An increase in concentration of abrasive particles in produced fluids caused by more intensive operation of oil wells has resulted in toughening operating conditions for electric submersible pumps. The widespread use of multi-stage hydraulic fracturing technology with a large volume of injected proppant has also contributed to this. Despite the significantly increased intensity of equipment operation and the significantly increased number of factors that complicate operations, the strategy implemented by Rosneft to extend the mean time between failures enables achieving an improvement of this indicator year on year. In their search for ways to further enhance operating performance of electric submersible pumps used in the conditions of high content of gas and abrasive particles in produced fluid, Rosneft initiated bench tests of the operated gas separators. The tests resulted in the first-ever study of separation factor degradation at various models of gas separators caused by equipment wear. It was found that the largest degradation of the separation factor occurs in rotary gas separators. As for screw and vortex gas separators, the tests evidenced a relatively small change in their separation factor. Gas separators were also studied for the depth of hydroabrasive damages of the protective sleeve. The deepest damages were found on rotary gas separators and the smallest – on screw gas separators. Following the testing results, manufacturers of gas separators were issued design debugging recommendations aimed to improve wear resistance qualities. The studies made it possible to identify best gas separator models for using in wells with high production of abrasive particles, and also to develop wear resistance criteria for inclusion in Rosneft specifications for such equipment. The use of gas separators found to have high wear resistance properties during the bench tests, will lead to lower oil production losses caused by an increase in gas content at pumps as a result of separation factor deterioration. Further, the switch to using gas separators with high wearing qualities will enable reducing operating costs for repairs and capital expenditures for purchase of such equipment. Another effect from this will be achieving a further extension of the mean time between failures.
References
1. Salikhova A.R., Loskutov K.Yu., Galkov I.T., Sabirov A.A., Well completion after hydraulic fracturing (In Russ.), Territoriya Neftegaz, 2020, no. 9, pp. 64–70.
2. 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.
3. Minchenko D.A., Yakimov S.B., Noskov A.B. et al., Project of introduction of gas separators of electrical submersible pumps with lower power consumption: preparation and start of implementation (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 11, pp. 64 – 67.
4. Gerasimov V.V., Highly reliable equipment for work in difficult conditions (In Russ.), Inzhenernaya praktika, 2012, no. 2 , pp. 18–25.
