The article analyzes the latest seismic data obtained during detailed seismic surveys in the development area of the Tyuysky, East Tyuysky and Biavashsky post-sedimentary trough-like troughs (“small grabens”), previously identified within the Republic of Bashkortostan on the northern slope of the Bashkir arch and in the Annunciation basin. The oil prospecting areas of the considered “small grabens” acquired after the discovery in the 1960-1980s. of the last century on the southeastern outskirts of the ancient East European platform with new oil and gas accumulation zones controlled by sedimentary grave-like troughs in terrigenous Devonian. Unlike the latter, post-sedimentary trough-like troughs are distributed along the section from Riphean-Vendian to Middle Carboniferous deposits (Vereiskian horizon), which corresponds to their geological characteristics as post-sedimentary disjunctive structures. It is shown that the interpretation of the seismic record indicates the phased development of the post-sedimentary trough-like troughs. In the Riphean-Vendian and Upper Paleozoic, semi-regional post-sedimentation micro-grabens resumed upon activation of tectonic phases as distinct disjunctives, whose morphological features weakened up the section. At the last - Vereiskian - stage, a shallow (2-3 km wide) shallow deflection was formed with a disjunctive western side and a flexure-like plicative eastern one. The oil-controlling role of post-sedimentary trough-like troughs has so far been proved only fragmentarily, but the latest seismic data allow us to detail their structure, the dynamics of their development and the influence of the conditions of their phased transformation on the formation of potential hydrocarbon traps.

The work demonstrates methodological techniques that allow using the capabilities of modern seismic packages, including obtaining information on the geomorphology of post-sedimentary trough-like troughs cavities in time.

References

1. Dragunskiy A.K., Tektonika i perspektivy poiskov zalezhey nefti v paleozoyskikh otlozheniyakh Priufimskogo rayona Bashkirii (Tectonics and prospects for the search for oil deposits in the Paleozoic sediments of the Ufa district of Bashkiria): thesis of candidate of geological and mineralogical science, Moscow, 1967.

2. Khat'yanov F.I., On the tectonic nature of buried Devonian micro-grabbers and the prospects for the search for oil-bearing structures in the southeast of the Russian platform (In Russ.), Geologiya nefti i gaza, 1971, no. 7, pp. 41–46.

3. Khat'yanov F.I., Paleorifty i transformnye mikrorazlomy na vostoke Russkoy plity (In Russ.), Metallogeniya i novaya global'naya tektonika, 1973, pp. 130-132.

4. Fattakhutdinov G.A., Oil deposits in the terrigenous Devonian of the southeastern slope of the Russian platform, shielded by grabens and faults (In Russ.), Geologiya nefti i gaza, 1970, no. 5, pp. 38-42.

5. Lozin E.V., Dragunskiy A.K., Age of graben-like troughs of Bashkiria (In Russ.), Izvestiya AN SSSR. Seriya geologicheskaya, 1988, no. 8, pp. 122–129.

6. Lozin E.V., On the mechanism of formation of sedimentary graben-like troughs in the east of the East European platform (In Russ.), Geologiya nefti i gaza, 1994, no. 2, pp. 16–17.

7. Lozin E.V., Geologiya i neftenosnost' Bashkortostana (Geology and oil content of Bashkortostan), Ufa: Publ. of BashNIPIneft', 2015, 704 p.

The article discusses the technology of automatic pattern recognition of standard GR logging graphs with the aim of quickly building facies models of terrigenous depositions. Well logs provide information on the change in the particle size distribution of sediments over time and, depending on the sedimentation environment, are characterized by individual forms. This allows us to preliminarily determine the genesis of sediments and establish their facies affiliation with its further refinement by core materials.

The algorithm for pattern recognition of well logs is developed using neural networks on the example of a delta reservoir, which includes two standard facies - channel and bar facies with cylindrical and funnel-shaped forms of GR, respectively. Neural network training was carried out on a control sections consisting of 15 wells, for which different facies sand bodies of the delta reservoir were identified by an expert sedimentologist.

To increase the reliability of the recognition of logging forms, additional procedures have been used into the operation of the neural network, including: 1) correction of the training library (transfer of part of non-standard curves to the class of uncertain ones); 2) expanding the training library by adding several smoothed options to the existing log images; 3) simplification the way images are stored - instead of color coded images in a neural network, black and white began to be used, which accelerated its training.

The developed technique of automated pattern recognition of logging curves will optimize the processes of sedimentological analysis and will ensure the construction of a realistic geological model of the field with a facies options. Its use will make it possible to quickly identify of individual sand bodies with the spread of reservoir properties within the boundaries of each facies, which will allow for spatial monitoring of the geological heterogeneity of the development objects.

References

1. Rykus M.V., Rykus N.G., Sedimentologiya terrigennykh rezervuarov uglevodorodov (Sedimentology of terrigenous hydrocarbons reservoirs), Ufa: Mir pechati Publ., 2014, 324 p.

2. Muromtsev V.S., Elektrometricheskaya geologiya peschanykh tel – litologicheskikh lovushek nefti i gaza (Electrometric geology of sand bodies - lithological traps of oil and gas), Leningrad: Nedra Publ., 1984, 260 p

3. Reading H.G., Sedimentary environments: processes, facies and stratigraphy, Blackwell Publishing Limited, Second edition, 1986.

4. Baykov V.Ya., Bakirov N.K., Yakovlev A.A., Matematicheskaya geologiya (Mathematical geology), Part 1. Vvedenie v geostatistiku (Introduction to geostatistics), Moscow – Izhevsk: Publ. of Institute of Computer Science, 2012, 228 p.

5. Voskoboynikov Yu.E., Gochakov A.V., Kolker A.B., Fil'tratsii signalov i izobrazheniy: fur'e i veyvlet algoritmy (s primerami v Mathcad) (Signals and images filtration: Fourier and wavelet algorithms (with examples on Mathcad)), Novosibirsk: Publ. of SIBSTRIN, 2010, 188 z.

6. Baykov V.A., Afanas'ev I.S., Sergeychev A.V., Asmandiyarov R.N., Ivashchenko D.S., Sakhanenko A.I., Automatic well test data processing: a time series wavelet analysis approach (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 11, pp. 34-37.

7. Douglas D., Peucker T., Algorithms for the reduction of the number of points required to represent a digitized line or its caricature, The Canadian Cartographer, 1973, no. 10(2), p. 112 – 122.

8. LeCun Y., Bottou L., Haffner P., Gradient-based learning applied to document recognition, Proceedings of the IEEE, 1998, V. 86(11), pp. 2278 - 2324.

9. Nikolenko S., Kadurin A., Arkhangel'skaya E., Glubokoe obuchenie (Deep Learning), St. Petersburg, Piter Publ., 2018, 480 p.

10. Vorontsov K.V., Mashinnoe obuchenie (Machine learning), URL: http://www.machinelearning.ru/wiki/images/0/0d/Voron-ML-Compositions.pdf

When planning production drilling within fields with a complex geological structure, the task was to determine the intervals of the productive reservoir and assess their distribution by area. A complicating factor was the core recovery mainly from the impermeable matrix, which made it difficult to build a petrophysical model of the fractured reservoir. For the analysis of well logging materials presented by the standard Russian Well-logging complex, in the conditions of a limited number of high-tech well-logging methods, it became necessary to use neural networks to determine the lithology of the section and the type of void space. The well with the HI-TECH complex acted as a training data set. The k-means algorithm was used as the most simple and widespread in software products. The parameters for the interval time of the longitudinal wave, the spectrum of uranium and thorium, and the photoelectric factor turned out to be significant for clustering. In total, 6 clusters were identified, three of which are lithologically represented by limestone, the rest are dolomite. Clusters of intermediate differences associated with secondary processes such as fracturing, shale, and dolomitization were identified. The results of the section typification are well comparable with the lithological description of the core. Cluster 4, which is represented by fractured dolomite has the best reservoir properties. Conductive fractures, according to the electric scanner, are most common in clusters 1 and 3. In smaller quantities, they are observed in cluster 4. Productivity was confirmed by production logs and well tests from clusters 1, 3 and 4. It was also revealed that increased well flow rates corresponded to a higher dolomite content. According to the results of the analysis a pilot hole accompanied by such well logs as spectrometry, cross-dipole broadband acoustics and lithology density logging is recommended to minimize the drilling risks and improve the efficiency of development. Horizontal completion is recommended in the intervals of the section composed of rocks similar to clusters 1, 3 and 4.

References

1. Dobrynin V.M., Vendelshteyn B.Yu., Kozhevnikov D.A., Petrofizika (Fizika gornykh porod) (Petrophysics (Physics of rocks)), Moscow: Nedra Publ., 1991, 368 p.

2. Itenberg S.S., Shnurman G.A., Interpretatsiya rezul'tatov karotazha skvazhin (Interpretation of complex reservoirs logging data), Moscow: Nedra Publ., 1978, 389 p.

3. Khusainova A.M., Burikova T.V., Privalova O.R. et al., Raspredelenie neftenasyshchennosti v karbonatnykh kollektorakh v zavisimosti ot strukturnykh osobennostey porody (Oil saturation distribution in carbonate reservoirs depending on rock structural features), Collected papers “Aktual'nye nauchno-tekhnicheskie resheniya neftedobyvayushchego potentsiala PAO ANK “Bashneft'” (Current scientific and technical solutions to the oil production potential of Bashneft PJSC), 2016, V. 124, pp. 62–67.

