Vol 21, No 1 (2021)
- Year: 2021
- Articles: 7
- URL: https://ered.pstu.ru/index.php/geo/issue/view/122
Abstract
The task to which this article is devoted has not received due attention in recent years, since the preparation of structures for deep drilling is carried out using seismic exploration. At the same time, there is a huge array of data on structured drilling, unfortunately, it has not been fully used. Thus, the goal of the study is to use data on structured drilling to solve not only structural problems for marking surfaces, but also more complex ones related to zonal oil and gas potential of territories. The forecast of oil and gas content for marking and oil and gas horizons was carried out in three zones of oil and gas geological zoning. Using the data on these territories, studies were carried out to build probabilistic models for the zonal forecast of oil and gas content. To substantiate the joint use of data on marking surfaces and data on the tops of oil-bearing horizons, materials were studied for 447 deep wells. Probabilistic models of zonal forecast of oil and gas content of the central part of the Permian uplift were developed according to structural and capacity criteria. The complex use of data on the absolute marks of deep and structured wells made it possible to rank the territory of the central part of the Permian uplift by the degree of zonal oil and gas content. Severokamskoye (0.73), Krasnokamskoye (0.67), Baklanovskoye (0.67), Polaznenskoye (0.67), Rassvetnoye (0.64) and Mezhevskoye (0.63) fields were characterized by the maximum values of P COM. For the Kozubaevskoye field, the P COM was 0.57. The Gorskoye, Lobanovskoye, Talitskoye, Zorinskoye and Shemetinskoye fields were characterized by minimum values of P COM, varying in the range of 0.51-0.53. This scheme can be used when designing prospecting and exploration works in this area.
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Abstract
To form the technological properties of clays, various methods of their activation have been developed, the essence of which is that when processing clays, their structure (defectiveness) changes, which forms the energy potential of clay particles, and the latter is realized in the form of "specified" physicochemical properties of clays. In this regard, the effect of stress pressure on the change in the defectiveness of structural elements of kaolin was studied. Experimental studies showed that the pressure value P = 150 MPa was the boundary value at which different conditions for the formation of defectiveness of structural elements of kaolin were observed. High pressure has a multidirectional effect on the defectiveness formation of the kaolin structural elements: a package, a mineral, a colloid and an aggregate. In a package of kaolinite mineral, the defectiveness increases with increasing pressure. Defects are formed due to the removal of Al, Fe, Mg, Si ions from the octahedral and tetrahedral sheets. Al ions are the most sensitive to pressure. The removal of ions entails deformation of the packet and the formation of "hole" energy centers. Pressure up to 0-150 MPa has a greater effect on the formation of defectiveness (calculated correlation coefficient rс = 0.86) than in the range 150-800 MPa ( rс = 0.82). In the kaolinite mineral at pressures up to 150 MPa, a decrease in defectiveness is observed due to the ordering of the structure under pressure ( rс = 0.67). At pressures above 150 MPa, an increase in the defectiveness of the kaolinite mineral ( rс = -0.72) is observed due to the destruction of hydrogen bonds between the packets, which entails the sliding and rotation of the structural packets among themselves. In a colloid (particle), with an increase in pressure to 150 MPa, the structural defect decreases due to an increase in the colloid density ( rс= 0.67). In the pressure range of 150-800 MPa, it is rather difficult to reveal the effect of pressure on the formation of defectiveness ( rс = 0.37). In the aggregate, with an increase in pressure to 150 MPa, the defectiveness of the structure increases due to crushing of particles, sliding and displacement of particles among themselves ( rс = 0.95). In the pressure range of 150-800 MPa, it is rather difficult to reveal the influence of pressure on the formation of defectiveness ( rс = 0.58), although the tendency increases with increasing pressure, the defectiveness of the aggregate remains.
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Abstract
On the territory of the Republic of Kazakhstan there is a significant number of identified deposits related to weathering crusts and titanium-ilmenite placers, bearing industrial mineralization of rare and rare-earth elements. Deposits of placers and weathering crusts, formed as a result of bedrocks denudation in coastal and continental sedimentation conditions, form the basis of the mineral resource base of titanium-zirconium ores in the Republic of Kazakhstan. Titanium-zirconium deposits of placers and weathering crusts usually have low average contents of the main useful components (rutile, ilmenite, and zircon), while containing associated mineralization of valuable rare and rare earth elements. Various aspects of the complex development of poor titanium-zirconium placers, which are currently of no practical importance, are considered. Associated useful components of titanium-zirconium placers are usually represented by rare and rare earth elements, which are of practical importance in high-tech industries. The study of associated useful components in titanium-zirconium placers will allow considering the possibility of profitable exploitation and assessing the prospects for strengthening their mineral resource base. As a result of the review, analysis and assessment of known titanium-zirconium placers on the territory of Kazakhstan, the most promising ore occurrences have been identified, which may be of practical importance in their integrated development: Karaotkel deposit - increased contents of rare and rare earth elements in placer ores can be considered, not only as a source monomineral concentrates of ilmenite, zircon, quartz and quartzite, mica and feldspar ceramic raw materials, but also as a source of rare and rare earth elements; The Kundybai, Zayachye and Druzhba ore occurrences have the potential for the integrated development of titanium-zirconium placers with rare and rare-earth elements. The selected objects deserve prospecting and appraisal work with technical and economic studies of the possibility of integrated development.
