Effect of temperature and contamination on the surface tension of Niger Delta crude oils

Abstract

Surface tension is an important property that affects the behavior and characteristics of reservoir fluids. It impacts the capillary pressure and fluid dynamics in porous media. This study investigated the surface tension of Contaminated Niger Delta crude oil at varying temperatures. Laboratory tests were carried out on samples from four fields in the Niger Delta using DuNouy Tensiometer under standard conditions. The results show that for Niger Delta Crudes of gravity between 25 - 49 API, Surface Tension varies between 25.8 - 31.2 dynes/em at 29°C and decreases to between 21.5-26.6 dynes/em at 90°C. Surface Tension of the crudes was also affected by salt contamination, bentonite and mud filtrate and surfactant contamination. Contamination by bentonite also increased the surface tension from about 28 to 34 dynes/em. Predictive models have been developed as a quick-look tool for estimating surface tension of Niger Delta crude oil and similar reservoir fluids.