Amino Acid as a Novel Wettability Modifier for Enhanced Waterflooding in Carbonate Reservoirs

Abstract

Summary Reservoir wettability plays an important role in waterflooding, especially in fractured carbonate reservoirs since oil recovery from the rock matrix is inefficient because of their mixed wettability. This paper presents the first investigation of amino acids as wettability modifiers that increase waterflooding oil recovery in carbonate reservoirs. All experiments used a heavy-oil sample taken from a carbonate reservoir. Two amino acids were tested, glycine and β-alanine. Contact angle experiments with oil-aged calcite were conducted at room temperature with deionized (DI) water, and then at 368 K with three saline solutions: 243 571-mg/L salinity formation brine (FB), 68 975-mg/L salinity injection brine 1 (IB1), and 6898-mg/L salinity injection brine 2 (IB2). IB2 was made by dilution of IB1. The contact angle experiment with 5-wt% glycine solution in FB (FB-Gly5) resulted in an average contact angle of 50°, in comparison to 130° with FB, at 368 K. Some of the oil droplets were completely detached from the calcite surface within a few days. In contrast, the β-alanine solutions were not effective in wettability alteration of oil-aged calcite with the brines tested at 368 K. Glycine was further studied in spontaneous and forced imbibition experiments with oil-aged Indiana limestone cores at 368 K using IB2 and three solutions of 5 wt% glycine in FB, IB1, and IB2 (FB-Gly5, IB1-Gly5, and IB2-Gly5). The oil recovery factors from the imbibition experiments gave the Amott index to water as follows: 0.65 for FB-Gly5, 0.59 for IB1-Gly5, 0.61 for IB2-Gly5, and 0.33 for IB2. This indicates a clear, positive impact of glycine on wettability alteration of the Indiana limestone cores tested. Two possible mechanisms were explained for glycine to enhance the spontaneous imbibition in oil-wet carbonate rocks. The primary mechanism is that the glycine solution weakens the interaction between polar oil components and positively charged rock surfaces when the solution pH is between glycine's isoelectric point (pI) and the surface's point of zero charge (pzc). The secondary mechanism is that the addition of glycine tends to decrease the solution pH slightly, which in turn changes the carbonate wettability in brines to a less oil-wet state. The amino acids tested in this research are nontoxic and commercially available at relatively low cost. The results suggest a new method of enhancing waterflooding, for which the novel mechanism of wettability alteration involves the interplay between amino acid pI, solution's pH, and rock's pzc.

Surface Properties of Graffiti Coatings on Sensitive Surfaces Concerning Their Removal with Formulations Based on the Amino-Acid-Type Surfactants

“…To maintain the integrity of the nanoemulsion formed during the high-pressure homogenization, a variety of commercially available, mild, and environmentally friendly anionic surfactants of the amino-acid-type (AAS) were chosen and utilized (their structures and abbreviations are shown in Table 1 ). Currently, there are only a few studies [ 36 , 37 , 38 , 39 , 40 ] that examine the possibility of using AAS to manufacture nanostructured fluids (NFs) to be used as graffiti cleaners. One of the criteria for selecting a suitable AAS was the presence of a glycine molecule or its direct analog in the structure of the amino acid composing the AAS.…”

A Guide for Selection of Aging Time and Temperature for Wettability Alteration in Various Rock-Oil Systems

“…For instance, they indicated that it takes from 14 to 30 days based on the lithology and temperature to change wettability from initial water-wet to oil-wet. 37,38,40,45 Other authors such as Al-Mahrooqi et al 1 reported 100 days for such wettability alteration. Nonetheless, the result analysis led to a conclusion that changing the wettability of a strongly water-wet sample takes a relatively longer time than that of initially weakly wet or neutral wet.…”

“…It is possible that the asphaltenes, which are acidic compounds, deposit on the sample surface and get adsorbed making the zeta potential more negative, which alters the wettability toward oil wet. Lara Orozco et al reported that to alter the wettability of the rock sample from water-wet to oil-wet using asphaltene content of 14 wt%, it took 21 days at 95 °C temperature. The sample needed 35 days to alter its wettability using crude oil with 5% asphaltene at reservoir temperature conditions (it was aged for 56 days, but there is no change in wettability after 35 days) .…”

“…The wettability of a core sample aged for 10–14 days at 50–80 °C temperatures changed from strongly water wet to weakly water wet. − Additionally, it took 14 days at 50–90 °C to alter the wettability from strong water wet to neutral wet. , Other authors reported a longer duration to turn the initial wettability from water-wet to oil-wet. For instance, they indicated that it takes from 14 to 30 days based on the lithology and temperature to change wettability from initial water-wet to oil-wet. ,,, Other authors such as Al-Mahrooqi et al reported 100 days for such wettability alteration. Nonetheless, the result analysis led to a conclusion that changing the wettability of a strongly water-wet sample takes a relatively longer time than that of initially weakly wet or neutral wet.…”

“…Results indicated that carbonates in general require less aging time to alter their wettability condition to oil-wet, around 1–7 days, compared with sandstones, around 14–21 days, based on the temperature and oil used. It took 10–14 days to alter the wettability of carbonate rock samples with temperatures ranging between 25 and 90 °C. ,,,,− On the contrary, it takes a longer duration ranging between 14 and 21 days at higher temperatures of 60–90 °C to change the rock sample wettability of sandstone. ,,,, …”