At present, method, developed at Gas Research Institute (GRI method), has an international status for assessing petrophysical properties of shale rocks. A comprehensive study of shale rocks based on this method revealed significant shortcomings, which in some cases become critical. The article proposes method for determining gas-saturated and open porosity, as well as gas, water and oil saturation of shale rocks on crushed samples. The method is adapted for main shale formations in Russia, as it is based on the investigation of more than 2700 core samples from 33 wells. Gas-saturated porosity of fresh samples (the core is in state of natural saturation) and open porosity of dry samples (the core is after extraction) are calculated based on bulk and grain densities. Grain density was determined by means of the gas injection porosimetry method. Two methods are proposed for determining bulk density of crushed fresh samples. There are the gas injection porosimetry method and the modified fluid saturation method. Authors of the article substantiate obligatoriness to determine bulk density of dry samples and suggest a method. Gas saturation of shale rocks was calculated based on gas-saturated and open porosity. Water saturation of shale rocks was determined by means of the direct method in the Zaks apparatus. Oil saturation of shale rocks was calculated by means of the material balance method of phases in void space. Approbation of offered method is carried out and main results of researches are given. Developed method can be used for routine research with high discreteness (1 sample for every 30-50 cm of core sampled). Applying of different fraction sizes for measuring bulk and grain densities, as well as water saturation, makes it possible to determine petrophysical properties independently of each other. All this allows to reduce time capacity of core investigation. The results obtained by means of the method can be used to identify promising intervals of reservoir, build correlation between well logging data and petrophysical core properties, calculate reserves, and also plan exploration work.

References

1. Sigal R.F., Mercury capillary pressure measurements on Barnett core, SPE Reservoir Evaluation & Engineering, 2013, V. 16, no. 4, pp. 432–442, DOI:10.2118/167607-PA

2. Yao Y., Liu D., Che Y. et al., Petrophysical characterization of coals by low-field nuclear magnetic resonance (NMR), Fuel, 2010, V. 89, no. 7, pp. 1371–1380, DOI:10.1016/j.fuel.2009.11.005

3. Glotov A.V., Mikhaylov N.N., Molokov P.B. et al., Saturation of rocks of the Bazhenov formation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 3, pp. 28–33, DOI: 10.24887/0028-2448-2021-3-28-33

4. Kuila U., McCarty D.K., Derkowski A. et al., Total porosity measurement in gas shales by the water immersion porosimetry (WIP) method, Fuel, 2014, V. 117, pp. 1115–1129, DOI:10.1016/j.fuel.2013.09.073

5. Kazak E.S., Kazak A.V., Sorokoumova Ya.V., Alekseev A.D., The efficient method of water content determination in low-permeable rocks of Bazhenov formation (Western Siberia) (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 7, pp. 73–78, https://doi.org/10.24887/0028-2448-2019-7-73-78

6. Glotov A.V., Skripkin A.G., Gorshkov A.M., Laboratory evaluations of bazhenov suite sediments porosity and saturation by different methods (In Russ.), Karotazhnik, 2019, no. 6(3), pp. 23–40.

7. Luffel D.L., Guidry F.K., Curtis J.B., Development of laboratory and petrophysical techniques for evaluating shale reservoirs: Final report. GRI-95/0496. Gas Research Institute, Des Plaines, Illinois, 1995, 304 p.

8. Sun J., Dong X., Wang J. et al., Measurement of total porosity for gas shales by gas injection porosimetry (GIP) method, Fuel, 2016, V. 186, no. 15, pp. 694–707, DOI:10.1016/j.fuel.2016.09.010

9. Fomin A.N., Katagenez organicheskogo veshchestva i neftegazonosnost’ mezozoyskikh i paleozoyskikh otlozheniy Zapadno-Sibirskogo megabasseyna (Catagenesis of organic matter and oil and gas bearing of Mesozoic and Paleozoic deposits of the West Siberian megabasin), Novosibirsk: Publ. of IPGG SB RAS, 2011, 331 p.

10. Kontorovich A.E., Ponomareva E.V., Burshteyn L.M. et al., Distribution of organic matter in rocks of the Bazhenov horizon (West Siberia) (In Russ.), Geologiya i geofizika = Russian Geology and Geophysics, 2018, V. 59, no. 3, pp. 357–371.

11. Gorshkov A.M., Khomyakov I.S., Mazurova A.S., Some aspects to develop method for determining the open porosity of ultralow-permeability rocks on crushed core, IOP Conf. Ser.: Earth and Environmental Science, 2020, V. 459, no. 2, pp. 1–7, DOI:10.1088/1755-1315/459/2/022068

12. Gorshkov A.M., Method for determiting porosity in ultra-low permeability rock of Bazhenov formation on crushed core (In Russ.), Uspekhi sovremennogo estestvoznaniya, 2017, no. 12, pp. 129–133.

13. Glotov A.V., Skripkin A.G., Molokov P.B., Mikhaylov N.N., Residual water saturation of oil source rocks of the Bazhenov formation (In Russ.), Neftegaz.RU, 2022, no. 3, pp. 40–46.

14. Behar F., Beaumont V., De B., Penteado H.L., Rock-Eval 6 technology: Performances and developments, Oil & Gas Science and Technology, 2001, V. 56, no. 2, pp. 111–134, DOI:10.2516/ogst:2001013

15. Bilibin S.I., Kalmykov G.A., Ganichev D.I., Balushkina N.S., Model of the petroliferous rocks of the Bazhen formation (In Russ.), Geofizika, 2015, no. 3, pp. 5–14.

Russian oil and gas companies rebuild and look for effective approaches and technologies to continue their activities under sanctions pressure in 2022. Many companies in the oil and gas sector are currently working on the systematic replacement of imported equipment and software. Telemetry measurements and logging while drilling (LWD) is one of the areas, where oil and gas industry dependend on foreign technologies and equipment. Horizontal wells drilling allows Rosneft to maintain the level of hydrocarbon production at a high level and remain one of the main taxpayers of the Russian Federation. The transition from imported equipment to domestic (or equipment of "friendly countries") does not happen simultaneously, companies need some time. This work is carried out everywhere with local developers and suppliers.

Rosneft Oil Company annually drills more than 3,000 horizontal wells and horizontal sidetracks. The number of wells with a complex design (multi-latteral) is constantly growing; the diversity of the geology of the target formations is increasing. It is very important for the company to maintain the variability of the logging while drilling programs for effective geological support of well drilling and to obtain the maximum amount of geophysical information. In this situation, the fast adaptation of the current plans and LWD programs to the changed conditions comes very important. In this regard, this article will describe several examples of the use of the new industry indicator Geosteering Difficulty index (GDI) of wells when adjusting current plans for directional drilling or LWD programs.

References

1. Golovchenko M.A., Miroshnichenko A.V., Kudashov K.V., Filimonov V.P., Method for determining the geosteering difficulty index of wells and their classification (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 11, pp. 33–37, DOI: 10.24887/0028-2448-2019-11-33-37

2. Filimonov V.P., Kudashov K.V., Shirshov A.Yu., Increase in drilling efficiency on an example of ERD well in Odoptu-more field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 6, pp. 38-40.

