Relationship between residual saturations and wettability using pore-network modeling

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The relationship between residual saturation and wettability is critical for modeling enhanced oil recovery (EOR) processes. The wetting state of a core is often quantified through Amott indices, which are estimated from the ratio of the saturation fraction that flows spontaneously to the total saturation change that occurs due to spontaneous flow and forced injection. Coreflooding experiments have shown that residual oil saturation trends against wettability indices typically show a minimum around mixed-wet conditions. Amott indices, however, provides an average measure of wettability (contact angle), which are intrinsically dependent on a variety of factors such as the initial oil saturation, aging conditions, etc. Thus, the use of Amott indices could potentially cloud the observed trends of residual saturation with wettability. Using pore network modeling (PNM), we show that residual oil saturation varies monotonically with the contact angle, which is a direct measure of wettability. That is, for fixed initial oil saturation, the residual oil saturation decreases monotonically as the reservoir becomes more water-wet (decreasing contact angle). Further, calculation of Amott indices for the PNM data sets show that a plot of the residual oil saturation versus Amott indices also shows this monotonic trend, but only if the initial oil saturation is kept fixed. Thus, for the cases presented here, we show that there is no minimum residual saturation at mixed-wet conditions as wettability changes. This can have important implications for low salinity waterflooding or other EOR processes where wettability is altered.

Original languageEnglish (US)
Title of host publicationSociety of Petroleum Engineers - SPE Annual Technical Conference and Exhibition 2021, ATCE 2021
PublisherSociety of Petroleum Engineers (SPE)
ISBN (Electronic)9781613997864
DOIs
StatePublished - 2021
EventSPE Annual Technical Conference and Exhibition 2021, ATCE 2021 - Dubai, United Arab Emirates
Duration: Sep 21 2021Sep 23 2021

Publication series

NameProceedings - SPE Annual Technical Conference and Exhibition
Volume2021-September
ISSN (Electronic)2638-6712

Conference

ConferenceSPE Annual Technical Conference and Exhibition 2021, ATCE 2021
Country/TerritoryUnited Arab Emirates
CityDubai
Period9/21/219/23/21

All Science Journal Classification (ASJC) codes

  • Fuel Technology
  • Energy Engineering and Power Technology

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