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21ANALYSIS OF METHODS FOR COMBATING ASPHALT-RESIN-PARAFFIN DEPOSITS IN THE
FIELDS OF WESTERN KAZAKHSTAN
Kuzenbayev A.
Master of Oil and Gas Faculty 6M07202 - Petroleum Engineering Atyrau University of Oil and Gas named after Safi Utebayev
DOI: 10.5281/zenodo.7467696
Abstract
The operation of oil wells in Kazakhstan is accompanied by such complications as an increase in the water content of products, a drop in reservoir pressure, a decrease in the rate of fluid extraction, the formation of solid asphalt-resin-paraffin deposits (ASF). Since the main oil production in Western Kazakhstan is carried out at depleted fields that have entered the late stage of development, the issue of maintaining the operational fund in working condition is relevant at the current stage of the development of the oil industry. During the extraction and transportation of oil with a high content of paraffin, as a result of the deposition of ASF on the inner surface of the downhole equipment, wear occurs, the diameter of the tubing narrows, malfunctions occur in the operation of the ESP, as well as clogging of the capillaries of the productive reservoir and deterioration of the filtration-capacitance properties of rocks. Throughout the entire production process, oil workers face these problems, as deposits occur in downhole equipment, discharge lines, as well as in field pipelines of oil collection systems. There are several well-known and widely used technologies for preventing the formation of deposits, as well as methods for their removal. But the conditions of field development and the characteristics of the products produced are diverse and often require an individual approach or the development of new technologies. However, many modern methods of combating the formation of ASF only increase the inter-repair period of wells for some time, and it is not always possible to completely avoid the formation of deposits.
Keywords: analysis, deposit, ASF, ESP, operational fund.
Introduction. In order to choose the most suitable method of dealing with deposits and, accordingly, chemical reagents, it is necessary to have an idea of the composition and properties of ASF. The deposits themselves are a solid mixture of hydrocarbons, similar in structure to a thick ointment-like substance, dark brown or black in color. The main components of the composition are asphalt-resinous substances (DIA) (20-40% by weight) and paraffins (20-70% by weight), as well as silicone-magnesium resin, bound oil and mechanical impurities in the form of sand, clay, salts and water. Also, metal oxides in small amounts (vanadium, iron) may be present in the composition. They are capable of forming complexes with macromolecules of surfactants, thereby enhancing the intermolecular interactions occurring inside the deposits. The composition and percentage of components are influenced by the nature of the oil produced within the oil-producing region, as well as the deposits and solid hydrocarbons from which they consist, the sampling location J1J, and a number of other geological, hydrodynamic and thermodynamic factors.
Oil paraffins in the ASF are the main part of deposits. They are hydrocarbon compounds of the methane series. At high reservoir pressures and temperatures, paraffins in oil are in a dissolved state. They can also be in a suspended or crystalline aggregate state under oil transportation conditions that differ from reservoir conditions. According to GOST 11851-85, depending on the content of paraffins, oil is classified into:
• low-paraffin - less than 1.5% by weight;
• paraffin - from 1.5 to 6%;
• high-paraffin - more than 6%.
In some cases, the paraffin content can reach 25%. Paraffin has a non-reactive nature and therefore does
not dissolve in acids, alkalis and other chemical reagents. It has a predominantly linear structure and is written with the chemical formula CnH 2n+2, in which the value of n is in the range from 16 to 64. The main solvents of paraffin are organic, such as benzene, gasoline, acetone, ethyl ether, etc. It also dissolves in petroleum products when heated and oils containing mineral components. The melting point of paraffin under standard conditions is 45-65 oC [2].
To date, long-term research by scientists has allowed us to identify several main factors affecting the formation of paraffin deposits and the intensity of their formation, which can vary in depth and time [3, 4].
1. Due to the movement of the oil system from the bottom of the well to its mouth, the pressure in the well itself decreases. In the bottomhole zone of the formation, changes occur from the periphery to the central part. This leads to a violation of the hydrodynamic equilibrium of the gas-liquid system. The volume of the gas phase begins to increase, which affects the decrease in the stability of the liquid phase and the formation of crystals of paraffin hydrocarbons. Paraffins begin to be released from oil if the pressure of oil saturation with gas begins to exceed the pressure at the bottom, due to this, light hydrocarbon fractions are released. This can occur both in the well and in the formation, since a violation of the equilibrium state is possible at any point. In the fields, when the well is operated by pumping, the main areas of sediment accumulation are located in the receiving part of the pump.
