The Rosneft Oil Company is consistently working on Hi-Tech well logging development. Research efforts involves cooperation with the leading Russian manufactures and research centers targeted at further development of both instrumentation pool and software support, as well as the in-house projects aimed at well logging efficiency and self-descriptiveness improvement having the industrial expansion potential. Search for new ways to develop domestic well logging has laid the foundation of cooperation between Rosneft Oil Company and State Corporation Rosatom»(FSUE VNIIA). The joint efforts brought to technological independence in the area of Hi-Tech well logging and resulted in the domestic pulse neutron gamma-ray spectral logging appliance (АINK-PL) manufacturing. The АINK-PL is not only comparable to the most recent developments, but does predominate in terms of engineering design.

The article presents application efficiency assessment for АINK-PL under various geological and process environment conditions of the Rosneft oil fields. The pilot field trials have been carried out in almost every Russian oil and gas province both for terrigenous and carbonate deposits of complicated mineral composition. The results have demonstrated substantiation of the given technology able to accomplish with the full range of petrophysical tasks. The planned extensive АINK-PL implementation within the Rosneft Oil Company will provide substantial decrease of well logging operating costs and increase the oil and gas production efficiency.

References

1. Makhmutov I.R., Rakaev R.I., Mitrofanov D.A. et al., Application of innovative instrumentation & methodic equipment complex AINK-PL for petrophysical modeling in Rosneft Oil Company (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2023, no. 2, pp. 66–71, DOI: https://doi.org/10.24887/0028-2448-2023-2-66-71

2. Rakaev I.M., Gadel'shin E.V., Khanafin I.A. et al., Developing market of domestic hi-tech well survey appliances (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 12, pp. 78-82, DOI: https://doi.org/10.24887/0028-2448-2022-12-78-82

3. Basyrov M.A., Mitrofanov D.A., Makhmutov I.R. et al., The development of the technique for measuring mass fractions of chemical elements using AINK-PL logs (In Russ.), Karotazhnik, 2021, no. 8(314), pp. 121–130.

In order to be approached comprehensively in exploration of geological environment by seismic is actively developing the direction of research using wide-azimuth 3D seismic data and its subsequent use to processing and interpretation of azimuth-dependent formation characteristics. The possibility of a special HTI analysis of medium anisotropy at the final processing stage is provided by a systematic approach in processing flow design – from the stage of data entry to regularization and migration, focused on saving the values of the azimuths of the SP-RP pairs in the trace headers and the wavefield properties of the seismic record. The azimuth values of the SP-RP pairs at the final processing stage can provide additional information about the medium under study. The available procedures for analyzing azimuthal velocities in modern seismic data processing software make it possible, on the one hand, to improve the wave field, and on the other hand, allow calculating azimuthally varying velocity attributes. The latter are the intensity and direction of the anisotropy of seismic waves, and can help in identifying geological objects in space that generate anisotropy of properties. The article considers similar azimuthal processing flow of seismic data, implemented within the production project; it reflects the main requirements for 3D-CDPM seismic surveys data that can be regarded as wide-azimuth. The expediency and method of splitting data into classes of offsets-azimuths COV (common offset vector) or OVT (offset vector tile) is also described. The theoretical part of the article reveals the mathematical basis of the interpolation algorithms for the involved 5D interpolation procedure and at the same time shows the resulting problems of the classically configured algorithm and the method of modifying it to maximize the preservation of the original characteristics of the survey geometry for the data.

References

1. Cary P.W., Common-offset-vector gathers: An alternative to cross-spreads for wide-azimuth 3D surveys, Proceedings of 69th Annual International Meeting, SEG, Expanded Abstracts, 1999, pp. 1496–1499, DOI: https://doi.org/10.1190/1.1820804

2. Liu B., Sacchi M.D., Minimum weighted norm interpolation of seismic records, Geophysics, 2004, V. 69, pp. 1560–1568, DOI: https://doi.org/10.1190/1.1836829

3. Naghizadeh M., Sacchi M.D., On sampling functions and Fourier reconstruction methods, Geophysics, 2010, V. 75, pp. 137–151, DOI: https://doi.org/10.1190/1.3503577

4. Cabrera S.D., Parks T.W., Extrapolation and spectrum estimation with iterative weighted norm modification, IEEE Trans-actions in Signal Processing, 1991, V. 39, pp. 842–850, DOI: https://doi.org/10.1109/78.80906

The article provides the findings of studying the physical properties of formation fluids at oil fields under high pressure drawdown due to the extraction of separated gas from the wellbore annulus. The porous media were prepared using the centrifugation method because of its greater accuracy and less labor intensity compared to capillary impregnation or semi-permeable membrane methods. Creating a recombined (gas-saturated) sample of reservoir oil and its gradual degassing made it possible to determine the degree of reduction in oil viscosity and density. Every sample of partially degassed oil was examined within the monophase domain in the range of pressures: oil saturation pressure of that stage - reservoir pressure. As the pressure decreases, the density and viscosity of the monophase oil decrease. By comparing the values of density and viscosity at saturation pressures of each partially degassed reservoir oil sample, it has been established that during gas release the density and viscosity of oil increase with each stage, the density increases by 0.7%, the viscosity - by 23%. The dissolution of gas does not produce a significant (multiple) reduction in the density and viscosity of the sample. This is due to the fact that the degassed oil is originally bituminous (the density is above 895 kg/m3) with low gas content and saturation pressure. It has been discovered in the course of the research that at some values of permeability (less than 2·10-3 μm2) the oil relative permeability connate water saturation is equal to the kerosene relative phase permeability under connate water saturation (within a measurement error of 5%). This effect is attributed to the pseudoplastic behavior of oil. The final results of phase permeability measurements for both oil and kerosene, given the measurement error of 5%, have no effect on further calculations. Decreasing the bottomhole pressure at low GOR (up to 40 m3/t) does not affect oil relative permeability; that is why application of the sets of equipment for gas extraction from wellbore annulus (KOGS) causes no damage to the reservoir fluid inflow to a well's bottomhole.

References

1. Isaev A.A., Takhautdinov R.Sh., Malykhin V.I., Sharifullin A.A., Oil production stimulation by creating a vacuum in the annular space of the well, SPE-198401-MS, 2019,

DOI: https://doi.org/10.2118/198401-MS

2. Isaev A.A., Malykhin V.I., Sharifullin A.A., Feasibility evaluation of vacuum presence in a well annulus (In Russ.), Neftepromyslovoe delo, 2020, no. 1, pp. 60–64,

DOI: https://doi.org/10.30713/0207-2351-2020-1(613)-60-64.

3. Isaev A.A., Takhautdinov R.Sh., Malykhin V.I., Sharifullin A.A., Development of the automated system for gas extraction from wells (In Russ.), Neft'. Gaz. Novatsii, 2017, no. 12, pp. 65–72.