4. Khusainova A.M., Burikova T.V., Privalova O.R., Nugaeva A.N., The influence of structural and lithological features on the saturation model of Middle Carboniferous reservoirs of the Republic of Bashkortostan (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 8, pp. 74-77.

5. Akhmetzyanov R.V., Privalova O.R., Burikova T.V., Khusainova A.M., Sozdanie unifitsirovannoy petrofizicheskoy modeli srednego karbona po mestorozhdeniyam Respubliki Bashkortostan (Creation of a unified petrophysical model of Middle Carbon in deposits of the Republic of Bashkortostan), Proceedings of XI “Aktual'nye problemy razvitiya neftegazovogo kompleksa Rossii” (Actual problems of the development of the oil and gas complex of Russia), Moscow: Publ. of Gubkin University, 2016, p. 12.

In Western Siberia major reservoirs of oil fields with traditional geological structure were entering later and closing phase of development. It poses new challenges to Rosneft Oil Company and opens prospects for exploration and production of hydrocarbons in reservoirs with a complex geological structure and the poorly understood productive formations of the Achimov complex and Tyumen suite. Achimov deposits confined to the fundoform area of the X oil field’s clinoform complex are one of such productive formations. These deposits are characterized by sufficient net pay, a large number of permeable intervals, low permeability, weak connectivity and also both lateral and vertical reservoir heterogeneity, which is primarily associated with the conditions of formation of these sediments. Oil of Achimov deposits is classified as tight oil.

This paper presents the results of an integrated approach to the analysis of geophysical data, geological structure and defines development plan for Achimov deposits. The key issues are a high degree of reservoir heterogeneity, a low degree of predictability, saturation determination and, high water-cut as well as rapid decrease of production rates. Based on results of geology and petrophysics analysis and production data, geological model of the productive formation was detailed with intra-layer correlation taking into account the clinoform structure of the reservoir. Petrophysical dependencies were corrected, the saturation model was refined, which made it possible to construct a predictive map of the water cut, assess the risks and optimize the purpose and order of well drilling. This approach in using a two-dimensional geological model and forecasting the initial parameters was translated to other Company's oil fields with a similar geologic structure, which made it possible to improve the predictive ability of productive formations models.

References

1. Rykus M.V., Rykus N.G., Sedimentologiya terrigennykh rezervuarov uglevodorodov (Sedimentology of terrigenous hydrocarbons reservoirs), Ufa: Mir pechati Publ., 2014, 324 p.

2. Baykov V.A., Zhonin A.V., Konovalova S.I. et al., Petrophysical modeling of complex terrigenous reservoirs (In Russ.), Territoriya Neftegaz, 2018, no. 11, pp. 34–38.

3. Muromtsev V.S., Elektrometricheskaya geologiya peschanykh tel – litologicheskikh lovushek nefti i gaza (Electrometric geology of sand bodies - lithological traps of oil and gas), Leningrad: Nedra Publ., 1984, 260 p

4. Leverett M.C., Capillary behavior in porous solids, Transactions of the AIME, 1941, V. (142), pp.159–172.

5. Dremin D.S., Tuktamysheva L.Yu., Yantudin A.N., Rykus M.V., New approaches to the simulation of the Achimov deposits on the basis of production-geophysical data on the example of the Tarasovskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 11, pp. 92–95.

In the face of reserves depletion the alternative solution aimed to maintain oil production level is unconventional reservoirs development. Due to increasing percentage of wells targeted to unconventional reserves and on some oil fields to oil rims presented by low permeability (less than 0.0005 mkm2) and low net-to-gross ratio (less than 30%), the investigation of available and development of new approaches to analysis of the geological features of the heterogeneous reservoirs (particularly estimation of the reservoir’s connectivity and effective permeability) and approaches to simulation (matching and forecast) of production profiles for complex geology is required. Adoption of advanced technologies in oil industry as to well stimulation techniques (hydraulic fracturing and horizontal wells drilling with multi-stage hydraulic fracturing) and mathematical modelling of the field development requires application of the knowledges about geological heterogeneity of the reservoir considered as the uncertainty. Most commonly, geological uncertainty is one of the most important factors influencing the field development design. Hydrocarbon reserves, amount and rate of change of oil/gas/water production determine basic types of geological uncertainty: static and dynamic respectively.

The article presents the results of numerical calculations performed on the base of synthetic stochastic 3D geological and simulation models. The method used for geological models creation, based on variation of geological parameters (net-to-gross ratio, vertical and horizontal variogram ranges) is described. Impact of the parameters changes on the results of statistical estimation of the static constituent of geological uncertainty (value of the parameters characterizing geological uncertainty such as reservoir compartmentalization, thickness, length, and portion of connected volumes) and dynamic constituent of geological uncertainty (oil recovery factor) are analyzed. Influence of the geological parameters on geological heterogeneity and influence of geological heterogeneity on forecasted oil recovery factor are revealed. Thus, based on the abovementioned analysis the approach for multivariate optimization of the field development of tight oil reservoirs with low connectivity is provided.

References

1. Zakrevskiy K.E., Popov V.L., Variogram analysis of geological bodies (In Russ.), Ekspozitsiya Neft' Gaz, 2018, no. 1, pp. 27–31.

2. Zakrevskiy K.E., Lepilin A.E., Novikov A.P., The parameter interdependency analysis for geological hydrocarbon field modeling (In Russ.), Territoriya Neftegaz, 2018, no. 10, pp. 20–26.

3. Viktorov E.P., Nurlyev D.R., Rodionova I.I., Tight reservoir simulation study under geological and technological uncertainty (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 10, pp. 60–63.

4. Dehua Liu, Jing Sun, The control theory and application for well pattern optimization of heterogeneous sandstone reservoirs, Petroleum Industry Publishing House, 2017, 223 p.

5. Ran Xinquan, Advanced water injection for low permeability reservoirs: Theory and practice, Elsevier Science, 2013, 264 p.

6. Larue D.K., Hovadik J.,. Connectivity of channelized reservoirs: a modelling approach, Petroleum Geoscience, 2006, V. 12, pp. 291–308.

7. Dem'yanov V.V., Savel'eva E.A., Geostatistika. Teoriya i praktika (Geostatistics. Theory and practice), Moscow: Nauka Publ., 2010.

8. Dubrule O., Geostatistics for seismic data integration in Earth models, Tulsa, Society of Exploration Geophysicists & European Association of Geoscientists and Engineers, 2003, 281 p.

9. Delhomme A.E.K., Giannesini J.F., New reservoir description techniques improve simulation results in Hassi-Messaoud field - Algeria, SPE 8435-MS, 1979.

10. Timonov A.V., Sergeychev A.V., Yamalov I.R. et al., Influence of reservoir heterogeneity characteristics on ultimate oil recovery in Priobskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 11, pp. 38–40.

11. Zheltov Yu.P., Razrabotka neftyanykh mestorozhdeniy (The oil fields development), Moscow: Nedra Publ., 1986, 332 p.

The authors consider improving the quality of the mounting of wells in unstable terrigenous sediments, through the improvement of methods for monitoring the technical state of the wellbore, the development of sedimentation-resistant cement materials and buffer liquids. The objective was to determine the optimal drilling conditions, ensuring maximum short-term and long-term stability of the open well bore based on the analysis of previously drilled wells stock. Based on this, authors have proposed an appraisal system qualifying the well bore stability and designed a counting pattern. The main idea of the work was implemented in the development of the method for assessing the technical state of the wellbore, using color clusters taking into account the drilling events conducted during the construction of wells, and the time spent on the construction of the drilled section. Based on multivariate iterations we formulated conditions for increasing the stability of terrigenous deposits in the well casing process on the R. Trebs and A. Titov oil fields. In particular, as one of the solutions, new recipes of the sedimentation-resistant and high-strength light-weight oil-well cement and buffer liquids with polymers were proposed. The test results of the viscoelastic buffer fluid showed the lowest static filtration loss compared with standard buffer fluid containing anti-absorbing additives. Besides gel-cement solution with the addition of the reagent in the complex state with a density of 1500 kg/m3 showed high sedimentation stability according to the strength characteristics similar to the cement slurry density of 1600 kg/m3.

References

1. Zeynalov N.E., Suleymanov E.M., On the deformation of clay rocks of the wellbore wall after cementing (In Russ.), Izvestiya vuzov. Neft' i gaz, 1982, no. 7, pp. 30–34.

2. Rykus M.V., The influence of secondary transformations on terrigenous reservoirs quality (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2018, no. 12, pp. 40–45.

3. Galiev A.F., Samsykin A.V., Teoreticheskie aspekty razrabotki tsementno-polimernykh sostavov dlya bor'by s vysokointensivnymi pogloshcheniyami (Theoretical aspects of the development of cement-polymer compositions to combat high-intensity absorption), Collected papers “Prakticheskie aspekty neftepromyslovoy khimii” (Practical aspects of oilfield chemistry), Ufa, 2014, pp. 50–53.

4. Galiev A.F., Agzamov F.A., Analysis of a well drilling process for a technical casing string in the fields named after R. Trebs and A. Titov (In Russ.), Stroitel'stvo neftyanykh i gazovykh skvazhin na sushe i na more, 2018, no. 8, pp. 9–14.

5. Blaiszik B.J., Kramer S.L.B., Olugebefola S.C. et al., Self-healing polymers and composites, Annual Rev. Mater. Res., 2010, pp. 179–211.

