Effective Technology to Fix Horizontal Wells with a Liner for Subsequent Development by the P&P Method

Summary One of the priority directions of technological development of RUE "Production Association" Belorusneft "is the involvement in the development of unconventional oil reserves and enhanced oil recovery. Achievement of this goal was hampered by such a technological challenge in the field of well construction, as providing reliable support for a well with an extended horizontal completion during development by the P&P method. The essence of the challenge was that when performing a cluster or multi-stage hydraulic fracturing, increased loads are created on the well support, which can violate its isolation. The complexity of the geological and technical conditions in the Pripyat trough lies in the large length of horizontal ends in salinized carbonate reservoirs and high hydraulic fracturing pressures during well development. The article discusses solutions for the design and creation of a reliable cement sheath for the given geological and technical conditions. To overcome the technological challenge, a cementing technology was developed, including a plugging slurry formulation with elastic properties of a cement stone and a casing rotation technology during the cementing process. The plugging slurry formulation was developed with the elastic properties of a cement stone with cement mixing in salt water, adapted to the conditions of the salinized rocks of the Pripyat trough. To develop the formulation, the simulation of the pressure effect during the development by the P&P method on the cement stone behind the casing was used, as well as the simulation of the process of displacement of the drilling mud by the plugging slurry. The technology was successfully tested at five sites when horizontal wellbores were fastened with 114 mm tie-back casings, while high cementing quality indicators were achieved. The lengths of the tie-back casings ranged from 509 to 1000 m. The article presents the results of assessing the quality of cementing using acoustic cementometry and assessing the density of the medium behind the casing by gamma-gamma cementometry, as well as comparing the quality of cementing with casing rotation and without rotation, before and after the impact of P&P development. In RUE "Production Association" Belorusneft "it was decided to use the developed technology in default for attaching 114 mm liners with subsequent development using the P&P method.

Results of Bench Tests of Tube Steels of the Production Tubing with a Chromium Content of 1%, 3% and 5% on a Unit Simulating the Operating Conditions of Producing Wells

Currently, most of the fields of RUE Production Association Belorusneft are at a late stage of development, which is characterized by a high water cut of well production. One of the main tasks in such conditions is the search for engineering solutions aimed at preventing corrosion of well equipment during oil production. Under the operating conditions of producing wells of the fields of RUE Production Association Belorusneft, well equipment is subject to electrochemical carbon dioxide corrosion [1]; mainly the inner surface of the tubing is subject to corrosion attack. The average rate of local corrosion in the corrosive environments of the oil fields of Belarus is 2–3 mm/a. The first cases of corrosion damage to production tubing were identified in 2010. Taking into account the high cost of stainless tubing, since 2011, the technology of inhibitory corrosion protection has been successfully implemented in the fields of Belarus by the method of constant dosing of the reagent into the annulus of production wells. The use of inhibitors made it possible to eliminate well failures due to tubing leakage, extend their service life by at least 4 times and reduce the local corrosion rate to 0.1 mm/a. However, an increase in the number of production wells damaged by corrosion caused by water encroachment of the wells, as well as an increase in the cost of reagents for oilfield chemicals require the use of new technological approaches, the search for alternative, economically more profitable solutions.

The peculiarities of archival heuristics in seeking information on the history of Soviet industry of Sevastopol in the central archives (on the example of the source complex on the history of Sevastopol branch of the Central Research Institute “Compass” in the Central State Archive of Scientific and Technical Documentation of St. Petersburg)

The subject of this research is the information potential of the source complex of archival documents dedicated to the history of Sevastopol Central Research Institute “Compass” in the Central State Archive of Scientific and Technical Documentation of St. Petersburg. Since Sevastopol was not only an industrial, but also a scientific and technological center, the engineering departments lead unique developments, which were later implemented in various sectors nationwide. Both, enterprises and engineering departments were integrated into a unified all-Union system, which justifies using not only the city archive, but also central archives to find sources on the history of industrial development of Sevastopol during the Soviet period. This article is dedicated to determination and detailed analysis of the documents related to the history of Sevastopol Central Research Institute “Compass”. The authors dwell on the types of the preserved departmental documents, provide explicit examples, and analyze the peculiarities of documentation. The work is based on the range previously unpublished archival documents. The conclusion is made that materials from the fund of the Central Research Institute “Compass” of the Central State Archive of Scientific and Technical Documentation of St. Petersburg demonstrates the place and role of Sevastopol branch within the system of this organization, unlike the local documents stored the city archive of Sevastopol, which are focused on the local tasks and problems, and do not fully reflect the structural issues of the entire Scientific Production Association. Analyzing the extracted archival information on the Scientific Production Association “Compass”, the authors conclude that both the association itself and the Ministry of Shipbuilding Industry of the Soviet Union were focused on strengthening integration and interrelation of enterprises both within the Central Research Institute “Compass “ and industry as a whole, which manifested in establishment of the Council of the Scientific Production Association “Compass”; its documents are also stored in the fund.

