Indexed by:期刊论文

Date of Publication:2017-12-01

Journal:GREENHOUSE GASES-SCIENCE AND TECHNOLOGY

Included Journals:SCIE、EI、Scopus

Volume:7

Issue:6

Page Number:972-987

ISSN No.:2152-3878

Key Words:CO2; X-ray CT; pore scale; heterogeneity; wettability

Abstract:The geological sequestration of CO2 is considered to have great potential. However, the heterogeneity that characterizes most geological reservoirs significantly affects the migration, trapping, and leakage of CO2. The present study involved a pore-scale investigation of the effects of heterogeneity in pore size and wettability using stratified sand packs. A stratified glass bead (BZ06+BZ02) pack and a quartz+dolomite pack were introduced in flow experiments at gaseous CO2 (gCO(2)) and supercritical CO2 (scCO(2)) conditions. Different injection rates, namely, 0.1, 0.3, and 0.6 mL/min, were applied to the drainage while a constant rate of 0.1 mL/min was maintained for the imbibition. High resolution CT imaging and subsequent processing of the images were used to analyze the effects of heterogeneity in pore size and wettability. The results indicate that heterogeneity in pore size and wettability alters the intrinsic percolation abilities of the individual layers of the stratified structure and weaken the linear correlation between CO2 volume and slice-averaged porosity. It was also observed that water films sometimes exist in the layers with smaller pore spaces after drainage and it can trigger snap off events. (c) 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.