Effect of Low-Concentration of 1-Pentanol on the Wettability of Petroleum Fluid–Brine–Rock Systems

Abstract

High-concentration brines generally cause the wettability of petroleum fluid–brine–rock systems to become less water-wet (more oil-wet). The addition of alcohols to the brine, however, may produce an opposite effect. In this work, we investigate the synergic effects of a low concentration of 1-pentanol and brines on the wettability of petroleum fluid–brine–rock systems. The variables examined include the mineral type (mica, quartz, calcite), brine concentration (0–3 M), ion type (monovalent and divalent), crude oil (samples from sandstone and carbonate reservoirs), and 1-pentanol concentration (0.5 and 1 wt %). Adding 1 wt % 1-pentanol to the brine only slightly affects the wettability of a petroleum fluid on sandstone-like mineral surfaces (mica and quartz), whereas the effect is significant for carbonate-like mineral surfaces (calcite). A maximum reduction of 80° in contact angle (measured through the brine phase) is observed at 0.1 M NaCl and 0.5 wt % 1-pentanol. ζ-Potentials of both brine–petroleum fluid and brine–rock interfaces are found to be insensitive to the presence of 1-pentanol in the brine. Based on these observations, we propose that the accumulation of 1-pentanol in the thin brine film confined between the petroleum fluid and the rock surface results in a significant change of the wettability. Our finding may have various practical applications, one of which is the use of a low concentration of 1-pentanol for improving oil production.

1-Pentanol-Assisted Waterflooding in High Salinity Brine up to 140 °C in Carbonate Reservoirs

“…Similarly, the contact angle of the oil droplet on the calcite surface reduces from 162°to 103°F at 140 °C and 40 MPa. This observation is in line with the work of Lu et al 13 who report that adding 1-pentanol alcohol (1 wt %) to high salinity brine (1 M NaCl) reduces the contact angle of the oil droplet on the calcite surface from 135°( without 1-pentanol) to 70°, a 65°reduction, with a strong shift of the wettability from a strongly oil-wet system toward a weakly water-wet system, although they did not test at high temperature and high pressure. This observation is also in agreement with our previous study, 14 showing that the contact angle of oil−brine−calcite reduces from 165°to 125°while mixing 1-pentanol alcohol (1 wt %) to high salinity brine (1 mol NaCl + 0.01 mol CaCl 2 ) at ambient conditions.…”

“…This is also in line with our previous work, 14 which illustrates that the contact angle of the oil droplet on the calcite surface reduces from 105°to 90°. Analogously, Lu et al 13 reported that the contact angle of the oil droplet on the calcite surface reduces to 23°w hen mixing 1-pentanol alcohol (1 wt %) with low salinity brine (0.01 M NaCl). Moreover, similar to HS brine, Figure 8 demonstrates that increasing the temperature increases the contact angle and, thus, the hydrophobicity in LS brine with 1pentanol alcohol (1 wt %).…”

“…Therefore, there is a pressing need to develop a cost-effective approach to unlock remaining oils in carbonate reservoirs at high temperature and high salinity conditions where low salinity water (i.e., freshwater resources) is not available. Recently, Lu et al 13 reported that a small concentration of 1pentanol alcohol can trigger a significant reduction in the contact angle of the oil−brine−carbonate system, suggesting a more hydrophilic system. For instance, they show that the contact angle of the carbonate system reduces to 80°by adding 1-pentanol alcohol (0.5 wt %) to 0.1 M NaCl brine.…”

Comparative Study of Ketone and Surfactant for Enhancement of Water Imbibition in Fractured Porous Media

“…In addition to surfactant, alcohol solution was studied in the literature for wettability alteration. Lu et al presented a study of 1-pentanol solution for wettability alteration . Their experimental results showed that the contact angle of a petroleum fluid on calcite was significantly decreased in 1 wt % 1-pentanol solution.…”

“…Lu et al presented a study of 1-pentanol solution for wettability alteration. 26 Their experimental results showed that the contact angle of a petroleum fluid on calcite was significantly decreased in 1 wt % 1-pentanol solution. The effect was more evident with 0.5 wt % 1-pentanol at a high NaCl or MgCl 2 concentrations.…”