Investigation of Low Salinity Waterflooding Predictive Capability and the Development of a Tool for Screening Candidates

Golmohammadi, Meysam | 2021

331 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54316 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Mahani, Hassan; Ayatollahi, Shahab
  7. Abstract:
  8. Among different enhanced oil recovery (EOR) methods, low salinity waterflooding (LSWF) has been attractive to researchers because of its relative simplicity and lower environmental problems compared to other conventional EOR methods. Numerous researchers have attempted to find the main cause of the low salinity effect (LSE). According to previous studies, several experimental techniques have been proposed for predicting LSE and screening potential field candidates. However, there is a lack of a systematic investigation of all (or even some of) the methods to compare and determine their LSE predictive capability. Predictive capability development is essential because it saves costs and time during the early screening of candidates. The primary purpose of this study is to find a method with the best LSWF predictive capability and develop a tool for screening candidates for this EOR method. In this regard, different screening methods were investigated and tested on several crude oil/brine/rock (COBR) systems. Each technique was then compared with the oil recovery resulting from the spontaneous imbibition test, which was considered the main proof of LSE. The most common types of carbonate rocks, including dolomite, Indiana limestone, and chalk, were used to comprehensively investigate the response of each carbonate rock type to LSE. The rocks were thoroughly characterized and analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF), and field emission scanning electron microscopy (FESEM). The results of analyzing the rocks show that they are very pure, and the amount of other minerals such as clay and anhydrite is negligible. The low salinity waters were prepared by two to ten times diluting the seawater (SW). The effect of lowering brine salinity was investigated by conducting the techniques based on solid/liquid interactions such as flotation and contact angle measurement, as well as techniques based on liquid/liquid interactions, including interfacial tension (IFT), interfacial viscoelasticity and micro-dispersion formation. The results of spontaneous imbibition show that for all rock types, the oil recovery factor increases as the brine salinity decreases. In dolomite, for example, four-times-diluted seawater and seawater increased the recovery factor by 21 and 10 percent, respectively. Among the mentioned techniques, flotation and contact angle measurement results matched the outcomes of spontaneous imbibition tests. Also, the number of microdispersions increased in low salinity brines, which shows a good match with imbibition results. On the other hand, the results of IFT and viscoelasticity measurements revealed that they could not predict the LSE observed in spontaneous imbibition tests. Therefore, it is concluded that the techniques based on solid/liquid interactions have the best LSWF predictive capability. Moreover, microdispersion can predict LSE, but it cannot be considered a mechanism for LSE, as it does not directly involve rock. In summary, flotation technique, contact angle, and microdispersion have the best LSWF predictive capability, and they can be used for quickly screening candidates
  9. Keywords:
  10. Enhanced Oil Recovery ; Wettability Alteration ; Low Salinity Water Flooding ; Interfacial Phenomena ; Spontaneous Imbibition ; Screening Analysis ; Predictive Capability

 Digital Object List