The Importance of Early Water Detection and Water Salinity Measurement in Multiphase Production Systems and a New Measurement Technology That Addresses This Challenge

Abstract

Abstract Early water detection and on-line measurement of water salinity is important for many applications in multiphase and wet gas flow metering. Applications range from detecting formation water breakthrough for reservoir management and flow assurance purposes to updating water property input for multiphase flow meters. This paper addresses the value of early water detection and having knowledge of water salinity in an oil and gas production systems. It also presents a measurement solution to this challenge. The development of an open-ended coaxial reflection probe for estimating water salinity in three-phase flow is described. The shallow sensitivity depth of the reflection probe, based on microwave technology, means that it is sensitive to the bulk electrical properties of the fluids in its close vicinity. The reflection probe works well for both the multiphase and wet gas flow conditions when placed in a liquid-rich location of the production flow line. This provides good salinity-estimate accuracy for the full range, from low to very high GVF. While a microwave transmission system will fail to measure salinity for many oil-continuous flows, the intermittent presence of water in the close vicinity of the reflection probe flush at the pipe wall helps achieve an accurate salinity estimate even at very low water fractions. The extensive testing of this measurement probe will be presented and discussed. The novelty of the new sensor technology is that it works over the full range of water-liquid ratios, independent of whether the liquid is in an oil continuous, transition, or water continuous phase.