Key Engineering Materials Vol. 785

Abstract: A lithofacies model of the Fainsk oil field YUS₁¹ formation was built. The results of interventions for oil production stimulation and enhanced oil recovery depending on the section penetrated by wells were considered. Criteria for selection of various types of interventions in particular geophysical conditions were given, and recommendations on the selection of technologies for bottomhole zone processing (BZP) and enhanced oil recovery (EOR) were made. The research objective is to evaluate the effectiveness of interventions in terms of enhanced oil recovery, adapted to the specific features of the field geologic structure aspects. Through the use of sedimentary deposits facies analysis method, a lithofacies model of the Fainsk oil field YUS₁¹ formation was constructed. The application of field-geologic analysis gave an option to evaluate the technological effectiveness of interventions for oil production stimulation and enhanced oil recovery depending on the reservoir units genesis penetrated by wells.

Abstract: Effective development of oil deposits includes the measures to restore and improve the porosity and permeability properties (PPP) of reservoir units, which inevitably deteriorate during the operation of the field. For this purpose, various technologies of bottomhole formation zone acid treatment (BFZAT) are used. These approaches are sufficiently developed and usually do not require additional laboratory adaptation. Specific requirements for technologies that include acid effect on the formation are required for interventions on low-permeability reservoirs (LPR), where the influence of the mineralogical composition of rocks and their porosity and permeability properties on the efficiency of BFZAT is the most significant. Therefore, during interventions development for LPR using acid methods, it is necessary to correctly assess the capabilities of a particular method (composition) in relation to specific conditions. This can be achieved by conducting standard laboratory tests (determination of rock carbonation and mass loss in 12% hydrochloric acid) and additional experiments to determine the mass of the secondary sediment, as well as the optimum reaction time at the formation temperature. The research objective is a laboratory research on the selection of acid compositions for bottomhole formation zone treatment for a number of low-permeability reservoirs in Western Siberia. Standard and special laboratory studies have allowed suggesting the most optimum acid compositions adapted to “rigid” formation conditions.

Abstract: An era of a high-gravity oil of the Samotlor field formations AV_2-5 and BV_8-10 is near to its end. The production deposits of the AV₁^1-2 horizon are the main reserve of oil production and the basic prospect in this area. Stratigraphically, the AV₁^1-2 horizon belongs to the Alym suite of the early Aptian Age that was distinguished as an individual unit at the 1967 interdepartmental stratigraphic meeting with the stratotype in the Uvat test well. This part of the section started to form around 400,000 years ago and is represented by siltites with interlays of clays and sandstones, primarily bioturbated ones, which causes the specific lens-clustered laminarity of these rocks (Ryabchik) with rare double leafs and single pancake-shaped primitive foraminifers such as saccamina. Specific features of the geological structure and oil-and-gas content of the AV₁^1-2 horizon within the area under consideration were in various aspects described earlier in the works of many researchers [1-8]. Nevertheless, when new geological and geophysical information had been accumulated, the need arose to cover this issue once again. Since it makes us consider the geological modeling of formations in the horizon from quite a different angle, we need to create various structural models of HC reservoirs, development flow diagrams, etc. The research objective is to define the genesis of producing deposits of the AV₁^1-2 horizon and identify fascia complexes in them. Using a system of special studies and methods for analyzing geological development and structure (paleotectonic, grain size, fascia, electrometric, etc.), the areas of sedimentation and fascia systems were diagnosed within the area under research.

Abstract: The productive formations YUS₁¹ and YUS₁² are characterized by a strong lithologic and facies instability. The article shows the results of the analysis of the geological and technical interventions efficiency carried out on these sediments and defines their genetic dependence on the specific features of geological structure. The research objective is to analyze the geological structure of productive deposits, identify facies complexes and assess the effectiveness of geological and technical interventions. With the help of geological-field analysis, a quantitative evaluation of the technological effect obtained during the hydraulic fracturing of well formations, the repair and insulation works and a whole range of measures on intensification of inflow was carried out.