4. Isaev A.A., Takhautdinov R.Sh., Malykhin V.I., Sharifullin A.A., Gas removal efficiency from a well (In Russ.), Georesursy = Georesources, 2018, no. 20(4), Part 1,

pp. 359–364, DOI: https://doi.org/10.18599/grs.2018.4.359-364

5. Isaev A.A., Malykhin V.I., Sharifullin A.A., Investigation of the oil physical properties and the main indicators of well operation when creating vacuum in a well annulus (In Russ.), Neftepromyslovoe delo, 2019, no. 5, pp. 46–52, DOI: https://doi.org/10.30713/0207-2351-2019-5(605)-46-52

6. Takhautdinov R.Sh., Isaev A.A., Malykhin V.I., Sharifullin A.A., Developing KOGS-1M set of equipment for pumping associated petroleum gas from the annulus of a well (In Russ.), Burenie i neft', 2021, no. 9, pp. 9–13.

7. Bulatov A.I., Savenok O.V., Yaremiychuk R.S., Nauchnye osnovy i praktika osvoeniya neftyanykh i gazovykh skvazhin (Scientific foundations and practice of oil and gas well development), Krasnodar: Yug Publ., 2016, 576 s.

8. Brekhuntsov A.M., Historical development of West Siberian petroleum province and hydrocarbon resources replacement issues at the present stage (In Russ.), Geologiya i mineral'no-syr'evye resursy Sibiri, 2010, no. 3, pp. 20-25.9. Isaev A.A., Takhautdinov R.Sh., Malykhin V.I., Sharifullin A.A., Measurement of free and dissolved gas in oil in conditions of formation water presence in a well production (In Russ.), Neftepromyslovoe delo, 2018, no. 12, pp. 59–63, DOI: https://doi.org/10.30713/0207-2351-2018-12-59-63.

10. 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.

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

12. Cannella W.J., Huh C., Seright R.S., Prediction of xanthan rheology in porous media, SPE-18089-MS, 1988, DOI: https://doi.org/10.2118/18089-MS

The article describes an approach to the study of the effect of low-volume chemical enhanced oil recovery (EOR) methods using the control group method on the example of the Vankorskoye oil-gas-condensate field. The study involved comparing the performance indicators of the producing wells in the waterflooding blocks that had their injection wells treated with cross-linked polymer compounds and the performance indicators of wells in neighboring waterflooding blocks with similar properties that did not have their injection wells subjected to such treatments. The study has been motivated by the general features of the low-volume chemical EOR methods: they have an effect that is small relative to the flow rates of the reactive wells; this effect is not bound to the wells treated; and the effect manifests itself gradually over a sufficiently long time. These features lead to the possibility of a systematic error significant in the scale of the effect of the low-volume chemical EOR methods when assessing said effect by predicting watercut using standard displacement characteristics for a specific reservoir. The choice of the control group method in addition to the means of instrumental control and assessment by displacement characteristics has been necessitated by the relative simplicity of this approach, as well as the possibility of its application without additional costs, using already available field data. Through the application of this method, the real effect of the low-volume chemical EOR method for the Vankorskoye field has been verified. The absence of a significant systematic error in the forecast of watercut for the displacement characteristics used in the methodology adopted by Rosneft Oil Company has been confirmed. As a result, it became possible to proceed with the full-scale implementation of the low-volume chemical EOR method throughout the Vankorskoye field.

References

1. Mazhnik V.I., Leshkovich N.M., Analysis of the current state of development of the Vankorskoye oil-gas-condensate field (In Russ.), Nauka. Tekhnika. Tekhnologii = Science. Engineering. Technology, 2018, no. 4, pp. 72–98.

2. Zemtsov Yu.V., Mazaev V.V., Sovremennoe sostoyanie fiziko-khimicheskikh metodov uvelicheniya nefteotdachi: literaturno-patentnyy obzor (The current state of physical and chemical methods for enhanced oil recovery: literature and patent review), Ekaterinburg: Izdatel'skie resheniya Publ., 2021, 240 p.

3. Ismagilov T.A., Ganiev I.M., Sorokin A.V. et al., Effective use of gel-polymer compositions in horizontal wells of the Vankorskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 12, pp. 117–121, DOI: https://doi.org/10.24887/0028-2448-2017-12-117-121

4. Morozovskiy N., Kanevskaya R., Yulmukhametov D. et al., Verification technique of technical efficiency of physical-chemical EOR (In Russ.), SPE-191573-18RPTC-MS, 2018, DOI: https://doi.org/10.2118/191573-18RPTC-MS

The reservoir heterogeneity in terms of permeability and availability of high-water-cut wells in the Botuobinsky horizon within the Eastern Siberia fields determines the need for introducing conformance control by creating seals and barriers to the injected water in the flushed zones of the formation. The Eastern Siberia reservoirs are generally characterized by low reservoir temperatures and high salinities of formation water. The paper describes the results of laboratory studies of cross-linked polymer systems in low-temperature formations (12 C) with high salininy of formation water (up to 400 g/l). It also presents the technologies based on high-molecular polymers of partially hydrolyzed acrylamide with chromium-salts-based crosslinking agents. Laboratory tests and simulations have confirmed the performance of polymer-based conformance control technologies for the Bt reservoir of Srednebotuobinskoye field. The polyacrylamide (PAA) brands available on the domestic market dissolve in 140 g/l formation water, and, as part of solutions with chromium acetate, form strong structured gels at low reservoir temperatures. At reservoir temperatures of 10-12 C, the gelling time increases up to 3-4 days. The rheological parameters of cross-linked gels at low temperatures are comparable to the strength of gels which are structured at elevated temperatures. Structured PAA gels under the influence of high-salinity water are not subject to destructive changes at low reservoir temperatures. The highly permeable cores of the Botuobinsky horizon were used in physical modeling units and allowed to demonstarte the ability to create high water flow resistances using cross-linked polymer systems. The results of rheological tests and flow experiments allow to recommend cross-linked polymers for injection into the Botuobinsky horizon rocks. A pilot program has been developed, candidate wells have been selected for technology testing, the volume of polymer slug and the well shut-in period required for structuring have been determined, and incremental oil production has been estimated.

References

1. Akulov N.I., Vallev R.R., Peculiarities of the Srednebotuobinsk oil-and-gas deposit geological structure (In Russ.), Izvestiya Irkutskogo gosudarstvennogo universiteta. Seriya: Nauki o Zemle, 2016, V. 18, pp. 3–13.

2. Kobyashev A.V., Mandrugin A.V., Valeev R.R. et al., Analysis of injection wells operation at Srednebotuobinskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 6, pp. 59–61, DOI: https://doi.org/10.24887/0028-2448-2019-6-59-61

3. Shilov A.V., The results of the pilot development of the oil deposit of the Botuobinsky horizon of the Srednebotuobinsky oil and gas condensate field (In Russ.), Geologiya, geofizika i razrabotka neftyanykh i gazovykh mestorozhdeniy, 2005, no. 7, pp. 55–61.

4. Guidelines for PJSC Rosneft Oil Company No. P1-01.03 M-0089 version 1.00 “Kriterii primenimosti metodov uvelicheniya nefteotdachi dlya obosnovaniya opytno-promyshlennykh rabot na mestorozhdeniyakh Kompanii” (Criteria for applicability of enhanced oil recovery methods to justify pilot work at the Company's fields), Moscow: Rosneft, 2019, 43 p.

5. Cherepanova N.A., Sovershenstvovanie potokootklonyayushchikh tekhnologiy uvelicheniya nefteotdachi terrigennykh kollektorov (Improvement of flow-diverting technologies for enhanced oil recovery in terrigenous reservoirs): thesis of candidate of technical science, Ufa, 2008.