Tritium in the urine of the Mayak PA workers in the period from 2017 to 2019

Objectives. To define the levels of volume activity of tritium compounds and fraction of organically bound tritium in urine of chemical production workers of “Mayak Production Association” in present-day conditions; to identify the relationship between volume activity levels and professional occupation (department and profession). Material and methods. 245 urine samples from 171 workers of Mayak Production Association tritium production facility were collected in the period from 2017 to 2019. Volume activity of tritium compounds was measured by liquid scintillation method using spectrometer Quantulus-1220. The samples were distilled or dried and then combusted using an automatic preparation and oxidization system Sample Oxidizer A307. The “R” software was used for statistical analysis and for processing the measurement results and occupational factors. Chaddok’s scale was applied to determine the degree of correlation. The significance level was taken equal to 5%. Results. The value of total tritium volume activity in the urine and tritium volume activity in the water phase varied within 4 orders of magnitude (from ~30 Bq/dm3 to ~250 kBq/dm3). The value of volume activity of organically bound tritium in the urine varied within 2 orders of magnitude (from ~6 Bq/dm3 to ~3000 kBq/dm3). The fraction of organically bound tritium in the urine of the workers was within the range from 0,07% to 74%, and did not differ statistically significantly from lognormal distribution with parameters GM=2,7% and GSD=3,7. Very high rank correlation was detected between total volume activity of tritium compounds and tritium volume activity in the water phase in the urine. Noticeable rank correlations were detected between the total volume activity of tritium compounds in the urine and volume activity of organically bound tritium, as well as between tritium volume activity in the water phase and volume activity of organically bound tritium in the urine. The total tritium volume activity and tritium volume activity in the water phase in the urine of the workers of the 1st department and of the analytical laboratory of Mayak Production Association tritium production facility were statistically significantly higher than in the workers of the 2nd department according to median values. Statistically significant differences between medians of the total tritium volume activity in the urine and tritium volume activity in the water phase related to profession were observed only in the workers in the 1st department. Conclusion. Estimation of tritium volume activity in the water phase by the level of total tritium volume activity in the urine without sample preparation is possible with 95% reliability within limits of one order of magnitude towards the model value. Estimation of volume activity of organically bound tritium in the urine without sample preparation by the level of total tritium volume activity in the urine without sample preparation is possible with 95% reliability within limits of two orders of magnitude towards the model value. The effect of occupational factors to the levels of volume activity of tritium compounds in the urine of Mayak Production Association professional workers was detected.

Value Chain Production Association for Pink Pepper Bananas: Research in Yen Lac District, Vinh Phuc Province, Vietnam

In Vietnam, there are various types of bananas, some of them have become regional specialties of many regions such as: Pink Pepper banana, Western banana, King banana, old banana, etc. Nowadays, Pink Pepper banana is the most popular grown banana with high potential for domestic and international markets. In order to contribute to adding value to agricultural products, linking production along the value chain for Pink Pepper bananas is an urgent issue for policy makers as well as businesses and farmers. This article focuses on analyzing the current status of value chain production linkage for this specific type of bananas in Yen Lac District, Vinh Phuc Province, Vietnam, at the same time, showing results, limitations, causes and recommendations to promote production linkages in the value chain for Vietnamese Pink Pepper banana products in the context of world economic integration.

Registry of plutonium-induced lung fibrosis in a cohort of nuclear workers of the Mayak Production Association

The registry of plutonium-induced lung fibrosis cases (PuLF) diagnosed in members of a cohort of the first Russian nuclear industry facility Mayak Production Association was established in the clinical department of the Southern Urals Biophysics Institute of the Federal Medical-Biological Agency (SUBI). The registry includes 188 plutonium-induced lung fibrosis diagnoses: 117 (62.23%) in males and 71 (37.77%) in females. This paper describes the structure and detailed characteristics of the registry. The number of PuLF cases was shown to have no association with cumulative lung absorbed dose from external gamma rays as of the date of diagnosis. On the contrary, the PuLF rate was shown to be associated with cumulative lung absorbed dose from in-corporated alpha particles and to increase significantly with increasing dose from internal radia-tion exposure. This paper discusses potential applications of the registry to scientific investiga-tions in the future.

Risk of malignant neoplasms in the first generation offspring of female workers of Mayak Production Association

The study of the role of parental preconception exposure in development of malignant neo-plasms (MN) in the offspring is a topical point in cancerogenic factors’ research. The objective of the work is assessment of cancer risk among the offspring of female workers of the country’s first atomic production facility – Mayak Production Association (PA) – exposed to long-term occupa-tional radiation exposure prior to conception. We have performed a retrospective epidemiological analysis in a cohort of offspring born in 1949-1990 that contained 2061 children from 1404 fe-male workers. Mothers of 1145 children (55.6%) had accumulated doses of preconception exter-nal gamma-exposure to the ovaries (main group); the remaining 916 children (44.4%) were re-garded as internal control (comparison group) as the offspring of female workers that were not exposed to preconception irradiation of genital organs. We have followed up the vital status and cancer incidence in the offspring up to 31.12.2018. We have performed an analysis of the struc-ture and cancer incidence rates. We had calculated the relative risk (RR) and the excess relative risk (ERR) to a dose unit of external gamma-exposure with a 95% confidence interval using the AMFIT module of the EPICURE software. A total of 92 MN cases were registered in 1949-2018 among the first generation offspring of female workers. A comparative analysis of cancer inci-dence showed no significant difference in the structure and incidence rate of MN in the groups. The only exception were the offspring of the females not exposed to preconception occupational irradiation of genital organs; in this group we had indicated a significant increase of brain MN in male offspring and of the MN of corpus uteri among female offspring. We had registered MN of digestive organs and MN of breast most often in the main group of the offspring. The range of maternal doses of preconception external gamma-exposure to the ovaries varied greatly: maxi-mum dose in male offspring reached 2954.82 mGy and 4075.61 in female offspring. Calculation of RR of MN in the offspring of the main group showed no significant difference from the com-parison group for all the MN, for solid cancers separately, and for other most frequent cancers. Assessment of ERR coefficients in relation to maternal accumulated absorbed dose of precon-ception external gamma radiation to the ovaries had revealed no statistically significant increase of cancer incidence among the offspring of female workers exposed to occupational irradiation of genital organs. We had obtained no reliable evidence in our investigation of the relation be-tween MN in the offspring of Mayak PA female workers and accumulated doses of preconception external gamma-exposure to the gonads. Further research is needed taking into account relative-ly young average age of the observed cohort of the offspring.