Production casing leak detection issues are of current interest due to oil production at late stages of fields development, ageing well stock and high water cut. Well logging is the most common method used to identify potential well integrity issues. This method, however, entails pulling the equipment out of hole to result in non-productive time, oil production losses, and upset of steady-state well operation process. Note also high risk of failed efforts to detect any loss of production casing integrity. The authors have analyzed the existing methods for production casing leak detection. Production well logging data has also been analyzed. This has enabled determination of average depths of well integrity failures, as well as identification of leaking hole sections. Indirect approaches to casing leak detection have been investigated; in particular, component ratio analysis based on six-component chemical analysis of water. On top of that, a new indirect method for analysis of production casing leak probability based on feature correlation matrix has been proposed. The authors have also developed and implemented a machine learning model for well integrity failure detection. It allows understanding of the primary factors contributing to the loss of wellbore integrity. Analysis of the effects of such factors suggests that the impacts of well age, sulfates concentration in produced fluid, water density, primary salts, and hole curvature are the most noticeable. The results of the research enabled development of production casing leak detection method together with indirect method for diagnosing and predicting the severity of production casing fatigue and related risks of casing integrity failure.
References
1. Khuzina L.B. et al., To the problem of production columns leakage (In Russ.), Stroitel’stvo neftyanykh i gazovykh skvazhin na sushe i na more, 2023, no. 4, pp. 35-38, DOI: https://doi.org/10.33285/0130-3872-2023-4(364)-35-38
2. Mukhametshin V.G., Dubinskiy G.S., Aver’yanov A.P., About the causes of the flow tubing tightness fault and preventive actions (In Russ.), Problemy sbora, podgotovki i transporta nefti i nefteproduktov, 2016, no. 3, pp. 19-24, DOI: https://doi.org/10.17122/ntj-oil-2016-3-19-24
3. Nabiullin A.Sh., Sinitsyna T.I., Vorontsov S.Yu., Studying the causes of casing leakages in production wells. Developing preventive methods for casing protection
(In Russ.), Ekspozitsiya Neft’ Gaz, 2023, no. 8, pp. 88-93, DOI: https://doi.org/10.24412/2076-6785-2023-8-88-93
4. Nazarov V.F., Mukhutdinov V.K., Monitoring the tightness of casing and tubing in injection wells by measurements using complex equipment (In Russ.), Innovatsionnaya nauka, 2015, no. 12-2, pp. 107-112.
5. Valiullin R.A. et al., Ecological questions of control for operation of underground gas storages wells (In Russ.), Izvestiya Samarskogo nauchnogo tsentra RAN, 2015, no. 5, pp. 256-262.
6. Kubrak M.G., Possible consequences from wells operation with casing integrity damage (In Russ.), Neftegazovoe delo, 2012, no. 2, pp. 434-446,
URL: https://ogbus.ru/article/view/vozmozhnye-posledstviya-ekspluatacii-skvazhin-s-narusheniyami-/23797
7. Dzyublo A.D., Ruban G.N., Reliable diagnostics and liquidation of behind casing flows as an ecological safety guarantee during the oil and gas fields development
(In Russ.), Aktual’nye problemy nefti i gaza, 2018, no. 4, pp. 1-10, URL: https://oilgasjournal.ru/issue_23/dzyublo-ruban.pdf
8. Nazarov V.F., Mukhutdinov V.K., Monitoring the tightness of casing and tubing in injection wells by measurements using complex equipment (In Russ.), Innovatsionnaya nauka, 2015, no. 12, pp. 107-112.
9. Aslanyan A.M. et al., Identification of leakage in couplings of tubing, casing and intermediate casing for wells of underground gas storage in salt caverns by means of spectral noise logging (In Russ.), Georesursy, 2016, no. 18, pp. 186-190, DOI: https://doi.org/10.18599/grs.18.3.7
10. Valiullin R.A. et al., The thermal convection study of behind-casing flow directed from up to down on a well model with induction heater (In Russ.), Vestnik Bashkirskogo universiteta, 2017, no. 2, pp. 325-329.
11. Kanafin I.V. et al., Research of formation thermal label in wellbore during case induction heating for assesment rate of cross-flow between layers (In Russ.), Bulatovskie chteniya, 2017, V. 1, pp. 70-72.
12. Davletshin F.F. et al., Investigation of thermal field in a well under fluid movement under induction impact (In Russ.), Izvestiya Tomskogo politekhnicheskogo universiteta. Inzhiniring georesursov, 2023, no. 3, pp. 153-164, DOI: https://doi.org/10.18799/24131830/2023/3/3896
13. Ramazanov A.Sh. et al., Assessment of the possibility of exploring the well’s backwater space by active thermometry (In Russ.), Neftegazovoe delo, 2023, no. 6,
pp. 43-50, DOI: https://doi.org/10.17122/ngdelo-2023-6-43-50
14. Azamatov M.A., Shorokhov A.N., Production casing leakage determining method (In Russ.), Nedropol’zovanie XXI vek, 2015, no. 6, pp. 43-47.
15. Aslanyan A. M. et al., Well noise logging as energy saving innovation technology (In Russ.), Neftegazovoe delo, 2016, V. 15, no. 2, pp. 8-12.
16. Leshkovich N.M., Improvement of the technology for determining casing leakages using the example of the Anastasievsko-Troitskoye field (In Russ.), Nauka. Tekhnika. Tekhnologii (politekhnicheskiy vestnik), 2019, no. 4, pp. 194-220.
17. ERB 2286-2022. Metodicheskie ukazaniya po provedeniyu ekspertizy po promyshlennoy bezopasnosti skvazhin na neftyanykh mestorozhdeniyakh Respubliki Tatarstan (Guidelines for conducting an examination of the industrial safety of wells in oil fields of the Republic of Tatarstan), Bugul’ma, 2022, 44 p.