6. Zemtsov Yu.V., Mazaev V.V., Sovremennoe sostoyanie fiziko-khimicheskikh metodov uvelicheniya nefteotdachi: literaturno-patentnyy obzor (The current state of physical and chemical methods for enhanced oil recovery: literature and patent review), Ekaterinburg: Izdatel'skie resheniya Publ., 2021, 240 p.

7. Tagirov K.D., Lytkin A.E., Popovich M.I., Morozovskiy N.A., Experience in applying physical and chemical EOR methods at the examples of "Samotlorneftegas" JSC fields. Results and development prospects (In Russ.), Neft'. Gaz. Novatsii, 2021, no. 7, pp. 72–77.

8. Khalin V.V., Mazitov R.F., Mal'shakov E.N. et al., Practical experience in applying flow-diverting procedures for enhanced oil recovery (In Russ.), Neft'. Gaz. Novatsii, 2022, no. 8, pp. 60–67.

9. Kelland M.A., Production chemicals for the oil and gas industry, CRC Press, Taylor & Francis Group, 2014. XVIII, 412 p.

10. Manyrin V.N., Shvetsov I.A., Fiziko-khimicheskie metody uvelicheniya nefteotdachi pri zavodnenii (Physical and chemical methods of enhanced oil recovery for water flooding), Samara: Rosing Publ., 2002, 392 p.

11. Telin A.G., Khlebnikova M.E., Singizova V.Kh. et al., Regulation of rheological and filtration properties of cross-linked polymer systems in order to increase the efficiency of reservoir stimulation (In Russ.), Vestnik Inzhiniringovogo Tsentra YuKOS, 2002, no. 4, pp. 41–45.

12. Putilov I.S., Barkovskiy N.N., Yakimenko O.I. et al., Integrated approach to laboratory studies of chemical agents for waterflood sweep efficiency control technology (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2017, no. 4, pp. 72–75.

13. Gaysin A.Sh., Musin R.A., Khokhlov D.I. et al., The testing of flow diverting compositions in conditions of VCNG PJSC fields (In Russ.), Nauchno-tekhnicheskiy vestnik OAO “NK “Rosneft'”, 2016, no. 4, pp. 64–68.

Deposits of Eastern Siberia characterized by a complex geological structure as well as cavity-fractured reservoir in Riphean dolomite deposits. The uniqueness is caused by high anisotropy of permeability, absence of permeability of rock matrix, ultra-low porosity of formation (1-2%), abundance of tectonic disturbances, subvertical fracturing. These special aspects create significant difficulties in assessment of residual reserves and saturation nature when selecting wells-candidates for wellwork operations. The absence of reliable methods for forecasting distribution of poroperm properties in interwell space and impossibility of the definition of the carbonate reservoir saturation with porosity less than 2% lead to the high risks of unprofitability of the activities. The article summarizes the accumulated experience of geological and technological measures implementation at the wells of the Kuyumbinskoye oil-gas-condensate field. The main method of improved oil recovery for carbonate reservoir is treatment by compositions on the basis of hydrochloric acid, including the use of diverters due to the specific distribution of permeability. Besides acid treatment methods, additional reservoir perforation is used as a tool to increase the coverage. New for this reservoir is the method of limiting water inflow by lowering liners with sleeves to enable bridging of water / gas breakthrough intervals during operation. In 2022, work began on testing multistage hydraulic fracturing technology. The uniqueness of such works lies in the properties of the rock matrix - it is impermeable and has almost zero porosity (0.5-0.7%). Under such conditions, multistage hydraulic fracturing has not been performed in the Russian Federation. Pilot work is scheduled to be completed in 2023. The tested and potentially effective technologies mentioned in the article have been reworked and adapted to the geological conditions of the field.

References

1. Bagrintseva K.I., Krasil’nikova N.B., Sautkin R.S., Formation conditions and properties of the Riphean carbonaceous reservoirs of the Yurubcheno-Tokhomsk deposit (In Russ.), Geologiya nefti i gaza, 2015, no. 1, pp. 24–40.

2. Kutukova N.M., Birun E.M., Malakhov R.A. et al., The conceptual model of Riphean carbonate reservoir in Yurubcheno-Tokhomskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2012, no. 11, pp. 4-7.

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

4. Kruglov R.V., Yarkeeva N.R., Kruglova Z.M., Analysis of well intervensions carried out at PJSC «Bashneft» (In Russ.), Neftegazovoe delo, 2016, no. 6, pp. 81-101. -http://ogbus.ru/files/ogbus/issues/6_2016/ogbus_6_2016_p81-101_KruglovRV_ru.pdf

5. Babayan E.V., Shurygin M.N., Yakovenko V.N., Improving the efficiency of choosing a working agent for treating the bottomhole formation zone (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 1999, no. 3, pp. 30–32.

6. Wu X.J., Water plugging and acidizing combination technology on fractured water breakthrough oil well in low permeability reservoirs, Advances in Petroleum Exploration and Development, 2016, V. 11, no. 1, pp. 24–29, DOI: http://dx.doi.org/10.3968/7959

7. Svetashov V.N., Frolov S.A., Vodorezov D.D., On application of reusable inflatable packers (In Russ.), Izvestiya vysshikh uchebnykh zavedeniy. Neft' i gaz = Oil and Gas Studies, 2017, no. 1, pp. 83-87, DOI: https://doi.org/10.31660/0445-0108-2017-1-83-87

The article considers the main approaches to the choice of water and gas flow restriction technologies in horizontal wells of the Kuyumbinskoye oil-gas-condensate field. Characteristics of carbonate Riphean reservoir is given, relevance of water and gas flow limitation in all intervals of horizontal wellbore – «heel», «middle» and «toe» is noted. Taking into account and using the field experience in applying technologies with similar conditions, the main types of insulating compositions with the potential to limit the inflow of water and gas in carbonate reservoirs, including polymer compositions, organosilicon compositions and high-viscosity emulsions, are considered. The results of laboratory studies of three brands of gel-forming compositions capable of forming extended insulating screens with a different mechanism of formation of the insulating mass (two compositions based on organosilicon compounds and one composition based on cross-linked polyacrylamide with the addition of reinforcing components) are presented. Filtration studies used fracture models of different openness – from 50 to 650 μm. The results of the studies show that all studied compositions are technologically simple to prepare and are able to form an insulating mass for blocking water and gas inflow. In order to apply under field conditions the technology of water shutoff by means of controlled injection of plugging compound into the target interval of the drilled hole, the organosilicon compound with the highest values of residual resistance factors both for water and gas was chosen. A two-packer arrangement with an injection port in the inter-packer space was used for injection. After the work was done, a significant decrease in fluid flow rate was observed.