6. Shaydullin V.A., Levchenko E.A., Valieva O.I., Akhmerov I.A., Selection of grouting compositions for water shut-off in low-permeability intervals (In Russ.). Neftyanoe khozyaystvo = Oil Industry, 2019, no. 6, pp. 94–98.

Methods of FTIR spectroscopy, NMR and MALDI mass-spectrometry were used to study asphaltenes, resins and oil of the Varadero oil field (Cuba). We determined the content of macro elements of oil: С = 76.11, H – 9.32, N – 0.56 and S– 8.35 %, the content of metal V and Ni in the oil 0,0103 and 0,0064% , in asphaltene 0,029 and 0.022 % respectively. The most probable molecular masses of resins and asphaltenes were established which amounted to 765 and 929 atomic units respectively. The features of the structural-group composition and molecular characteristics of oil, asphaltenes and resins are revealed. According to the spectral coefficients obtained from the IR-Fourier spectra, oil and resins of the Varadero oilfield have high aliphaticity, branching, condensation, oxidation and sulfur content; in addition, the resins have a relatively high content of carboxyl, sulfoxide and sulfonic groups. Asphaltenes are highly aromatic, aromatic compounds mainly have a condensed structure and are paramagnetic. According to 1H and 13C NMR spectroscopy, the ratio of alkyl group protons and aromatic fragments was found to be 12.6:1. Asphaltenes in oil are unstable, having a high colloidal instability index – 1.24, in the conditions of formation and production are able to stabilize the water-oil emulsion (WNE) and form solid deposits. Rheological method shows that at a temperature of 21 °C there is a structural reorganization of VNE. Temperature dependences in the temperature ranges from 10 to 21 °C and from 21 to 40 °C obey the Arrhenius equation. The activation energy of the viscous flow in the first temperature range is 44.3 kJ/mol, and in the second – 61 kJ/mol.

References

1. Danilova E., Heavy oils of Russia (In Russ.), The Chemical Journal, 2008, no. 12, pp. 34–37.

2. Speight J.G., Heavy and extra-heavy oil upgrading technologies, Houston, TX, USA: Gulf Professional Publishing, 2013, 137 р.

3. Speight J.G., Petroleum asphaltenes. Part 1: Asphaltenes, resins and the structure of petroleum, Oil & Gas Science and Technology, 2004, V. 59, pp. 467–477.

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5. Gonzalez B.M., Barrionuevo S., Peralba M.C., Kalkreuth W., Geochemical characterization of Jurassic source rocks from Cuba: 2. Constancia formation in onshore Varadero oils fields, Energy Exploration & Exploitation, 2014, V. 32, no. 5, pp. 847–872, DOI:10.1260/0144-5987.32.5.847.

6. Ryl'kov A.V., Poteryaeva V.V., Global naphthene-base crudes (propagation, genesis, application) (In Russ.), Izvestiya vuzov. Neft' i gaz, 2013, V. 97, no. 1, pp. 32–44.

7. Yakubova S.G., Manaure D.A., Machado R.A. et al., Effect of oxyethylated isononylphenol (neonol) on viscosity characteristics of water-oil emulsions, Petroleum Science and Technology, 2018, no. V. 36, no. 17, pp. 1389–1395, DOI:10.1080/10916466.2018.1482318.

8. Conaway C., The petroleum industry: A nomenclature guide, Tulsa: Pennwell Publ. Co., 1999, 289 р.

9. Yakubov M.R., Milordov D.V., Yakubova S.G., Borisov D.N., Ivanov V.T., Sinyashin K.O., Concentrations of vanadium and nickel and their ratio in heavy oil asphaltenes (In Russ.), Neftekhimiya = Petroleum Chemistry, 2016, V. 56, no. 1, pp. 19–23.

10. Rakhmatullin I.Z., Efimov S.V., Margulis B.Ya., Klochkov V.V., Qualitative and quantitative analysis of oil samples extracted from some Bashkortostan and Tatarstan oilfields based on NMR spectroscopy data, J. Petrol. Sci. Eng., 2017, V. 156, pp. 12–18, DOI: 10.1016/j.petrol.2017.04.041.

11. Petrova L.M., Abbakumova N.A., Borisov D.N. et al., Influence of component contents and structure characteristics of the components on heavy oils stability to asphaltene precipitation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 1, pp. 74–76.

12. Guzmán R., Ancheyta J., Trejo F., Rodríguez S., Methods for determining asphaltene stability in crude oils, Fuel, 2017, V. 188, pp. 530–543, DOI: 10.1016/j.fuel.2016.10.012.

13. Gusakov V.N., Kashtanova L.E., Nazarova S.V. et al., Design of technologies for processing bottom-hole zone of Varadero oilfield (Cuba) (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 12, pp. 126–130.

14. Zadymova N.M., Skvortsova Z.N., Traskine V.Yu. et al., Rheological properties of heavy oil emulsions with different morphologies, J. Petrol. Sci. Eng., 2017, V. 149, pp. 522–530.

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Due to the intensive increase in the number of horizontal wells with multi-stage hydraulic fracturing, the need for studies of fluid inflow from each hydraulic fracture in horizontal wells also increases. This paper presents the experience of using liquid chemical tracers (markers) to control the profile of fluid flow in horizontal wells with multi-stage hydraulic fracturing. To solve this problem, geophysical research methods are most often used with registration of flow measurement, thermometry, moisture metering, etc. at different well operating modes. However, the use of geophysical research methods in horizontal wells with multistage hydraulic fracturing is associated with a number of drawbacks that significantly reduce the reliability of the studies. As an alternative to geophysical methods for studying the inflow profile in horizontal wells in the world, tracer methods of inflow studies that do not require stopping the well or changing operating modes are widely used. The development of this direction has led to the development of new technologies for the study of horizontal wells using various types of indicators.

In this paper, we compare the distribution of the fluid flow of hydraulic fractures by two different methods: liquid chemical tracers and geophysical instruments. The main technological limitations of research methods and their features are determined. The uniqueness of the work lies in the joint conduct of tracer and geophysical studies in each well. The analysis showed that the use of liquid chemical tracers is an alternative to the classical methods of PIP. Further development of tracer technologies is necessary in terms of reducing their cost and increasing the duration of the informative research period.

References

1. Zakharov V.P., Ismagilov T.A., Telin A.G., Silin M.A., Regulirovanie fil'tratsionnykh potokov vodoizoliruyushchimi tekhnologiyami pri razrabotke neftyanykh mestorozhdeniy (Regulation of filtration flows by waterproofing technologies in the development of oil fields), Moscow: Publ. of Gubkin University, 2010, 225 p.

2. Dulkarnaev M., Ovchinnikov K., Gur'yanov A., Anopov A., Malyavko E., The first comprehensive study of tracer-based technologies in reservoir conditions (In Russ.), SPE 192564-RU, 2018, https://doi.org/10.2118/192564-RU.

3. Mukhametshin I.R., Nukhaev M.T., Semikin D.A., Monitoring lateral wells with multi-stage fracturing using the chemical markers embedded in completion equipment (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 3, pp. 46–49.

4. Panichelli P., Martínez J.R., Crespo P. et al., Advanced reservoir characterization in Vaca Muerta using chemical tracer technology, SPE 188923-MS, 2017, https://doi.org/10.2118/188923-MS.

5. Lal M.K., Singh A.K., Ezernack J., Spencer J., Advanced reservoir characterization in Antelope Shale using chemical tracer technology, SPE 184819-MS, 2017, https://doi.org/10.2118/184819-MS.

6. Sokolovskiy E.V., Solov'ev G.B., Trenchikov Yu.I., Indikatornye metody izucheniya neftegazonosnykh plastov (Indicator methods for the study of oil and gas reservoirs), Moscow: Nedra Publ., 1986, 157 p.

A methodology for building and history matching of an oil deposit model is presented, the parameters of which are consistent with the actual well production and initial geological and geophysical data. Petrophysical, geologic and hydrodynamic models are considered as parts of a unified model, or as submodels, when synchronous adjustment of the parameters of submodels is carried out using laws describing the whole system. Productive layers of the modeling object are terrigenous deposits with clay and carbonate cements, characterized by significant lithological vertical heterogeneity. Multiparameter dependencies connecting the porosity and permeability of rocks with the content of clay and carbonate cements are used for building a petrophysical submodel. Clay and carbonate rock properties are introduced through the normalized values of gamma and neutron logs. The principle of invariance of the differential filtration equations is applied to find the connate water saturation of rocks. Timur-Coats equation is used as an invariant. Spectral modeling of geophysical fields is applied to propagate the geologicl features of heterogeneous reservoir, which are further interpreted by petrophysical dependencies. Core data are used for the initial determination of parameters of petrophysical dependencies, their correction is carried out during the history matching of the hydrodynamic submodel. Closing relationships of the filtration equations system provide synchronous adjustment of the parameters of the petrophysical, geologic and hydrodynamic submodels and automatic history matching. Testing of the proposed methodology was carried out at one of the oil deposits in Western Siberia, which is characterized by interbedding of sandstones and siltstones with clay and carbonate interlayers. Good convergence of calculated and actual deposit development indicators with a minimum number of iterations is achieved.

References

1. Bezrukov A.V., Mukharlyamov A.R., Baikov V.A., Savichev V.I., Multivariant modelling support system: uncertainty space analysis (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2007, no. 11, pp.. 14 –16.

2. Baikov V.A., Zhonin A.V., Konovalova S.I. et al., Petrophysical modeling of complex terrigenous reservoirs (In Russ.), Territoriya Neftegaz, 2018, no. 11, pp. 34–38.

