# Asphaltene aggregation onset during high-salinity waterflooding of reservoirs (a molecular dynamic study)

## TL;DR

This study uses molecular dynamics simulations to show that high-salinity brine delays asphaltene aggregation during waterflooding by reducing water miscibility in oil, contrasting with low-salinity effects.

## Contribution

It provides new molecular-level insights into how high salinity influences asphaltene aggregation onset during reservoir waterflooding.

## Key findings

- High salinity delays asphaltene aggregation onset.
- High salinity reduces water miscibility in oil at reservoir conditions.
- Salt-in effect varies across different asphaltenic oils.

## Abstract

The primary objective of this study is to establish an understanding of the role of high-salinity brine on the intensity of asphaltene aggregation onset during waterflooding of petroleum reservoirs. We already have shown that asphaltenes have a high tendency to form aggregates during waterflooding process when pure- and low salinity-water are injected into reservoirs. To fulfill the present objective, molecular dynamic simulations are performed on asphaltenic-oil/aqueous systems. The oil phase consists of asphaltenes and ortho-xylene, in which asphaltene molecules are completely soluble. Our simulations results reveal that the salt-in effect of high-salinity brine on seven different model asphaltenic oils causes a significant reduction of the onset of asphaltene aggregation as compared with pure-water. Such salt-in effect is primarily due to a considerable reduction of water miscibility in the oil phase at high pressure and temperature.

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Source: https://tomesphere.com/paper/1906.08114