One of the main problems in operating the wells equipped with ESCP units at the Samotlorskoye oil field developed by Oil Company Rosneft is the increased flow back of the abrasive particles. These particles are represented mainly by quartz and a small proportion of plagioclase, in size related to coarse aleurolitic and fine sandy groups. The presence of abrasive particles in the produced liquid causes accelerated depreciation and clogging of the working parts of the ESCP and has a significant negative effect on the operating parameters of the units. The article gives an analysis of the effectiveness of using sand separators (descenders) to protect equipment when operating the wells significantly complicated by the abrasive particles flowback. The change in the overall reliability of the ESCP units was studied using the data on the failures before and after application of sand separators in 168 wells of the AV and PK formations. The use of sand separators allowed to increase the mean time between failures by 78 days. When the equipment is operated without sand separators, the distribution of the number of failures over the run periods is described by a logarithmic function: most of the failures occur at a short run period and as the run period increases, the failure rate decreases. In case of using sand separators, most of the failures do not occur in the first months of operation, but it is distributed according to the polynomial dependence with a maximum frequency within 180-240 days. The main effect of using the sand separators is achieved by reducing the cases of pump jamming and its performance reducing due to clogging or accelerated depreciation of the working parts. In addition, it has been established that the use of sand separators does not have a noticeable effect on the structure of depreciation patterns of the pump working parts, but it allows to increase operating time of the equipment. Taking into account the current cost of sand separators and the achieved average effect in terms of increasing the run period, the use of these devices in the conditions of the Samotlorskoye field is economically feasible. At the same time, the use of sand separators in the conditions of the Samotlorskoye field does not completely solve the problem of protecting the ESCP units, therefore, in order to increase the time between failures in wells that are most complicated by sand production, new technologies should be searched for.
References
1. Coffee St., Briffett M., Downhole desander prevents ESP damage in high-watercut well, World Oil, 2008., V. 229(2008).
2. Yakimov S.B., Sand separation plant to protect downhole pumps. Current situation and prospects for the technology application (In Russ.), Territoriya NEFTEGAZ, 2014, no. 2, pp. 44–58.
3. Ivanovskiy V.N., Sabirov A.A., Bulat A.V., Yakimov S.B., Research of desenders' efficiency used for protection of submersible pumps (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2013, no. 3, pp. 19–25.
4. Garifullin A.R., Basov S.G., Methods for protecting ESP from mechanical impurities (In Russ.), Territoriya NEFTEGAZ, 2010, no. 9, pp. 70–73.
5. Lykova N.A., Equipment for ESP operation under conditions of intensive removal of mechanical impurities (In Russ.), Inzhenernaya praktika, 2017, no. 3, pp. 58–62.
6. Kolmakov E.A., Zen'kov I.V., Perspektivnye konstruktsii fil'trov v sostave UETsN (Promising designs of ESP filter), Proceedings of Mezhdunarodnyy nauchno-prakticheskaya konferentsiya “Prirodnye i intellektual'nye resursy Sibiri. SIBRESURS 2016” (Natural and intellectual resources of Siberia. SIBRESURS 2016), Kemerovo: Publ. of KuzSTU, 2016.
7. Yakimov S.B., The index of aggressiveness of the rentrained solids at TNK-BP fields in Western Siberia (In Russ.), Neftepromyslovoe delo, 2008, no. 9, pp. 33–38.
8. Ivanov M.K., Burlin Yu.K., Kalmykov G.A. et al., Petrofizicheskie metody issledovaniya kernovogo materiala (Terrigennye otlozheniya) (Petrophysical methods for the study of core material (Terrigenous sediments)), Part 1, Moscow: Publ. of MSU, 2008, pp. 14–15.
9. Takacs G., Electrical submersible pump manual, Gardners Books, 2009, 420 p.
10. Yakimov S.B., Ivanovskiy V.N., Degovtsov A.V. et al., On the influence of the fraction composition of abrasive particles in produced fluid on the wear types of the elements of electric centrifugal pumps (In Russ.), Territoriya NEFTEGAZ, 2017, no. 11, pp. 32–38.
11. Yakimov S.B., Shportko A.A., Shalagin Yu.Yu., Ways of improving gas separators reliability used to protect electric centrifugal pumps (ESP) in the deposits of PJSC "NK "Rosneft" (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2017, no. 1, pp. 33–39.
12. Yakimov S.B., Some aspects of choosing technology providing protection of underground equipment from sand with account of dynamics of the sand removal while putting wells into operation at Samotlor oil field (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2013, no. 6, pp. 81–89.
13. Yakimov S.B., Pushkarev A.V., Vetokhin E.G., Podkorytov S.M., Some techniques of increasing the time of de-sanders’ effective operation to protect electric centrifugal pumps from sand at Samotlor field (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2015, no. 6, pp. 55–60.
14. Yakimov S.B., On the perspectives of radial stabilized compression electric submersible pumps application for wells operation efficiency improvement at AB group of the Samotlor field formations (In Russ.), Territoriya NEFTEGAZ, 2016, no. 7–8, pp. 79–86.
