Wettability of two types of sandstone cores, Berearn(permeability of the order of 600 md), and a reservoir rockrn(permeability of the order of 10 md), is altered from liquid-wettingrnto intermediate gas-wetting at a high temperature ofrn140℃. Previous work on wettability alteration to intermediaterngas-wetting has been limited to 90 ℃. In this work, chemicalsrnpreviously used at 90 ℃ for wettability alteration are found tornbe ineffective at 140℃. A new chemical is used which altersrnwettability at high temperatures. The results show that: (1)rnwettability could be permanently altered from liquid-wettingrnto intermediate gas-wetting at high reservoir temperatures, (2)rnwettability alteration has a substantial effect on increasingrnliquid mobility at reservoir conditions, and (3) wettabilityrnalteration does not have a measurable effect on the absoluternpermeability of the rock when a suitable chemical is used. Wernalso found out that the reservoir rock, unlike Berea is notrnstrongly water-wet in the gas-water-rock system.
展开▼
