Abstract: A method for assessing thermophysical properties of a study fluid includes isolating a first a slug of a study fluid within an isolation fluid in a microfluidic channel; conducting a first optical investigation of the first slug to assess a thermophysical property of the first slug; while maintaining the first slug in the microfluidic channel and within the isolation fluid, modifying at least one of a pressure within the microfluidic channel and a temperature within the microfluidic channel; and conducting a second optical investigation of the first slug to re-assess the thermophysical property of the study fluid.

Abstract: A microfluidic device includes a microfluidic substrate having a porous media channel, an oil inlet port in fluid communication with the porous media channel, a fluid inlet port in fluid communication with the porous media channel, and an outlet port in fluid communication with the porous media channel. The porous media channel has a plurality of dividers that provide the porous media channel with a network of fluid pathways. A method for assessing miscibility of an oil composition and a fluid includes flowing an aliquot of a fluid through a porous media channel to displace at least an oil composition from the porous media channel, and conducting an optical investigation of the porous media channel to assess the miscibility of the oil composition and the fluid at the test pressure and test temperature.