A Critical Review of Wettability Alteration of Retrograde Gas Condensate Reservoirs Using Nanoparticles

Abstract

Condensate and liquid blockage is a serious problem in gas condensate reservoirs as it reduces gas production. There are many methods to solve this problem, however, most of them are temporary or expensive. Wettability alteration of reservoir rocks from a liquid-wet state to a gas-wet state via nanoparticles is a long-lasting, cheap, and environmentally friendly solution to condensate blockage. With the aim of promoting this treatment in field scales, this review article presents a report of almost all the research carried out in this area. The results of different research teams are compared and the advantages and disadvantages of each research are detailed. Furthermore, the mechanisms and effects of gas-wetting alteration are fully explained, and the existence of an optimum wettability state is discussed. We found that silica nanoparticles are the most commonly used type of nanoparticles in wettability alteration towards a gas wet state due to their effectiveness and endurance. Most importantly, we present two new theories about the application of nanoparticles in the wettability alteration process of condensate reservoirs. First, it may be possible to inject nanoparticles into reservoirs via foam which not only stabilizes foam but also increases the effectiveness of wettability alteration treatment. Second, nanoparticles can be used to alter the wettability and prevent fines migration and sand production simultaneously. This review can be utilized as a reference in expanding the use of nanoparticles in gas-wetting alteration in field scales.

Keywords

• fines migration
• gas-wetting alteration
• liquid blockage
• nanoparticles
• sand production
• wettability alteration