of seasonally operating cooling devices for some time prior to the beginning of construction, or placing on site various technical systems that are sources of heat. The results of numerical calculations illustrating the effectiveness of preliminary thermal stabilization of the soil under the base of the engineering structure are presented. © 2018 Author(s).The work was supported by Russian Foundation for Basic Research 16–01–00401 and program of scientific research UrB RAS 18–1–1–8

Optimization of location of injection wells in an open geothermal system

A geothermal open loop system consisting of one production well and several injection wells is considered. The production well serves to raise hot water from a geothermal underground reservoir, which can be used for building heating or for other purposes. As a result, the water is cooled and then pumped through injection wells back into the geothermal reservoir. The cooled water begins to be filtered in the reservoir in the direction of the production well. A mathematical model describing the distribution of a cold water front in such a system is presented. A software package has been developed that makes it possible to evaluate the efficiency of the location of injection wells in a geothermal reservoir in order to increase the operating time of such a system, since the operation of the geothermal system life is over as soon as the cold water front reaches the production well. © 2019 Author(s).Russian Foundation for Basic Research, RFBR: 19–07–00435The work was supported by Russian Foundation for Basic Research 19–07–00435

Simulation of permafrost changes due to technogenic influences of different ingeneering constructions used in nothern oil and gas fields

Significant amount of oil and gas is producted in Russian Federation on the territories with permafrost soils. Ice-saturated rocks thawing due to global warming or effects of various human activity will be accompanied by termocarst and others dangerous geological processes in permafrost. Design and construction of well pads in permafrost zones have some special features. The main objective is to minimize the influence of different heat sources (engineering objects) inserted into permafrost and accounting long-term forecast of development of permafrost degradation due to different factors in particular generated by human activity. In this work on the basis a mathematical model and numerical algorithms approved on 11 northern oil and gas fields some effects obtained by carrying out numerical simulations for various engineering systems are discussed. © Published under licence by IOP Publishing Ltd.This work was supported by RFBR projects (16-01-00401, 14-01-00155) by contract 02.A03.21.0006 (reg.N211 of RF Government) and Program of UB RAS, project 15-7-1-13

Simulation of Optimal Operation of a Multiple Wells Open Geothermal System

Geothermal energy is a promising type of renewable energy. To analyze and improve the efficiency of the system, a three-dimensional mathematical model of an open geothermal loop system is developed. The proposed model takes into account thermophysical characteristics of the geothermal aquifer and the most important technical parameters of the wells. The pump pressures in producing and injection wells, as well as the distances between these wells are considered as parameters to be optimized in terms of achieving the longest period of effective operation of the geothermal loop. The results of numerical calculations are discussed. © 2018 Institute of Physics Publishing. All rights reserved.This work was supported by RFBR (projects No. 16-01-00401 and by Program of UB RAS (project No. 18-1-1-8).Russian Foundation for Basic Research (RFBR

A general model of an open geothermal system

Geothermal aquifers may be considered as a renewable resource of heat and energy. Internal earth heat may be transported with underground water to the surface by wells, and to not overexploit the aquifer, this water should be returned back. As a rule such systems consist of two wells. Hot water from the producing well is used, as example, for greenhouse complex or other buildings needs, which cools the water, and the injection well returns the cold water into the aquifer. To simulate this open geothermal system a three-dimensional nonstationary mathematical model and numerical algorithms are developed taking into account the most important physical and technical parameters of the wells to describe the heat distribution and thermal water transportation in the aquifer. Results of numerical calculations are presented. © Published under licence by IOP Publishing Ltd

The price of oil as a pricing factor of the residential real es-tate at the regional market

The article is to study the influence of oil price variation on the parameters of the residential real estate market, which is a significant factor of the development of the country’s living standards. The analysis of oil price variation as one of the key figures determining price variation of goods and services in Russia, covers the period of the 2008 crisis and the postcrisis period of 2011-2017 (on a quarterly basis). The price variation of living space per square meter in the primary and secondary housing markets in remote federal districts (Central, Siberian, Far Eastern) has been analyzed. That allowed to identify the specifics of the process investigated in far-flung territories with significantly different indicators of economic development. As an assessment tool of the impact of structural changes in the Russian economy on price variation a statistical Chow-test, showing the presence of structural instability during the crisis, has been used. Based on the data, modeling of the interconnection between the oil price variation and a housing square meter price variation has been carried out in the period of 2011- 2017. The official data of the Federal State Statistics Service of the Russian Federation have been used

Thawing of Permafrost During the Operation of Wells of North-Mukerkamyl Oil and Gas Field

Thawing of ice-saturated rocks due to climate change or various technological impacts will be accompanied by subsidence of the earth’s surface and development of dangerous permafrost geological processes called thermokarst, leading to accidents, which may destruct the wells. Currently, the investment programs of the development of new northern oil and gas fields are restricted. In this regard, reducing the cost of developing the oil and gas fields is an urgent problem. For example, diminishing the area of well pads and maintaining efficiency in the northern oil and gas fields can significantly reduce the costs, in particular, during the design stage. A model of unsteady thermal fields propagation in frozen soil from new well construction for the North Mukerkamyl oil and gas field is developed, taking into account the construction features, the annulus, and the complex lithology of the soil surrounding the well. It is planned to take into account climatic and technological factors, in particular, an annual rest period of well operation, which held from several hours to two weeks. The paper discusses the computational features of the thermal fields calculating in frozen ground from wells and explores the influence of various parameters, which in the computations may lead to a significant increasing of thawing area in the well pads. © Siberian Federal University. All rights reserved.The work was supported by Russian Foundation for Basic Research 19–07–00435

Simulation of thermal effects of engineering objects in the arctic regions on the permafrost boundaries

The paper discusses a mathematical model for describing heat distribution in the surface layer of soil from various sources of heat, or cold, which, together with seasonal climatic changes, form unsteady thermal fields in the soil. The developed algorithms are focused on high-performance computers and were used in the design of various oil and gas fields located in permafrost zone. The main attention is paid to adequate setting of boundary conditions and maximum consideration of various parameters, including technical characteristics of engineering objects, climatic conditions and soil lithology in the field of modeling thermal fields. The presented numerical calculations show the possibility of using these models and algorithms for forecasting of the development of thermal processes in the soil. Minimization of heat effect of the systems inserted into permafrost will avoid accidents, in particular, at oil and gas fields related to the changes in temperature of the soil, and increase the stability of the building with pile foundations. In the paper the possibility of the heat impact compensation in permafrost is discussed. © 2021 Author(s).The work was supported by Russian Foundation for Basic Research 19–07–00435