Vol 4, No 1 (2022)
- Year: 2022
- Articles: 13
- URL: https://vestnik-ngo.kz/2707-4226/issue/view/4608
- DOI: https://doi.org/10.54859/kjogi.202241
Full Issue
Articles
About subsidizing socially significant exchange commodities
Abstract
The article is devoted to the issues of subsidizing, which are very relevant in the light of recent discussions on improving the mechanisms of direct and implicit price subsidies. The paper discusses the issues of subsidizing of socially important goods, which include, for example, oil refinery products, liquefied gas and others, provides formulas for the amount of subsidies, determining the cost of subsidizing, the trader's margin from the exchange price. These calculations will contribute to the correct planning of regional budgets for subsidies.
Evaluation and scientific justification of polymer flooding application in the Uzen oilfield
Abstract
The Uzen field is at the late stage of development, with an average field water cut of over 90% due to a long-term non-shale waterflooding. At the same time, the current oil saturation of the reservoir is estimated as more than 50%, which may provide a promising future for the field. According to world practice, the application of chemical enhanced oil recovery (CEOR) methods can provide high oil recovery, and extend the cost-effective life of the field. Therefore, the application of chemical enhanced oil recovery is particularly relevant considering the current status of the Uzen field. The main method of CEOR is polymer flooding (PF), which has proven its high efficiency over 60 years of application in the industry.
The objective of this study is to evaluate and justify the application of the polymer flooding technology to the conditions of the Uzen field. According to this objective, first of all, the world experience of polymer flooding was studied, including the latest large-scale projects in the fields of China, the USA, Canada, India, Oman and other countries. Criteria for the effective application of polymer flooding were developed and screening of the geological and physical characteristics (GPC) of all objects of the field was carried out. In addition, facies maps and the current state of development were analyzed to select a potential pilot test site. A review of the surface facilities, an analysis of the water supply sources and the characteristics of different polymers were carried out to develop a project for the pilot test of the technology. Preliminary hydrodynamic calculations show reduced water cut, increased oil production and an increase of 7% in oil recovery. Feasibility studies prove the profitability of the polymer flooding at oil prices above $55/bbl. This study is the basis for further implementation, adaptation and optimization of polymer flooding
The evaluation of the efficiency of horizontal wells
Abstract
The number of fields that have reached stage IV of development is increasing every year. Due to the high level of water cut, it becomes difficult to develop residual recoverable reserves. Also, due to the increase in the share of high-viscosity oils in Kazakhstan, the task of their effective development becomes more complicated. The development of terrigenous reservoirs, which have a complex structure and contain high-viscosity oil, is usually characterized by low production rates and oil recovery factors. Currently, technologies that ensure high efficiency in the development of such deposits are very expensive.
In this regard, the development of oil fields through the commissioning of horizontal wells is becoming more in demand, capable of increasing the efficiency of developing oil reserves. Drilling of horizontal wells is considered for:
- floating reservoirs with low reservoir production coverage due to high water cut. High levels of water cut are due to breakthroughs of bottom water and degraded technical condition of wells (annular flows, wear and leakage of the string, depressurization of previously isolated intervals and poor quality of cement adhesion);
- thin layers, not involved in the production. Basically, thin layers are not involved in the production due to the low performance of vertical wells;
- on horizons with high-viscosity oil. In highly viscous horizons, the injected water breaks through to the bottom of production wells along the base of the reservoir when the horizon is not developed.
Also in the Atyrau region, fields with hard-to-recover reserves (fields with high oil viscosity and low permeability of the productive horizon) are being developed. It is in such fields that horizontal wells have already been drilled and will be drilled in the future.
The presented article discusses the results of the analysis of the drilled horizontal wells in the North Volga and Aknur oil fields.
Tectonic zoning of paleozoids of Kazakhstan and its oil and gas-bearing regions
Abstract
The article deals with the issues of tectonic zoning of the Paleozoic and Mesozoic-Cenozoic structures of Kazakhstan. The principles of tectonic zoning are outlined, on the basis of which the zoning and indexation of tectonic units of the territory of Kazakhstan was carried out. For this, various data of complex geological and geophysical analysis of Paleozoids were used, including tectonic, structural, stratigraphic, lithological-paleogeographic, petrographic, geodynamic and other studies.