References

1. Vakhrushev S.A., Litvinenko K.V., Folomeev A.E. et al., Testing of new technologies for bottom-hole treatment and water shutoff jobs in Rosneft Oil Company (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 6, pp. 31-37, DOI: https://doi.org/10.24887/0028-2448-2022-6-31-37

2. Mukhametov F.Kh., Nigmatullin T.E., Nikulin V.Yu. et al., Razrabotka dizayna RIR dlya ogranicheniya pritoka vody i gaza v gorizontal'nykh skvazhinakh Kuyumbinskogo mestorozhdeniya, ekspluatiruyushchikh karbonatnye kollektory (Development of a design for repair and isolation works to limit the inflow of water and gas in horizontal wells of the Kuyumbinskoye field operating carbonate reservoirs), Collected papers “Dobycha i transport nefti i gaza. Novye tekhnologii i resheniya” (Production and transportation of oil and gas. New technologies and solutions), Proceedings of scientific and technical conference, Ufa, 19–20 October 2022, Ufa: Publ. of RN-BashNIPIneft', 2022, pp. 17–18.

3. Litvinenko K.V., Valiakhmetov R.I., Integrated engineering services as a factor in improving the efficiency of oil production (In Russ.), Inzhenernaya praktika, 2021, no. 7, pp. 60–69.

4. Nikulin V.Yu., Nigmatullin T.E., Mikhaylov A.G. et al., Selection of insulation compositions and technologies for horizontal wells under difficult conditions (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2021, no.10, pp. 96–101, DOI: https://doi.org/10.24887/0028-2448-2021-10-96-101

5. Nigmatullin T.E., Nikulin V.Y., Shaymardanov A.R. et al., Water-and-gas shutoff technologies in horizontal wells on North Komsomolskoe field: Screening and successful trial (In Russ.), SPE-206496-MS, 2021, DOI: https://doi.org/10.2118/206496-ms

6. Mukminov R.R., Nigmatullin T.E., Edinyy podkhod k laboratornomu testirovaniyu khimreagentov kak zalog uspeshnogo provedeniya remontno-ikholyatsionnykh rabot (A unified approach to laboratory testing of chemicals as a guarantee of successful repair and cooling work), Collected papers “Prakticheskie aspekty neftepromyslovoy khimii” (Practical aspects of oilfield chemistry), Proceedings of scientific and technical conference, Ufa, 23–25 May 2023, Ufa: Publ. of RN-BashNIPIneft', 2023, pp. 122–125.

7. Presnyakov A.Yu., Lomakina I.Yu., Nigmatullin T.E. et al., An integrated approach to the selection of technologies for controlling water and gas inflow under the conditions of Yurubcheno-Tokhomskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 6, pp. 94–98.

8. Nikulin V.Yu., Shaymardanov A.R., Mukminov R.R. et al., Justification of technologies to control fluid loss during remedial cementing in the fields of RN-Purneftegas LLC (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 10, pp. 48–54, DOI: https://doi.org/10.24887/0028-2448-2022-10-48-54

9. Grebenyuk A.N., Kurshev A.V., Korytko I.A. et al., Substantiation of effective well killing technologies in fractured carbonate reservoirs of Eastern Siberia (In Russ.), Inzhenernaya praktika, 2023, no. 3, pp. 16-22.

The formation of organic deposits as paraffins and asphaltenes on the rock and equipment surface leads to a deterioration of reservoir properties of formation, complications in the operation of downhole pumping equipment and, as a result, a decrease of oil production. In this regard, it is an important task to develop reliable approaches and tools for predicting of forming of these depositions. These approaches are implemented by phase diagrams construction taking into account wells thermobaric conditions and oil treatment facilities or thermodynamic models which based on equations of state using experimental data for tuning. For the successful application of both approaches, it is extremely important to develop reliable methods of experimental investigations of the phase behavior of paraffin in reservoir fluids samples.

The article considers the possibilities of application of experimental methods for reservoir oil phase behavior studying to identificate thermobaric conditions characterized by an increased risk of paraffin deposition. The saturation pressure and the wax appearance temperature of oil under study were determined experimentally, depending on thermobaric conditions. Investigation of the conditions of the solid paraffin phase deposition was carried out by recording the amount of formed solid particles from temperature at a fixed pressure using a high-pressure microscope. Based on the results obtained, the authors constructed a phase diagram combined with thermobarimetric measurements in the well, depending on its depth. The areas of increased risk of complications in the studied well were assessed. The proposed approach can be used in the economic and technological justification of the applied methods for the prevention and removal of paraffin deposits in the fields.

References

1. Ivanova L.V., Burov E.A., Koshelev V.N., Asphaltene-resin-paraffin deposits in the processes of oil production, transportation and storage (In Russ.), Neftegazovoe delo = Oil and Gas Business , 2011, no. 1, pp. 268–284, URL: http://ogbus.ru/authors/IvanovaLV/IvanovaLV_1.pdf

2. Tronov V.P., Mekhanizm obrazovaniya smolo-parafinovykh otlozheniy i bor’ba s nimi (Mechanism of formation of resin-paraffin deposits and its control), Moscow: Nedra Publ., 1969, 192 p.

3. Ahmed T., Equations of state and PVT analysis, Houston: Gulf Publishing Company, 2007, 562 p.

4. Zuo J.Y., Zhang D., Wax formation from synthetic oil systems and reservoir fluids, Energy & Fuels, 2008, V. 22, no. 4, pp. 2390–2395,

DOI: https://doi.org/10.1021/ef800056d

5. Lobanov A.A., Pustova E.Yu., Zolotukhin A.B., Wax phase behavior in reservoir hydrocarbon fluids (In Russ.), Vestnik Severnogo (Arkticheskogo) federal’nogo universiteta. Seriya: Estestvennye nauki = Arctic Environmental Research, 2016, no. 4, pp. 75–83, DOI: https://doi.org/10.17238/issn2227-6572.2016.4.75

6. Iksanov I.M., Voloshin A.I., Ragulin V.V., Telin A.G., Physical modeling of the phase state of paraffin wax in a porous medium and in the free volume under temperature and pressure changing (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2011, no. 6, pp. 18-21.

The article summarizes the results of the welltest and field data results which have proved spontaneous fracture growth in injection wells. Numerous experiments show induced fractures merging in linear development system. The cases of the hydrodynamic connection identification between the injection wells are given. Tracer analysis results obtained in the linear development system are presented. The injection well blowing allows to include it in the researching program as the control well and to take well production samples for studying. In the result of the tracer analysis there were no fixed tracers in the well production samples. 3D modeling of virtual tracer filtration was done to identify the reasons of tracer absence in well production samples. Modeling was implemented for several variants. In the first one virtual tracer propagation was considered in case of the actual mass injection. Hence, increase mass cases also were considered. Besides, modeling was done for porous medium bridge between fractured injection wells changes. It is shown that the tracer delivery in a row of injection wells in liner development system depends on injected tracer mass and distance porous medium bridge between fractured injection wells. It is advisable to plan and interpret tracer studies using a reservoir simulator at fields with fractured production wells and induced fractured injection wells.

References

1. 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.

