Application of non-positive and positive displacement pumps in water injection system: challenges and opportunities

UDK: 622.276.43

DOI: 10.24887/0028-2448-2020-7-56-59

Key words: energy efficiency, energy saving, specific energy consumption, non-positive displacement pump, positive displacement pump, variable frequency drive

Authors: R.A. Gabdrakhmanov (Oil and Gas Production Department Leninogorskneft, RF, Leninigorsk), E.L. Mitrofanov (Oil and Gas Production Department Leninogorskneft, RF, Leninigorsk), V.A. Konnov (TatNIPIneft, RF, Bugulma), O.M. Krasnov (Tatneft PJSC, RF, Almetyevsk)

At the final stage of oil field development, energy efficiency of oil production processes applying pressure maintenance methods, among which water flooding is the most common one (>90%), takes on great importance. Present-day water flooding is a complex system of various technologies, methods and facilities. Improvement of water-injection system energy efficiency increases oil field productive life. In this regard, reduction of energy consumption is a sophisticated problem to be solved, including search for integrated solutions concerning process design, techniques, procedures, and facilities, especially pumping equipment. More than half of unproductive energy consumption in a water-injection system is attributed to low efficiency of non-positive displacement pumps and forced pressure restriction in order to achieve the required water injection conditions. However, technological development of positive displacement pumps has come ever closer to limitations due to physical features of centrifugal pump units. Nevertheless, centrifugal pumps are still the most commonly used pumping units in water injection systems. Meanwhile, search for new technical solutions and innovative facilities are underway. Plunger-type positive displacement pumps find ever-growing use today. The paper reviews issues of using both non-positive and positive displacement pumps for water injection at NGDU Leninogorskneft’s assets. The authors present energy efficiency indicators for the nearest decade, discuss basic limitations of using non-positive displacement pumps at a present-day stage of field development, compare specific energy consumption for various-size non-positive displacement pumps and plunger-type pumps as a function of pressure. The paper presents the results of studying applicability of a variable frequency drive with high-pressure non-positive displacement pumps. Based on the research results, application of variable frequency drives is limited in terms of both energy efficiency and possibility of injection control, since maximum achievable pump head is restricted along with pump rate reduction, which is often unallowable according to water flooding conditions. The paper also discusses the results of plunger pump implementation at a cluster pumping station as compared with a low-capacity non-positive displacement pump. Process design solutions are presented to improve operational integrity of positive displacement pumps. References 1. Oganesyan S.A., The energy strategy of Russia until 2020, its implementation and prospects for the development of the fuel and energy complex (In Russ.), Energonadzor i energobezopasnost', 2006, no. 2, pp. 30–38. 2. Konnov V.A., Razrabotka energoeffektivnykh metodov i tekhnologicheskikh skhem podderzhaniya plastovogo davleniya pri razrabotke neftyanykh mestorozhdeniy (Development of energy-efficient methods and technological schemes for maintaining reservoir pressure in the development of oil fields): thesis of candidate of technical science, Bugul'ma, 2012. 3. Fattakhov R.B., Konnov V.A., Energy-efficient operation of the pumping equipment of the reservoir pressure maintenance system – a way to reduce the cost of oil (In Russ.), Nefteservis, 2012, no. 4, pp. 33–35. 4. Fattakhov R.B., Konnov V.A., Abramov M.A., Gilyazov R.A., Difficult issues of a “simple” VFD (In Russ.), Izhenernaya praktika, 2013, no. 6, pp. 54–56. 5. Konnov V.A., Fattakhov R.B., Abramov M.A., Application of positive displacement plunger-type pumps in reservoir pressure maintenance systems (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2019, no. 1, pp. 62–65. 6. Fattakhov R.B., Konnov V.A., Ibragimov N.G. et al., Application of positive-displacement pumps for energy savings in reservoir-pressure maintenance systems (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2013, no. 7, pp. 54–57. 7. Konnov V.A., Fattakhov R.B., Analysis of results of experimental operation of positive displacement pumps used for water injection into a formation (In Russ.), Oborudovanie i tekhnologii dlya neftegazovogo kompleksa, 2014, no. 5, pp. 12–15.