Abstract: The modern state of the raw material base of the “Kogalymneftegaz” TMC is characterized by deterioration in the structure and quality of the field reservoirs at the latter development stage. The depletion of the main developed oil formations has long exceeded 60%. Despite the high depletion rate, the complete coverage of all recoverable resources by flooding has not been achieved. The differences in zone and area irregularities of the production facilities and the imperfection of the existing development systems at the present stage lead to the formation of non-drainable resources. In order to involve them into production in formations, various types of interventions are carried out in order to improve the existing development systems. The research objective is to develop a detailed approach to planning a transfer of wells which have completed their purpose from one development facility to another. Using a detailed geological and routine analysis of results of carrying out various interventions on the formation, an active application of the most effective of these has been proposed.

Abstract: Microseismic monitoring of hydrocarbon fields is one of the promising areas of modern seismology. In recent years, the methodology of microseismic monitoring for seismic emission has been actively developing in the oil and gas industry in order to study the impact of various technogenic processes on the hydrocarbon (HC) fields being developed. The technology does not require powerful sources of sounding signals, but uses constantly existing weak seismic fields of artificial or natural origin. During the development of the field, periodic monitoring of the intensity and spatial position of the zones of microseismic activity allows controling the behavior of HC deposits in order to optimize their development. Distinctive features of this technology are high mobility, fast deployment time, high resolution, and low cost of receiving, transferring and processing of microseismic data. The purpose was to analyze the results and evaluate the effectiveness of MFHF using microseismic monitoring of seismic emission processes. The results were obtained with the help of quantitative microseismic monitoring of seismic foci occurring successively near the well ports at different times during MFHF.

Abstract: The paper presents a technique of three-dimensional geological modeling of one of the most complex formations, reef deposits. The research objective is an investigation of how the reef structure genesis influences the three-dimensional geological grid of reef mass. Using the paleogeographic and paleofacies methods of investigation, the conceptual and three-dimensional geological models of a natural reservoir have been constructed.

Abstract: The development and use of the radial drilling technology has been a controversial issue in the oil and gas industry for a long time. Nowadays, almost all big oil and gas producers deal with the question of its practical use at particular fields. The results of works carried out at carbonate reservoir units of the Orenburg Region were analyzed in the article. The ways to improve the existing technology of radial drilling were also offered. The research objective is to evaluate the technological efficiency of radial drilling application at the fields of the Volga-Ural oil and gas region with carbonate reservoir units. The results of radial drilling were characterized with the help of the detailed geological and field analysis and their quantitative evaluation was given.

Abstract: The mature stage of field production is reported to observe a significant decline in oil production rates; watercut either grows slowly or (with the regulation of the production processes) somewhat stabilizes. In some periods, it even somewhat decreases, usually due to the cut-off of the highly watered well stock. During the multi-foundation field production, joint exploitation of the productive foundation is often applied; these foundations are often allocated to different sites. The research objective is to justify the directions for further production of the geological and commercial site, which is at the mature production stage; choose the most technologically "productive" and economically feasible interventions in order to increase oil recovery. Applying the classical methods of geological-field analysis and calculation of displacement characteristics, the main trends in the field production have been revealed; using the data of field and geophysical research, the reasons for obtaining unsatisfactory results in joint foundation operation have been revealed.

Abstract: The developed litho-sedimentological model of deposits of the YUV₁ productive horizon makes it possible to choose the most effective technique for supplementary exploration of a natural reservoir and improve the quality of geological justification for its subsequent development. The research objective is to carry out paleogeographic and paleostructural reconstructions, to identify facies complexes in the Upper Jurassic productive deposits, and to identify zones for the development of improved reservoir units. With the help of paleogeographic and facies methods, the geological regularities of the development of the territory encompassing the Tagrinsko-Yarainersky Bar in the Late Callovian-Oxfordian Stage were studied.