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RESEARCH OF THE COLMATATION OF THE PRE-FILTER ZONE OF WELLS AND THE FACTORS THAT INFLUENCE IT DURING THE OPENING OF URANIC DEPOSITS Alikulov Sh.Sh.1, Mardonov R.Kh.2
1Alikulov Shukhrat Sharofovich - Head of the Department;
2Mardonov Rustam Khikmatullayevich - Doctor of Technical Sciences, Trainee Researcher, DEPARTMENT OF LIFE SAFETY, MINING FACULTY, NAVOI STATE MINING INSTITUTE, NAVOI, REPUBLIC OF UZBEKISTAN
Abstract: colmatation significantly affects the productivity of wells, the permeability of the formation, determined by the results of hydrodynamic studies. The study of the causes of colmatation and the factors affecting it will contribute to the development of perfect methods to prevent the occurrence of this phenomenon. This article provides a brief overview of the factors affecting colmatation, and provides information about methods for its elimination. Keywords: colmatation, colmatant, ammonium carbonate, colmatation processes, bentonite, clay.
Today, to the most advanced methods in the field of extraction of urban deposits is the method of underground borehole leaching of ores. Underground dissolution and leaching of minerals with the use of boreholes has been successfully used for more than one decade along with the traditional methods of extraction of minerals - open and underground. In particular, this is how boiled salt is obtained, the PSV method is effectively used in the development of deposits represented by slack-cemented ores, the zone of oxidation and crust of iron and weathered quarters. Under these conditions, it is also used when collecting an urn (one).
Colmatation - a decrease in the permeability of the mat due to the deposition of various substances in it, which impede the passage of the leaching solutions.
Especially often, the closure of the mat occurs due to the precipitation of iron hydroxide. With a subsequent increase in acidity, these deposits dissolve. In such a way, the fraction of dissolution-settling-dissolution is advanced to the production well.
In the conditions of PSV, the following types of cultivation are distinguished:
1) Chemical, associated with the formation in the pores of chemical precipitates, is subdivided into reversible, caused by temporary precipitation from solutions of aluminum and iron hydroxides, and irreversible, due to hypotension;
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2) Gas, conditioned by the formation of carbon dioxide and hydrogen sulfide in the bed as a result of the interaction of acid with the host rocks;
3) Ion exchange, associated with a change in the size of pores in the presence of organic substances and clay minerals in permeable rocks during the movement of a solution containing large ions;
4) Mechanical, caused by the closure of the porous channels by mechanical suspensions.
To the greatest extent exposed to the action of colmatation near the filtering zone of the
wells, especially the boreholes, since from the filter zone of the fine wells there are a bit of solid, continuous
The chemical composition of the colmating compounds is very different, among them there are alumenite (aluminum hydrogen sulfate), iron hydroxides and sulfates, gypsum, etc.
The development of colmatation is also influenced by the chemical and mineralogical composition of the host rocks.
The existing methods of recovery of the productivity of wells can be divided into several directions:
1) Physicomechanical and dynamic action on the water-permeable part of the wells (flushing with water, pumping, high-frequency vibration, impulse depressions during the breakdown of wells);
2) Hydrodynamic methods (wells vacuuming, air injection into wells);
3) Chemical treatment of wells.
Clay is a fine-grained sedimentary rock, dusty in a dry state, plastic when wet. Clay consists of one or several minerals of the kaolinite group, montmorillonite or other layered aluminosilicates (clay minerals), but it can contain both sandy and carbonate particles. As a rule, caolinite Al4[Si4Oi0](OH)8 is a transforming mineral in clay, its composition is 47% (wt.) silicon oxide (IV) (SiO2), 39% aluminum oxide (Al2O3) and 14% water (H2O). Al2O3 and SiO2 - make up a significant part of the chemical composition of clays of yellow, brown, blue, green, purple and even black colors. In terms of structure, clay minerals can have a rigid and extensible crystalline structure.
Ammonium carbonate is more selective with respect to uran than sodium carbonate. It does not react at all with silicic acid, aluminum and iron oxides. Nickel, copper, forming ammonia complexes can go into the solution. Ammonium carbonate is about 4 times more expensive than soda, but it can easily be regenerated and returned to production, easy regeneration is due to its thermal instability.
