An apparatus (and method) for characterizing interfacial tension between a non-wetting phase fluid and a wetting phase fluid of a slug flow employs a capillary structure that is configured to contain a slug of the non-wetting phase fluid of the slug flow. The slug has a leading edge meniscus and a trailing edge meniscus, and the capillary structure has a venturi-like section. A pressure sensor is configured to measure differential pressure between first and second locations of the capillary structure. The first location is disposed upstream of the leading edge meniscus of the slug with the leading edge meniscus of the slug contained within the venturi-like section. The second location is disposed downstream of the trailing edge meniscus of the slug. Data processing means is configured to derive a measure of interfacial tension based upon the differential pressure measured by the pressure sensor and, optionally, geometry of the capillary structure.

Claims data not available