Pore-scale systematic study on the disconnection of bulk gas phase during water imbibition using visualized micromodels

• DOI: 10.1063/5.0094930
• Publication Date: 2022-06-06T00:34:32Z
• Authors: Jian Tian; Qiang Chen; Chaozhong Qin; Yili Kang; Na Jia; Zhiyu Xi
• Keywords: 0211 other engineering and technologies; 02 engineering and technology

When water imbibes into tight rocks, the disconnection of bulk gas phase will significantly impact the performance of gas recovery. In this work, we have conducted a systematic micromodel study on the disconnection of gas phase during water imbibition. Seven types of micromodels were designed that can geometrically mimic basic pore structures of a tight sandstone. Then, we conducted capillary-dominant imbibition experiments and analyzed the effects of pore geometry and pore-throat ratio on the transient evolutions of gas–water interfaces. Our pore-scale results reveal that snap-off and bypassing flows are the two main mechanisms that determine disconnection and entrapment of the gas phase. Moreover, we qualitatively linked the pore-scale two-phase displacements to the core-scale “permeability jail” phenomenon (i.e., nearly immobile of non-wetting and wetting phases across a wide range of saturation values). Our study will enrich the knowledge of entrapment behaviors of the gas phase during water imbibition into tight formations.