Experimental investigation of the mechanism of supercritical CO2 interaction with tight sandstone

Abstract

One of the important technologies for combating global climate change is CCUS (Carbon Capture, Utilization, and Storage), which aims to address the issue of “greenhouse effect” generated by a significant amount of greenhouse gas emissions. Supercritical CO2, a new type of anhydrous fracturing fluid with broad application prospects in low-pressure tight sandstone gas reservoirs, has several advantages over traditional water-based fracturing fluids, including quick flowback, minimal damage to the reservoir, and the ability to realize in-situ storage of greenhouse gases. The tight sandstone cores from the Jinqiu Gas field in the Sichuan Basin were used in an experimental investigation on the interaction mechanism between supercritical CO2 and tight sandstone to examine the viability of supercritical CO2 fracturing with tight sandstone, and analysis of the samples’ post-reaction samples’ mineral composition, microstructure, mass change, and total salinity change. The interaction of tight sandstone with supercritical CO2 results in an increase in quartz content, a decrease in clay mineral content, the formation of new minerals, and partial mineral dissolution on the surface of the sample. Since the degree of mineral dissolution of sandstone samples increases with time, CO2 can be stored in tight sandstone as carbonate minerals. This study evaluates how supercritical CO2 interacts with tight sandstone and can offer a solid theoretical foundation and experimental evidence in favor of CO2in-situ storage in tight sandstone gas reservoir.

The Microscopic Production Characteristics of CO2 Flooding AF-Ter Water Flooding for Tight Oil Sandstones Reservoirs Utilized NMR and Microscopic Visualization Apparatus

“…CO2 can dissolve oil, thereby reducing its viscosity and increasing its fluidity within the reservoir [20,21]. When CO2 become a supercritical state, it is allowed to penetrate smaller pores more easily in tight reservoirs and drive out the oil [22][23][24].When CO2 reaches a miscible phase with oil, the displacement effect significantly increases due to the formation of a single-phase system [25,26], the interfacial tension between the gas and liquid phases disappears, which resulted in a significant reduction in capillary resistance within the reservoir, this will greatly improve oil recovery. In summary, CO2 injection can be an effective method to improve oil recovery from tight reservoirs while simultaneously addressing the issue of greenhouse gas emissions by storing CO2 underground.…”

Analyzing the Microscopic Production Characteristics of CO2 Flooding after Water Flooding in Tight Oil Sandstone Reservoirs Utilizing NMR and Microscopic Visualization Apparatus

“…CO 2 can dissolve oil, thereby reducing its viscosity and increasing its fluidity within the reservoir [17,18]. When CO 2 reaches a supercritical state, it is allowed to penetrate smaller pores more easily in tight reservoirs and drive out the oil [19][20][21]. When CO 2 reaches a miscible phase with oil, the displacement effect significantly increases due to the formation of a single-phase system [22,23], and the interfacial tension between the gas and liquid phases disappears, which results in a significant reduction in capillary resistance within the reservoir; this will greatly improve oil recovery.…”

Experimental Study for the Effects of Different Factors on the Sand-Carrying Capacity of Slickwater

“…In shale gas and tight sandstone fracturing, due to the low viscosity of slickwater, poor sand-carrying capacity, and fast settling rate of proppant, the exorbitant concentration of proppant during operation is likely to cause sand plugging [18,19]. However, the low concentration of proppant will reduce the concentration of sand laid in the fractures and the effects of fracturing stimulation.…”