Mixing in a three‐phase system: Enhanced production of oil‐wet reservoirs by CO₂ injection

Abstract

We recreate three‐phase reservoir conditions (high‐pressure/temperature) using a microfluidics system and show that the use of scCO2 for restimulation operations, such as hydraulic fracturing, can enhance mixing and production. The results inform hydrocarbon extraction from deep shale formations, which has recently generated an energy boom that has lowered hydrocarbon costs. However, production decreases rapidly and methods to increase efficiency or allow restimulation of wells are needed. In our experiments, the presence of residual brine from initial production creates spatiotemporal variability in the system that causes the injected scCO2 to more effectively interact‐mix with trapped hydrocarbon, thereby increasing recovery. We apply volume‐averaging techniques to upscale brine saturation, which allows us to analyze the complex three‐phase system in the framework of well characterized two‐phase systems. The upscaled three‐phase system behaves like a two‐phase system: greater mixing with larger non‐wetting content and higher heterogeneity. The results are contrary to previous observations in water‐wet systems.

Wettability impact on supercritical CO2 capillary trapping: Pore‐scale visualization and quantification

“…Another advantage of our micromodels is that they can withstand up to 10 MPa pressure drop. The widely used overburden pressure cell [ Zhang et al ., , ; Wang et al ., ; Chang et al ., , ; Jimenez‐Martínez et al ., ] is not needed in our experiment system, allowing us to directly record immiscible displacement behavior at the pore scale without using dyes to enhance the difference of fluorescent signal intensity between scCO 2 and brine phases. Our micromodels exhibited no significant changes in contact angles before and after experiments and retained relatively uniform spatially distributed wettability (see Figure and supporting information Figures S1–S5).…”

Introductory Chapter: Developments in the Exploitation of Unconventional Hydrocarbon Reservoirs

“…rheology, density and viscosity), formation rock properties, the reservoir condition (thermal gradient, pre-existing fluid compositional variation) and other drivers such as capillarity and diffusion. The practicability of this process involving a threephase fluid system (scCO 2 -brine-oil) is demonstrated in Jiménez-Martínez et al [36], where supercritical CO 2 (as an injection fluid) is used to restimulate an oil-wet shale formation containing brine and hydrocarbon as the major resident fluids.…”

Interplay between Fingering Instabilities and Initial Soil Moisture in Solute Transport through the Vadose Zone

“…Water flow and solute transport through unsaturated soil control the movement and distribution of pollutants in the vadose zone [1] and the contamination of groundwater resources [2,3]. Current important applications include the design of sustainable unconventional irrigation processes [4,5], understanding the transport of colloids [6] and viruses [7,8] through the unsaturated zone, and characterizing the role of pore-scale processes on mixing and dispersion in two-phase [9,10] and three-phase [11] fluid systems. Key mechanisms that determine the distribution of water and solutes in soil include heterogeneity [12], structure and layering [13][14][15], the presence of macropores and their connectivity [16], the presence of vegetation and crops [17], and the particular protocols and water compositions used for irrigation in water-scarce arid and semiarid regions [4,18].…”