2. A continuous decrease in the flow temperature occurs in the borehole and in the tubing due to heat transfer to rocks, as well as during transportation through the pipeline due to contact with a cooled metal surface, which leads to the release of crystals of paraffin hydrocarbons. In this case, the temperature gradient
is directed to the center of the pipe and in the direction of heat transfer, 21 formed crystals are deposited on the surface under the action of molecular diffusion. The greater the temperature gradient between the environment and the oil flow, the greater the number of formed ASPs. It is also possible to accumulate ASF on the walls of tubing, in discharge lines, reservoirs of collection points, especially in winter, when the temperature difference between the environment and the gas and oil flow increases. At the beginning of the process, the maximum sedimentation rate is observed, which gradually decreases due to the thickening of the ASPO layer.
3. The intensity of sediment formation is affected by the speed of movement of the gas-liquid mixture. The laminar flow regime of the liquid is characterized by low flow rates. Due to the slow transfer of the substance, the formation of ASF occurs with less intensity. In the turbulent flow regime, the flow velocity increases, as does the intensity of sedimentation and reaches its maximum at critical values of the Reynolds number. But when the speed reaches the maximum values, the accumulation rate decreases. This is due to the fact that paraffin crystals are better retained in the oil in a suspended state, and there is also a high probability of washing away paraffin deposits. The shear stress forces exceed the adhesion forces of the paraffin crystals with the inner surface of the pipes.
4. The adhesion strength of PU to the walls of pipes depends on the properties of the surface, its condition, as well as on the material that was used in the manufacture. At the initial stage of sedimentation, the main influence of the quality of metal surface treatment is traced. The roughness and micro-roughness of the pipe surface act as foci of vortex formation, which intensify the mixing of the liquid and slow down the flow rate. As a result, gas and paraffin begin to be released, the adhesion of crystals of paraffin hydrocarbons on the inner surface of the walls increases. Over time, the cleanliness of the surface treatment ceases to play a significant role, since all irregularities are filled with a layer of paraffin of small thickness. The intensity of sediment formation is influenced by the properties of the material, namely the degree of their polarity, from which the oilfield equipment is made. The higher the polarity value of the material, the lower the intensity of ASF formation and the better the hydrophilic properties. This is due to the low adhesion of crystals of paraffin hydrocarbons. Glass has the highest polarity, respectively, it has the lowest intensity of ASF formation. Polyethylene, due to its structure similar to the limit hydrocarbons of the normal range, has a high intensity of PU formation. Thus, the higher the polarity value of the pipe surface material and the better the processing quality, the lower the adhesion of paraffin crystals and the lower the rate at which deposits will be washed away.
5. The intensity of formation and composition of deposits largely depends on the component composition of oil and on the content of asphaltenes, resins and paraffins in it. Thanks to various studies, it has been found that oil with a high content of naphthenic and aromatic hydrocarbons in its composition is less inclined
to form strong paraffin deposits, unlike oil, where compounds of the normal methane series or paraffin are predominant. The components in oil determine the solvent capacity of the system in relation to paraffin hydrocarbons [5]. The formation of ASF occurs more intensively in oil, which has a large content of light fractions in its composition, capable of boiling up to 350 oC. Its dissolving capacity is higher than that of heavy and affects the crystallization temperature of PU. Basically, the structure formation and aggregative stability of paraffins are influenced by resinous-asphaltene components, their composition, structure and mutual ratio. They are inhibitors in the formation of deposits, reducing the surface tension during adsorption on the surfaces of paraffin crystals. There is a disordering and thinning of the adsorption layer, that is, desolvation of the crystal with a change in the nature of crystallization. The forces of coagulation adhesion decrease and the crystals remain in a mobile state in the oil stream, since the formation of a volumetric structural grid does not occur. Dissolved resinous-asphaltene components in oil cause the peptization process, which consists in the adsorption inhibition of paraffin crystals, and act as natural depressants. Asphaltenes will have a depressive effect, that is, inhibit the process of structure formation, when their content in oil is more than 5%. They can be germinal centers. The paraffin molecules, in turn, will crystallize with alkyl chains of asphaltenes, thereby forming a point structure. As a result, the release of paraffins on the surface worsens, since there is no formation of a solid lattice. Resins, on the contrary, will contribute to the formation of ribbon aggregates of paraffin crystals, as well as the creation of conditions for paraffins to adhere to the surface, having the opposite effect on the influence of asphaltenes.
