Flow-through Drying during CO2 Injection into Brine-filled Natural Fractures: A Tale of Effective Normal Stress. (July 2021)

• Record Type: Journal Article
• Authors: Lima, Marina Grimm; Javanmard, Hoda; Vogler, Daniel; Saar, Martin O.; Kong, Xiang-Zhao
• Is Part Of: International journal of greenhouse gas control. Volume 109(2021)
• Publication Date: 2021-07
• Subjects: Fracture -- Flow-through drying -- Evaporation -- Formation dry-out -- Supercritical CO2 -- Effective normal stress; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2021.103378
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: Drying of brine-filled fracture by supercritical carbon dioxide flow in two stages, and effective normal stress impacts sweep efficiency. Lower effective normal stress promotes higher brine relative mobility and less evaporation, at later stages, as consequence of less fingering. Higher effective normal stresses increase the chance of injectivity impairment. Abstract: Injecting supercritical CO 2 (scCO 2 ) into brine-filled fracture-dominated reservoirs causes brine displacement and possibly evaporite precipitations that alter the fracture space. Here, we report on isothermal laboratory experiments on scCO 2 -induced flow-through drying in a naturally fractured granodiorite specimen under effective normal stresses of 5-10 MPa, where two drying regimes are identified. A novel approach is developed to delineate the evolution of brine saturation and relative permeability from fluid production and differential pressure measurements. Under higher compressive stresses, the derived relative permeability curves indicate lower mobility of brine and higher mobility of the scCO 2 phase. The derived fractional flow curves also suggest an increase in channelling and a decrease in brine sweep efficiencies under higher compressive stresses. Finally, lowering compressive stresses seems to promote less water evaporation. Our experimental results assist in understanding the injectivity of single fractures and eventually of fracture networks during subsurface applications that involve scCO 2 injection into saline formations.