The authors identified the evolution stages of development system for the central section of the Priobskoye field (southern part) and evaluated the effectiveness of the implemented solutions. The object of study is the low-permeable horizons AC10 and AC12, identified at the beginning as a single development object. Joint exploitation of different-permeable formations AС10 (6.9·10-3 mkm2) and AС12 (2·10-3 mkm2) led to a twofold lag in the production of oil reserves from the worst formation. The authors explored key issues in the development of low-permeability reservoirs: if it is it possible to obtain relatively high rates of oil recovery under the indicated conditions and by what means can they be ensured; what will be the characteristic of the water-flooding of the area developed with the massive and repeated use of large-volume hydraulic fracturing; are there any prospects to ensure oil recovery at such facilities - more than 0.3. The study of the 20-year history of the development of the central section of the AC10-12 reservoir allowed to answer positively the above questions. The factors for a rapid increase in oil production in the area at stages I-II are high drilling rates, repeated large-volume hydraulic fracturing in wells, creation of low bottomhole pressures (less than 5 MPa) in production wells and high wellhead injection pressures (more than 20 MPa) , correct consideration of the probable direction of development of hydraulic fractures in the reservoirs. The factors for maintaining oil production at the III stage of the development of the site were quick commissioning of infill production wells; mass drilling of horizontal wells with multi-stage hydraulic fracturing into separate layers in order to locally subdivide the AС10-12 object; selective sidetracking from idle wells; reduction of bottomhole pressure in high-watered wells − up to 3 MPa; regulation of water injection volumes by area zones, reduction of the current withdrawal compensation by injection. Due to these effective measures, it was possible to ensure a favorable characteristic of oil displacement by water. As a result, the final recovery factor expected for the area will be 20% higher than the oil recovery approved in general for the AC10-12 facility in the southern part of the Priobskoye field.

References

1. Yanin A.N., The design principles of ultra-low permeability reservoirs (In Russ.), Burenie i neft', 2016, no. 11, pp. 22–24.

2. Yanin A.N., Gidravlicheskiy razryv neftyanykh plastov v Zapadnoy Sibiri (Hydraulic fracturing of oil reservoirs in Western Siberia), Tyumen – Ekaterinburg: Publ. of PB TERM, 2021, 615 p.

3. Cherevko S.A., Yanin A.N., Analysis of the problem related to the choice of systems of low-permeable formations development in the large oil fields of the Western Siberia (In Russ.), Neftepromyslovoe delo, 2017, no. 9, pp. 5–11.

4. Cherevko M.A., Yanin A.N., Yanin K.E., Razrabotka neftyanykh mestorozhdeniy Zapadnoy Sibiri gorizontal'nymi skvazhinami s mnogostadiynymi gidrorazryvami plasta (Development of oil fields in Western Siberia by horizontal wells with multi-stage hydraulic fracturing), Tyumen – Kurgan: Zaural'e Publ., 2015, 265 p.

5. Kolupaev D.Yu., Bikkulov M.M., Solodov S.A. et al., Mass hydraulic fracturing is a key technology of the southern part Priobskoye field development (In Russ.), PROneft', 2019, no. 1, pp. 39–45, DOI: https://doi.org/10.24887/2587-7399-2019-1-39-45

6. Cherevko M.A., Yanin A.N., Yanin K.E., Assessment of perspectives of well pattern''s selective densing at Southern license territory of Priobskoe field (In Russ.), Burenie i neft', 2014, no. 6, pp. 24-29.

7. Cherevko M.A., Yanin A.N., Zakirova R.A. et al., The effectiveness of the wells netting seal on Priobskoye field ultra low-permeability layers (In Russ.), Burenie i Neft', 2015, no. 6, pp. 60–65

8. Cherevko M.A., Yanin A.N., Yanin K.E., Retrospective analysis of the systemic application of hydraulic fracturing at the Priobskoye field (southern license area) (In Russ.), Territoriya Neftegaz, 2014, no. 9, pp. 16–25.

9. Cherevko S.A., Yanin A.N., The influence of the hydrofracturing cracks direction on the performance indicators of wells (In Russ.), Territoriya Neftegaz, 2016, no. 2, pp. 14–19.

10. Cherevko S.A., Yanin A.N., Rogachev M.K., On the inexpediency of pumping fresh water into ultralowpermeable reservoirs of Western Siberia (In Russ.), Nedropol'zovanie XXI vek, 2018, no. 1(70), pp. 54-64.

11. Yanin A.N., Kreynin A.G., Water-oil displacement ratio in extremely low-permeable (less than 1 md) terrigenous West Siberian reservoirs (by the example of the Priobsky field) (In Russ.), Nedropol'zovanie XXI vek, 2020, no. 3(86), pp. 60–69.

12. Yanin A.N., Bikkulov M.M., "Generalized" dependences for determination of displacement factors in low-permeable (up to 10 md) formations of the Priobskoye field (In Russ.), Neftepromyslovoe delo, 2022, no. 6, pp. 20–30, DOI: 10.33285/0207-2351-2022-6(642)-20-30

13. Baryshnikov A.V., Yanin A.N., Regulirovanie razrabotki Priobskogo mestorozhdeniya s primeneniem tekhnologii odnovremenno-razdel'noy zakachki vody (Regulation of the development of the Priobskoye field using the technology of simultaneous-separate water injection), Tyumen – Kurgan: Zaural'e, 2013, 344 p.

This paper presents an integrated experience in injection horizontal wells (HW) using with a varied well completion type, including multi-stage hydraulic fracturing. The historical path of development systems: from multi-row with directional wells (DW) and low rigidity of the reservoir pressure maintenance system to oriented dispersed waterflood systems with HW are considered. Based on the data of hydrodynamic studies of wells, Hall plots, well interference analysis, well tests results, the development self-induced hydraulic fracturing in HW was proved. In the low-permeability reservoirs the achievement of the planned injectivity is determined by the presence of a self-induced hydraulic fracture, which is initiated when the bottomhole pressure exceeds the formation fracture pressure. It is noted that with an increase reservoir pressure, a decrease in the self-induced hydraulic fracturing effect and degradation of the fracture is observed. To assess the horizontal wells effectiveness, a comparison was made of the starting parameters and dynamics of the injection HW vs. DW. The results of studies of HW injectivity profiles are analyzed, potential reasons for the uneven injection distribution across hydraulic fracturing ports are considered. The areas of injection HW applicability in different geological and physical conditions, that is, when the injection HW allows a complete replacement of two DW to achieve the planned injectivity and injection ratio, as well as the sweep efficiency in linear development systems, have been identified. Recommendations on the further research program for horizontal injection wells and on improving the efficiency of this waterflooding method were given. The study is important due to the constant increasing technological complexity of well completion and the HW increasing share.

References

1. Davletbaev A.Ya., Baykov V.A., Ozkan E. et al., Multi-layer steady-state injection test with higher bottomhole pressure than the formation fracturing pressure (In Russ.), SPE 136199-RU, 2010, https://doi.org/10.2118/136199-RU

2. Baykov V.A., Zhdanov R.M., Mullagaliev T.I., Usmanov T.S., Selecting the optimal system design for the fields with low-permeability reservoirs (In Russ.), Neftegazovoe delo, 2011, no. 1, pp. 84–98.

