Dear Colleagues! I would like to welcome scientists and engineers working in the oil and gas industry to the first issue of the Journal of Hydrocarbon Power Engineering. Currently the Ivano-Frankivsk National Technical University of Oil and Gas publishes five scientific and technical journals. However, taking into account global challenges in the oil and gas industry, university's focus on long-term scientific and technical research and development solutions and extensive international contacts of our academic community, we have initiated the Journal of Hydrocarbon Power Engineering as an attempt to bridge the gap between the science of hydrocarbons and practical engineering issues. Hopefully, the Journal of Hydrocarbon Power Engineering will introduce our research to a broad readership and provide an excellent forum to cover a variety of topics: - Geology and Geophysics; - Oil and Gas Exploration and Production; - Oil and Gas Transportation; - Oil and Gas Measurement and Testing. We would like to encourage research articles, case histories, field process reports, review articles on topics of special current interest from oil and gas professional and scientific community to ensure a success of our Journal. The Journal of Hydrocarbon Power Engineering will be published twice a year and is planned to be registered by Scopus. Prospective Author Guidelines can be found at http://ogpe.nung.edu.ua Established in 1967, the Ivano-Frankivsk National Technical University of Oil and Gas (IFNTUOG) is the market leader in providing high-level technical and nontechnical training services to Ukraine's energy sector-a major driver of Ukrainian economy. Recognizing its special obligations to the oil and gas industry, IFNTUOG offers a unique blend of teaching, training, and industrially focused expertise. All the available indicators of research quality and academic standing place IFNTUOG in the highest echelon of Ukrainian technical universities. IFNTUOG's academic experience is firmly rooted in seven faculties and four institutes comprising 57 departments that offer a wide selection of comprehensive programs at the baccalaureate (24), specialist (30), master (23) and doctoral (25) levels. 11,000 students from Ukraine and 37 countries can explore academic disciplines from drilling and reservoir engineering to management and oil and gas translation. Instruction for international students is in Ukrainian, Russian and English. As the rapidly developing oil and gas industry calls for professional engineers who are well-educated to perform a wide range of operations, IFNTUOG provides courses in issues such as: oil and gas geochemistry; drilling; well logging, completion, testing and evaluation; mathematical modeling; thermodynamics and phase behavior, reservoir modeling and simulation; production techniques, enhanced recovery methods; phase behavior and thermodynamics; sales gas transmission and storage. IFNTUOG's In-Service Institute offers lifelong professional development and certification programs to meet the demands of managerial staff and specialists in different branches of the oil and gas industry. The University has long-established relations with the government, senior industry executives, and leading players in the national oil, gas, and power sectors. IFNTUOG's primary objective is to become a sustainable, effective and efficient school that will promote lifelong learning and embed internationalism into its activities. Видавництво Івано-Франківського національного технічного університету нафти і газу вул. Карпатська, 15, м. Івано-Франківськ, 76019, Україна, тел. (03422) 42453, факс (03422) 42139, http://nung.edu.ua, e-mail: public@nung.edu.ua Свідоцтво про внесення до Державного реєстру видавців ІФ № 18 від 12.03.2003 р. Підписано до друку за рекомендацією Вченої Ради ІФНТУНГ від 26.02.2014 р. № 03/537 Формат 60x84 ty Друк цифровий. Наклад 300 примірників. Ivano-Frankivsk National University of Oil and Gas Publishing House 15, Karpatska str., Ivano-Frankivsk, 76019, Ukraine, phone +38 034 2242453, fax +38 034 2242139, http://nung.edu.ua, e-mail: public@nung.edu.ua The journal is listed in the State Publishers' Record (ІФ № 18 of 12.03.2003) Approved and signed for publication according to the recommendation of the Academic Council of IFNTUOG (protocol number 03/537 of 26.02.2014) BombaA.Ya., MyslyukM.A., YaroshchakS.V. Mathematic modelling of thermodynamic effects in gas formation well bore zone………………………....1 Boiko V.S., Mishchuk B.M. Probabilistic behavior of well rate decrease laws through time. Universal dependence of Weibull-Makeham law…………………………………… 2 KopeyB.V., Mykhailiuk V.V., Liakh M.M. Research of stress-deformation state of worn sucker rod thread connection……………………………………………13 Oil and Gas Transportation Polutrenko M.S., Kryzhanivskyy Ye.l., Pilyashenko-Novohatnyi A.I., Peretyatko T.B. The main aspects of microbiological protection of underground oil-and-gas pipelines 21 Luhe M. V. Calculating the steady-state operations of profile gas pipelines with high and ultrahigh pressures 30 Kryzhanivskyy Ye.l., SusakO.M., Zaytsev Val.V. Optimization of unloading modes of compressed natural gas that is transported by container ships 36 Oliynyk A.P., Shtayer LO. Modeling of fluid flow in pipeline with the leaks due to the surface…………………………………………………..45 Oil and Gas Measurement and Testing Pistun Ye., Lesovoy L, Fedoryshyn R. Optimization of the differential pressure flowmeters by means of "RASKHOD-RU" CAD 53 MandraA.A., Lyutak I.Z., LyutakZ.P. Modeling of ultrasonic guided waves propagation in a waveguide with cross-section of finite size 58 Kisili.S., BodnarR.T., PatlovskyyI.R., Malko O.H., Kuchirka Yu.M. Control of surface active agents content in aqueous environment by measuring surface tension………………………..66