3. Baikov V.Ya., Bakirov N.K., Yakovlev A.A., Matematicheskaya geologiya (Mathematical geology), Part 1. Vvedenie v geostatistiku (Introduction to geostatistics), Moscow – Izhevsk: Publ. of Institute of Computer Science, 2012, 228 p.

4. Amyx J.W., Bass D.M., Whiting R.L., Petroleum reservoir engineering, McGraw-Hill Book Company, 1960.

5. Gimatudinov Sh.K., Shirkovskiy A.M., Fizika neftyanogo i gazovogo plasta (Physics oil and gas reservoir), Moscow: Al'yans Publ., 2005, 311 p.

6. Kolonskikh A.V., Mavletov M.V., Mikhaylov S.P., Murtazin R.R., Prediction of the residual water saturation value of terrigenous hydrophilic rocks by the standard complex of wells geophysical studies (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2018, no. 5, pp. 71–74.

7. Emel'yanov V.V., Kureychik V.V., Kureychik V.M., Teoriya i praktika evolyutsionnogo modelirovaniya (Theory and practice of evolutionary modeling), Moscow: Fizmatlit Publ., 2003, 432 p.

8. Gagarin A.V., Makeev G.A., Baikov R.A., Volkov V.G., An experience of parametric estimation of digital oil reservoir models (In Russ.), Vestnik Yuzhno-Ural'skogo gosudarstvennogo universiteta. Seriya: Matematicheskoe modelirovanie i programmirovanie, 2010, no. 35(21), pp. 12–24.

The article deals with the risks generated by the Paris UN Climate Agreement for the Russian oil sector, relevant for all enterprises of the industry. Agreement is assessed from the point of view of the provisions of the Energy Security Doctrine of the Russian Federation approved by the President of the Russian Federation this year, as an international climate construction posing threats and challenges for Russia. The risks built in the type of the commitments, assumed by the countries under the Paris Agreement, including primarily the principle of ever raising "increasing ambitions" and the mechanism of the so-called global stocktake, are studied.

Particular attention is paid to the threats associated with the promotion of the idea of the carbon tax, including the direct burden on the oil companies and the emergence of an anti-market handicap for alternative energy projects, and the risks of non-market restrictions that lead to a decrease in global demand for oil and oil products from Russia. The article assesses possible financial losses of the leading Russian oil companies at different rates of carbon tax and the possibility of new type restrictions for our oil exports. Recommendations are given on possible hedging of the relevant risks, in particular, in connection with the situation of the US withdrawal from the Paris agreement announced by President Donald Trump.

References

1. URL: https://www4.unfccc.int/sites/submissions/indc/Submission%20Pages/ submissions.aspx

2. Doktrina energeticheskoy bezopasnosti Rossiyskoy Federatsii (Energy Security Doctrine of the Russian Federation), URL: http://www.kremlin.ru/acts/news/ 60516

3. Stockman L., IEA acknowledges fossil fuel reserves climate crunch, URL: http://priceofoil.org/2012/11/12/iea-acknowledges-fossil-fuel-reserves-climate-crunch/

4. McGlade Ch., Ekins P., The geographical distribution of fossil fuels unused when limiting global warming to 2 °C, Nature, 2015, V. 517, pp. 187–190. https://www.nature.com/articles/nature14016

5. Höhne N., Elzen M., Admiraal A., Analysis beyond IPCC AR5: Net phase out of global and regional greenhouse gas emissions and reduction implications for 2030 and 2050, The Agreement on Climate Transformation 2015, URL: https://www.pbl.nl/sites/default/files/cms/publicaties/pbl-215-act-factsheet-net-phase-out-of-global...

6. Hausfather Z., Why the IPCC 1.5C report expanded the carbon budget, URL: https://www.carbonbrief.org/analysis-why-the-ipcc-1-5c-report-expanded-the-carbon-budget

7. Decision 1/CP.21. (FCCC/CP/2015/10/Add.1), Adoption of the Paris Agreement, URL: https://unfccc.int/resource/docs/2015/cop21/eng/10a01.pdf

8. UNEP emissions-gap-report-2017, URL: https://www.unenvironment.org/resources/

9. URL: https://en.wikipedia.org/wiki/File:Paris_agreement_emission_reduction_targets.png

10. UNEP emissions-gap-report-2018, URL: https://www.unenvironment.org/resources/

11. Decision FCCC/CP/2018/L.16 Matters relating to Article 14 of the Paris Agreement and paragraphs 99–101 of decision 1/CP.21, URL: https://unfccc.int/sites/default/files/resource/FCCC_CP_2018_L.16.pdf

12. Proceedings of Conference of the Parties Twenty-first session Paris, 30/11 – 11/12/2015, Decision -/CP.21, Adoption of the Paris Agreement. UNFCCC, 2015

13. State and trends of carbon pricing, 2017, World Bank, URL: https://openknowledge.worldbank.org/handle/10986/28510

14. Ivanter A., Kudiyarov S., Tales of the Paris Forest (In Russ.), Ekspert, 2017, no. 26(1035), pp. 28-32, URL: http://expert.ru/expert/2017/26/skazki-parizhskogo-lesa/

15. New U.N., Climate report says put a high price on carbon, The New York Times, Oct. 8, 2018, URL: https://www.nytimes.com/2018/10/08/climate/carbon-tax-united-nations-report-nordhaus.html

16. Republican Platform 2016, Republican National Convention, Cleveland 2016, URL: https://www.npr.org/2016/07/19/486571605/2016-republican-national-convention-partys-platform .

17. Roginko S., Prince Lemon's new taxes, or who needs a carbon tax (In Russ.), Neft' i kapital, 2018, no. 10, pp. 44-50.

We developed software for the numerical simulation and inversion of galvanic and induction log data. The simulation algorithm is based on a finite-element approach to calculating electrical and electromagnetic responses in a 2D model that includes horizontal layers, cylindrical near-borehole zones changed by drilling, borehole with drilling mud and tool body. Unfocused lateral logging tool with gradient arrays) signals are applied to estimate resistivity values in the horizontal and vertical directions, whereas high-frequency electromagnetic sounding tool logs are employed to evaluate the frequency dispersion of electrical conductivity and dielectric constant of formations. Using the developed programs, high-accuracy field data acquired with the SKL logging equipment on the Bazhenov formation intervals in the central regions of Western Siberia were interpreted. We determined the electrophysical parameters of the high-resistivity impermeable Bazhenov rocks. The correlation of the parameters with the data of other logging methods was investigated, with establishing their relationship with the structural-material composition. We compared the frequency-dependent values of electrical conductivity and dielectric constant with the petrophysical core measurements data. The results of the numerical inversion of the electromagnetic log data measured on the Bazhenov formation interval are consistent with the laboratory measurements. We carried out SKL data interpretation with the determination of the material composition, identification of the lithological types and study of the electrophysical parameters of the Formation rocks for the central regions of Western Siberia. By applying the mixture formulas for electrical conductivity and dielectric constant, more than three dozen of litho-electrophysical models and several correlation schemes for the Russkinskoye, Fedorovskoye, Vostochno-Surgutskoye and Tailakovskoye fields were constructed according to SKL logging signals.

References

1. Aksel'rod S.M., The influence of the frequency dispersion of the electrical properties of rocks on the results of determining the resistivity of formations (based on foreign literature) (In Russ.), Karotazhnik, 2007, no. 10, pp. 103–126.

2. Epov M.I., Bobrov P.P., Mironov V.L., Repin A.V., Dielectric relaxation in oil-bearing clayey rocks (In Russ.), Geologiya i geofizika, 2011, V. 52(9), pp. 1302–1309.

3. Anderson B.I., Barber T.D., Luling M.G. et al., Observations of large dielectric effects on LWD propagation-resistivity logs, Transactions of the SPWLA 48th Annual Logging Symposium, Austin, Texas, June 3–6, 2007, paper BB, 11 p.

4. Toumelin E., Torres-Verdin C., Bona N., Improving petrophysical interpretation with wide-band electromagnetic measurements, SPE-96258-PA, 2008, https://doi.org/10.2118/96258-PA.

5. Epov M.I., Glinskikh V.N., Linearization of the relative characteristics of a high-frequency magnetic field in two-dimensional conducting media (In Russ.), Geologiya i geofizika, 2004, V. 45, no. 2, pp. 266–274.

6. Glinskikh V.N., Nikitenko M.N., Epov M.I., Processing high-frequency electromagnetic logs from conducting formations: Linearized 2D forward and inverse solutions with regard to eddy currents (In Russ.), Geologiya i geofizika, 2013, V. 54, no. 12, pp. 1942–1951.

7. Kontorovich A.E., Yan P.A., Zamiraylova A.G. et al., Classification of rocks of the Bazhenov formation (In Russ.), Geologiya i geofizika, 2016, V. 57, no. 11, pp. 2034–2043.

8. Petrov A., Determining the resistivity anisotropy of high-resistivity sediments, based on lateral logging sounding data from vertical wells, SPE-189295-STU, 2017, https://doi.org/10.2118/189295-STU.

9. Petrov A.M., Sukhorukova K.V., Nechaev O.V., Geoelectric model of the Bazhenov formation deposits according to electrical and electromagnetic logging sounding data, Proceedings of EAGE/SPE joint workshop on shale science 2017: Prospecting and development the science of shales: The problem of exploration and development, 2017, paper M12, pp. 5, DOI: 10.3997/2214-4609.20170018.

