Experimental investigation of chemical solutions effects on wettability alteration and interfacial tension reduction using nano-alkaline–surfactant fluid: an EOR application in carbonate reservoirs

M. Sadegh Rajabi,Masoud Mehrizadeh,Rasoul Moradi

doi:10.1007/s13202-021-01155-9

M. Sadegh Rajabi, Masoud Mehrizadeh + Show 1 more

Open Access

https://doi.org/10.1007/s13202-021-01155-9

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Abstract

The wettability preference of carbonate reservoirs is neutral-wet or oil-wet as the prevailing of hydrocarbon reserves that affects approximately half of the total production of hydrocarbons of the world. Therefore, due to surface wettability of carbonate rocks the notable fraction of oil is held inside their pores in comparison with sandstones. Since shifting the wettability preference toward water-wet system is of great interest, numerous components were used for this purpose. In this experimental research, the wettability alteration of dolomite surface by interacting with a novel nano-surfactant–alkaline fluid has been investigated in order to diminish its adhesion to crude oil droplets. The solutions were prepared by homogenous mixing of nanosilica particles with cetyl trimethyl ammonium bromide and sodium carbonate, respectively, as a cationic surfactant and alkaline agent. The maximum wettability alteration from oil-wet to water system was obtained by employing a mixture of nanoparticles in association with surfactant–alkaline. Then, the fluids were employed in core-surface from detached and attached forms to compare their interfacial effects on saturated thin sections by crude oil and to measure the wettability. In addition, the interfacial tension (IFT) between solutions and crude oil was investigated and the maximum IFT reduction was obtained from nano-surfactant. Finally, all chemical solutions were flooded to the dolomite plugs separately after water flooding in order to evaluate the maximum oil recovery factor acquired by nano-surfactant.

Highlights

Over the past decades, enhanced oil recovery (EOR) processes have been implemented, in several oilrich countries, to increase the amount of oil that can be extracted from the oil fields after primary and secondary productions
Considering great potential of the applications of chemical enhanced oil recovery (CEOR) methods, recently they have been taking into account for implementation in carbonate reservoirs (Pal et al 2018)
It should be emphasized that wettability was not changed after three weeks for these examined sections; thereby, it can be stated that the highest wettability preference of sections is moderately oil wet

Summary

Introduction

Over the past decades, enhanced oil recovery (EOR) processes have been implemented, in several oilrich countries, to increase the amount of oil that can be extracted from the oil fields after primary and secondary productions. The offered conventional chemical enhanced oil recovery (CEOR) methods are polymer flooding, surfactant and alkaline flooding (Samanta et al 2012). Meantime, combinations of these flooding types such as alkaline–polymer (AP), alkaline–surfactant (AS) and alkaline–surfactant–polymer (ASP) flooding were generated to assist with their separate unique properties to improve and rectify the shortcoming of the individual component chemical flooding process (Mandal 2015). Considering great potential of the applications of CEOR methods, recently they have been taking into account for implementation in carbonate reservoirs (Pal et al 2018). ASP and polymer flooding have been the most widely used

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