GEOLOGY, PROSPECTING AND EXPLORATION OF OIL AND GAS FIELDS
Significant amounts of liquid industrial and domestic waste are generated at oil fields in the north territory of Western Siberia. There are currently no reliable methods of purification and utilization for many of them. It is very difficult to ensure long-term isolation of the waste from the hydrosphere and biosphere on the Earth. Underground disposal of wastewater in deep horizons (depths of the Earth) is one way to prevent from their negative impact on the environment and public health.
The article deals with the results of a comprehensive study of the geothermal conditions of oil and gas bearing deposits in the western part of Yenisei-Khatanga regional trough. Four types of vertical geothermal zonality are established, the characteristics of which depend on the geological evolution of different parts of the sedimentary basin. The minimal geothermal gradients (1,80–2,2 0 C/100 m) are established there in the near edge zones with a small thickness of the sedimentary cover and the development of the infiltration system. The maximum gradients (3,2–3,4 0 С/100 m) are established in the zones of disjunctive tectonics, which had a significant heating effect on the geological section due to the ascending discharge of groundwater from deep-lying aquifers.
The article describes some features of the application of modern software for the full-waveform seismic modeling in the training of students for topqualification level in the specialty «Technology of geological exploration». Seismic modeling is the solution to the building a seismic image of the examined object with the given parameters of the geological model. These parameters are reservoir thickness, velocity and density. Additionally, mentioned software can be applied for modeling both seismograms and time sections, cubes for various geological models, and these models can be of any complexity: from rapid lateral changes in velocity to the block structure of the subsurface geology. We show software capabilities in comparison of real and model sections a case study of one of the areas in the territory of Eastern Siberia. This area is characterized by complicated seismic conditions, such as large differences in surface altitudes, abnormally high reservoir pressure, salt layers and various tectonic faults. Conclusions are drawn that modern software can be useful in analysis of reservoir properties.
In recent years, there has been a downward trend in easily recoverable hydrocarbon reserves in the Cretaceous sediments of Western Siberia. In this regard, interest in the horizon US2 has increased. Collectors of this horizon have a complex structure, which leads to the appearance of significant errors in geological models. The development of the methodological basis for the analysis of the accuracy of geological models, in particular three-dimensional, can solve this issue.
The article gives a technique for analyzing the quality of a 3D geological model: a case study of horizon US2. As a result of the work, the following conclusions were drawn: firstly, there is the need to update geological models after drilling each well; secondly, the possible causes of the discrepancy between the actual and forecasted indices are revealed; thirdly, usage a map of the residuals of the absolute elevations of the horizon US2, as additional information, can minimize risks when drilling wells and increase the reliability of 3D geological model.
DESIGNING, CONSTRUCTION AND OPERATION OF PIPELINE TRANSPORT SYSTEM
Most of accidents and failures of vertical steel tanks are related to metal corrosion of their shells and equipment. The choice of optimal corrosion protection to extend the life of such tanks is impossible without an understanding of the mechanisms of its origin and development, as well as the degree of influence of operational factors on these mechanisms.
Of particular interest is the study of corrosion processes taking place in tanks to prepare for the transport of high-viscosity oils operating in the specific conditions of the Far North. The complex effect of factors such as temperature, total salt content of bottom water, the concentration of corrosion inhibitors, demulsifiers, and mechanical impurities on the rate of corrosion processes is not fully understood to date.
This article analyzes the process of corrosion destruction of settling tanks for the preparation of high-viscosity oil to transport through main oil pipelines using the example of the RVS-5000 of the park of input tanks of the Yareganeft oil and gas department. Analysis of operating conditions made it possible to identify factors affecting corrosion processes and to identify potentially the most dangerous zones of contact between media entering the reservoir and the shell metal, the bottom and roof of the tank. The study have showed that the greatest interest is the study of the effect of the presence of mechanical impurities in the fluid supplied to the settling tank on the intensity of corrosion processes on the internal surfaces of the tank in potentially dangerous areas.
DRILLING OF WELLS AND FIELDS DEVELOPMENT
The article is devoted to the results of laboratory studies of blocking compounds with a condensable solid phase based on calcium. The features of such systems have been revealed and their positive characteristics have been determined. It made it possible to conclude that such systems compounds are promising as blocking compounds for usage in wells with complicated mining and geological conditions (abnormally low reservoir pressures, in reservoirs with complex mineralogical and chemical composition with a high clay content fractions, with a highly fractured bottomhole formation zone, etc.).
Based on the data obtained, we have developed blocking compounds with a condensable solid phase (the patent RU 2543003 and the patent RU 2651687), which have high blocking properties (withstand pressure drop up to 20 MPa) and ensure the preservation of reservoir properties (permeability recovery coefficient is more than 95 %) and inhibition of clay minerals swelling. In addition, as a result of studies we have found that for the blocking of productive deposits with a nonuniform permeability (for reservoirs with an average permeability about 1 Darcy) the usage of compounds with a close to stoichiometric ratio of precipitating components with a condensed solid phase content about 11 wt. % is optimal.