10. Fedoseev A.A., Glinskikh V.N., Kazanenkov V.A., Relative content of rock-building components and basic lithological types of rocks of the Bazhenov formation and its stratigraphic analogues according to log and core data (In Russ.), Neftegazovaya geologiya. Teoriya i praktika, 2018, V. 13, no. 2, pp. 1–19.

The article discusses early well logging operation. The authors suggest using a new piece of equipment, MGG-3x168x21 logging rig with a sealing device. This equipment was developed by specialists of RN-Uvatneftegas LLC together with Neftegazdetal LLC colleagues. The MGG-3x168x21 rig allows for well logging immediately after moving the drilling rig to the next well. Alternative well logging options existing today are considered. The first option is to use a well completion rig. The disadvantage of this method is that the completion crew is idle while only the rig itself is used. The second option is to use lubricators available on the market, but the lubricators’ diameters are limited and guy-lines are needed to ensure stability.

The article provides information on the rig design. To make it easier to install logging tools, the rig is placed at the well horizontally. To fix the tools in the receiving chamber, a “trap" is installed in the lower part of the rig. After that, the rig is put into a vertical position using a hydraulic pump. The MGG-3x168x21 rig has been tested at RN-Uvatneftegas LLC fields and in has proved effective. The rig made it possible to reduce well completion time by 12 hours per well. Well completion time with and without using the rig was compared. It is demonstrated that the MGG rig can be installed close to the batch drilling rig, which allows for well logging immediately after moving the rig to the next well.

References

1. Federal standards and rules for industrial safety “Pravila bezopasnosti v neftyanoy i gazovoy promyshlennosti” (Safety rules in oil and gas industry), 12.01.2015 N 1.

2. Soprotivlenie materialov (Strength of materials): edited by Aleksandrov A.V., Moscow: Vysshaya shkola Publ., 2003.

The analysis of current situation concerning the technology of well construction in the Bolivarian Republic of Venezuela at Junin-6 block, which is developed by the joint venture state companies PDVSA (Petroleos de Venezuela) and Rosneft Oil Company, has been presented in the paper. The reference of general solutions concerning well plans and extremely viscous production operation procedure without thermal methods involvement has been given. Technical and technological solutions concerning well construction efficiency increase, as well as currently existing optimization solutions for drilling process have been exposed. Horizontal wells construction is implemented under the conditions of low stratum depth of producing horizons – from 100 to 300 m, which sufficiently obstructs WOB. The engineering analysis of drilling and completion of extended horizontal wellbores has been presented. The implementation aspects for different technologies of horizontal wellbores extension in different price tiers have been considered. The solutions concerning friction factors decrease by means of hydrocarbon phase (direct emulsions) volume increase, semi-automatic drilling systems (Slider and its equivalents) implementation, the use of weeper subs for hole cleaning from drilled cuttings and liners rotation while running with low residual weight values have been proposed. The scenarios of well completion using the simulation of rotation-free liners running, as well as with rotation and the BHA with 178 mm DC, which were not previously used in drilling and completion practice, have been considered. The running using limited rotation (10 rpm maximum) and DC top weighting has been accepted according to the results of the analysis. The authors of the paper recommend approaching the problem of horizontal holes extension using complex methods and thorough analysis of implemented technologies.

The paper presents the results of a study of the properties of water-based drilling fluids with ethylene glycol and various polymer additives. The mass concentration of ethylene glycol varied from 0 to 80 %. Technical starch, xanthan biopolymer Duo-Vis (M-I Swaco, USA), Gammaxan (MIRRICO, Russia), cationic flocculant FLOPAMTM AN934 VHM (SNF, France) were considered as additives. Rheological and thermophysical characteristics of the considered drilling fluids and the process of clay swelling were investigated. It was shown that the addition of ethylene glycol leads to a significant decrease in the coefficient of thermal conductivity and heat capacity of the drilling fluid without a significant degradation in the rheological characteristics. Thus, at 65 % concentration of ethylene glycol in drilling fluid the thermal conductivity coefficient and heat capacity decrease by 70 % and 40 % respectively. It was found that ethylene glycol has a weak effect on the viscosity and rheological characteristics of drilling polymer fluids at concentrations below 65 wt%. The swelling of clay minerals is another important factor affecting the stability of the well walls in the process of drilling permafrost. Studies of clay swelling considered drilling fluids have shown that the addition of ethylene glycol leads to a significant inhibition of the swelling process. Addition of 50 wt% ethylene glycol is reduced the swelling ability almost three times in comparison with the base polymer drilling fluid. The possibility of controlling the thermophysical and hydration characteristics of drilling fluids by the introduction of ethylene glycol without degradation of their rheological properties has been shown. The data obtained will be useful in the development of drilling fluids for drilling in permafrost conditions.

References

1. Bulatov A.I., Izmaylov L.B., Lebedev O.A., Proektirovanie konstruktsiy skvazhin (Design of wells construction), Moscow: Nedra Publ., 1979, 280 p.

2. Kudryashov B.B., Yakovlev A.M., Burenie skvazhin v merzlykh porodakh (Frozen well drilling), Moscow: Nedra Publ., 1983, 286 p.

3. Zverev G.V., Tarasov A.Yu., Calculation and analysis of the influence of permafrost on well no. 338 fixing of Vankorskoe field during operation (In Russ.), Vestnik Permskogo natsional'nogo issledovatel'skogo politekhnicheskogo universiteta. Geologiya. Neftegazovoe i gornoe delo = Perm Journal of Petroleum and Mining Engineering, 2013, no. 8, pp. 41–51.

4. Gorelik, Ya.B., Soldatov P.V., O narushenii prodol'noy ustoychivosti ekspluatatsionnykh skvazhin v intervale zaleganiya merzlykh porod (On the violation of the longitudinal stability of production wells in the interval of frozen rocks), Collected papers “Nauchnaya i proizvodstvennaya deyatel'nost'‒sredstvo formirovaniya sredy obitaniya chelovechestva” (Scientific and industrial activity ‒ means of forming the human environment), Proceedings of All-Russian Youth Scientific and Practical Conference with International Participation, 26‒27 April 2016, Tyumen, pp. 236‒244.

5. Medvedskiy R.I., Stroitel'stvo i ekspluatatsiya neftegazovykh skvazhin v vechnomerzlykh porodakh (Construction and operation of oil and gas wells in permafrost), Moscow: Nedra Publ., 1987, 230 p.

6. Maramzin A.V., Ryazanov A.A., Burenie razvedochnykh skvazhin v rayonakh rasprostraneniya mnogoletnemerzlykh porod (Exploratory drilling in permafrost areas), Moscow: Nedra Publ., 1971, 148 p.

7. Vasil'ev N.I., Talalay P.G., Zubkov V.M., Krasilev A.V., Zubkov M.V., Elimination of complications and accidents when drilling deep wells in glaciers (In Russ.), Zapiski Gornogo instituta, 2008, V. 178, pp. 181–187.

8. Tunc S., Duman O., The effect of different molecular weight of poly(ethylene glycol) on the electrokinetic and rheological properties of Na-bentonite suspensions, Colloids Surf., A., 2008, V. 317, pp. 93–99.

9. De Souza C.E.C., Nascimento R.S.V., Lima A.S., Hydrophobically modified poly(ethylene glycol) as reactive clays inhibitor additive in water-based drilling fluids, J. Appl. Polymer Sci., 2010, V. 117, no. 2, pp. 857–864.

10. Minakov A.V., Rudyak V.Ya., Guzei D.V., Pryazhnikov M.I., Lobasov A.S., Measurements of the thermal conductivity coefficient of nanofluids by the hot-wire method, J. Eng. Phys. Thermophys., 2015, V. 88, no. 1, pp. 149–162.

11. Tsvetkov F.F., Grigor'ev B.A., Teplomassoobmen (Heat and mass transfer), Moscow: Publ. of MEI, 2005, 550 p.

The article is enlightened to the study of the problem of searching for the nature of the hydrodynamic interference of wells in the form of permeability coefficients along communication lines. The article highlights the theoretical foundations and mathematical description of the mathematical model that underlies the method of reference pressure curves for the search of permeability coefficients in the zones of impact of wells in the drainage radius and in directions to other wells of research area. For the first time, it is proposed to separate permeability to effect mass transfer processes and pressure impulse transmission. The permeability coefficient is characterized by a dichotomy: on the one hand, the higher the permeability, then smaller change in pressure during self-listening, on the other hand, the higher the permeability, then greater pressure change at a significant distance from the well. Thus, the article distinguishes piezoconductive permeability, which causes the directional propagation of the pulse, and, on the other hand, hydraulic conductive permeability, which causes pressure dispersion deep into the research zone of the formation. Also for increasing the reliability the authors proposed to introduce an additional coefficient of friction pressure loss in injection wells. This is extremely important, since the pressure at the mouth is measured, and the bottomhole pressure is significant. The pressure loss on linear friction in tubing is significant, reaching 1.5–2.0 MPa.

The model considered in the article and the method implemented on its basis were tested on synthetic hydrodynamic models and showed a good result. The method under consideration has a several limitations, for example, a representative time range within which reference pressure curves are selected. A formula for calculating the optimal value of this range is proposed.

References

1. Stepanov S.V., Sokolov S.V., Ruchkin A.A. et al., Considerations on mathematical modeling of producer-injector interference (In Russ.), Vestnik Tyumenskogo gosudarstvennogo universiteta. Fiziko-matematicheskoe modelirovanie. Neft', gaz, energetika = Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy, 2018, V. 4, no. 3, pp. 146–164.

