Experimental Investigation of Aluminosilicate Nanoparticles for Enhanced Recovery of Waxy Crude Oil Tito Wijayanto,* ,†,‡ Masanori Kurihara, § Teguh Kurniawan, ∥ and Oki Muraza* ,∥ † Department of Earth Sciences, Resources and Environmental Engineering, Graduate School of Creative Science and Engineering, Faculty of Science and Engineering and § Department of Resources and Environmental Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan ‡ Research and Development Centre for Oil and Gas Technology “LEMIGAS”, Ministry of Energy and Mineral Resources, Jalan Ciledug Raya Kavling 109, Kebayoran Lama, Jakarta Selatan 12230, Republic of Indonesia ∥ Department of Chemical Engineering and Center of Excellence in Nano Technology (CENT), King Fahd University of Petroleum and Minerals (KFUPM), Post Oﬃce Box 5040, Dhahran 31261, Kingdom of Saudi Arabia ABSTRACT: Recently, research on cost-eﬀective nanoparticles for improved and enhanced oil recovery has attracted increasing attention. Most of the existing research activities on the eﬀects of nanoﬂuids were focused on the alteration of wettability and the reduction of interfacial tension. However, in those studies, the nanoparticle solutions were presumably composed of not only bare nanoparticles but also with stabilizers or surfactants. It becomes ambiguous which components in the nanoparticle solutions played a role. In this work, we used a waxy crude oil and aluminosilicate nanoparticle to resolve the ambiguity. The objective of this work is to investigate the oil displacement mechanism by nanoﬂuid through the measurements of the wettability index and interfacial tension as well as through core-ﬂooding experiments. These experimental results showed that aluminosilicate nanoparticles could alter the rock surface wettability from water-wet to stronger water-wet and decrease the interfacial tension between oil and injection ﬂuid. On the basis of the results, the eﬀects of aluminosilicate injection on the improvement of oil recovery were conﬁrmed, which suggests that aluminosilicate nanoparticles can increase the recovery of paraﬃnic oil with an asphaltene content of 25% in a water-wet reservoir. 1. INTRODUCTION Many oil ﬁelds around the world have approached the declining stage of total production rates, 1 and the crude oils are being produced from mature ﬁelds. 2 Recently, the world faces abandonment of the ﬁelds, with more than 50% of the original oil in place (OOIP) unrecovered. 3 Many countries have changed their status from a net crude oil exporter to a net oil importer, including Indonesia, where the oil production in 2017 is around 800 000 barrels of oil equivalent per day (BOED), while oil consumption has reached 1.3 million BOED. 4 Consequently, the primary challenge now is how to produce more oil with low and reasonable cost and to retard the abandonment of ﬁelds. New technologies have been used to produce more oil from mature ﬁelds, to increase the oil recovery compared to the traditional methods. Nanotechnol- ogies may help us to attain these challenges. Nanotechnologies have expanded the research window in the oil and gas industries in recent years, 5 with numerous applications in geochemical exploration, 6 drilling and sand controls, 7,8 heavy oil ﬁeld development, 9 and reservoir engineering. Especially, in reservoir engineering, the eﬀects of nanotechnologies on improving oil recovery have attracted major attention. Miranda et al. reported that nanoparticles (NPs) as part of nano- technology oﬀered several beneﬁts. 10 Vert et al. deﬁned NPs as any particle with a size from 1 to 100 nm. 11 Furthermore, according to Das et al., the NP is typically composed of a core and a thin shell. 12 The NPs can be re-engineered to alter speciﬁc reservoir conditions, such as wettability, mobility ratio, or control formation ﬁnes migration. 13 Idogun et al. reported that there were many advantages to use NPs, which, in general, had to be converted to nanoﬂuids. 14 Zhang et al. proposed to optimize the properties of nanoﬂuids, such as thermal conductivity, viscosity, and speciﬁc heat. 15 Hendraningrat et al. 16 and Zargartalebi et al. 17 applied hydrophilic and hydrophobic NPs to identify ﬂuid−ﬂuid and ﬂuid−rock interactions, such as stability, interfacial tension (IFT), contact angle, and wettability. Moreover, almost all of the existing work studied the eﬀects of nanoﬂuids from the viewpoints of wettability alteration and IFT reduction. In those studies, however, the NP solutions were usually composed of not only bare NPs but also with stabilizer agents or surfactants to prevent agglomeration, which could have aﬀected the wettability and IFT and made it ambiguous which components in the NP solution had played a role. The NPs have unique properties as a result of their small size and large speci ﬁc surface area. 18 After treatment or functionalization of the surface of the NPs, the shield around them will be established, which inhibits particle−particle attraction and reduces the potential for the aggregation of NPs. The NPs possibly modify the reservoir ﬂuid composition and rock−ﬂuid properties to result in mobilizing trapped oil. 19 These eﬀects might involve several physical and/or chemical interactions, both of which can induce the mechanisms for Received: March 14, 2019 Revised: May 7, 2019 Article pubs.acs.org/EF Cite This: Energy Fuels XXXX, XXX, XXX-XXX © XXXX American Chemical Society A DOI: 10.1021/acs.energyfuels.9b00781 Energy Fuels XXXX, XXX, XXX−XXX Downloaded by KENT STATE UNIV at 15:18:15:768 on July 05, 2019 from https://pubs.acs.org/doi/10.1021/acs.energyfuels.9b00781.