3. Baykov V.A., Davletbaev A.Ya., Usmanov T.S., Stepanova Z.Yu., Special well tests to fractured water injection wells (In Russ.), Neftegazovoe delo, 2011, no. 1, pp. 65-75, URL: http://ogbus.ru/files/ogbus/authors/Baikov/Baikov_1.pdf

4. Syundyukov A.V., Khabibullin G.I., Trofimchuk A.S., Sagitov D.K., Metodika podderzhaniya optimal'noy geometrii tekhnogennoy treshchiny putem regulirovaniya rezhima nagnetaniya v nizkopronitsaemykh kollektorakh (A method for maintaining the optimal geometry of induced fracture by regulating the injection mode on low-permeability reservoirs), Ufa: Publ. of USPTU, Ufa.

5. Patent RU 2547848 C2, Method of development of low-permeable oil deposits, Inventors: Baykov V.A., Kolonskikh A.V., Evseev O.V., Afanas'ev I.S.

6. Wolcott D., Applied waterflood field development, Publ. of Schlumberger, 2001, 142 p.

7.
Eaton B.A., Graphical method predicting pressure worldwide, World Oil, 1972, V.
185, pp. 51–56.

The article proposes a set of stimulation methods for oil reservoirs of one of the field in Western Siberia, which has been in operation since 1982. The authors selected and analyzed such methods of improved oil recovery as hydraulic fracturing, horizontal wells drilling, and sidetracking. Based on the data obtained from the field, the results were analyzed. Total for the period from 2012 to 2016 years 26 hydraulic fracturing operations were performed at the field. The largest increments in oil production rates were obtained for wells with hydraulic fracturing performed in 2012 - on average 17.0 t/day, in 2016 - 23 t/day. The most effective for the period under consideration was hydraulic fracturing of the BS12 formation, where the maximum oil production rate was obtained. Cumulative production from 3 horizontal wells for 2009-2016 years amounts to 81 thousand tons or 1.1% of the accumulated production at the field for this period. The initial oil production rate of horizontal wells ranged from 10.9 to 82.4 t/day. Comparison of the performance indicators shows that the oil flow rates of horizontal wells exceed the flow rates of vertical wells by 2-3 times Water cut of production at horizontal wells in 2009-2010 years exceed the water cut of vertical wells. Total additional production from sidetracking for 2014-2016 years is 14.47 thousand tons. The share of additional oil production from sidetracking in the total volume of additional production from geological and technical measures for the period 2012-2016 years is 2.7%. A conclusion is given on the effectiveness of the application of methods for improved oil production for design periods. The analysis of the data obtained showed that drilling of horizontal wells has the greatest prospects, due to the ratio of the number of activities and the additional production obtained. Sidetrack drilling is also promising.

References

1. Malyshev A.G., Malyshev G.A., Zheludkov A.V., Osobennosti ekspluatatsii skvazhin posle GRP (Features of well operation after hydraulic fracturing), Moscow: Publ. of VNIIOENG, 2010, 156 p.

2. Ibatullin R.R., Experience in North America tight oil reserves development. Horizontal wells and multistage hydraulic fracturing (In Russ.), Georesursy, 2017, V. 19, no. 3, pp. 176-181, DOI:10.18599/grs.19.3.4

3. Salimov V.G., Ibragimov N.G., Nasybullin A.V., Salimov O.V., Gidravlicheskiy razryv karbonatnykh plastov (Hydraulic fracturing of carbonate formations), Moscow: Neftyanoe khozyaystvo Publ., 2013, 472 p.

4. Gudok I.O., Izuchenie fizicheskikh svoystv v poristykh sredakh (Study of physical properties in porous media), Moscow: Nedra Publ., 2010, 315 p.

5. Economides M., Oligney R., Valko P., Unified fracture design. Bridging the gap between theory and practice, Orsa Press, Alvin, Texas, 2002, 262 p.

6. Neskoromnykh V.V., Burenie naklonnykh, gorizontal’nykh i mnogozaboynykh skvazhin (Drilling of deviated, horizontal and multilateral wells), Krasnoyarsk: Siberian Federal University, 2016, 322 p.

7. Kiryushin A.Yu., Analysis of the efficiency of drilling sidetracks in the Muravlenkovskoye field (In Russ.), Akademicheskiy zhurnal Zapadnoy Sibiri, 2018, no. 6, pp. 128–130.

Gas methods of oil enhancement recovery allow to significantly increase the oil recovery in case of water-flooded depleted reservoirs at the late stage of oil fields development. Before implementation these methods at the oil field, it is necessary to substantiate efficiency of using gas agents in specific conditions of the production object. The aim of the research work was to determine the optimal regime of oil displacement with gas agents - carbon dioxide and associated petroleum gas (APG). An assessment of miscibility conditions at the Tsarichanskoye+Filatovskoye oil field in the Orenburg region with different gas agents in the pressure range, corresponding to the current values of the studied reservoir, was made. The object of the research was a wellhead oil sample of Dkt formation. The results of physical recombination, using a stable wellhead sample and recombination gas model, are three saturated systems with different gas contents, which simulate, in the first approximation, the processes of isothermal formation depletion. To confirm the efficiency of gas injection, physical simulation of the oil displacement process was carried out on the slim tube model using the recombined oil samples, carbon dioxide and associated petroleum gas of the Tsarichanskoye+Filatovskoye field.

A comprehensive analysis of the dynamics of oil displacement was carried out during laboratory studies. Based on a series of displacement experiments, the displacement regimes of carbon dioxide and associated petroleum gas injection have been determined. The highest displacement efficiency was observed when injecting carbon dioxide at pressure 19 MPa (displacement efficiency is 96.42%), when injecting APG at pressure 12.5 (displacement efficiency is 96.49%) and at pressure 9.5 MPa for the recombined sample with lower saturation pressure (displacement efficiency is 97.80%). The selected injection regimes for carbon dioxide and APG when the miscibility is achieved are the most effective in terms of residual oil recovery in the studied field.

References

1. Cao C., Liu H., Hou Z., A review of CO2 storage in view of safety and cost-effectiveness, Energies, 2020, V. 13(3), DOI:10.3390/en13030600

2. Graue D.J., Zana E.T., Study of a possible CO2 flood in Rangely Field, Journal of Petroleum Technology, 1981, V. 33(07), pp. 1312–1318, DOI:10.2118/7060-PA

3. Rutherford W.M., Miscibility relationships in the displacement of oil by light hydrocarbons, Society of Petroleum Engineers Journal, 1962, V. 2(04), pp. 340–346, DOI: https://doi.org/10.2118/449-PA

4. Holm L.W., Josendal V.A., Effect of oil composition on miscible-type displacement by carbon dioxide, Society of Petroleum Engineers Journal, 1982, V. 22(01), pp. 87–98, SPE-8814-PA, DOI: https://doi.org/10.2118/8814-PA

5. Wu R.S., Batycky J.P., Evaluation of miscibility from slim tube tests, Journal of Canadian Petroleum Technology, 1990, V. 29(06), DOI:10.2118/90-06-06

6. Polishchuk A.M., Khlebnikov V.N., Gubanov V.B., Usage of a formation slim tubes for physical modeling of oil displacement processes by miscible agents. Part 1. Methodology of the experiment (In Russ.), Neftepromyslovoe delo, 2014, no. 5, pp. 19–24.