2. Savast'in M.Yu., Strekalov A.V., Purtova I.P., Analysis and interpretation of the dynamics of well operation modes (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2007, no. 6, pp. 34–36.

3. Batalov D.A., Razrabotka metoda lokalizatsii ostatochnykh zapasov nefti na pozdnikh stadiyakh razrabotki (Development of a method for localization of residual oil reserves in the late stages of field development): thesis of candidate of technical science, Tyumen, 2015.

Currently number of oil and gas field with easy recoverable reserves is decreasing dramatically. Therefore oil companies consider assets with complex geological conditions and wide range of uncertainty more frequently. Eastern Siberia carbonate deposits can be considered as such complex fields where prediction of geological and petrophysical properties can be a very challenging task due to sedimentary processes, tectonics and following secondary processes. Conventional approaches and methods for reservoir properties forecasting and field development strategy optimization almost cannot be applied for those fields due to they are not capable to take into account all complex geological factors. In such a situation development of new methods, approaches and tools for properties estimation capable to integrate whole amount of available geological data become a crucial necessity. Machine learning algorithms can act as such a tool due to their ability to handle any amount of information and capability for solving different oil and gas task was already confirmed by many researches in last few years.

The main goal of presented work was testing of machine learning algorithms applicability in tasks of wells productivity index forecasting for complex oilfields. Wide range of different factors was tested as features for proposed machine learning models. Those factors included geological, tectonic, stratigraphic and technological (well drilling and completion) data. Presented method could help reservoir engineer to optimize field development strategy not only via improvement of well productivity forecasting robustness but also by exploration of new complex relationships within data which could be not obvious for specialist.

References

1. Shiwei Yu, Kejun Zhu, Fengqin Diao, A dynamic all parameters adaptive BP neural networks model and its application on oil reservoir prediction, Applied Mathematics and Computation, 2008, V. 195, pp. 66–75.

2. Belozerov B., Bukhanov N., Egorov D., Zakirov A. et al., Automatic well log analysis across Priobskoe field using machine learning methods (In Russ.), SPE 191604-18RPTC-MS, 2018.

3. Cawley G.C., Talbot N.L.C., On over-fitting in model selection and subsequent selection bias in performance evaluation, JMLR, 2010, no. 11(Jul), pp. 2079−2107.

4. Zhihua Zhou, On the doubt about margin explanation of boosting, Artificial Intelligence, 2013, V. 203, pp. 1–18.

5. Chawla V.N., Bowye W.K., Hall O.L., Kegelmeyer W.Ph., SMOTE: Synthetic minority over-sampling technique, Journal of Artificial Intelligence Research, 2002, V. 16, pp. 321–335.

6. David M.W., Powers evaluation: From precision, recall and F-measure to ROC, informedness, markedness & correlation, Journal of Machine Learning Technologies, 2011, V. 2 (1), pp. 37–63.

The analysis of changes in the chemical composition of seawater during the injection into the anhydrous granitoid reservoir of the White Tiger deposit, in which the cracks are partially filled with minerals that are active to cation exchange (calcite and lomontite), has been analyzed. It is shown that these minerals interact with injected seawater, as a result of which Mg2+ seawater is absorbed by minerals to release equivalent amounts of Ca2+ into the solution, which leads to precipitation of anhydrite in the reservoir cavities, and in more surface conditions: in the producing wells and surface equipment - calcite . According to the quantitative change in the composition of the injected seawater, which showed a sharp increase in the Ca2+ ion in the associated water (5 times), with a simultaneous decrease in the Mg2+ content (10 times) and the SO42- ion (5 times) and using the equations chemical reactions, was carried out analytical calculation of the amount of salts that may fall as a result of flooding. This calculation showed that 2.9 g of CaSO4 and 0.05 g of CaCO3 can be deposited fr om each liter of injected water. Considering the scale of waterflooding, which cannot be less than 100 tons / day for profitable extraction, the amount of salt deposited will be 295 kg / day, with most of the salts represented by anhydrite, will be deposited in reservoir conditions. The calculation of the decrease in reservoir permeability due to sulphate scaling, carried out using the converted Kozeny – Karman formula, showed a possible decrease in reservoir permeability by 8.3 %. The transition of drilling to ever greater depths (more than 4000 m), wh ere the rocks almost everywhere contain lomontite (lomontite stage of metamorphism), requires to take into account the phenomena of cation exchange between injected water and rock in the predictions of scaling.

References

1. Kashchavtsev V.E., Mishchenko I.T., Prognozirovanie i kontrol' soleotlozheniy pri dobyche nefti (Prediction and control of salt deposits in oil production), Moscow: Neft' i gaz Publ., 2001, 134 p.

2. Mulyak V.V., Poroshin V.D., Gattenberger Yu.P. et al., Gidrokhimicheskie metody analiza i kontrolya razrabotki neftyanykh i gazovykh mestorozhdeniy (Hydrochemical methods of analysis and control of oil and gas fields development), Moscow: GEOS Publ., 2007, 244 p.

3. Tien Kh.D., Gidrogeologicheskie usloviya mestorozhdeniya Belyy Tigr (Hydrogeological conditions of the White Tiger field), Proceedings of 2nd conference of NIPImorneftegaz, Vungtau, 1998, pp. 103–119.

4. Areshev E.G., Dong Ch.L., Kireev F.A., Oil and gas content in White Tiger field basement granitoids (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1996, no. 8, pp. 50–59.

5. Kraynov S.R., Ryzhenko B.N., Shvets V.M., Geokhimiya podzemnykh vod (Teoreticheskie, prikladnye i ekologicheskie aspekty) (Groundwater geochemistry (theoretical, applied and environmental aspects)), Moscow: Nauka Publ., 2004, 677 p.

6. Nazina T.N., Belyaeva S.S., Biologicheskoe i metabolicheskoe raznoobrazie mikroorganizmov neftyanykh mestorozhdeniy (Biological and metabolic diversity of oilfield microorganisms), Proceedings of T Winogradsky Institute of Microbiology RAS, 2004, V. XII, pp. 289–317.

The most promising current research efforts worldwide are associated with the development of efficient physical and chemical enhanced oil recovery methods that enable production of both mobile oil reserves due to improved reservoir sweep efficiency and recovery of residual oil, thus increasing achievable oil recovery factors. Out of many enhanced oil recovery methods, polymer-based flow diversion technologies have gained the widest acceptance internationally. Under conditions of unstable oil prices, determination of optimal injection volumes and componential concentrations becomes increasingly important to ensure cost-effective application of enhanced oil recovery technologies. Such decisions should be made based on extensive studies, while analysis of the results should consider volatile economic environment. Reservoir simulation modeling is commonly used to adjust parameters of formation stimulation technologies. The present study involved investigation of physical and chemical properties of the compositions used in the process, laboratory analysis of fluid-loss and oil-displacement characteristics of polymer compositions using reservoir models under conditions simulating a terrigenous reservoir. Laboratory studies provided initial data for numerical modeling of polymer-based formation stimulation process. Polymer flooding simulations were run for various polymer injection volumes and types of polymer composition. Evaluation of economic efficiency of optimal polymer treatment scenarios obtained from modeling data was conducted with due consideration of oil price changes over a wide range.

References

1. Bos S.F.M., A framework for uncertainty quantification and technical-to-business integration for improved decision making, SPE 94109-MS, 2005, https://doi.org/10.2118/94109-MS.

2. Rafikova K.R., Sabakhova G.I., Khisametdinov M.R., Application of micro-gel polymer systems at the fields of PJSC «Tatneft» (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2015, no. 5, pp. 43–46.

3. Abdulbaki M.R., Stimulation study of polymer microgel conformance treatments, https://repositories.lib.utexas.edu/handle/2152/ETD-UT-2012-08-5936.

4. Frampton H., Denyer P., Ohms D.H., Husband M., Mustoni J.L., Sweep improvement from the lab to the field, Proceedings of 15th European Symposium on Improved Oil Recovery, 27-29 April 2009, Paris, France, 2009.

5. Seright R.S., Examination of literature on colloidal dispersion gels for oil recovery, New Mexico Tech, Socorro, NM, 2015, 63 р.

6. Varlamova E.I., Khisametdinov M.R., O vliyanii destruktivnykh faktorov na svoystva mikrogelevoy sistemy, prednaznachennoy dlya uvelicheniya nefteotdachi iz terrigennykh plastov (On the influence of destructive factors on the properties of the microgel system, designed to enhance oil recovery from terrigenous reservoirs), Proceedings of TatNIPIneft’, 2012, V. 80, pp. 143–147.

A method for choosing a gas agent and an approach to assessing the possible results of gas injection for one of the fields of the Central Khoreyver uplift confined to carbonate reservoirs is described. Several gas compositions were tested as injection agents: inorganic individual compounds (nitrogen, carbon dioxide, methane) and mixtures of hydrocarbon gases with different mole fraction of methane and "fat" components (C2-C4). To evaluate the effectiveness of the selected compositions, experiments were performed on a Slim Tube formation model under thermobaric formation conditions (pressure – 30 MPa, temperature – 67 °C). A detailed description of the experimental unit of Slim Tube is given. A theoretical assessment was also made of the degree of miscibility of gas agents and oil in situ using a triple diagram based on a tuned PVT formation fluid model. Due to the limited reserves of flare gas and a decrease in its available volumes in the future, the option of pumping the gas rim with the highest content of “fat” components and then displace it with nitrogen with different sizes of the rim of “wet” gas (15 and 30% of the pore volume) was considered. The use of such gas rims leads to a significant reduction in the cost of gas exposure with a slight decrease in the coefficient of oil displacement. The displacement rate when using 30 % of the pore volume of the rim of the "wet gas" fell by only 2.5 % compared with the use of pure "wet" flare gas.

