Low Salinity Waterflooding (LSF) is a rapidly emerging IOR/EOR technology that improves oil recovery by lowering the injection water salinity. A membrane-based desalination process provides additional advantages such as reduction of souring, scaling and it can prevent injectivity decline. Proper screening of LSF for a particular field requires performing laboratory SCAL tests to (i) measure relative permeability curves to enable field-scale quantification of the LSF benefits by modeling and (ii) de-risk the potential of formation damage through clay swelling and deflocculation.

Salym Petroleum Development (SPD; JV Shell/GazPromNeft) is actively looking into IOR/EOR methods to increase the water flood recovery factor. While ASP is being matured as the main EOR option, several LSF laboratory tests have been performed recently to assess the potential of this technique for West Salym. A key LSF enabler in the area is the presence of large, relatively low-saline aquifers in the vicinity of the field, which can serve as a plentiful source of low salinity (LS) injection brine.

This study focuses on the initial Salym LSF SCAL tests performed at reservoir conditions, using representative reservoir core and crude oil, with synthetic brines that reflect the formation and injection water compositions accurately. The experiments comprised a suite of Amott and coreflood tests, following the internal Shell LSF protocol. The tests clearly show a positive LSF effect, with additional oil produced in absence of formation damage. The data indicates that LSF causes a shift in wettability towards a more water-wet behavior, and results in a reduction of Sorw. Upscaling the core flood results to field scale indicated that incremental recoveries within the life time of the field could be 1.7% of oil initially in place (OIIP) in tertiary mode, while a secondary mode LSF scheme would have increased the oil recovery over the same time by almost 4% of OIIP.

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