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Abstract
From theoretical studies and experiments on the core, the so-called capillary end effect, or, as it is also called, the effect of phases capillary entrapment, is known. When carrying out laboratory experiments to determine the relative phase permeabilities, capillary end effects appear on the core models of the reservoir. These effects can occur as a result of capillary ruptures at the ends of the core sample, which leads to the accumulation of one phase in relation to the other, and thereby affects the movement and retention of the fluid. The region of capillary end effect, which occurs due to the rupture of capillaries at the exit from the sample, affects the change in pressure drop and saturation of a particular fluid. If the influence of capillary end effects is significant, then the experimental conditions are modeled incorrectly, which can lead to serious errors in predicting the productivity of the studied formation. This paper presents the results of studying the porosity-permeability properties of determining the relative phase permeabilities and the studies analysis of the capillary end effects influence mechanism on the filtration capacity of rock samples during laboratory studies using the example of terrigenous and carbonate types of the Pavlovskoye reservoir. According to the results of the studies, the significance of capillary end effects in filtration experiments was established using the example of determining the relative phase permeabilities. Recommendations are given with the aim of minimizing the negative influence of end effects. Capillary effects can be overcome by increasing the length of the test sample, as well as by increasing the flow rate of the fluid during a laboratory experiment to determine the relative phase permeabilities.
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Abstract
As an option for enhancing oil recovery of a high-viscosity Permo-Carboniferous reservoir associated with the Usinskoye field, the use of technology based on technogenic carbon dioxide as an injection agent is considered. In the world practice, several fields are known as close in their parameters to the parameters of the Permo-Carboniferous reservoir, and in which CO2 injection was accepted as successful. Based on this, CO2 injection can potentially be applicable in the conditions of a Permo-Carboniferous reservoir. At present, as a result of the various development technologies implementation, reservoir zones are distinguished, characterized by different thermobaric properties. Depending on reservoir conditions, when displacing oil with gases, various modes of oil displacement can be realized. This article describes the results of studies carried out to study the effect of the concentration of carbon dioxide on the properties of high-viscosity oil in the Permo-Carboniferous Reservoir of the Usinskoye field, as well as the results of filtration experiments on slim models performed to assess the oil displacement regime under various temperature and pressure conditions of the Permo-Carboniferous Reservoir. The study of the influence of CO2 concentration on oil properties was carried out using the standard PVT research technique. The displacement mode was assessed using the slim-tube technique. Based on the performed experiments, it was established that an increase in the concentration of CO2 in high-viscosity oil led to a noticeable change in its properties; for the conditions of a Permo-Carboniferous Reservoir, the most probable mode of oil displacement by carbon dioxide was established. Difficulties associated with the preparation of the CO2-heavy oil system were described separately. Based on a literature review, it was shown that the rate of mixing of oil with carbon dioxide depended on certain conditions
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Abstract
The influence of reservoir rock properties on sand production in wells is considered. It was concluded that the rock should be considered rather not from the point of view of its strength, but from the point of view of the type of cementitious substance and its distribution. When predicting sand production, it is necessary to take into account the internal stresses of the rocks, as well as the change in these stresses during drilling, perforation and operation of the formation due to the violation of their initial state. Within the framework of this work, an analysis of the main causes of sand production during the operation of gas wells and the negative consequences of sand production for gas production equipment is presented. It has been established that water breakthrough, formation depletion, pressure drop at the bottom of the wells due to their frequent shutdown are the main prerequisites for the removal of sand from the bottomhole formation zone. Sand production is associated with such negative consequences as plugging in wells, erosion of underground and surface equipment, collapse of the top of the bottomhole formation zone and production strings. The main technologies for the prevention and elimination of accidents associated with the removal of mechanical particles from the reservoir are considered. Based on the research results, an algorithm was proposed for selecting technological modes of well operation in conditions of water and sand. The parameters for choosing the optimal operating mode of a gas well are substantiated, in which sand is not extracted with the subsequent disabling of downhole and wellhead equipment, the integrity of the bottomhole zone is not violated, and the well is not self-contained. The results obtained can be applied to improve the efficiency of gas wells operation and predict their trouble-free operation.
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Abstract
Depending on reservoir conditions, composition of reservoir oil and gas agent, various modes of oil displacement by gas can be implemented in reservoir conditions. The most preferable mode from the standpoint of the completeness of oil recovery is the mode of miscible displacement of oil by gas. The main parameter indicating the achievement of the miscible displacement mode is the minimum miscibility pressure. The most popular and reliable laboratory method for determining the minimum mixing pressure is the slim-tube method. The results of laboratory studies performed to determine the value of the minimum miscibility pressure of reservoir oil from the Tolumskoye field and associated petroleum gas of the Semividovskaya group of fields and also to determine the mode of oil displacement by associated petroleum gas are presented. To determine the parameters of reservoir oil and change its properties at various molar concentrations, the standard PVT research technique was used. To determine the minimum miscibility pressure, the slim-tube technique was used. To assess the mechanism of miscibility process development, chromatographic analysis of the sampled gas composition and visual analysis of the phase fluids behavior by means of a visual cell were additionally performed. Two series of filtration experiments were performed to displace the recombined oil model of the Tolumskoye field by the model of associated petroleum gas from the Semividovskaya group of fields on slim models. According to the obtained dependence of the oil displacement coefficient on pressure, when oil from the Tolumskoye field was displaced by associated petroleum gas of the Semividovskaya group of fields, the minimum miscibility pressure would be 14.8 MPa. Based on the criteria for determining the mixing mode, as a result of generalization and comprehensive analysis of the research results, it was found that for the conditions of the Tolumskoye field, the mode of oil displacement by associated petroleum gas of the Semividovskaya group of fields was the mode of the developed multi-contact miscible displacement (the mechanism of condensation of solvent components into the oil phase).
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