A justification of the application of low-mineralized flooding at the later stage of offshore oil field development

Известно, что для поддержания пластового давления используется вода совместимая по своему химическому составу с пластовой. В этом случае обеспечивается возможность сохранить присущую эксплуатируемому объекту поровую структуру. Данная работа посвящена обоснованию применения низкоминерализованного заводнения нефтяных месторождений на поздней стадии разработки. На основе изученного материала разработаны методические рекомендации для повышения эффективности системы поддержания пластового давления за счет закачки низкоминерализованной воды. Результаты теоретического анализа (литературная и патентная проработки) дополнительно были подтверждены проведенным гидродинамическим моделированием низкоминерализованного заводнения на примере нефтяного месторождения. It Has been known that the water used for reservoir pressure maintenance has to be compatible in its chemical composition with the reservoir water. In this case, it is possible to preserve the pore structure inherent in the exploited object. This article is devoted to the justification of applying low-mineralized water flooding at the later stage of offshore oil field development. Authors developed a method to improve the efficiency of reservoir pressure maintenance system with applying low-mineralized water injection. The novelty of this article is the mathematical determination of the optimal period for the start of the application of low-mineralized water flooding. Theoretical analysis results were also confirmed by hydrodynamic modeling of low-mineralized water flooding in an offshore oil field at a late stage of development. Based on the analysis results, authors identified requirements and recommendations for the low-mineralized water flooding.

Statistical analysis of predictors of the effectiveness of complex therapy in patients with skin scarring

The variation of indicators that characterize skin scarring increases in patients with metabolic syndrome, which may affect the effectiveness of therapeutic measures. It has been found that pathological processes in the skin scar in the initial state correlate to the greatest extent with the index of insulin resistance, the atherogenic coefficient and the coefficient of antioxidant protection. It is proved that the effectiveness of complex physiotherapy with the addition of the internal intake of medium-mineralized water «Essentuki №17» directly correlates with an increase in tissue sensitivity to insulin and the activation of antioxidant enzymes, as well as with a decrease in dyslipidemia. Linear regression equations are presented to determine significant predictors of treatment effectiveness, which can lead to the creation of individualized therapeutic programs using preformed and natural physical factors.

Study of corrosion resistance of pump-compressor pipes made of ferrite-pearlite steel under the action of carbon dioxide mediums

To ensure required complex of steel strength properties, pipes heat treatment is widely used as a quenching for martensite followed by tempering. It is accepted, that metal microstructure formed at that, has a little effect on a steel corrosion resistance in carbon dioxide mediums. Studies were accomplished of steel microstructure effect of the carbon dioxide corrosion speed. In particular, a low-alloyed structural steel, used for production of oil field pipes was selected. As the object of the study, seamless pumpcompressor pipes (PCP), made of medium-carbon steels of several grades with chrome content about 1% (mass.), subjected to two methods of heat treatment: quenching with tempering or normalization with tempering. Corrosion resistance of the steels were accomplished under laboratory conditions of JSC “RusNITI” by application of autoclave facility imitating operation conditions parameters of a working medium at oil extraction. The speed of general metal corrosion was measured as samples mass loss during tests (from 360 to 70 hours) by gravimetric method. By the results of laboratory tests the steel 35ХГФА was recommended to the industrial production of PCP of K72 and N80 strength groups due to GOST 31446 with normalization and tempering. It was established that pipes of steel 35ХГФА with ferrite-pearlite microstructure have higher corrosion resistance in mineralized water mediums at carbon dioxide partial pressure up to 0.20 atm, comparing with regular pipes, manufactured with quenching and tempering. A complex of field tests of PCP was carried out, the pipes made of experimental steel 35ХГФА at an oil deposit. The result of operation of CPC of 88.9×6.45 mm made of steel 35ХГФА having K72 group of strength (after normalization with tempering) during 550 days under conditions of high-mineralized water phase at СО2 partial pressure up to 0.27 atm was found positive. After an intermediate inspection (550 days) the column of PCP was assembled and is in operation at present, the current running time exceeding 1000 days. Based on the results of the complex comparative tests carried out in the corrosion laboratory and under field oil extraction conditions it was established that usage of experimental steel 35ХГФА containing 1% of Cr, after application of normalization technology with tempering resulted in increasing of operating reliability of CPC.

