Wettability and Its Implications for Enhanced Oil Recovery

摘要

Reservoir rock wettability determines capillary pressure, fluid distribution, relative permeability and electrical properties and may play an important role in waterflood recovery efficiency. This report covers a literature survey of wettability, its significance, and its effect on oil recovery processes. Wettability is usually indicated by a contact angle that is measured on single crystals of quartz or calcite using crude oil and formation or synthetic brine. For porous samples, displacement methods are commonly used. The wettability of reservoir rock depends largely on polar compounds and asphaltenes in the crude oil and can range from strongly water-wet to strongly oil-wet, the latter being fairly common in carbonate reservoirs. Recovery efficiency has been reported to be most favorable at intermediate or mixed wettability. Modification of natural wettability has been conducted in the laboratory and observed in field applications. 56 refs., 5 figs., 2 tabs. (ERA citation 11:033674)