The objective of the paper is to assess incremental oil production due to low-salinity waterflooding (LSW) in the Pervomaiskoye oil field operated by PJSC TATNEFT vs. conventional waterflooding by high-salinity water. In this field, low-salinity water has been injected for a relatively lengthy period enabling to assess the effects of low-salinity flooding. The procedure was as follows. Laboratory coreflood experiments included preparation of cores, their saturation with formation water and oil, core flooding using high-salinity and low-salinity water. In both cases, oil production was recorded and fines release was analyzed. Core test results were adjusted using a special numerical fines migration model, and relative permeabilities were calculated. Then a 3D model was built and history matched using the function that allows change of relative permeability to water. After this, the model was recalculated without this function and incremental oil production due to LSW was estimated. 3D modeling showed that cumulative additional oil production due to LSW in Pervomaiskoye oil field is 4.2 million m3, incremental oil recovery is 3.5 %. The effect was prominent in wells with wellstream water cut from 20 % to 90 %. Targeted application of LSW is recommended - in injection wells as an EOR method when wellstream water cut ranges from 20 % to 90 %, and in production wells as a water control technology.
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