7. Amao A.M., Siddiqui S., Menouar H., Herd B.L., A new look at the minimum miscibility pressure (MMP) determination from slimtube measurements, SPE-153383-MS, 2012, DOI:10.2118/153383-MS

8. Yu H., Lu X., Fu W. et al., Determination of minimum near miscible pressure region during CO2 and associated gas injection for tight oil reservoir in Ordos Basin, China, Fuel, 2019, V. 263, DOI:10.1016/j.fuel.2019.116737

9. Sorokin A., Bolotov A., Varfolomeev M. et al., Feasibility of gas injection efficiency for low-permeability sandstone reservoir in Western Siberia: Experiments and numerical simulation, Energies, 2021, V. 14(22), DOI:10.3390/en14227718

10. Yellig W.F., Metcalfe R.S., Determination and prediction of CO2 minimum miscibility pressures, Journal of Petroleum Technology, 1980, V. 32, no. 1, pp. 160–168, DOI:10.2118/7477-PA

11. Glaso O.S., Generalized minimum miscibility pressure correlation, Society of Petroleum Engineers journal, 1985, V. 25, no. 6, pp. 927–934, DOI:10.2118/12893-PA

12. Cronquist C., Carbon dioxide dynamic miscibility with light reservoir oils, Proceedings of Fourth Annual US DOE Symposium, 1978, V. 1, pp. 28–30.

13. Lee I.J., Effectiveness of carbon dioxide displacement under miscible and immiscible conditions, 1979.

14. Alston R.B., Kokolis G.P., James C.F., CO2 minimum miscibility pressure: a correlation for impure CO2 streams and live oil systems, Society of Petroleum Engineers Journal, 1985, V. 25, no. 2, pp. 268–274, DOI:10.2118/11959-PA

15. Emera M.K., Sarma H.K., Use of genetic algorithm to estimate CO2-oil minimum miscibility pressure–a key parameter in design of CO2 miscible flood, Journal of Petroleum Science and Engineering, 2005, V. 46, no. 1–2, pp. 37–52, DOI:10.1016/j.petrol.2004.10.001

16. Chen B.L., Huang H.D., Zhang Y. et al., An improved predicting model for minimum miscibility pressure (MMP) of CO2 and crude oil, Journal of Oil and Gas Technology, 2013, V. 35, no. 2, pp. 126–130.

17. Zhang H., Hou D., Li K., An improved CO2-crude oil minimum miscibility pressure correlation, Journal of Chemistry, 2015, no. 5, DOI:10.1155/2015/175940

18. Maklavani A.M., Vatani A., Moradi B., Tangsirifard J., New minimum miscibility pressure (MMP) correlation for hydrocarbon miscible injections, Brazilian journal of petroleum and gas, 2010, V. 4(1), pp. 11–18.

19. Frimodig J.P., Reese N.A., Williams C.A., Carbon dioxide flooding evaluation of high-pour-point, paraffinic red wash reservoir oil, Society of Petroleum Engineers Journal, 1983, V. 23(04), pp. 587–594, DOI: 10.2118/10272-PA

Cyclic and polymer-cyclic flooding of fractured-porous reservoirs is investigated by the method of computational experiment. As a research tool, the Tempest-More software package from ROXAR was selected, which makes it possible to perform hydrodynamic modeling of fractured-porous systems taking into account dual porosity and dual permeability. It is shown that the dependence of the oil recovery factor on the proportion of fractures in the reservoir has a non-monotonic character. It was revealed that for the selected parameters of the simulated technologies, the highest final oil recovery factor under cyclic and polymer-cyclic impact is achieved with the smallest injection half-cycle. The combination of cyclic flooding with polymer flooding increases the final recovery factor, but at the same time, injectivity of injection wells may decrease due to the achievement of injection pressure limitation due to the increased viscosity of the fluid and, as a result, lower efficiency at the end of the effect compared to conventional polymer flooding. It is shown that the assessment of the results of the impact on the reservoirs significantly depends on at what point in time the assessment is made: at the end of the impact, at the end of the effect of the impact or when the maximum water content of the well production is reached.

References

1. Barenblatt G.I., Zheltov Yu.P., Kochina I.N., On the basic concepts of the theory of filtration of homogeneous fluids in fractured rocks (In Russ.), Prikladnaya matematika i mekhanika = Journal of Applied Mathematics and Mechanics, 1960, V. XXIV, no. 5, pp. 852–864.

2. Surguchev M.L., Cyclic (pulsed) impact on the reservoir as a method of increasing oil recovery during flooding (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1965, no. 3, pp. 52–57.

3. Bokserman A.A., Zheltov Yu.P., Muzafarov K.E., Ogandzhanyants V.G., Eksperimental’noe izuchenie kapillyarnogo uderzhaniya vody v poristykh sredakh pri uprugo-kapillyarnom rezhime (Experimental study of the capillary retention of water in porous media in the elastic-capillary regime) Proceedings of VNII, 1967, no. 50, pp. 94–101.

4. Tsynkova O.E., On the issue of the mechanism of cyclic impact on oil reservoirs (In Russ.), Izvestiya AN SSSR. Mekhanika zhidkosti i gaza = Fluid Dynamics, 1980, no. 3, pp. 58–67.

5. Sharbatova I.N., Surguchev M.L., Tsiklicheskoye vozdeystviye na neodnorodnyye neftyanyye plasty (Cyclical effects on heterogeneous oil layers), Moscow: Nedra Publ., 1988, 121 p.

6. Muslimov R.Kh., Sovremennye metody povysheniya nefteizvlecheniya: proektirovanie, optimizatsiya i otsenka effektivnosti (Modern methods of enhanced oil recovery: the design, optimization and assessment of efficiency), Kazan’: Fen Publ., 2005, 688 p.

7. Akulshin A.L., Study of oil displacement from a fractured-porous reservoir using POLYCAR polymer (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2000, no. 1, pp. 36–38.

The main producing formations of Central-Khoreiver Uplift fields are carbonate Devonian deposits (Famenian stage) that are characterized by predominantly hydrophobic wettability. Reservoir temperatures is around 70 °C and high salinity formation water is up to 210 g/l, hardness of water (Ca+Mg) is up to 20 g/l. Oil viscosity at reservoir condition is 7 mPa·s, bubble-point pressure is 8 MPa, gas-oil ratio is 36 m3/t. The current reservoir pressure is about 20 MPa. A study is currently in progress these object to evaluate the injection of different chemical agents to increase oil recovery factor. The paper discusses the process of development of surfactant-polymer flooding technology for carbonate reservoirs with high salinity formation water and high reservoir temperature. The initial selection of compositions for enhanced oil recovery included experiments to assess the physicochemical properties: viscosity, interfacial tension with oil, etc. These parameters are determined under conditions close to reservoir conditions. The effective surfactant-polymer composition was selected on the basis of a set of key parameters measured in screening and complex laboratory testing. Coreflooding experiments on composite core model were conducted to evaluate the efficiency of selected composition. At the target concentration values, an additional oil displacement coefficient of 7% is provided after pumping one pore volume of the surfactant and 14% after pumping one pore volume for the surfactant-polymer composition. The effectiveness of surfactant and surfactant-polymer compositions was confirmed in-situ with single well chemical tracer test (SWCTT) conducted at the oilfields of RUSVIETPETRO JV.