Selection of a strata pressure reduction method to extract deeper level reserves of Mir pipe

The article presents the chronology and stages of mining resumption at Mir pipe. The initiatory steps of the conceptual approach to underground mining of ore reserves at the depth greater than 1500 m are described. The primary measures on catchment of highly mineralized water from Metegero-Ichersky aquifer are identified. The exploratory study results on deeper level mining safety in the future underground mine in terms of the strata pressure reduction are given. The authors in detail discuss two methods of rock mass destressing: destressing drilling and formation of protection layers with different parameters at the depths of 1000 m and greater. Natural stress state of rock mass is modeled in Rocscience RS3 environment. The analyses of the mathematical models of ore and enclosing rock destressing show that the safest and the most effective methods of dеstressing of deeper level rock mass in Mir Mine is creation of a protective separation layer both in ore body and in enclosing rock mass on the both sides of the ore body at a distance of 15 m. Such destressing measures can allow safe mining of ore reserves using the sublevel stoping method with sublevels to 50 m high. The research findings will be used in the front-end engineering as the basis for the further mine planning and design.

Influence of water mineralization and dissolved main cations on survival, size and seismosensory characteristics of perch fry (Perca fluviatilis L.)

Within two months the growing of the perch fry Perca fluviatilis L. carried out in the aquarium experiment. Fertilized eggs of this fish species were taken from the spawning ground of a small and unpolluted natural reservoir and placed in laboratory conditions for subsequent incubation under different hydrochemical conditions. Experimental groups of perch were created in two replicates that developed under control conditions with a water salinity of 160 mg/l, under conditions of fresh water diluted to 100 mg/l, and under conditions with water whose salinity was increased relative to the control to 400 mg/l in three different ways - by adding calcium, magnesium or sodium chloride salts. Temperature, light, and oxygen conditions for growing fry in all groups were the same. The perch larvae were fed first with small natural zooplankton, then with artificially grown nauplia of Artemia; perch fry - with tubificid from vermiculture. The average survival rates of late larvae and early fry of perch in the second half of the experiment were maximal in the groups that developed under hydrochemical conditions with the addition of Na+ and Mg2+ (73% and 67%), and minimal in the groups that developed in the least mineralized water (46%). At the end of the experiment, the surviving fry from the groups affected by the increased content of sodium chloride had statistically significantly (p < 0.05) larger linear sizes than the fry from the control groups and groups that developed in the least mineralized water. Perch fry from the groups affected by increased concentrations of Ca2+ were characterized by a statistically significant (p < 0.05) smaller number of pores in the infraorbital and mandibular seismosensory canals of the head, compared with fry formed in conditions of least water mineralization and the minimal content of this main cation in it. Thus, salinity values and features of the ionic composition of fresh water can significantly affect the development of perch fry, which should be taken into account when breeding it in aquaculture.

Species Composition Features of Zoopankton in Mineralized Water Bodies from Specially Protected Natural Territories in Ulug-Khem Basin (Republic of Tuva)

The species composition of zooplankton in mineralized water bodies located in the Ulug-Khem basin (Republic of Tuva) was studied. These lakes have the status of natural monuments of regional significance. In total we recorded 53 species of microscopic Custaceans and Rotifers from 32 genera, 13 families, and 8 orders. Cladocera comprises 53% of the species. The dependence of the species diversity on the level of mineralization was revealed; 89% of the species were found in brackish water bodies. The zooplankton composition of the hyperhaline lakes Dus-Khol (Svatikovo) and Cheder has remained constant for many dozen years. The zooplankton includes some species known only from Republic of Tuva in Russia, namely, Microcyclops afganicus and Macrotrix tabrizensis. M. asiaticus and Alona irinae, rare for the fauna of Russia, live in the lake Haak-Hol. A decrease in the total numbers of zooplankton is observed in the lakes, namely: in the lake Dus-Khol, it has decreased by 4 times, in the lake Khadyn it has decreased by 10–19 times as compared to the middle of the last century. Despite the lack of intermediate information, we regard this as a consequence of anthropogenic impact. The emergence of an indicator of pollution (Brachionus nilsoni) in the lake Khadin confirms this version. At the same time, the stable finding of species rare for the fauna of Russia indicates the presence of favorable conditions for their development and life, which increases the value of the reservoirs themselves, which are already unique natural objects.