Wettability alteration in the gas condensate reservoirs to intermediate gas-wet during gas recycling process via gas-soluble non-ionic surfactants

Document Type : Research Paper

Authors

1 IAu Shiraz University

2 هیات علمی

3 IAU Shiraz University

10.22078/pr.2025.5655.3506

Abstract

In the gas condensate reservoirs, the condensate blockage leads to decrease the gas production and also trapes the valuable component near the wellbore. However, the wettability alteration from liquid-wet to gas-wet can be a permanent method due to improve this technical issue. In the current study, the gas recycling process is modified via dissolution of non-ionic surfactant (2EH-PO5-EO9) in methane. Therefore, at first the dissolution pressures of non-ionic surfactants into the methane are measured through cloud point pressures calculation. In addition, the interfacial tension (IFT) and wettability alteration are investigated in presence of methane/surfactant solutions. Moreover, the condensate production is investigated through core flooding test (two phase relative permeability data). Based on the results, the contact angles between rock and oil change from 18o (strongly oil-wet) to 86o (intermediate gas-wet) after 24 hours soaking of the carbonate substrates with methane/surfactant solution at 5000 ppm surfactant concentration. Also, the IFT decrease from 52 to 8 dyn/cm at reservoir conditions; i.e. 2800 psi and 70 oC. Furthermore, the condensate trapping decrease 12% during the methane/surfactant solution at 3000 ppm surfactant concentration at reservoir conditions compared to pure methane scenario. It is indicating that the gas-soluble non-ionic surfactants can improve the condensate recovery in the gas condensate reservoirs.

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