Novel application of PEG/SDS interaction as a wettability modifier of hydrophobic carbonate surfaces

Nasim Heydari,Mahdi Asgari,Zahra Fakhroueian,Narjes Shojai Kaveh

doi:10.1007/s12182-018-0260-z

Abstract

Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of surfactants in EOR applications. In this study, the interaction of polyethylene glycol (PEG) with an ionic surfactant, sodium dodecyl sulphate (SDS), is evaluated on an oil-wet carbonate rock surface by using contact angle measurements. The results reveal that wettability alteration of carbonate rocks is achieved through PEG/SDS interaction on the rock surface above a critical aggregation concentration (CAC). The behaviour of PEG/SDS aqueous solutions is evaluated using surface and interfacial tension measurements. Furthermore, the effect of PEG and SDS concentrations and impact of electrolyte addition on PEG/SDS interaction are investigated. It is shown that electrolyte (NaCl) can effectively decrease the CAC values and accordingly initiate the wettability alteration of rocks. Moreover, in a constant SDS concentration, the addition of NaCl leads to a reduction in the contact angle, which can also be obtained by increasing the aging time, temperature and pre-adsorption of PEG on the rock surface.

Highlights

The recovery of oil in naturally fractured carbonate reservoirs is low in general and can be improved significantly by the alteration of the wettability of carbonates from oil-wet conditions to water-wet conditions (Jarrahian et al 2012; Karimi et al 2012; Nazari Moghaddam et al 2015)
The results reveal that wettability alteration of carbonate rocks is achieved through polyethylene glycol (PEG)/sodium dodecyl sulphate (SDS) interaction on the rock surface above a critical aggregation concentration (CAC)
PEG/SDS interaction in the bulk solution has been widely studied in the previous literature, little attention has been devoted to their interaction at the solid–liquid interface

Summary

Introduction

The recovery of oil in naturally fractured carbonate reservoirs is low in general and can be improved significantly by the alteration of the wettability of carbonates from oil-wet conditions to water-wet conditions (Jarrahian et al 2012; Karimi et al 2012; Nazari Moghaddam et al 2015). Unless the injected water contains surface-active wettability-modifying chemicals, no spontaneous imbibition of water can take place under these conditions due to a negative capillary pressure (Standnes and Austad 2003). For this purpose, chemicals such as surfactants have been widely considered before (Babadagli and Boluk 2005; Golabi et al 2012; Hirasaki and Zhang 2004; Jarrahian et al 2012; Kumar et al 2016; Salehi 2009; Standnes and Austad 2000, 2003).

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Conclusion