References

1. Petrakov A.M., Rogova T.S., Makarshin S.V. et al., Selection of surfactant-polymer technology for enhanced oil recovery project in carbonate formations of Central-Khoreiver uplift (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2020, no. 1, pp. 66–70, DOI: 10.24887/0028-2448-2020-1-66-70

2. Kornilov A., Zhirov A., Petrakov A. et al., Selection of effective surfactant composition to improve oil displacement efficiency in carbonate reservoirs with high salinity formation water, SPE-196772-MS, 2019, DOI: 10.2118/196772-MS

3. Hu Guo, Ma Dou, Wang Hanqing, Review of capillary number in chemical enhanced oil recovery, SPE-175172-MS, 2015, DOI: 10.2118/175172-MS

4. Patent 3590923 US, Method of determining residual oil saturation in reservoirs, Inventor: Cooke C.E. Jr.

5. Dean R.M., Walker D.L., Dwarakanath V. et al., Use of partitioning tracers to estimate oil saturation distribution in heterogeneous reservoirs, SPE-179655-MS, 2016, DOI: 10.2118/179655-MS

6. Galeev R.I., Bolotov A.V., Varfolomeev M.A. et al., New and simple methods of determination partition coefficient and degree hydrolysis of tracer for estimating residual oil saturation by SWCTT technologies, Petroleum Science and Technology, 2021, V. 39, pp. 1043-1059, DOI: 10.1080/10916466.2021.1970181

7. Kruglov D.S., Smirnov A.E., Tkachev I.V. et al., Design of pilot test to evaluating the efficiency of surfactant-polymer flooding in field conditions using single well chemical tracer test (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 12, pp. 102–106, DOI: 10.24887/0028-2448-2021-12-102-106

The paper presents an adjusted mathematical model of two-phase filtration processes in fractured porous media. Traditionally, the equations of two-phase filtration in a medium of dual porosity are based on the laws of conservation of oil and water phases in fractured and matrix (block) rock spaces. These equations are interconnected by some functions that describe phases flow between fractures and blocks, and these functions are taken proportional to the pressure difference between the phases in the rocks matrix and fractures. With the exception of transient processes, characterized by a sharp change in reservoir pressure, as occurs, for example, during hydrodynamic studies in wells, the indicated difference in hydrodynamic pressures in long-term waterflooding of productive formations is due only to capillary forces. For this reason, it is traditionally assumed that the displacement of oil from hydrophilic rocks matrix is due precisely to the processes of capillary impregnation of these blocks. At the same time, as shown in the article, mass transfer between rock matrix and fractures is also determined by the processes of mixing of two-phase fluid flows in the fractured space of the rock, and comparable in intensity to capillary impregnation, which also leads to a decrease in oil saturation of matrix and, accordingly, an increase in oil saturation of the fractured space. The proposed mathematical model, which takes into account both the processes of capillary impregnation of matrix and the mass transfer due to mixing of fluid flows in fractures, will allow a more adequate description of the processes of two-phase filtration in fractured-porous reservoirs.

References

1. Barenblatt G.I., Zheltov Yu.P., Kochina I.N., On the basic concepts of the theory of filtration of homogeneous fluids in fractured rocks (In Russ.), Prikladnaya matematika i mekhanika – Journal of Applied Mathematics and Mechanics, 1960, V. XXIV, no. 5, pp. 852–864.

2. Barenblatt G.I., Entov V.M., Ryzhik V.M., Dvizhenie zhidkostey i gazov v prirodnykh plastakh (Movement of liquids and gases in natural reservoirs), Moscow: Nedra Publ., 1982, 211 p.

3. Golf-Racht T., Fundamentals of fractured reservoir engineering, Amsterdam, New York: Elsevier, 1982.

4. Odeh A.S., Unsteady-state behaviour of fractured reservoirs, SPE-966-PA, 1965, DOI:10.2118/966-PA

5. Khasanov M.M., Bulgakova G.T., Nelineynye i neravnovesnye effekty v reologicheski slozhnykh sredakh (Nonlinear and nonequilibrium effects in rheologically complex media), Moscow - Izhevsk: Institute for Computer Research, 2003, 288 p.

6. Svalov A.M., Features of inflow and pressure-buildup curves in porous fractured reservoirs (In Russ.), Inzhenerno-fizicheskiy zhurnal = Journal of Engineering Physics and Thermophysics, 2021, V. 94, no. 2, pp. 377–383.

7. Warren J.E., Root P.E., The behavior of naturally fractured reservoirs, SPE-426-PA, 1963, DOI:10.2118/426-PA

8. Kazemi H., Merril L.S., Posterfeld L., Zeman P.K., Numerical simulation of water-oil in naturally fractured reservoirs, SPE-5719-PA, 1976, DOI:10.2118/5719-PA

9. Gudok N.S., Bogdanovich N.N., Martynov V.G., Opredelenie fizicheskikh svoystv neftevodosoderzhashchikh porod (Determination of the physical properties of oil-and-water-containing rocks), Moscow: Nedra Publ., 2007, 592 p.

10. Tiab D., Donaldson E C., Petrophysics: theory and practice of measuring reservoir rock and fluid transport, Elsevier Inc., 2004, 926 p.

11.
Craig F., Reservoir engineering aspects of waterflooding, H. L. Doherty
Memorial Fund of AIME, 1971, 164 p.

In the conditions of the Far North, the construction and operation of oil and gas wells on permafrost soils is associated with the possible manifestation of dangerous technogenic processes that require solving issues of ensuring operational reliability and longitudinal stability of wells, as well as reducing the negative impact on the ecological and geocryological situation during operation. The key factor is the thawing of permafrost soils in the wellhead zone. Production wells, from the moment they start their operation until its completion, continuously have a significant thermal effect on the enclosing permafrost soils. To reduce the negative thermal impact from production wells at oil and gas production fields located in the conditions of the distribution of permafrost, as a rule, passive methods of temperature stabilization of soils are used, in particular, thermally insulating directions or thermally insulated lift pipes.

In order to reduce the negative thermal impact on the soils of the wellhead space of production wells, the authors proposed to cover the elements of the direction, conductor or technical column with ultra-thin thermal insulation to the entire depth of the permafrost. Depending on the conditions of construction, ultra-thin thermal insulation is proposed to be applied to the conductor of a production well (new construction) or tubing (existing fund). The described technical solution makes it possible to significantly reduce the heat flux transmitted to permafrost soils to the entire depth of their occurrence. The efficiency of using a liquid composite heat-insulating material is confirmed by the results of predictive heat engineering calculation. The solution of the problem is carried out by preparing a model and obtaining a forecast of changes in conditions that simulate the process of operating a production well, taking into account geology, external climatic factors, and technical characteristics of the heat-insulating material. According to the results of mathematical modeling, the use of ultrathin liquid thermal insulation to cover elements of a production well in terms of the effectiveness of thermal insulation properties is comparable to the use of such measures as the installation of thermally insulating wellheads or thermally insulated lift pipes. This method is easy in implementation and has obvious economic advantages.

References

1. Koloskov G.V., Ibragimov E.V., Gamzaev R.G., On the issue of choosing optimal systems for thermal stabilization of soils during construction in the permafrost zone (In Russ.), Geotekhnika, 2015, no. 6, pp. 4-11.

2. Chikalov S.G., Pyshmintsev I.Yu., Zasel’skiy E.M. et al., Experience of application of insulated lift pipes in the conditions of gas fields in the north of Western Siberia (In Russ.), Gazovaya promyshlennost’, 2018, no. 12(778), pp. 38-42.

