A method for short-term cyclic injection of fluid into wells to maintain reservoir pressure

Abstract

The objective of this technical solution is to reduce operating costs for water injection during water utilization and reservoir pressure maintenance (RPM) at hydrocarbon fields. We have developed a new short-term cyclic fluid injection (SCIFI) mode for oil fields. Our SCIFI method is designed not for fluid extraction from wells, but for pumping fluid into RPM system wells and / or recycling associated water. For pumping units operating in RPM system wells, it is important to ensure a precise volume (integral performance) of water injection at a given pressure with minimal energy consumption. The proposed method is distinguished by the following: - fluid injection is performed by pumps located not in wells, but on the surface.The pump can be used for pumping into either a single well or multiple wells. Injection can be performed using either a single pump or multiple pumps operating in parallel. The duration of the Waiting phase is always longer than the Injection phase. The regulated duration of the "Injection + Waiting" cycle, where short-term Injection stages alternate with short-term Waiting stages, and the maximum cycle duration in our proposed method does not exceed 1.5 hours. At the same time, the increased pump capacity ensures stable maintenance of the injection volume. The use of pumps with higher capacity than required for pumping liquid in the KTsZhS-PPD allows for a reduction in specific energy consumption (by ensuring optimal power) required to pump the same volume of liquid over the same distance compared to continuous and intermittent pumping systems.- The pump intake pressure must be no lower than 0.02 MPa, compared to pumps operating in continuous mode (standard), which is no less than 0.05 MPa. This means that the KTsZhS-RPM technology, thanks to the alternating stages of the Injection-Standby cycles, provides more comfortable conditions at the pump intake. A significant indicator of the effectiveness of the cyclic water injection technology used with a horizontal centrifugal sectional pump unit (GNK or GNU) is the energy savings, which undoubtedly helps reduce the share of electricity in the total energy consumption of the reservoir pressure maintenance (RPM) system at oil fields.The developed new technological mode of short-term cyclic injection of liquid into wells for pressure maintenance (SCI) at oil fields is one of the methods of influencing the reservoir to increase the efficiency of flooding and involve new reservoir volumes in development and, ultimately, increase the oil recovery factor (ORF).

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