GEOLOGY, PROSPECTING AND EXPLORATION OF OIL AND GAS FIELDS
This article analyzes the prospects of petroleum potential in Kurgan region. The relevance of the work is due to the high degree of development of the traditional oil and gas recovery areas of Western Siberia, which leads to the need to organize search activities in areas with a low density of hydrocarbon resources. We have analyzed the results of exploratory drilling in the area of the Alabuga river in Kurgan region, and have studied the history of detections of onshore oil occurrences there. Based on the results of the retrospective analysis, the research area was determined, field work was performed to determine the state of search wells in the area, and a collection of geochemical soil and liquid samples was selected. The analysis of the samples revealed that all of them contain methane and its homologues up to and including pentane. The genesis of light methane homologs is related to the processes of catagenesis; their detection on the surface indicates active processes of generation and migration of petroleum hydrocarbons. Based on the analysis of archival materials and estimated ground-based geochemical studies, a conclusion is made about petroleum potential in Kurgan region.
At the present stage, the development of the oil industry of the Russian Federation is impossible without replenishing the resource base, and therefore an urgent task is to analyze and assess the conditions and characteristics of oil-andgas content in unexplored regions.
Purpose of the study is an analysis and an assessment of reservoir properties of rocks of the Aptian horizon Р1+2- К2 within the Akhlovskaya structure.
We analyzed the graphs of the distribution of indicators in wells R-212 and R-213 in the Akhlovsky area and concluded that the reservoir is heterogeneous, and there are interlayers of mudstones with other reservoir properties and geophysical characteristics. The following pairs of parameters (porosity coefficient and oil-saturated thickness of rocks, rock resistivity and porosity coefficient, rock resistivity and oil-saturated thickness of rocks) have a significant positive correlation. Having studied the distribution of indicators in the Akhlovsky area for wells R-212 and R-213 along one horizon, we concluded that these indicators differ very slightly, which indicates the homogeneity of the reservoir properties. Qualitative indicators Qualitative indicators don't change. Thus, we can expect similar indicators within the entire area of the explored layer Р1+2- К2 in the territory of the Akhlovsky area.
A variant of the thermoelectric model of the Earth's dipole magnetic field is considered. It is based on geothermoelectric currents present in the planet's core. The currents cyclically change their direction, which leads over time either to warming on the Earth, if their movement is directed towards the Earth's crust, or to cooling, when moving towards the inner core. With each change in the direction of movement of the thermal currents, the poles of the Earth's magnetic field are inverted simultaneously. The inversion process is instantaneous (on the scale of planetary time) and is not the result of a gradual reversal on the 180° Earth's magnetic axis. At the moment of inversions of thermal currents in the core, the total geomagnetic field decreases to the level of 4.6∙10-6 T, which is constantly supported by thermal currents of semi-conducting rocks of the lower mantle. The considered version of the thermoelectric model of the Earth's magnetic field may be promising for studying the magnetic fields of planets in the Solar system.
DRILLING OF WELLS AND FIELDS DEVELOPMENT
Chemical enhanced oil recovery methods are widely used in field development. One of the methods for leveling injectivity is emulsion-based technologies. The mechanism of this technology is to create an increased filtration resistance of the most depleted reservoir intervals. To establish the actual oil-displacing characteristics of the emulsifier grades accepted for testing in the pore space of oil-containing reservoir rocks, a set of laboratory filtration studies was carried out on high-permeability core models at the AS12 horizon of the Nizhne-Sortymskoye oil field.
Processing laboratory data after filtration of ready-to-use emulsions through core samples gives an increase in the oil displacement coefficient by water from 1.31 to 10.79 %. When constructing their correlation dependence, it is possible to identify the range of the final dynamic viscosity (from 5 to 9 mPa∙s) of the compositions of the emulsion-based technology, which is optimal for the most effective application on groups of AS formation.
Based on the laboratory studies of rocks, it was established that carrying out geological and technical measures using the emulsifier Neftenol-NZ, which has proven itself in high efficiency from well treatments, will give a large volume of additional oil production, in comparison with the currently emulsifier Sinol-EM.
The actual scientific and production task is the prevention of loss wellbore stability for West Siberia companies. The process of well drilling in clay intervals is consisting of many additional actions for stabilization wellbore. There is analysis of wells with problems due to caving and falling in this article. It was allowed to determine that almost 50 % of drilling time is non-production time, which connects with clay warping. The design of new inhibitory bath compound is necessary to avoid loss wellbore stability. It was applied Box-Behnken method for planning of experiment and for a mathematical analysis of synergistic effects components and thermo-baric conditions among each other. The result of this work is the development of the optimal composition of the bath to stabilize clay rocks for more than 13 hours, which is enough for drilling complicated intervals.
Estimation of recoverable oil reserves is an actual problem in field development. One way to estimate reserves is to use the characteristics of oil displacement by water. This method, in contrast to hydrodynamic modeling, doesn't take a long computational time and doesn't require information on the geological and filtration properties of the objects under consideration.
The article discusses the use of integral displacement characteristics based on a probabilistic method for assessing potentially recoverable oil reserves. We describe an algorithm for estimating reserves by this method. In the course of the comparative analysis, the efficiency of the method was demonstrated depending on the watercut at the end of the approximation interval. As a result, with a watercut of less than 90 %, a better forecast was found than in the classical application of the characteristics of oil displacement by water.