3. Utility patent no. 187211 RF, Termoizoliruyushchee napravlenie burovoy skvazhiny (Thermally insulating direction of the borehole), Inventors: Perfilov P.V., Sampara E.V., Shanaenko V.V., Novotel’nov S.V.

4. Shanaenko V.V., Drilling in permafrost is no longer a problem (In Russ.), TERRITORIYa NEFTEGAZ, 2013, no. 11, pp. 15.

5. Shats M.M., Permafrost as a stumbling block, or time to save permafrost (In Russ.), Territoriya i planirovanie, 2010, no. 3(27), URL: http://terraplan.ru/arhiv/50-3-27-2010/870-582.html

6. Artemenkov V.Yu., Erekhinskiy B.A., Zaryaev I.A., The usage of insulated lift pipes in oil and gas industry (In Russ.), TERRITORIYa NEFTEGAZ, 2017, no. 3, pp. 40–44.

7. Malyukov V. P., Khadziev M.K., Features of the development Bovanenkovskoe oil and gas field on Yamal. Protection of environment (In Russ.), Gornyy informatsionno-analiticheskiy byulleten’, 2016, no. 11, pp. 286–294.

8. Utility patent no. 211471 RF, Nasosno-kompressornaya truba s tonkosloynoy teploizolyatsiey (Tubing with thin-layer thermal insulation), Inventors: Poverennyy Yu.S., Zenkov E.V., Gilev N.G., Georgiyadi V.G., Agapov A.A.

9. Utility patent no. 202494 RF, Konduktor so sverkhtonkoy teploizolyatsiey (Surface casing with ultra-thin thermal insulation), Inventors: Poverennyy Yu.S., Zenkov E.V., Gilev N.G., Georgiyadi V.G., Agapov A.A.

Capillary imbibition of the mud filtrate into the reservoir during drilling is involved, together with filtration flow, in increasing the water saturation of the bottomhole zone. At the same time, the ratio of capillary imbibition and filtration flow depends on a large number of factors, some of which cannot be directly measured, or this measurement is quite laborious, such as the contact angle of wetting phase, the radius of the pore channels, the initial saturation of the reservoir with gas, water and oil, relative phase permeability. Also, in addition to capillary absorption, other physico-chemical processes occur, the separate influence of each of which is quite difficult to identify. Moreover, the most important thing is to characterize the reservoir as a whole, and not to separate individual factors, the combination of which can reduce the accuracy of the forecast in other situations. To determine the nature of the interaction of the reservoir with the drilling fluid filtrate, it is proposed to use a complex parameter, which combines the above properties of the reservoir rock, namely, capillary pressure and relative permeability of the aqueous phase. Capillary pressure contains data about the radius of the pore channels and the contact angle. This article presents the results of studies by the gravimetric method of the kinetics of capillary imbibition of sandstone rock samples with the aqueous phase of the drilling fluid, determined during the experiment. As a result, the sensitivity of a gas-saturated reservoir to capillary imbibition of the aqueous phase is determined taking into account its initial water saturation without the need for instrumental measurements of porosity, permeability and capillary pressure. Options of capillary absorption at initial water saturation of 0, 10, 20 and 50% were considered. The classification of reservoir rocks based on the complex parameter can simplify the task of selecting the optimal drilling fluid to solve the problem of reducing the formation damage during the initial drilling into the formation.

References

1. Zonn M.S., Dzyublo A.D., Kollektory yurskogo neftegazonosnogo kompleksa severa Zapadnoy Sibiri (Collectors of the Jurassic oil and gas complex in the north of Western Siberia), Moscow: Nauka Publ., 1990, 88 p.

2. Tiab D., Donaldson E C., Petrophysics: theory and practice of measuring reservoir rock and fluid transport, Elsevier Inc., 2004, 926 p.

3. Borozdin S.O., Podgornov V.M., Reservoir sensitivity to physical and chemical process under invasion zone building (In Russ.), Gazovaya promyshlennost’, 2016, no. 4 (736), pp. 21–25.

4. Mikhaylov N.N., Motorova K.A., Sechina L.S., Geological wettability factors of oil and gas reservoir rocks (In Russ.), Neftegaz.ru, 2016, no. – № 3. – S. 80–90.

5. Mezentsev D.N., Tupitsyn E.V., Ledovskaya T.I. et al., Recovery of wettability of core samples in preparation to filtration research (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 11, pp. 60–61.

6. Li K., Chow K., Horne R.N., Effect of initial water saturation on spontaneous water imbibition, SPE-76727-MS, 2002, DOI: https://doi.org/10.2118/76727-MS

If in traditional terrigenous reservoirs organic matter is represented by free mobile oil that migrated from oil source deposits, then the Bazhenov formation simultaneously contains kerogen, hydrocarbon compounds physically associated with kerogen or the mineral matrix, as well as free hydrocarbon compounds that form accumulations of mobile oil in connected and isolated pores. This explains the need to create an unconventional approach to conducting multi-stage hydraulic fracturing on the reservoirs of the Bazhenov formation. The paper considers the experience of performing the multi-stage hydraulic fracturing on the Bazhenov formation reservoirs using low-viscosity fluids in horizontal wells with ball&drop completion. Various approaches to the hydraulic fracturing are described and their modeling is performed in the hydraulic fracturing simulator RN-GRID. The results of design remodeling based on actual data of two horizontal wells multistage hydraulic fracturing are presented. New modified technology of Bazhenov formation multistage hydraulic fracturing, based on gained experience and developed injection method, is presented. The prospects of using the proposed technology are shown, based on the obtained results. The authors give the comparison of the geological and geomechanical conditions in all horizontal wells considered in this paper to confirm the similarity of the conditions. The information presented in this article can be useful for a wide range of engineers searching for the ways of optimizing the hydraulic fracturing processes in the fields, improving the methods to increase the well productivity, reducing the cost of activities to stimulate the production and enhance oil recovery.

References

1. Fedorova D.V., Astaf'ev A.A., Nadezhdin O.V., Latypov I.D., Petrophysical model of the Bazhenov formation of the Priobskoye field of Rosneft (In Russ.), Delovoy zhurnal “Neftegaz.RU”, 2020, no. 6(102), pp. 76-84.

2. US Crude Oil Field Production, URL: https://ycharts.com/indicators/us_crude_oil_field_production

3. US Crude Oil Field Production, URL: https://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=WCRFPUS2&f=W

4. Rystad Energy: US oil output poised to set yet another record in 2019, Oilfield Technology, 06 June 2019, URL: https://www.oilfieldtechnology.com/drilling-and-production/06062019/rystad-energy-us-oil-output-pois...

5. Kalmykov G.A., Balushkina N.S., Model neftenasyshchennosti porovogo prostranstva porod bazhenovskoy svity Zapadnoy Sibiri i ee ispolzovanie dlya otsenki resursnogo potentsiala (Model of oil saturation of the pore space of rocks of the Bazhenov formation in Western Siberia and its use for assessing the resource potential), Moscow: GEOS Publ., 2017, 247 p.