2. Tulenkov S.V., Shirokov A.S., Grandov D.V. et al., Determination of bottomhole excess pressure limits for preventing formation fracturing and propagation fractur in NH-I formation of Suzunskoye field (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2020, no. 8, pp. 42–46, DOI: https://doi.org/10.24887/0028-2448-2020-8-42-46

3. Syundyukov A.V., Khabibullin G.I., Trofimchuk A.S., Sagitov D.K., A method for maintaining the optimal geometry of induced fracture by regulating the injection mode on low-permeability reservoirs (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 9, pp. 96–99, DOI: https://doi.org/10.24887/0028-2448-2022-9-96-99

4. Kalinin S.A., Baykin A.N., Abdullin R.F. et al., Modeling and analysis of hydraulic fractures coalescence during waterflooding in a direct line drive pattern (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2022, no. 12, pp. 40–45, DOI: https://doi.org/10.24887/0028-2448-2022-12-40-45

5. Gubaydullin M.R., Davletbaev A.Ya., Shtinov V.A. et al., Numerical study of spontaneous development of autohf crack in injection well (In Russ.), Vestnik Akademii nauk RB, 2022, V. 45, no. 4 (108), pp. 47–59, DOI: https://doi.org/10.24412/1728-5283-2022-4-47-59

6. Asalkhuzina G.F., Davletbaev A.Ya., Abdullin R.I. et al., Welltesting for a linear development system in low permeability formation (In Russ.), Neftegazovoe delo, 2021, V. 19, no. 3, pp. 49–58, DOI: https://doi.org/10.17122/ngdelo-2021-3-49-58

7. Asalkhuzina G.F., Davletbaev A.Ya., Kuzin I.G. et al., Issledovanie raznosti davleniy mezhdu nagnetatel'nymi skvazhinami s treshchinoy gidrorazryva v ryadnoy sisteme razrabotki (In Russ.), Neftegazovoe delo, 2021, V. 19, no. 5, pp. 43–52, DOI: https://doi.org/10.17122/ngdelo-2021-5-43-52

8. Izotov A.A., Afonin D.G., The mechanism of the indicator propagation in a terrigenous formation during tracer studies (In Russ.), Ekspozitsiya Neft' Gaz, 2021, no. 5, pp. 31–34, DOI: https://doi.org/10.24412/2076-6785-2021-5-31-34

9. Mirzayanov A.A., Asalkhuzina G.F., Pityuk Yu.A. et al., Matrixes of applicability of tracer research on the example of the element of nine-point development system with hydraulic fracturing (In Russ.), Neftegazovoe delo, 2021, V. 19, no. 4, pp. 41–49, DOI: https://doi.org/10.17122/ngdelo-2021-4-41-49

10. Badykov I.Kh., Baykov V.A., Borshchuk O.S., The software package "RN-KIM" as a tool for hydrodynamic modeling of hydrocarbon deposits (In Russ.), Nedropol'zovanie XXI vek, 2015, no. 4, pp. 96–103.

11. Davletbaev A.Ya., Nuriev R.I., Simulation of interference interference in wells with vertical technogenic main hydraulic fractures (In Russ.), Proceedings of the Mavlyutov Institute of Mechanics = Multiphase Systems, 2012, V. 9, no. 2, pp. 43-46.

Cost-effective wells operations in tight reservoirs require the introduction of innovative approaches, including advancements in hydraulic fracturing technology. The standard hydraulic fracturing fluid (cross-linked borate gel on a guar basis) is characterized by high viscosity and low residual conductivity of the fracture. Alternative low–viscosity hydraulic fracturing fluids based on a synthetic polymer - polyacrylamide (PAA), used in low-permeable reservoirs, require studying their effect not only on the proppant pack, but also on the filtration properties of the formation.

In the laboratory of RN-BashNIPIneft LLC, tests were carried out for the regained conductivity of the proppant pack and the regained core permeability for various hydraulic fracturing fluids. Cross-linked gel, linear gel and synthetic hydraulic fracturing fluid were provided to Kondaneft Oil Company JSC by three service companies. Recommended formulations were tested, and the possibilities of increasing the cleaning degree of a proppant pack or core sample from hydraulic fracturing fluid were considered. According to tests results the least colmatating fluid was a synthetic liquid based on polyacrylamide. A cross-linked gel based is characterized by low values of residual conductivity and showed a low permeability recovery potential (32-53%). The injection of uncapsulated breaker before the cross-linked gel allowed to increase the coefficient of permeability recovery from 53 to 75%. In comparison linear gel slightly exceeds the indicators of restoring the permeability of the core sample (54-64%). For synthetic hydraulic fracturing fluid based on PAA, according to recommended formulations from service companies with high concentrations of polymer and low concentration of the breaker, a recovery of residual core permeability comparable to cross-linked and linear gels (38-59%) was obtained. With the modification of the formulation (the reduction of polymer loading and the use of a high concentration of non-encapsulated breaker) the residual permeability was improved from 59 to 86%. The conclusion was made that a decrease in the polymer concentration and an increase in the concentration of the uncapsulated breaker for standard and synthetic hydraulic fracturing fluids should contribute to a minimal impact on the permeability of the rock. In laboratory conditions low-viscosity hydraulic fracturing fluids showed a high cleaning degree of the proppant pack and rock sample compared to standard hydraulic fracturing fluid.

References

1. The US shale revolution has reshaped the energy landscape at home and abroad, according to latest IEA policy review, URL: https://www.iea.org/news/the-us-shale-revolution-has-reshaped-the-energy-landscape-at-home-and-abroa...

2. Kazakov E., Fayzullin I., Sheremeev A. et al., Unconventional approach for fracturing stimulation in conventional low-permeability formation by the example of experimental part South Priobskoe field (In Russ.), SPE-196964-RU, 2020, DOI: https://doi.org/10.2118/196964-MS

3. Fayzullin I.G., Metelkin D.V., Berezovskiy Yu.S. et al., An up-to-date approach to the integration of engineering solutions for stimulation of low-permeable reservoirs of the Achimov thickness (In Russ.), SPE-202053-RU, 2020, DOI: https://doi.org/10.2118/202053-MS

4. Cadykov A.M., Kapishev D.Yu., Erastov S.A. et al., Innovative hydraulic fracturing designs and recommendations for putting wells into production in conditions of ultra-low-permeability reservoirs on the example of the Erginsky license block of the Priobskoye field (In Russ.), Ekspozitsiya Neft' Gaz, 2022, no. 7, pp. 80–85. DOI: https://doi.org/10.24412/2076-6785-2022-7-80-85

5. Weijers L., Wright C., Mayerhofer M. et al., Trends in the North American frac industry: Invention through the shale revolution, SPE-194345-MS, 2019, DOI: https://doi.org/10.2118/194345-MS

6. Warpinski N., Mayerhofer M., Vincent M. et al., Stimulating unconventional reservoirs: maximizing network growth while optimizing fracture conductivity, SPE-114173-MS, 2008, DOI: https://doi.org/10.2118/114173-MS

7. Warpinski N., Kramm R., Heinze J., Waltman C., Comparison of single- and dual-array microseismic mapping techniques in the Barnett shale, SPE-95568-MS, 2005, DOI: https://doi.org/10.2118/95568-MS

8. Dahlgren K., Green B., Williams B. et al., Case studies of high viscosity friction reducers HVFR in the STACK play, SPE-189893-MS, 2018, DOI: https://doi.org/0.2118/189893-MS

9. Loginov A., Pavlova S., Olennikova O. et al., Introduction of novel alternative to guar-based fracturing fluid for Russian conventional reservoirs (In Russ.), SPE-196971-RU, 2018, DOI: https://doi.org/10.2118/196971-MS

10. Latypov I.D., Makatrov A.K., Kuznetsov A.M., Sitdikov S.S. et al., Filtration parameters calculation in the design of hydraulic fracturing (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2014, no. 11, pp. 70–72.