The development of oil and gas condensate fields is accompanied by phase transformations of reservoir mixtures, i.e. the transition of condensate from the gas state at the formation pressure below the condensation start pressure and its reverse evaporation when the maximum condensation pressure passes. Dynamic condensation leads to a decrease in permeability in the bottomhole zone, as a result, the productivity of the well is reduced.
We have used the method of gas-dynamics research at steady-state filtration conditions in our work in order to minimize the influence of retrograde processes and the justification of the technological well operation conditions of usage gasdynamics research at steady-state filtration conditions.
Especially, set up a problem is important in conditions of low-permeability reservoirs with a significant potential content of condensate in the formation gas.
The article raises a question about the qualitative preparation of separator oil under the conditions of the formation of stable emulsion, which is stabilized by the products of the production of hydraulic fracturing and acid treatments. We present relations that make it possible to determine the flow parameters of produced gas-liquid mixture in an oil gathering pipeline. As a result, we propose a technological scheme for oil treatment, which provides the required quality of oil treatment. The scheme is based on the developed and justified method of dynamic combined oil treatment.
The study of the causes of changes in the effectiveness of the reservoir pressure maintenance system in terms of the interaction of injection and production wells is an important and insufficiently studied problem, especially in terms of the causes of the attenuation of stable connections between the interacting wells. Based on the results of the calculation of the Spearman pair correlation coefficient, the reasons for the change in the interaction of wells during the flooding process at various stages were estimated. Of particular interest are identified four characteristic interactions, which are determined by the periods of formation of the displacement front.
The volumetric coefficient is widely used in various calculations related to the estimation of petroleum reserves, crude oil production, preparation and transport of oil. The existing methods of its calculation determination are mainly empirical that makes it difficult to use them in solving various tasks, primarily optimization problems. The article is devoted to the development of similar technique in the form of analytical dependence, devoid of the noted shortcomings. For this purpose, the provisions of the hole theory of the dropping liquid are used, on the basis of which a theoretically and physically justified expression acceptable for a wide range of gas-saturated oils under different conditions is obtained. The acceptability of dependence is tested on oil data from different regions of the country and near abroad. The obtained dependence makes it possible to calculate the volume coefficient at a pressure equal to the pressure of oil saturation with gas.
Capillary imbibition is the most important stage in many technological processes. The article is devoted to studying the special question of the influence of the non-constant slope on the solutions of counter-current capillary imbibition problem in the isothermal case.
MATERIALS AND STRUCTURES IN THE OIL AND GAS INDUSTRY
We have studied the temperature dependence of the thermal conductivity of a series of experimentally obtained aluminum-silicon alloys with different silicon addition and additional iron content of 1 % by weight. The article shows how the change in the silicon content affects the thermal properties of the experimentally obtained alloys at room temperature. Also, the article describes the character of the change in thermal conductivity when the samples are heated up to 150 °C. Based on the obtained data, we con clude that the alloy containing 4 % silicon by weight is the most prospective for usage as a material for solving heat transfer problems.
MACHINERY, EQUIPMENT AND FIELD CONSTRUCTION
The article analyzes the conditions of the stress-strain state in which preventer bonnets operate. We give the dependences for the strength calculation of fixing preventer bonnets. We identify the advantages and disadvantages of various designs of fastening devices and seals of fasteners. Also, we consider the issues of testing, repairing and operating preventer bonnets.
Assessment of the quality of separation of hydrocarbon raw during its field preparation is necessary to determine the efficiency of the entire technological process of preparation. The absence of complex criteria for assessing the quality of separation for multi-stage processes does not allow one to obtain unambiguous solutions in justifying the process flow diagrams and equipment for separation. We have analyzed the typical technological scheme of separation of hydrocarbon raw materials and existing criteria for separation processes. It is proposed to use the criterion for a comprehensive assessment of the separation processes of hydrocarbon raw materials, allowing calculating the efficiency of the process, taking into account the possible production of intermediate fractions and their qualitative composition
ORGANIZATION OF PRODUCTION AND ENSURING THE SAFETY AND ENVIRONMENTAL FRIENDLINESS OF PRODUCTION PROCESSES IN THE OIL AND GAS INDUSTRY
The article is devoted to the study of deformation of support structure of horizontal steel tank, which is located in the North of Tyumen region. This study was carried when performing frequency analysis. It is found that the hardness ring was great deformation when performing frequency analysis of support structure of horizontal steel tank. The support structure of tank has lost its balance, but retained its integrity.