References
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2. Buktukov, N., Mergenov, M. IMPROVEMENT of OIL FIELD DEVELOPMENT USING ENHANCED OIL RECOVERY METHODS. Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, 2021, (6), pp. 23-28
3. Moldabayeva, G.Zh., Suleimenova, R.T., Bimagambetov, K.B., Logvinenko, A., Tuzelbayeva, S.R. EXPERIMENTAL STUDIES OF CHEMICAL AND TECHNOLOGICAL CHARACTERISTICS OF CROSS-LINKED POLYMER SYSTEMS APPLIED IN FLOW-DIVERSION TECHNOLOGIES. News of the National Academy of Sciences of the Republic of Kazakhstan, Series of Geology and Technical Sciences, 2021, 4(448), pp. 50-58.
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5. Moldabaeva G.Zh., Agzamov A. Kh., Abileva reservoir to reduce viscosity and increase oil recovery. S. Zh., Baldanov B. A., Karimova A. S. The Complex use of mineral raw materials. No. 1 (316), effectiveness of physical impact on the productive pp.53-61., 2021, ISSN 2224-5243.
ИССЛЕДОВАНИЕ ТЕХНОЛОГИЧЕСКОЙ ОСОБЕННОСТИ КОНСТРУКЦИЙ НАСЛОННЫХ
СТРОПИЛЬНЫХ СИСТЕМ
Манапов Р.А.,
магистрант г. Омск, Россия Михалик Е.А.
магистрант г. Омск, Россия
RESEARCH OF TECHNOLOGICAL FEATURES OF DESIGNS OF INCLINED RAILING SYSTEMS
Manapov R.,
undergraduate student Russia, Omsk Mikhalik E. undergraduate student Russia, Omsk DOI: 10.5281/zenodo.7467714
Аннотация
Неизбежный факт того, что в процессе эксплуатации зданий и сооружении кровельные покрытия и ограждающие конструкции подвергаются физическому износу, воздействию многочисленных природных и технологических факторов, и как следствие появляются различные неисправности и дефекты ухудшающие эксплуатационные качества ограждающих конструкций. В данной статье рассматриваются технологические особенности наслонной стропильной системы, в том числе, применяемой при реконструкции и ремонте ограждающий конструкций зданий «старого фонда».
Abstract
The inevitable fact is that during the operation of buildings and structures, roofing and enclosing structures are subject to physical wear and tear, the influence of numerous natural and technological factors, and as a result, various malfunctions and defects appear that worsen the performance of enclosing structures. This article discusses the technological features of the layered truss system, including those used in the reconstruction and repair of the enclosing structures of buildings of the "old fund".
Ключевые слова: стропила, наслонная стропильная система.
Keywords: rafters, layered rafter system.
Введение
Актуальность данного исследования в том, что благодаря своей технологической особенности, наслонные стропильные системы, позволяют с достоинством выдерживать большие нагрузки: сильные снегопады, резкие порывы ветра, обильные ливни. И именно, в массовом строительстве гражданских, общественных, медицинских и прочих зданий «старого фонда», устраивались в основном чердачные скатные крыши с применением наслон-ных стропильных систем.
Целью является исследование эффективной технологии возведения стропильной системы, которая делает упор на несущие элементы строения, что служит также каркасом для различных видов материалов кровли: утеплителей, гидроизоляции, разнообразных покрытий. [1]
Основные выводы и рекомендации, полученные в результате исследования, использованы при реконструкциях и капитальных ремонтах скатных крыш, тем самым нашли практическое применение.
Основная часть
В соответствии с СП 17.13330.2017, крыша [3] - верхняя несущая и ограждающая конструкция здания или сооружения для защиты помещений от внешних климатических и других воздействий. Существует две технологии устройства наслонных стропильных систем: безраспорная и распорная. Узлы опирания и способ соединения стропильных ног [5] определяют, будет ли создаваться распор на стены или нет.
1. Технология безраспорной наслонной системы стропил.
В безраспорной наслонной системе [4] стропильная нога [5] работает на изгиб и не передает распирающего горизонтального усилия на стены. Существует три варианта реализации безраспорных наслонных стропил:
а) Вариант 1 - «Жесткий низ - свободный верх».