6. Raterman K.T., Farrell H.E., Mora O.S. et al., Sampling a stimulated rock volume: An Eagle Ford example, URTEC-2670034-MS, 2017, DOI: https://doi.org/10.15530/URTEC-2017-2670034

7. Akhtyamov A.A., Makeev G.A., Baydyukov K.N. et al., Corporate fracturing simulator RN-GRID: from software development to in-field implementation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 5, pp. 94–97, DOI: https://doi.org/10.24887/0028-2448-2018-5-94-97

8. Malhotra S., Lehman E.R., Sharma M.M., Proppant placement using alternate-slug fracturing, SPE-163851-PA, 2014, DOI: https://doi.org/10.2118/163851-PA

The publication describes the stages of development,
testing and organization of production of thread greases for oil country
tubular goods. In bench and pilot tests the main exploitative characteristics
of thread greases were evaluated. In qualification tests on full-scale pipe
samples, the wear resistance of casing pipes with a diameter of 178 mm, tubing
pipes with a diameter of 73 mm and welded locks ZP-127-62 was evaluated on the
STS-2500 bench. Leak tests were carried out on casing samples with a diameter
of 178 mm and tubing with a diameter of 73 mm. Pilot tests were carried out at
RN-Yuganskneftegaz LLC (Pyt-Yakh) on tubing with a diameter of 73×5.5 mm during
make-up and break-out and hydraulic tests on repaired and new pipes
manufactured by Sinarsky Pipe Plant PJSC, Gazpromtrubinvest OJSC and
Pervouralsk Pipe Plant OJSC. Under drilling conditions pilot tests were carried
out at LLC RN-Bureniye on drill pipes IEU 127×9.19 G NC50 manufactured by TMK
Company. Based on the results of the performed work thread greases were
approved for use in oil country tubular goods during the construction and
operation of wells. Industrial production of thread greases has been organized
at NK Rosneft-MZ Nefteprodukt PJSC. The installation and commissioning of an
industrial unit with a capacity of up to 600 tons/year was carried out.

The estimation of reserves and resources is one of the important tasks in the activities of any oil and gas company. The purpose of an independent estimation (audit) is to accurately report on reserves and resources in accordance with a specific classification system and applicable statutory and financial regulations. Since 2013, Zarubezhneft has been keeping records of reserves of its own assets not only according to the Russian reserves and resources classification, but it also conducts annual reserves audits according to the international SPE-PRMS classification developed by the International Society of Petroleum Engineers (SPE) and the U.S. Securities and Exchange Commission (SEC). Since 2021, the Reserves and Resources Team, which includes specialists of VNIIneft STC, performs reserves audits for the Zarubezhneft Group of Companies independently, without the involvement of international auditors. In 2021, the reserves audit was carried out for 43 fields of the Zarubezhneft Group of Companies: 27 fields in Russia, 3 fields in the Republic of Uzbekistan, 2 fields in the Arab Republic of Egypt, and 11 fields in the Socialist Republic of Vietnam. In 2022, the list of estimated assets increased up to 50 fields. Due to the increasing volume of work, there appeared a need to automate the estimation processes and reduce time costs. In 2021, the work began to create software for conducting HC reserves audits according to the international SPE-PRMS classification. At the moment, the web-based application has been tested and allows one to store the results of geological assessment in the format of volumetric tables, perform engineering calculations, and generate reporting materials.

References

1. Guidelines for application of the Petroleum Resources Management System, URL: https://millerandlents.com/wp-content/uploads/2020/03/2011-Guidelines-for-Application-of-the-PRMS.pd...

2. Petroleum Resources Management System (revised June 2018) Version 1.01, URL: https://www.spe.org/industry/docs/PRMgmtSystem_V1.01_RUS-FINAL.pdf

3. Khamitov A.T., Churanova N.Yu., Kozhemyakina I.A., Kalpakhchev N.O., Development of methodology and software for hydrocarbon reserves audit according to the international SPE-PRMS classification in the Zarubezhneft Group of Companies (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 11, pp. 88-93,

DOI: https://doi.org/10.24887/0028-2448-2021-11-88-93

RN-ROSPUMP is the software, which is daily employed by more than 25 of oil production subsidiaries of Rosneft Oil Company to design and analyze the oil equipment. For its more than 15-years history RN-ROSPUMP passed the way from the ordinary calculator for pumps calculations to one of the flagships of corporate line of software. Acting as the element of digitalization of the artificial lift RN-ROSPUMP becomes not only a tool for pump design, but a proactive assistant of technology staff in monitoring and control of the processes of oil production. The article presents a brief description of development stages and functional of RN-ROSPUMP as the corporate software for design and optimization of the oil production equipment. Today RN-ROSPUMP allows to provide these functions actually for all oil production technologies. Besides it helps to solve such problems as the forecast and selection the technologies against borehole complications and improving the energy efficiency of artificial lift. The program designers carry out continuous interaction with its users in production units, conduct training courses regularly and share experiences. The functional of RN-ROSPUMP constantly expands including due to the implementation of scientific results in the field of oil artificial lift of Rosneft Oil Company and digital technologies. The main directions of development of the software package related to the modern trends in oil artificial lift and new requirements for architecture and interaction with other IT-products of corporate line of Rosneft Oil Company.

References

1. Rosneft has expanded its commercial line of science-intensive software (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 3, pp. 6-7.

2. Topol’nikov A.S., Forecasting scale in a well with automated selection of pumping equipment (In Russ.), Inzhenernaya praktika, 2009, no. 1, pp. 16-21.

3. Pashali A.A., Khalfin R.S., Sil’nov D.V. et al., On the optimization of the periodic mode of well production, which is operated by submergible electric pumps in Rosneft Oil Company (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 4, pp. 92-96, DOI: 10.24887/0028-2448-2021-4-92-96

4. Volkov M.G., Khalfin R.S., Brot A.R. et al., Method of calculation and selection of designs installations of PCP pumps with submersible and surface drive for oil production (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2018, no. 6, pp. 32–37.

5. Urazakov K.R., Abramova E.V., Topol’nikov A.S., Minnigalimov R.Z., Technology for increasing oil from low-productiv wells (In Russ.), Neftegazovoe delo, 2013, no. 4, pp. 201–211.

6. Gilaev G.G., Bakhtizin R.N., Urazakov K.R., Sovremennye metody nasosnoy dobychi nefti (Modern methods of pumping oil production), Ufa: Vostochnaya pechat’ Publ., 2016, 410 p.

7. Urazakov K.R., Zdol’nik S.E., Urazakov K.R. et al., A comprehensive ESP temperature conditions prediction method (In Russ.), Nauchno-tekhnicheskiy vestnik OAO “NK “Rosneft’”, 2010, no. 1, pp. 36–41.

8. Bakhtizin R.N., Urazakov K.R., Ismagilov S.F. et al., Dynamic model of a rod pump installation for inclined wells, SOCAR Proceedings, 2017, no. 4, pp. 74-82.

