A microfluidic study of oil displacement in porous media at elevated temperature and pressure

Abstract

Microfluidics methods offer possibilities for visual observations of oil recovery processes. Good control over test parameters also provides the opportunity to conduct tests that simulate representative reservoir conditions. This paper presents a setup and procedure development for microfluidic oil recovery tests at elevated temperature and pressure. Oil recovery factors and displacement patterns were determined in single- or two-step recovery tests using two crude oils, high salinity salt solutions and low salinity surfactant solutions. Neither the displacement pattern nor the recovery factor was significantly affected by the pressure range tested here. Increasing temperature affected the recovery factor significantly, but with opposite trends for the two tested crude oils. The difference was justified by changes in wettability alteration, due to variations in the amounts and structure of the acidic and basic oil fractions. Low salinity surfactant solutions enhanced the oil recovery for both oils.

Physicochemical Characterization of Asphaltenes Using Microfluidic Analysis

“…The application of microfluidic devices to understand the physicochemical properties of asphaltenes and address related flow assurance problems continues to be an active research area. Microfluidic devices are also quickly advancing to mimic the HPHT conditions that are characteristic of those within a reservoir to probe oil recovery processes. − Additionally, new mineral coatings can be added to the microfluidic device to represent the surface chemistry of the reservoir rock. − It is clear that hydrodynamics and asphaltene solution properties govern its stability and deposition. What has not been well-characterized is the asphaltene-rock interactions, surface reactivity, and influence of HPHT conditions with multiphase fluid flow on asphaltene deposition.…”

Effects of Fluid Aging and Reservoir Temperature on Waterflooding in 2.5D Glass Micromodels

“…Again, the qualitative trends in the ROS can be expected to depend on the materials rather than the geometry. The finding in a recent study 46 that different CROs with distinct SARA/TAN profiles produced qualitatively different temperature dependences of ROS underlines this point. Numerical simulations, even if performed in simple 2D pore networks 83 could play an important role in mapping these varying experimental outcomes onto model parameters.…”

“…Several other studies aimed at mimicking recovery processes with micromodels have also used glass to define the pore space. ,, While it is clear that the surface composition of glass is significantly simpler than that of reservoir rock, glass is considered in many microfluidic and millifluidic studies to be “chemically similar” to sandstone rock. Both glass and sandstone present silicon dioxide groups at the surface, and in sandstone reservoirs that contain little clay, SiO 2 is by far the most abundant mineral species.…”

“…One example could be the introduction of clay particles adsorbed onto the pore walls; these particles could change the outcome of the IOR process via desorption or swelling. , Also, the sandstone rock itself may need to be better mimicked. Glass materials as used in the current fabrication of micromodels cannot represent aspects like heterogeneity, swelling, or dissolution. ,, …”

“…To better represent the complex structure of the porous rock medium, dual porosity/depth, , so-called 2.5D , and 3D micromodels, , have been used. Also, microfluidic studies at high temperature and pressure have recently seen the light. − Although the use of crude oil (CRO) in microfluidic devices has been relatively scarce, a growing trend can be observed here. ,− This has been made possible through the use of chemically resistant chip materials such as glass or silicon. Also, studies on the influence of chemical aging have thereby come within easy reach.…”