11. Sadykov A.M., Erastov S.A., Fedorov A.E. et al., Experience and prospects for the use of low-viscosity fluids during hydraulic fracturing in zones with poor reservoir quality and vicinity of water-oil contact (In Russ.), Ekspozitsiya Neft' Gaz, 2022, no. 7, pp. 72–77. DOI: https://doi.org/10.24412/2076-6785-2022-7-72-77

The article covers the record of dual completion application in Vietsovpetro JV wells including the specifics of the developed areas (GOR, gas condensate content, reservoir pressures and temperatures, composition of produced and injected fluids, presence of aggressive impurities, sand, paraffins, mineral salts and etc.). It also describes the main types and amount of dual completion systems applied from 2014 to the present day, functional capabilities of the equipment, and standard design of dual completion systems deployed in Vietsovpetro JV. The article comprises the analysis of dual completion efficiency and main geological factors which complicate the dual production. Dual completion allows: enhance oil recovery and existing production rates by developing the low permeability zones and layers; increase sweep efficiency and intensity of multilayered fields development by selective inclusion of separate layers with various permeability; greatly reduce the capital expenditures on well construction (particularly true to offshore fields); optimize sampling and injection by well log; prolong the commercial time of field development and operation; control over oil production from each zone and agent injection to every layer, etc. The paper includes the main application criteria and requirements to equipping the dual completion systems for Vietsovpetro JV fields; brief statistics of failure rates while adjusting the assemblies equipped with dual completion systems by wireline techniques, as well as during workovers for retrieving the downhole equipment with dual completions. The article covers the main complicating factors which lead to inefficient operation of the downhole equipment with dual completion systems, analysis of lessons-learned, main problems and applied solutions, as well as potential lines of approach for complications which may occur during operation of wells equipped with dual completion systems. The authors designate the perspectives for improving the dual completion systems for Vietsovpetro fields, considering adaptation to subsurface conditions, search and pilot tests of new systems, including lower completions and stepwise transition to intellectualization.

The article deals with the problem of the lack of information on the actual technical condition of production strings and the possible risks of complications arising during the operation of producing wells. The methods for determining the integrity damage of the production string during field geophysical surveys are described. Conditions are given under which a standard set of well logging is ineffective for detecting leaks in a well during routine repairs. A special well logging method is considered. This method makes is possible to study the size and geometric shape of the formed leak. Based on an actual example, the nature of the production string damage and its possible causes are analyzed. As one of the main factors that influenced the occurrence of complications in the well, the possible formation of corrosive deposits in the interval of the electric submersible pump is considered.

It has been suggested that deposits on the inner wall of the production string were formed due to metal corrosion during production of aggressive fluid of Jurassic deposits. The results of geophysical studies aimed at determining the degree of corrosion of the production string, including the allocation of the interval of its greatest development, are presented. The assumption about the cause of intense corrosion of production strings is indirectly confirmed by information on the degree of operating time of downhole equipment before its wear and other data. Measures are proposed to study considered problem in order to obtain reliable information on corrosion processes in production strings and the aggressiveness of fluids produced from Jurassic deposits. Increasing the degree of knowledge on the problem will make it possible to take timely optimal decisions that prolong the operation of the well.

The article presents the results of work on identification of the causes of through metal fracture of casing pipe and well completion elements during mechanized oil production at the Vankorskoe oil field. According to the results of scanning electron microscopy and X-ray phase analysis of metal samples and corrosion products from the surface of casing pipe it is established that the corrosion process is of carbon dioxide nature, the through fractures initially occurred due to corrosion of the inner surface of the pipe. Behavior of mechanical impurities carried by well products (transport, accumulation along the well profile) at different flow rates was evaluated in a dynamic multiphase flow simulator. For this purpose, a model of the wellbore section in the interval «intake of ESP system - upper part of the liner – bottomhole» was built and a parametric study of the well operation with the change of flow rate was carried out. Hydrodynamic modeling of multiphase flow with transport of mechanical impurities showed that at flow velocities less than 0.2 m/s there is an accumulation and transport of sand along the lower component of the pipe in horizontal and directional wells, which increases the probability of corrosion-erosion wear by the mechanism of rill and subsurface corrosion. Comparison of sand transport modeling data with the data of intra-pipe flaw detection (magnetic introscopy) showed that the nature and localization of casing pipe damage directly depend on the amount of accumulated sand at the site. Solution of the problem of rill and subsurface carbon dioxide corrosion of casing by increasing the flow rate requires a balanced approach. Increasing the flow rate implies the use of a high-capacity submersible electrical motor, which in its turn leads to acceleration of electrochemical erosion-corrosion due to the growth of vibration loads, the influence of stray currents, high flow rate with mechanical impurities between the submersible electrical motor and the wall of casing pipe. The results of the conducted research allow to reasonably approach the definition of a set of measures aimed at the selection of technologies and materials for protection of casing pipe from corrosion-erosion wear.

References

1. Dolgikh S.A., Tkacheva V.E., Shakirov F.Sh. et al., Katodnaya zashchita obsadnykh kolonn neftyanykh skvazhin (Cathodic protection of oil well casings), Kazan: Publ. of KNRTU, 2018. – 200 p.

2. Gnedenko B.V., Belyaev Yu.K., Solov'ev A.D., Matematicheskie metody v teorii nadezhnosti (Mathematical methods in reliability theory), Moscow: Nauka Publ., 1965, 524 p.  

3. Atlas of Eh-pH diagrams. Intercomparison of thermodynamic databases, National Institute of Advanced Industrial Science and Technology. Geological survey of Japan open file report no. 419, 2005, P. 287, URL: https://www.eosremediation.com/download/Chemistry/Chemical%20Properties/Eh_pH_Diagrams.pdf

4. Zav’yalov V.V., Problemy ekspluatatsionnoy nadezhnosti truboprovodov na pozdney stadia razrabotki mestorozhdeniy (Pipelines operating reliability problems in the late stages of field development), Moscow: Publ. of VNIIOENG, 2005, 332 p.

5. Schmitt G., Horsremeier M., Fundamental aspects of CO2 metal loss corrosion. Part II: influence of different parameters on CO2 corrosion mechanisms, 2006, NACE.

6. NORSOK Standard, M-506, “CO₂ corrosion rate calculation model”, Rev. 2, June 2005.

7. Sajeev S.K., McLaury B.S., Shirazi S.A. Experiments and modelling of critical transport velocity of threshold (very low) particle concentration in single-phase and multiphase flows, Tulsa University Sand Management Projects (TUSMP), The University of Tulsa, BHR Group MPT, 2019, pp. 513 – 532.

8. Gamolin O.E., Litvinenko K.V., Nigmatullin T.E., Akhmerov R.I., Bench testing of steels of production casing and well equipment under the conditions of corrosion and erosion effects of the flow of well productions (In Russ.), Neft'. Gaz. Novatsii, 2022, no. 8, pp. 102–106.

9. Daminov A.A., Corrosion damage to underground equipment of production wells in the fields of the West Siberian region. Study of the causes of corrosion, development and application of measures to reduce the impact of corrosion (In Russ.), Inzhenernaya praktika, 2010, no. 6, pp. 26–36.