When leaching occurs, the following reaction occurs:
UOs + 3(NH4)2C03 + H-,O (M/4)4[U02(CO,),] + 2NHaOH
Fig. 1. Production well design: a) pumping well, b) pumping well 1 - bypass pipe under the submersible pump; 2 - side pipe 110x18; 3 - filter; 4 - sump; 5 - weighting agent; 6 - cement plug; 7 - gravel filling
Bentonite is a clay that contains at least 70 percent of the mineral of the montmorillonite group ((Na, Ca)0,3(Al, Mg)2Si4O10(OH)2 • nH2O), which is a highly dispersed, silica-free, non-siliceous alumina , a negative charge appears, which is compensated by exchange cations located in the interlayer space.
Aluminum is found in ore most often in the form of complex aluminosilicate compounds, less often in the form of clay soil (Al2O3). The degree of transition of aluminum into the solution depends on the chemical strength of its compounds. Clay is very resistant to diluted solutions of sulfuric acid. By reaction
Al2O3 + 3H2 SO4 ^ Al2 (SO4 )3 + 3H2O
it goes into solution in an amount not exceeding 3 -5% of its initial content in the ore.
References
1. Alikulov Sh.Sh., Markelov S. V., Narziev A.S. "Climate the rock of the productive horizon during the underground leaching of uranium." Mountain information and analytical bulletin. № 3, 2011. P. 239-241.
2. Alikulov Sh.Sh., Markelov S.V., Halimov I.U. et al. "The influence of chemical climate control of the porous-fractured massif on the productivity of underground leaching blocks." Mountain information and analytical bulletin. № 6, 2011. P. 211-215.
3. AltshulA.D. Hydraulic couplings. M.: Nedra, 1982.
4. Amiyan V.A., Amiyan A. V. Increasing the productivity of wells. M. Nedra, 1986.
СОВРЕМЕННОЕ СОСТОЯНИЕ ПРОБЛЕМЫ РАЗРАБОТКИ РЕАГЕНТОВ-СТАБИЛИЗАТОРОВ К БУРОВЫМ РАСТВОРАМ
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Холбаев Б.М. , Комилов Б.А. , Ахмедова Д.А.
1Холбаев Бахром Махмудович - кандидат технических наук, доцент;
2Комилов Ботир Аскар угли - стажёр-преподаватель;
3Ахмедова Дилфуза Азаматовна - ассистент, кафедра геологии и разведки полезных ископаемых, Каршинский инженерно-экономический институт, г. Карши, Республика Узбекистан
Аннотация: в последнее время все большее внимание уделяется проблеме создания новых, высокоэффективных и доступных буровых растворов, т.к. в основном большинство компонентов и модификаторов буровых растворов завозится из-за рубежа, они дорогие, труднодоступные, не устойчивые к климатическим условиям Центральной Азии, и в некоторых случаях - токсичные и вредные для окружающей среды. Основной функцией бурового раствора является также очистка забоя от разрушенной долотом породы и вынос шлама из скважины. Чем быстрее удаляются потоком бурового раствора осколки породы с забоя, тем эффективнее работает долото.
Ключевые слова: реагенты-стабилизаторы, карбоксиметилцеллюлоза, термоокислительной деструкции, гексаметилендиамид, лигносульфатный реагент, глинопорошка.
УДК 622.022.612.2 Б01: 10.24411/2412-8236-2021-10702
Реагенты-стабилизаторы предназначены в основном для снижения фильтрации и вязкости бурового раствора. Это органические соединения, обладающие высокой гидрофильностью и растворимостью в воде. Известны реагенты-стабилизаторы на основе целлюлозы (карбоксиметилцеллюлоза, карбаминол, карбофен), лигносульфонатов, лигнина, полифенолов, акриловых полимеров, биополимеров, натриевых и калиевых солей гуминовых кислот, крахмалов (технический крахмал, модифицированный крахмал) [1].
Однако выполненная нами статическая обработка многолетних данных по основным хозяйственным показателям, а также рекгносцировочные обследования (1986-2016) позволили провести тщательный анализ водных ресурсов бассейна р. Кашкадарья [2, 3].
Наиболее широко распространенным в практике бурения скважин является такой реагент-стабилизатор как карбоксиметилцеллюлоза (КМЦ). Известно, что карбоксиметилцеллюлоза (КМЦ) различных степеней полимеризации сохраняет свои защитные свойства до температуры 130-160°С. Однако с ростом глубин и, как
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