A downhole density-viscosity (D-V) sensor is introduced that provides a real time direct measurement of in-situ density and viscosity at reservoir conditions using a wireline formation tester (WFT). The new fluid measurements are obtained during open-hole sampling of reservoir fluids, or alternatively through fluid profiling where downhole fluid analysis (DFA) is performed at a number of depths to characterize the reservoir fluid properties at a vertical resolution much higher than traditional samping methods.
The utilization of these new measurements are outlined, to illustrate the emerging importance of quantifying fluid variations in real time. This leads to more complete reservoir understanding, resulting in better decisions regarding field modelling, facilities planning and production strategy.
An overview of the D-V sensor is presented together with specifications, and extensive laboratory testing is discussed to show validity of the measurements. Five case studies from around the world are examined to show different applications of this measurement in a wide range of environments.
Fluid density and viscosity have long been primary objectives of formation evaluation, as they bear significant impact on field production and economics. The ability to measure true fluid density and viscosity of formation fluids in-situ at reservoir conditions, is a major advancement for reservoir fluid characterization.