A geological and tectonic scheme (model) is proposed that reflects the main tectonic units that make up the structural framework of the Paleozoids of Kazakhstan, consisting of a crystalline basement on which the formation of sedimentary oil and gas basins took place. The main tectonic units of the earth's crust of the territory under consideration are identified and characterized, and the mosaic-block structure of the complexes is shown. The characteristic of the complex multi-stage evolution of the paleozoids of Kazakhstan and its oil and gas regions is given.
Transition to the use of digital assistants in the kinematic interpretation of the data of seismic exploration by the example of the problem of improving the quality of seismic data after summation and reliability of the tectonic model forecast
Abstract
Modern seismic exploration still faces the challenges of automating processes and increasing the reliability of work results, especially in regions with complex geological conditions. An important place in the cycle of seismic surveys is occupied by the stage of kinematic interpretation, the main purpose of which is a detailed understanding of the structural features of the geological section and obtaining a reasonable geological model of a particular region of study.
The cost of an error at this stage of the work is quite high, but the interpretation processes require significant labor costs, and the results often contain errors. Standard algorithms and methodological approaches do not fully provide solutions to the full range of tasks, which necessitates the search for new approaches to the interpretation of seismic data.
In recent years, there has been increasing interest in attracting the capabilities of artificial intelligence to solve production problems. New approaches to solving the problems of the stage of kinematic interpretation of seismic data based on the use of artificial intelligence through machine learning and deep neural networks are proposed:
– technology of elimination of irregular noises of the total seismic data to improve the quality of the initial seismic material and simplify the stage of structural interpretation;
– technology of probabilistic forecast of disturbance systems and obtaining a detailed tectonic model.
Theoretical foundations are presented and the results of applying technologies on a series of real production projects are demonstrated, which confirm the advantages of using neural networks in interpretation to eliminate subjectivity and significantly reduce time costs at the stage of structural constructions in various geological conditions.
Viscoelastic systems for well construction
Abstract
One of the most important factors ensuring the required quality of well cementing is the use of effective flushing fluids (spacers). Among these fluids are viscoelastic systems (VES), which provide the best displacement of the drilling fluid during the cementing process.
The article discusses the mechanism of polymerization of viscoelastic systems when using polyacrylamide cross-linked with polyvalent metal cations and the prospects for using these systems for oil and gas wells cementing. Models of the viscoelastic systems flow and their differences due to the presence of normal stresses in viscoelastic systems are shown in this article. The substantiation of the component composition of viscoelastic systems and their main properties, ensuring their efficiency as flushing fluids are given. The article also provides a description of the scientific instruments that were used during the research.
It has been experimentally confirmed that it is necessary to use additives with the highest oxidation state when choosing a polyvalent cation as a "cross-linker" for viscoelastic systems. This will help to increase the rate of strength characteristics development. The most adequate ratios of components have been experimentally substantiated and the best solids-carrying capacity of a viscoelastic flushing fluid in comparison with other types has been proven. This eliminates the possibility of cement slurry flowing down in the annular space after the completion of the cementing process.
The special installations proved the best degree of wellbore cleaning in vugular formation zones with a laminar flow regime. In order to minimize the negative effect of polymer films from viscoelastic systems on the adhesion of the cement stone to the casing strings it is recommended to inject a portion of the liquid containing the polymer destructor after a portion of the viscoelastic fluid.
Technical solutions for performing operations on RCP-proppant thermal fixing and thermoreagent impact on the bottomhole formation zones of production wells
Abstract
The article presents the results of the implementation of technologies based on the use of the thermal effect of a number of exothermic reactions occurring in reservoir conditions between the components of the composition injected into the reservoir. The main direction of using chemical compositions based on available inorganic and organic salts is the heat fixing of RCP-proppant (polymer-coated proppant) in hydraulic fractures (about three hundred wells in the Volga-Ural region) in terrigenous reservoirs. Technical solutions are proposed to combat the absorption of thermosetting compositions in wells with low reservoir pressure. Another option for the use of thermosetting compositions in conditions of consolidated reservoirs is to increase the oil flow rate of production wells due to an increase in the permeability of bottomhole formation zones due to the dissolution of asphaltene, resin and paraffin deposits, as well as an increase in the mobility of reservoir oil due to a decrease in its viscosity as a result of the action of released heat and reaction gases.
