Cardanol /SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part II: Nanocomposite Evaluation and Coreflooding Test.

This study aims to evaluate the behavior of Cardanol/SiO2 nanocomposites in the inhibition of the asphaltene damage based on the coreflooding test at reservoir conditions. The nanocomposite design was performed in Part I (https://doi.org/10.1021/acs.energyfuels.0c01114), leading to SiO2 nanoparticles functionalized with different mass fractions of cardanol on the surface of 5 (5CSN), 7 (7CSN), and 9% (9CSN). In this part of the study, the nanocomposite/reservoir fluid interactions were evaluated through interfacial tension measurements and nanocomposite/rock surface interactions using water imbibition and contact angle measurements. Results showed that the designed nanocomposite leads to a reduction of interfacial tension of 82.6, 61.7, and 51.4% for 5CSN, 7CSN, and 9CSN regarding silica support (SN). Whereas, the reduction of the Si-OH functional groups from SiO2 nanoparticles due to the increase of the cardanol content affects the effectiveness of the wettability alteration for 7CSN and 9CSN. Nevertheless, when 5CSN is evaluated, the system is altered from an oil-wet to a mixed-wet state. Coreflooding tests at reservoir conditions were performed to evaluate the oil recovery after asphaltene damage, after damage removal and nanofluid injection, and after induction of a second asphaltene damage to check inhibition. Results show that the selected nanocomposites at a dosage of 300 mg·L-1 enhance the oil recovery in comparison with the baseline conditions via the reduction of the interfacial/surface forces at the pore scale and wettability alteration. It is worth to remark that this improvement remains after the second asphaltene damage induction, which proves the high inhibitory capacity of the designed nanocomposite for the asphaltene precipitation/deposition. Also, the use of the nanocomposites favors the oil recovery more than 50% compared to the asphaltene damage scenario.

Synthesis, characterization and evaluation of two crosslinked polymeric resins and their comparison with walnut shell in oil removal from water.

The aim of this paper was to compare two kinds of adsorbents (walnut shell and polymeric resins) in terms of their efficiency to remove oil from water, since walnut shell losses weight during the process requiring interruption, while polymeric resins do not. Polymeric resins based on glycidyl methacrylate and divinylbenzene (GMA-DVB) and styrene and divinylbenzene (STY-DVB) were synthesized and characterized. All adsorbents were tested by continuous flow process, eluting 3,000 bed volumes of synthetic oily water, and the oil content was monitored by fluorescence spectroscopy. Although the walnut shell presented high efficiency (∼94%), STY-DVB was even better (∼100%) besides presenting better mechanical resistance. Moreover, polymeric resins, mainly when based on GMA, can be chemically modified to remove specific contaminants still remaining in water after conventional treatment.