10. Tyapov O.A., Mikhaylov A.G., Mezikov S.E., Presnyakov A.Yu., Integrated technologies for the repair and protection of columns in the wells of the Barsukovsky field (In Russ.), Neft'. Gaz. Novatsii, 2009, no. 5–6, pp. 108–112.

The article outlines the problem of long-term calculation of basin models, which remains relevant for many years of the technology existence. Information is provided on the theoretically possible increase in the performance of model calculation due to the use of parallel computing; factors that limit the achievement of a multiple increase in practice are identified. The analysis of the technical implementation of parallel computing of basin models in the PetroMod® software was carried out, its strengths and weaknesses were identified. The characteristics of the Hybrid and Combined petroleum migration modeling methods, created to reduce the total time for calculating basin models in comparison with the Darcy flow petroleum migration modeling method, are given. The key factors influencing the calculation time of basin models using different methods of petroleum migration modeling are determined. A benchmarking technique based on a set of calculations of a regional basin model consisting of more than 5,000,000 cells is described. The efficiency of parallel computing is determined depending on the number of CPU cores/threads involved in the calculation, channels and the total amount of RAM, as well as the configuration of the basin model. The increase in performance when using computers based on hardware of both the server and consumer segments is numerically estimated. Based on the benchmarking results, the main factors of high performance for all processes included in the calculation of the basin model were identified. Recommendations on the choice of hardware that allows to achieve the highest performance of basin model calculations in the PetroMod® software are given.

References

1. Baur F., Scheirer A.H., Peters K.E., Past, present, and future of basin and petroleum system modeling, AAPG Bulletin, 2018, V. 102, no. 4, pp. 549-561,

DOI: http://dx.doi.org/10.1306/08281717049

2. Hantschel T., Kauerauf A.I., Wygrala B., Finite element analysis and ray tracing modeling of petroleum migration, Marine and Petroleum Geology, 2000, V 17, pp. 815–820, DOI: https://doi.org/10.1016/S0264-8172(99)00061-6

3. Hantschel T., Kauerauf A., Fundamentals of basin and petroleum systems modeling, Berlin Heidelberg: Springer-Verlag, 2009.

4. Sutter H., The free lunch is over: A fundamental turn toward concurrency in software, Dr. Dobb’s journal, 2005, V. 30(3), pp. 202-210.

5. Amdahl G.M., Validity of a single processor approach to achieving large scale computer capabilities, Proceedings of American Federation of Information Processing Societies (AFIPS) Spring Joint Computer Conference, Atlantic City, NJ, USA, 1967, pp. 483–485, DOI: https://doi.org/10.1109/N-SSC.2007.4785615

6. Bücker H.M., Kauerauf A.I., Rasch A., A smooth transition from serial to parallel processing in the industrial petroleum system modeling package PetroMod, Computers & Geosciences, 2008, V. 34, pp. 1473-1479, DOI: http://dx.doi.org/10.1016/j.cageo.2008.01.011

7. Bogachev K., Milyutin S., Telishev A. et al., High-performance reservoir simulations on modern CPU-GPU computational platforms, ICE–2018.

8. Pegaz-Fiornet S., Carpentier B., Michel A., Wolf S., Comparison between the different approaches of secondary and tertiary hydrocarbon migration modeling in basin simulators, Basin Modeling: New Horizons in Research and Applications: AAPG Hedberg, Series, 2012, no. 4, pp. 221 – 236.

9. Patent US20140358502A1, Combined migration method for basin modeling, Inventors: Kleine A., Kauerauf A.I.

10. Baur F., Katz B., Some practical guidance for petroleum migration modeling, Marine and Petroleum Geology, 2018, V. 93, pp. 409–421,

DOI: https://doi.org/10.1016/j.marpetgeo.2018.03.003

The article is devoted to the problem of the scope of surveys to be carried out when inspecting construction sites of large-size steel tanks, which are composed of poorly bearing inhomogeneous soils. The information on tank accidents with oil product leakage and the main causes of such accidents is provided. It is shown that non-design loads caused by the process of uneven settling of the tank structure create zones of increased stresses and development of inadmissible deformations, which is the main cause of accidents at oil and oil products storage facilities. The reasons for the appearance of inhomogeneity zones are discussed. It is shown that the main cause may be erroneously planned and performed engineering surveys. The requirements of domestic and foreign regulations in terms of assigning the scope of survey works at the construction sites of large-sized vertical steel tanks have been analyzed. The geometrical approach to determination of probability of survey borehole hitting the inhomogeneity zone having a random location inside the contour of the tank was used. The generalization of previously performed calculations using the finite element method has been carried out and dependences of the acting equivalent stresses on the value of the vertical component of the non-uniform settlement of the central part of the bottom have been obtained. The dependence of the probability of getting a well (wells) into the inhomogeneity zone on the value of the radius of the zone of inhomogeneity for tanks of the most widespread standard sizes of tank is plotted. Conceptual approaches and ways to completely exclude the probability of development of local heterogeneity zones are proposed. One of them is based on application of multiview georadiotomography technology – scanning of continuous media by an antenna array with distributed receiving and transmitting high-frequency antennas of a wide range.

References

1. Chepur P.V., Napryazhenno-deformirovannoe sostoyanie rezervuara pri razvitii neravnomernykh osadok ego osnovaniya (Stress-strain state of the tank in the development of non-uniform drafts of its foundation): thesis of candidate of technical science, Moscow, 2015.

2. Tarasenko A.A., Gruchenkova A.A., Tarasenko M.A., Analysis of differences in the requirements of national regulations and USA standards in the development of the tank bottom differential subsidence (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 8, pp. 132-135.

3. Rukovodstvo po bezopasnosti vertikal'nykh tsilindricheskikh stal'nykh rezervuarov dlya nefti i nefteproduktov (Guide to the safety of vertical cylindrical steel tanks for oil and petroleum products), Moscow: Publ. of NTTs PB, 2013, 240 p.

4. Gruchenkova A.A., Napryazhenno-deformirovannoe sostoyanie rezervuarov pri lokal'noy neodnorodnosti gruntovogo osnovaniya (Stress-strain state of reservoirs with local inhomogeneity of the soil base): thesis of candidate of technical science, Tyumen, 2020.

5. Spravochnik geotekhnika. Osnovaniya, fundamenty i podzemnye sooruzheniya (Handbook of geotechnician. Subfoundation, foundations and underground structures): edited by Il'ichev V.A., Mangushev R.A., Moscow: ASV Publ., 2014, 728 p.