Redistribution of filtration flows and increased exposure coverage by regulation of the gel formation process
Abstract
Most of Azerbaijan's oil fields have entered the late stage of development, characterized by a decline in oil production and an increase in water cut. In order to increase the efficiency of the development of a watered formation by redistributing filtration flows and increasing the impact coverage by regulating the gel formation process, a gel-forming reagent, an aqueous solution of sodium silicate, is injected in the depth of the formation. Before injection of an aqueous solution of sodium silicate, carboxymethylcellulose is added to it, while the concentration of sodium silicate and carboxymethylcellulose in the aqueous solution is regulated depending on the temperature at a given reservoir depth and the time required for gelation, and after injection of the gelling agent, it is pushed through with a slug of softened sea or formation water.
Increased oil recovery through the use of combined technology
Abstract
There is a growing number of fields in the world that are at the last stage of development. These fields are characterized by high residual oil saturation and water saturation. In addition, newly discovered fields are characterized by the content of high-viscosity oil. The development of such reservoirs is associated with great difficulties. This paper considers a combined technology that allows to intensify oil production from oil reservoirs. The studies were carried out on a homogeneous reservoir model in the following sequence. First, we carry out the displacement of oil by injecting electrochemically modified water (catholyte). Then we pump in a gas-liquid emulsion slug, which we push through with water or catholyte. The combined action of the emulsion and catholyte leads to an increase in the pressure drop and a change in the filtration rate. As a result, this leads to an increase in the oil recovery factor.
Testing of a hydrodynamic chemical flooding simulator by comparing the results of polymer flooding simulation with similar results of existing simulators
Abstract
The use of numerical modeling tools, including reservoir simulators, helps oil companies in making decisions and ensuring successful field development. This work is devoted to the testing of a reservoir simulator based on a new formulation in partial derivatives of a compositional model of chemical flooding by comparing the results of polymer flooding simulation with similar results of Eclipse 100.
Express-diagnostics of rods’ parting-twist off at wells equipped with sucker rod pump
Abstract
The development of fields that are at a late or final stage of operation is carried out mainly with the use of downhole sucker rod pumps. The most characteristic failures for these installations are rods’ parting-twist off and malfunctions of pump valves. The methods of eliminating these accidents vary significantly – the parting or twist off of the rods involves lifting of the downhole equipment, and the "sticking" of the shut-off valve assembly of the pump is eliminated by "resuscitation" of the downhole equipment (flushing with water, hot oil or solvent). An error in fault identification leads to incorrect planning of work to restore the operability of the downhole equipment and, as a result, to economic losses.
The cause of malfunctions of the downhole equipment of downhole rod pumping units, as a rule, is determined by analyzing dynamograms. However, in many cases dynamograms do not allow to distinguish the lower twist off of the rods from the malfunction of the valves of the rod pump. In the presented work, a method for the operational determination of the parting or twist off of rods in the well is considered, which consists in creating an electrical circuit "rod string –tubing string" and monitoring its integrity. To determine the type of malfunction, the synchronization unit measures the resistance of the system on the dielectric insert via the electromagnetic channel. In case of parting or twist off of the rods, the electrical resistance of the "tubing-pump-rod string" circuit will be much higher (more than 2 ohms) than in the absence of this failure (0...2 ohms).
Economic efficiency due to increasing the turnaround period of operation of oil producing wells
Abstract
The turnaround period of well operation is influenced by an extremely large number of factors covering the geological, physical, technical and technolog ical conditions of their operation. The higher the indicator of the turnaround period of well operation, the more efficiently the stack of wells works according to planned indicators, as well as low, first of all, operating costs for well maintenance, which accordingly affects the economic efficiency of well operation.
In recent years, a number of oil companies have been paying close attention to the problem of increasing of the turnaround period of well operation. Measures being developed are aimed at:
– reducing the aggressiveness of the extracted products;
– improvement of the installation design of an electric centrifugal pump;
– improving the design of downhole pumping equipment.