This book provides a systematical investigation on the reservoir characteristics and percolation mechanism of ultradeep carbonate gas reservoirs, including reservoir characteristics and classification, gas storage and percolation capacities, gas-phase and gas-water two-phase percolation mechanism, microscale complex gas-water relationship, reservoir sensitivity characteristics, and gas production characteristics of heterogeneous carbonate reservoirs. Some advanced and improved experimental techniques and analytical methods are introduced and applied, including comprehensive evaluation...