6. Romanov D.B., Zykov A.A., Fedyanin I.S., Sukhobok Yu.A., Experimental investigations of a possibility of determining the physical and electrophysical properties of multilayer media using radiowave tomography (In Russ.), Izvestiya vuzov. Fizika = Russian Physics Journal, 2020, V. 63, no. 2(746), pp. 30-35, DOI: https://doi.org/10.17223/00213411/63/2/30

The authors propose a failure criterion for pipelines with surface and longitudinal flat through defects based on destructive testing of specimens with induced cracks over the width and thickness. The specimens are prepared from pipeline walls. The crack depth, the failure load, and the specimen metal deformation curve are used to build the rated rupture stress to crack depth function and to determine the failure toughness values for crack propagation over the wall thickness and for through crack propagation cases. The suggested criterion is found to be aligned with the ultimate crack resistance failure criterion. Assuming the stress-strain state at failure in a cracked specimen to be close to the stress-strain state at failure in the area of a longitudinal surface crack in a pipeline the suggested approach can be applied to assess the strength of a cracked pipeline, which has the wall thickness and the deformation curve similar to that of the specimen. The article considers the conditions for developing the so-called "leak to failure" in a pipeline depending on the failure toughness anisotropy coefficient. We have proposed and substantiated the approach to ranking flat defects in a pipeline depending on the severity level using the development of the leak to failure. The consequences of a leak are substantially less severe than that of a failure. This fact shall be taken into account when ranking flat defects by the severity level. Therefore, if the surface defect length is known from the smart pigging results the type of possible loss of tightness, i.e. rupture or leakage, can be assessed well before the accident. The defects which can lead to a rupture should be repaired as the first priority.

References

1. Kiefner J.F. et al., Failure stress levels of flaws in pressurized cylinders, American society of testing and materials report, 1973, ASTM STP 536, pp. 461–481,

DOI: http://dx.doi.org/10.1520/stp49657s

2. Cosham A., Hopkins Ph., Leis B., Srack-like defects in pipelines: the relevance of pipeline-specific methods and standards, Proceedings of the 2012 9th International Pipeline Conference, September 24–28, 2012, DOI: https://doi.org/10.1115/IPC2012-90459

3. Jason Y., Shenwei Zh., Shahani K. et al., Validate crack assessment models with in-service and hydrotest failures, Proceedings of the 2018 12th International Pipeline Conference September 24–28, 2018, DOI: https://doi.org/10.1115/IPC2018-78251

4. Yan Z. et al., Model error assessment of burst capacity models for energy pipelines containing surface cracks, International Journal of Pressure Vessels and Piping, 2014, August–September, pp. 120–121, DOI: https://doi.org/10.1016/j.ijpvp.2014.05.007

5. Scott C., Further development of the gamma exponent model for assessment of flaws in oil and gas pipelines, Journal of Pipeline Science and Engineering, 2021, V. 1, pp. 321–328, DOI: https://doi.org/10.1016/j.jpse.2021.06.002

6. Mekhanika katastrof. Opredelenie kharakteristik treshchinostoykosti konstruktsionnykh materialov. Metodicheskie rekomendatsii (Mechanics of catastrophes. Determination of crack resistance characteristics of structural materials. Guidelines), Part 2, Moscow: Publ. of FTsNTP PP “Bezopasnost'”, Assotsiatsiya KODAS, 2001, 254 p.

7. Pestrikov V.M., Morozov E.M., Mekhanika razrusheniya (Fracture mechanics), St. Petersburg: Professiya Publ., 2012, 552 p.

8. Varshitskiy V.M., Valiev M.I., Kozyrev O.A., Methodology of definition of retesting interval for a pipeline section (In Russ.), Nauka i tehnologii truboprovodnogo transporta nefti i nefteproduktov = Science & Technologies: Oil and Oil Products Pipeline Transportation, 2013, no. 3 (11), pp. 42–46.

9. Broek D., Elementary engineering fracture mechanics, Groningen: Noordhoff International Publ., 1974.

10. Kiefner J.F., Kolovich K.M., Models for predicting failure stress levels for defects affecting ERW and flash-weld seams, Final report as the deliverable of sub-task 2.4 on U.S. Department of Transportation Other Transaction Agreement No. DTPH56-11-T-000003, January 3, 2013.

11. Fracture: An advanced treatise: edited by Liebowitz H., V. 5: Fracture design of structures, Academic Press, 1969.

The article presents the results of laboratory study of the stability of the rheological parameters of oil mixture passing through a pump, and transported through the Atyrau – Uzen - Samara main pipeline. As an object for research we used two batch oil mixtures that differing in properties: Buzachi and Mangyshlak oil mixtures selected inlet T. Kasymova pumping station. The Mangyshlak oil mixture is characterized by a high content of waxes, which causes a high pour point temperature. The Buzachi oil mixture is characterized by a high content of resins and, accordingly, a high density. Results of mixtures modeling and studying showed, the highly paraffinic Mangyshlak oil is main component that affects the processes of structuring and, consequently, thixotropic properties of Buzachi-Mangyshlak oil mixtures. There were observed the most typical curves for thixotropic fluids at temperatures corresponding to or bordering on the fluidity loss temperature of the oil mixture - a gradual increase in the shear rate leads to shear deformation and destruction of the structured oil dispersed system, but with a decrease in the shear rate, a gradual restoration of the structure occurs. Highly solidifying Buzachi-Mangyshlak oil mixtures have thixotropic properties, due to which the structure and rheological properties of oil can be restored after prolonged and significant deformation effects, such as the passage of oil through a pump. In this case, the introduction of a depressant additive not only leads to a decrease in the rheological parameters of the oil mixture, but also contributes to a reduction in the time of the thixotropic response of the oil-dispersed system to shear effects. The study of the influence of the composition, depressant additives, temperature, and deformation conditions on the rheological and thixotropic properties is of great importance in the study of the possibilities of regulating the rheological parameters of anomalous oils. In addition, the obtained data are necessary for carrying out thermal-hydraulic calculations and determining the conditions for safe oil pumping.

References

1. Makhmotov E.S., Sigitov V.B., Ismurzin O.B. et al., Fiziko-khimicheskie i reologicheskie parametry neftey Respubliki Kazakhstan. Spravochnik (Physicochemical and rheological parameters of oils of the Republic of Kazakhstan), Almaty: Zhibek zholy Publ., 2008.

2. Matveenko V.N., Kirsanov E.A., Remizov S.V., Rheology of structured disperse systems (In Russ.), Vestnik Moskovskogo universiteta. Seriya 2: Khimiya = Moscow University Chemistry Bulletin, 2006, V. 47, no. 6, pp. 393–397.

3. Kirsanov E.A., Remizov S.V., Novoselova N.V., Matveenko V.N., Physical meaning of the rheological coefficients in the generalized Casson model (In Russ.), Vestnik Moskovskogo universiteta. Seriya 2: Khimiya = Moscow University Chemistry Bulletin, 2007, V. 48, no. 1, pp. 22–26.

4. Malkin A.Ya., Isaev A.I., Reologiya. Kontseptsii, metody, prilozheniya (Rheology. Concepts, methods and applications), Moscow: Professiya Publ., 2010, 560 p.

6. Allayarov I.R., Lazdin R.Yu., Kulish E.I., Study of the thixotropic properties of carboxymethylcellulose solutions (In Russ.), Vestnik Bashkirskogo universiteta, 2017, V. 22, no. 4, pp. 981–984.

7. Nikitin M.N., Gladkov P.D., Kolonskikh A.V. et al., Analysis of rheological properties of Yaregskoe field heavy high-viscosity oil (In Russ.), Zapiski Gornogo instituta, 2012, V. 195, pp. 73–77.

5. Vaseneva A.A., Nekuchaev V.O., Filippov I.S., Non-Newtonian and thixotropic properties of Timano-Pechorskaya region high waxy and high viscosity oil mixes (In Russ.), Neftegazovoe delo, 2013, no. 3, pp. 75–86.