9. Kosilov, D.A. Mironov, D.V. Naumov I.V., Mekhfond corporate system: achieved results, medium-term and long-term perspectives (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 11, pp. 70–73, DOI: 10.24887/0028-2448-2018-11-70-73

10. Volkov M.G., Presnyakov A.Yu., Klyushin I.G. et al., Monitoring and management the abnormal well stocks based on the Information System Mekhfond of Rosneft Oil Company (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no. 2, pp. 90–94, DOI: 10.24887/0028-2448-2021-2-90-94

For reducing evaporation losses during storage of volatile liquids in above-ground steel cylindrical tanks, external floating roofs are used. Due to the absence of a stationary roof, the structure of the external floating roof must be capable of absorbing snow and wind loads that reach significant values on the territory of the Russian Federation. A feature of these loads is their eccentric application, which increases the likelihood of tank failure. Previous studies have shown that snow and wind loads are interrelated, and the uneven thickness of the snow cover over the surfaces of constructions is caused by the heterogeneity of the snow and wind flow. The characteristics of the wind flow in the space inside the tank, which are the cause of the eccentricity of the snow and wind effects on the external floating roof, have not been studied.

In this paper, the nature of the flow and the distribution of wind flow velocities in the space inside the tank, which is a circular cylinder open from above, are studied. Research were carried out using a reservoir model of height / diameter ratio H/D = 0.53 on a scale of 1/100 in a wind tunnel. The influence of the position of the external floating roof relative to the tank and its design on the nature of the flow also has been studied. The flow velocity in the wind tunnel was 22–23 m/s, Re = (3–4)·105. It has been established that when a wind flows around a cylindrical tank open from above, a global vortex with a horizontal axis perpendicular to the direction of the undisturbed flow, as well as several local vortices, is formed in the space inside the tank above the surface of external floating roof. The global vortex forms reverse flows, directed opposite to the undisturbed flow, over most of the surface. The velocity of the return currents decreases with increasing relative height due to a decrease in the size of the global vortex. The reverse flow velocity on the external floating roof surface is inhomogeneous. The inhomogeneity of the flow velocities creates the eccentricity of the wind load affecting on the external floating roof. The values of the aerodynamic coefficients obtained as a result of the research can be used in calculating the wind load on the external floating roof of full-scale tanks with a ratio of characteristic dimensions H/D ≈ 0,5.

References

1. Penina E.S., Ecological and economic impact caused by the replacement of reinforced concrete tanks by vertical steel tanks with floating roof at Nikolskoe tank farm (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2012, no. 2, pp. 66–67.

2. Gadel'shin R.Z., Floating roofs of tanks: effectiveness analysis and development directions (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2017, no. 4, pp. 96–101.

3. Karavaychenko M.G., Babin L.A., Usmanov R.M., Rezervuary s plavayushchimi kryshami (Tanks with floating roofs), Moscow: Nedra Publ., 1992, 236 p.

4. Myers Ph.E., Above ground storage tanks, New York: McGraw-Hill, 1997, 685 p.

5. Dyunin A.K., Mekhanika meteley (Blizzard mechanics), Novosibirsk: Publ. of SB of USSR Academy of Sciences, 1963, 378 p.

6. Emission factor documentation for AP-42. Section 7.1 Organic liquid storage tanks. Final Report, URL: https://www3.epa.gov/ttn/chief/ap42/ch07/bgdocs/b07s01.pdf

7. Gadel'shin R.Z., A study on the effectiveness of rim seals operation for external floating roof tanks (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 4, pp. 102–106, DOI: 10.24887/0028-2448-2019-4-102-106

8. Palmer S.C., Design of floating roofs on oil storage tanks to withstand wind loading – A review with recommendations, Journal of the Institute of Mechanical Engineers, 1986, C257/86, pp. 23–31.

9. Gorlin S.M., Korenberg L.N., Aerodynamic studies of large capacity tank models (In Russ.), Stroitel'naya mekhanika i raschet sooruzheniy, 1968, no. 4, pp. 11–13.

10. Holroyd R.J., On the behavior of open topped oil storage tanks in high winds. Part 1. Aerodynamic aspects, Journal of Wind Engineering and Industrial Aerodynamics, 1983, no. 12, pp. 329–352.

11. Marchman J.F., Wind effects on floating surfaces in large open top storage tanks, Proceedings of 3d International Conference Wind Effects an Buildings and structures. Tokyo, 1971, pp. 327–334.

12. Ziolko J., Modelluntersuchungen der Windeinwirkung auf Stahlbehalter mit Schwimmdach, Stahlbau, 1978, no. 11, pp. 321–329.

13. Runchal A.K., Hydrocarbon vapor emissions from floating roof tanks and the role of aerodynamic modifications, Journal of the Air Pollution Control Association, 1978, 28/5, pp. 498–501.

14. Uematsu Y., Koo C., Kondo K., Wind loads on open-topped oil storage tank, Proceedings of VI International Colloquium Bluff Bodies Aerodynamics & Applications, Milano, 2008.

15. Fabrikant N.Ya., Aerodinamika (Aerodynamics), Moscow: Nauka Publ., 1964, 816 p.

The article describes the results of a model experiment on restoration soil fertility on natural substrates. The experiment was carried out on the territory of the Samotlorskoye field. Typically, these natural substrates are used in land reclamation measures. The study area has humid conditions with frozen rocks occurrence. The experiment investigated natural substrates in the form of peat or sand, or mixtures thereof, which are the most commonly used during reclamation. The analysis of the humus qualitative characteristics shows effective humus recovery on reclaimed lands. During the ten-year observation, the carbon deposition by the studied young soils was assessed. These data can be used in the development of car bon projects for green house gas sequestration. Due to the lack of information in the study area about car bon deposition in the phytomass and in the soil in the conditions of oil producing, the relevance of this topic is obvious. In particular, the study of the qualitative characteristics of carbon in soils and substrates, sufficient for reclamation measures, allows us to forma conception of ‘effective soil’. This will reduce the difference in balance between phytomass and carbon dioxide emission in to the atmosphere. The results of the model experiment can become the basis for planning reclamation measures of the Samotlorskoye field lands, which are disturbed by the oil industry, as well as other territories located in humid conditions with frozen rocks occurrence.

References

1. Dergacheva M.I., Humic substances and their information importance in biosphere, In: Advances in natural organic matter and humic substances research, Proceedings Book of the Communications presented to the 15th Meeting of the International Humic Substances Society, Puerto de la Cruz, 27 June – 02 July 2010, Puerto de la Cruz: Publ. of The Institutional The Institutional Repository of Consejo Superior de Investigaciones Científicas (CSIC), 2010, pp. 237-240.

2. Aleksandrova L.N., Organicheskoe veshchestvo pochvy i protsessy ee transformatsii (Soil organic matter and processes of its transformation), Leningrad: Nauka Publ., 1980, 287 p.

3. Bazilevich N.I., Titlyanova A.A., Bioticheskiy krugovorot na pyati kontinentakh: azot i zol'nye elementy v prirodnykh nazemnykh ekosistemakh (Biotic cycling on five continents: nitrogen and ash elements in natural terrestrial ecosystems), Novosibirsk: Publ. of SB of RAS, 2008, 376 p.

4. Tyurin I.V., Naydenova O.A., K kharakteristike sostava i svoystv guminovykh kislot, rastvorimykh v razvedennykh shchelochakh neposredstvenno i posle dekal'tsirovaniya (On the characterization of the composition and properties of humic acids soluble in dilute alkalis directly and after decalcification), Proceedings of Soil Institute named after Dokuchaev V.V., 1951, V. 38, pp. 59–64.

5. Korkina I.N., Vorobeichik E.L., Non-typical degraded and regraded humus forms in metal-contaminated areas, or there and back again, Geoderma, 2021, V. 404, DOI: https://doi.org/10.1016/j.geoderma.2021.115390

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