The article gives a preliminary assessment of the effectiveness of using various formulations of displacement agents. The joint conduct of filtration experiments and calculations on the PVT model made it possible to significantly reduce the amount of experimental work with a simultaneous increase in their information content.

References

1. Whitson C.H., Brulé M.R., Phase behavior, SPE Monograph Series, V. 20, 2000, 240 p.

2. Petrakov A.M., Egorov Yu.A., Nenartovich T.L., System and methodical aspects of physical modelling of gas and water-gas stimulation on oil reservoir (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 9, pp. 68–72.

3. Petrakov A.M., Egorov Yu.A., Nenartovich T.L., On the reliability of the experimental determination of oil displacement coefficients by gas and water-gas stimulation methods (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2011, no. 9, pp. 100–102.

4. Petrakov A.M., Egorov Yu.A., Nenartovich T.L., Experimental study of the oil displacement process at gas injection into the reservoir (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 8, pp. 24–26.

The development of bituminous oil fields associated with the solution of serious technological and economic challenges. The technology of steam assisted gravity drainage (SAGD), which is successfully used at the Ashalchinskoye field in the Republic of Tatarstan, is used to develop deposits of ultra-viscous oil. However, in the development of the boundary zones of the field, where significant oil reserves are concentrated, this technology cannot be used due to the small thickness of the formation and the inability to place paired production and injection wells to realize steam-gravity effects on the formation. The wells located in the boundary zones of the formation are subjected to steam cycling, alternating with the selection of heated oil, and are characterized by marginal economic efficiency. The solvent injection is considered method to be promising for increasing the production of reserves of the boundary zones formation, for additional washing off of oil, for increasing the drainage zone of wells and for developing reserves not affected by steam.

Therefore, the actual problem is to choose the optimal composition of chemical reagents for various solvent compositions based on a multipurpose method developed and presented in this work by specialists of the Almetyevsk State Oil Institute. An integrated approach is that the selection of the solvent composition is carried out by a high degree of viscosity reduction in a solution with bituminous oil, by a high degree of oil washing from the rock, by the ability to reduce surface tension, by a high degree of diffusion. The multipurpose approach consists of choosing a solvent composition of the highest degree of reduction in the viscosity of bituminous oil, the highest degree of washout of oil from the core, the ability to reduce surface tension and a high degree of diffusion. In addition, the solvent composition must be thermostable in a wide temperature range and must not contribute to the precipitation of asphaltenes in the sediment and the formation of persistent emulsions. Optical and rheological research methods were used to test various solvent compositions, but the final choice of the solvent composition was made taking into account the results of filtration experiments on formation models with bituminous oil. The developed solvent composition will be tested at the pilot site of the Ashalchinskoye field.

References

1. Zaripov A.T., Ob opyte OAO Tatneft' v oblasti razrabotki mestorozhdeniy sverkhvyazkoy nefti (About Tatneft's experience in the development of extra-viscous oil fields), Collected papers “Vysokovyazkie nefti i prirodnye bitumy: problemy i povyshenie effektivnosti razvedki i razrabotki mestorozhdeniy” (High viscosity oils and natural bitumen: problems and improving the efficiency of exploration and development of deposits), Proceedings of International Scientific and Technical Conference, Kazan': Fen Publ., 2012, pp. 187–189.

2. Khisamov R.S., Shargorodskiy I.E., Gatiyatullin N.S., Neftebitumonosnost' permskikh otlozheniy Yuzhno-Tatarskogo svoda i Melekesskoy vpadiny (Oil-and-bitumen-bearing Permian sediments of the South Tatar arch and Basin Melekessky): edited by Khisamov R.S., Kazan': Fen Publ., 2009, 431 p.

3. Charnyy I.A., Podzemnaya gidrogazodinamika (Underground fluid dynamics), Moscow – Izhevsk: Publ. of Institute of Computer Science, 2006, 436 p.

4. Khisamov R.S., Zakharova E.F., Gumerova D.M., Sayakhov V.A., An integrated approach to the research of the composition and properties of bituminous oil at the Ashalchinskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 10, pp. 68–71, DOI: 10.24887/0028-2448-2018-10-68-71.

5. Yakubov M.R., Yakubova S.G., Borisov D.N. et al., Changes in the composition and properties of asphaltenes during physical modeling of the process of displacement of heavy oils by solvents based on n-alkanes (In Russ.), Vestnik Kazanskogo tekhnologicheskogo universiteta, 2013, V. 16, no. 22, pp. 277–278.

6. Yakubov M.R., Yakubova S.G., Borisov D.N. et al., Photocolorimetric method for monitoring the deposition of asphaltenes during the displacement of natural bitumen with solvents based on light n-alkanes (In Russ.), Vestnik Kazanskogo tekhnologicheskogo universiteta, 2012, no. 22, pp. 128–131.

7. Zakirov I.S., Zakharova E.F., Razumov A.R., Beloshapka I.E., Evaluation of oil sweep efficiency based on the results of laboratory experiments with formation model using heat exposure and solvents (In Russ.), Neftyanaya provintsiya, 2019, no. 2(18), pp. 197–208.

The development of edge zones of bituminous formations using huff-and-puff (steam-cyclic) wells is characterized by low economic efficiency. Based on the simulation results, the authors showed that the use of a solvent together with steam contributes to additional oil recovery from the rock, lowering the viscosity of oil, increasing the drainage zone of wells and involving oil reserves not covered by steam in the development. For various types of occurrence of the reservoir (horizontal and dipping areas), the optimization problem was solved on a non-isothermal sector hydrodynamic model based on the averaged values of the geological and physical parameters of the Sheshminsky horizon of the super-viscous oil deposit. For these conditions, taking into account the geometry of the formation, the solvent injection volume is determined depending on the distance between adjacent horizontal wells and the location of the faces of horizontal wells relative to the oil-water contact. When scaling the data obtained using the sector hydrodynamic model to a real field, predictive calculations were performed until 2031 on a full-scale model of the pilot section of the North-Ashalchinsky uplift of the Ashalchinskoye field. The calculations were based on the results of physical modeling of using the solvent composition in the huff-and-puff treatment, according to which the formulation of the industrial solvent composition was developed, developed as part of the project with federal support. It was found that under the conditions of the pilot section of the Ashalchinskoye oil field, the greatest technological effect from the huff-and-puff treatment of horizontal wells with the injection of the solvent composition in single and areal versions is achieved with an injection volume of 75 m3. The areal injection of the solvent composition allows to increase the coverage area of the reservoir by exposure and to increase additional oil production by 8 thousand tons.

References

1. Patent no. RU2675276C1, Method of extracting high-viscous oil and natural bitumen from the reservoir, Inventors: Gus'kova I.A., Khisamov R.S., Gumerova D.M., Beloshapka I.E.

2. Patent no. RU2018118482A, Method of extracting high-viscosity oil and natural bitumen from a deposit, Inventors: Gus'kova I.A., Khisamov R.S., Nurgaliev R.Z., Khayarova D.R., Zakharova E.F., Beloshapka I.E.

3. Beloshapka I.E., Novye tekhnologicheskie resheniya v razrabotke mestorozhdeniy prirodnykh bitumov (New technological solutions in the development of natural bitumen deposits), Proceedings of 73th International Youth Scientific Conference “Neft' i gaz – 2019” (Oil and Gas - 2019), Moscow: Publ. of Gubkin University, 2019, pp. 44-48

4. Zakirov I.S., Zakharova E.F., Razumov A.R., Beloshapka I.E., Evaluation of oil sweep efficiency based on the results of laboratory experiments with formation model using heat exposure and solvents (In Russ.), Neftyanaya provintsiya, 2019, no. 2(18), pp. 197–208.

5. Zaripov A.T., Sozdanie i issledovanie kompleksa tekhnologiy dlya effektivnoy razrabotki melkozalegayushchikh zalezhey tyazheloy nefti s primeneniem termicheskogo vozdeystviya na produktivnyy plast (Creation and research of complex of technologies for efficient development of shallow heavy oil with application of thermal effects on the producing formation): thesis of doctor of technical science, Bugul'ma, 2015.

6. Shaykhutdinov D.K., Sovershenstvovanie sistemy razrabotki zalezhey sverkhvyazkoy nefti Respubliki Tatarstan v usloviyakh vysokoy neodnorodnosti neftenasyshchennogo plasta (Improving the system for the development of super-viscous oil deposits in the Republic of Tatarstan in conditions of high heterogeneity of the oil-saturated formation): thesis of candidate of technical science, Bugul'ma, 2018.

