Description

The apparatus is solely designed for the purpose of core wettability restoration prior to intensive SCAL studies. A single core chamber is supplied in the standard version but additional units can be provided upon request. The aging method firstly consists of fully saturating with brine a cleaned (and thus water-wet) core plug. Once this has been achieved, crude oil is injected into the sample and displaces the brine until initial water saturation has been obtained. During this process, it is generally assumed that the smaller pores remain water-filled, whereas the oil invades the remainder of the pore space, leaving thin water films on the pore walls and in crevices. Wettability changes are obtained by subjecting the core to reservoir conditions of temperature and pressure for many weeks. At this stage, a wettability transition may occur in the oil-invaded pores depending on the stability of the thin water films, located between the pore walls and the oil. An oil-wet status is obtained upon oil-rock contact due to the rupture of these films. After a certain period of time, the core will have achieved a mixed wettability state.