DESIGNING, CONSTRUCTION AND OPERATION OF PIPELINE TRANSPORT SYSTEM
The use of modern complexes for calculating the designed pipeline systems and for predicting their behavior for a period of more than ten years is necessary in modern conditions of the constantly developing hydrocarbon market and the development of new northern territories for greater oil production. It will allow avoiding accidents and environmental disasters that have become more frequent in recent years due to the deterioration of existing equipment. The article presents a method for monitoring the main reliability parameters of underground oil pipelines, taking into account changes in soil foundations, mainly in the Arctic zone of the Russian Federation. An oil pipeline section is considered as an object for monitoring of heat engineering processes and their influence on the reliability of the system. We describe the main results of calculations of the oil pipeline section and simulate changes in soil foundations. We used a multilayer pipe with polyurethane foam insulation and coating for the calculations to improve the reliability characteristics. This pipe has showed the best results of modeling in comparison with the design pipe.
The article discusses the issue of industrial compounding, which improves the quality of the raw materials supplied to the main pipelines. Compounding from "to compound" (English) - to mix. When mixing different types of oil obtained, "incompatibility" is possible, which is expressed in the precipitation of a solid sediment and violation of the stability of the colloidal system and due to the differing properties of oils. Attention to this problem is due to the tightening of requirements for the quality of raw materials that must comply with modern standards. The article discusses the causes of the problem of "incompatibility" of oil during compounding and effective ways of solving it, substantiates the need for a preliminary study of the properties of mixed oil in order to identify possible incompatibility of various types of oil. The standard tests for determination of incompatibility indices characterizing the ability of raw materials to mix are considered. The article substantiates the need to develop methods for diagnosing the incompatibility of oils as the most important task of modern chemical science, the solution of which will improve the quality of the raw material obtained and solve many technological problems in the compounding process.
Main pipelines are subjected to a complex of loads during operation. Monitoring of the stress state of the pipeline wall is necessary for performing strength calculations and evaluating the pipeline reliability.
The article is devoted to the method of computational and experimental study of the stress state of a pipe under a bending load and combined action of a bending load and internal pressure.
The experiments have been carried out on a laboratory bench. The object of the study is a pipe that has the following characteristics: an outer diameter of 325 mm, a wall thickness of 8.5 mm and steel grade of "14XGS". Electrical resistance strain gages were used to measure the strain of the pipe wall. Formulas for calculating the stress state components of the pipe wall in the elastic-plastic deformation stage are proposed. It is given formulas for calculating the stress state components of the pipe wall in the elastic-plastic deformation stage. Plots of hoop and longitudinal stresses as well as von Mises stress are obtained for the case of bending load on the pipe and the case of combined loading under bending and internal pressure. The areas of maximum values of von Mises stress where the transition to the limiting state is most likely have been determined.
When only the bending load is applied, the maximum von Mises stress zone is observed on the lower area of the pipe in its central region. When combined loading under bending and internal pressure, the maximum von Mises stress zone is observed on the lateral area of the pipe in its central region.
The current regulatory documents for infrastructure construction indicate the use of only thawed, mainly sandy soils. When erecting embankments during the winter period, a limited number of applied frozen soils are allowed. In this case, the stability and strength of the soil massif decrease. The absence of thawed soils in the regions of Siberia and the Arctic requires an expansion of the types of soils used, one of which is frozen soils. We have developed the designs of the subgrade that allow using frozen soils, enclosed in geosynthetic cages or without them. Increasing the stability and strength of the embankment by creating a dense soil skeleton is one of the scientific issues, which is solved in this article by applying the theory of granular media. In practice, the formation of dense systems from frozen soils is based on two principles: the method of dense mixtures and the method of impregnation, where the main layer of frozen soil is impregnated from above with dry frozen soils. Almost by selection of the composition, you can achieve the maximum density.
CHEMISTRY AND CHEMICAL TECHNOLOGIES
The development of deposits of hard-to-recover reserves, including heavy and high-viscosity oil, dictates the need to search for new and improve existing enhanced oil recovery methods. One of the well-known methods of increasing oil recovery is the use of reservoir treatments with chemical compositions containing surfactants. A new multifunctional chemical oil-displacing composition (MFC) capable of operating in a wide temperature range has been created at the Institute of Petroleum Chemistry, Siberian Branch of the Russian Academy of Sciences. The oil-displacing composition of MFC based on a surfactant, an adduct of inorganic acid, polyol, ammonium and aluminum salts, and urea is designed to increase the oil recovery of fields at both early and late stages of development.
The article presents the results of laboratory tests of the developed MFC for enhanced oil recovery. Experiments were carried out on the setup to study the filtration characteristics of models of heterogeneous formation.
As a result of experiments, it was found that the use of the MFC composition leads to a significant increase in the oil displacement coefficient at both low and high temperatures. The high oil-displacing capacity of MFC at low temperature is caused by the interaction of inorganic acid and polyol, which are part of the composition, with the formation of a strong acid that reacts with the carbonate rock of the reservoir. At high temperature, due to the processes of hydrolysis of urea and aluminum salt, MFC evolves into an alkaline composition with the formation of an alkaline buffer system (pH = 9), which is optimal for oil displacement purposes.
One of the serious troubles faced by the oil and gas industry is corrosion wear of equipment and pipelines. The major part of failures of the oilfield equipment and pipelines is the result of corrosion damage, so protection of equipment from corrosion is one of the most urgent scientific and technical issues. One of the most common ways to control corrosion is inhibitor protection. The paper presents the results of studies of corrosion inhibitors synthesized on the basis of polyethylene polyamines and three varieties of light tall oil in the presence of alcohol solvents using the stillage residue of butyl alcohols rectification. The optimal parameters of synthesis and the ratio of basic raw reactants and solvents have been determined. The inhibitory properties of the synthesized samples were evaluated by changes in the rate of corrosion and the value of their protective efficiency. It has been shown that the best of the synthesized samples is not inferior to the industrial reactant Sonkor 9601 in terms of the protective effectiveness, and in the area of low concentrations (up to 40 g/t) exceeds the basic inhibitor.