The improvement of the quality of producing formations’ secondary drilling and informational support of their development throughout the entire time between repairs can be achieved by the implementation of a complex technology of wells’ completion. The technology includes underbalanced drilling under down-hole pumps and long-term monitoring of the formation and equipment parameters using geophysical self-contained cables and optical fibre lines. The use of optical fibre lines as a DTS (distributed temperature sensor) allows to measure the thermal field along the entire wellbore at the same time, which represents an important advantage to electronic sensors. However, the current lack of reliable optical fibre sensors for determining the pressure and fluid contents does not allow measuring the bottom-hole and formation pressure values or determining the intervals of water feeding and hydrodynamic formation parameters. The development of explosion-proof remote downhole devices allowed filling this gap and combining geophysical and hydrodynamic research methods with optical fibre thermometry. Such an approach allows for the secondary underbalanced drilling, bringing the wells to stable production and their operation based on the information received from geophysical and optical fibre sensors. This results in the material improvement of hydrodynamic efficiency ratio of the secondary drilling and prompt evaluation of the formation energy parameters.

The experience of production application of the integrated approach has proven that a distributed temperature gauge helps to determine the operation intervals and the location of behind-the-casing flows, to control the pump temperature and accurately measure the depths of dynamic levels. The information obtained using the downhole device allows to promptly manage the values of bottom-hole pressure (drawdown) and perform the calculations of the formations’ hydrodynamic parameters. The combined technology of wells completion and operation materially reduces the costs of secondary drilling and geophysical and hydrodynamic well research. This is achieved by avoiding direct losses of oil production that are inevitable in case of well shutdowns for the conventional perforation and research.

References

1. Rybka V.F., Lapshina Yu.V., Optic fiber downhole temperature measurements. Gas-hydrate pluggeneration monitoring (In Russ.), Karotazhnik, 2018, no. 4, pp. 29–35.

2. Ipatov A.I., Kremenetskiy M.I., Kaeshkov I.S., Buyanov A.V., Horizontal well production monitoring with distributed temperature sensor (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 12, pp. 69–71.

3. Patent no. 2571790 RF, Secondary bed drilling-in at depression with lowering of perforator for subsurface pump and device to this end (versions), Inventors: Savich A.D., Chernykh I.A., Shadrunov A.A., Shumilov A.V.

4. Chernykh I.A., Razrabotka metoda monitoringa zaboynogo davleniya po dannym promyslovo-geofizicheskikh issledovaniy skvazhin (Development of a method for monitoring bottomhole pressure according to field geophysical studies of wells): thesis of candidate of technical science, Perm', 2018.

5. Gayvoronskiy I.N., Kostitsyn V.I., Savich A.D. et al., Ways of improvement of reservoir completion efficiency (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 10, pp. 62–65.

6. Naydanova E.S., Gubina A.I., Experience in using fiber optic technologies in production wells (In Russ.), Karotazhnik, 2017, no. 10, pp. 65–75.

7. Ipatov A.I., Kremenetskiy M.I., Kaeshkov I.S. et al., Undiscovered DTS potential of horizontal well inflow profile monitoring (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 5, pp. 96–100.

8. Savich A.D., Khalilov D.G., Chukhlov A.S., Denisov A.M., Well logging in horizontal boreholes equipped with tail pieces containing multistage hydrofrac devices (In Russ.), Karotazhnik, 2018, no. 10, pp. 48–60.

9. Kryuchatov D.N., Khalilov D.G., Savich A.D., Budnik D.A., Improving horizontal well logging technologies (In Russ.), Karotazhnik, 2016, no. 10, pp. 16–29.

Currently, most of fields in Krasnodar Krai are at the later and closing phase of development. Mature fields are characterized by a decrease in oil production and an increase in water-cut of wells. There is a need to involve in the development oil-saturated intervals with degraded reservoir properties. In this case operations are complicated by low permeability, heterogeneity of reservoir properties and a sharp increase in water-cut. The process of oil deposits development requires the implementation of technologies to restore and increase the wells productivity. One of the possible ways to increase the efficiency of stimulation is the use of combined technologies.

The article presents a technology which combines physical methods of stimulation. The first stage is pumping and treatment of the bottomhole zone using a source of elastic wave fields - rotary hydrodynamic vibrator. For the physical impact on the rock reservoir it is carried out a step-by-step pumping solvent to remove asphalts-resins-paraffins deposits, and plugging compound to block highly permeable interlayers. At the final stage, the acid composition is pumped. Selection of composition is based on the results of laboratory research of Maikop sediment core material. The combined technology ensures an increase in the uniformity of the acidic coverage of the reservoir by radius and thickness, involvement in the development of undraining reservoir sections, resulting in a uniform increase in the permeability of the reservoir after treatment and an increase in the flow rate of the well.

When performing the work, probabilistic-statistical methods for processing the initial field information and experimental methods of studying the interaction of rocks with process fluids were used.

References

1. Sergeev V.V., Razrabotka kompleksnoy tekhnologii intensifikatsii dobychi nefti (Development of a comprehensive technology for the intensification of oil production): thesis of candidate of technical science, Ufa, 2016, 150 р.

2. Patent no. 2542015 C1 RF, Rotary hydraulic vibrator, Inventors: Omel'yanyuk M.V., Pakhlyan I.A.

The article presents for consideration an approach to improving the accuracy of calculations of oil temperature (wall of a pipeline) for long sections (over tens of kilometers) of oil pipelines constructed in harsh geological and climatic conditions (including permafrost areas). The calculation method is based on the heat balance equation "pipeline-environment". The main difficulty is that due to significant temporal and spatial variability of the soil parameters at the base of the pipeline and conditions of interaction in the "soil-environment" system (e.g., the annual range of soil temperature at the depth of the pipe axis can reach tens of degrees), field studies allowing to determine their actual values with acceptable accuracy require enormous financial expenses. Therefore, approximated values are used in the calculations, which can result in significant errors of the calculated values relative to the actual ones. Increased accuracy of calculations is achieved by calibrating the computed model according to oil temperature (pipeline wall) sensors. Calibration of the computed model is performed for the time intervals during which the parameters of the medium containing the pipeline (temperature and thermal conductivity of soils, heat exchange rate between soil and atmosphere) are constant. The temperature value at the depth of the pipeline axis is used as the control parameter. The proposed method allows reducing the error of calculations and avoiding additional expenses for year-round study of the properties of soils containing the pipeline.

References

1. Radionova S.G., Lisin Yu.V., Kuznetsov T.I. et al., Improvement of methods and means of forecast calculations of thawing halos, penetration and stress-strain state of pipelines laid in permafrost (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2016, no. 1 (21), pp. 39–43.

2. Tugunov P.I., Novoselov V.F., Tipovye raschety pri proektirovanii i ekspluatatsii neftebaz i nefteprovodov (Typical calculations in the design and operation of oil depots and oil pipelines), Moscow: Nedra Publ., 1981, 177 p.

3. Kolosov B.V., The study of heating fluid due to friction when moving it in the pipeline (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1989, no. 10, pp. 51–52.

4. Kim D.P., Rakhmatullin Sh.I., About thermal design of oil-trunk pipelines (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2006, no. 1, pp. 104–105

5. Korotkov A.A., Emel'yanova L.V., Khilimonyuk V.Z. et al., A methodological approach to the creation of zoning maps based on engineering-geocryological features, to assess the cost of territory development for pipeline construction (In Russ.), Inzhenernye izyskaniya, 2017, no. 2, pp. 28–37.

6. Vladova A.Yu., Korotkov A.A., Fedorenko D.Yu., Intelligent support of method identifying the causes of defects of the man-made objects metallic shell (In Russ.), Matematicheskoe i programmnoe obespechenie sistem v promyshlennoy i sotsial'noy sferakh, 2014, no. 1 (4), pp. 37–41.

The hydrocarbons extraction is always followed by the influence on all components of nature including the surface waters. The influence on surface waters also leads to changes in hydrochemical condition of the region. All changes are observed during the ecological monitoring process, the gas-oil research and the field conservation.

The Polui River basin could possibly soon become the next object of Surgutneftegas PJSC business activity. The activity area increases from the center in Surgut to other regions including the Khanty-Mansiysk Autonomous District and administrative borders with the Yamal-Nenets Autonomous District and Trans-Urals region including Polui River. Taking into account that Polui River region is almost pure from human activities it’s important to keep its environmental condition safe, and most important – to preserve the water surfaces from pollution. This is all because the fact that water can spread the entire polluting chemicals on long distances. Not only the human business activities influence the condition of the region, but nature also forms major conditions. It’s a common fact that sometimes despite the lack of different activities the water already could not be used for drinking and other human consuming needs. To make sure in modern situation ecological monitors are performed. In this case, Surgutneftegas PJSC stands among other companies that perform ecological monitors.

References

1. Uvarova V.I., Hydrochemical characteristics of the Lower Ob watercourses (In Russ.), Vestnik ekologii, lesovedeniya i landshaftovedeniya, 2011, no. 11, pp. 132–142.

2. Sviridenko S.P., Kachestvo vody v reke Poluy Yamalo-Nenetskogo avtonomnogo okruga (Water quality in the Polui river of the Yamalo-Nenets Autonomous Okrug), Proceedings of mezhdunarodnoy nauchno-prakticheskoy konferentsii, Tyumen': Publ. of TyumGASU, 2013, pp. 231–233.

3. Kalinin V.M., Water resources of the Tyumen region (state, problems, prospects) (In Russ.), Nalogi. Investitsii. Kapital, 2003, no. 5–6, pp. 7–9.

4. Lezin V.A., Reki Yamalo-Nenetskogo avtonomnogo okruga (Rivers of the Yamalo-Nenets Autonomous District), Tyumen', Vektor-Buk Publ., 2000, 142 p.

5. Solodovnikov A.Yu., Khattu A.A., The ecological condition of the enviroment of Nadym-Soimlor minefield group (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2015, no. 6, pp. 104–109.