Abstract: By the study of characteristics of displacement pressure of caprock and pressures of reservoir, pressure matching types between caprock and reservoir of gas reservoirs and the relationship gas reserves abundance have been studied. Matching between highest pressure of caprock and low pressure of reservoir is considered to be the most favorable for gas to accumulate. The second are the matching between highest pressure of caprock and normal pressure of reservoir and the matching between higher pressure of caprock and low pressure of reservoir. The other matching types are bad. The statistics shows that there are 4 pressure matching types between caprock and reservoir in 46 large and medium gas fields in China. The most matching type is highest pressure of caprock with highest pressure of reservoir. The second matching is highest pressure of caprock with higher pressure of reservoir. The less matching is highest pressure of caprock with normal pressure of reservoir. The least matching is highest pressure of caprock with low pressure of reservoir. The statistics indicate that within the 46 large and medium gas fields in China the most are in low gas reserves abundance. The second are in high and middle gas reserves abundance. The minor are in lower gas reserves abundance. The study of relation between pressure matching types of caprock and reservoir and gas reserves abundance of 46 large and medium gas fields in China suggests that matching type of highest pressure of caprock with normal pressure of reservoir and matching type of highest pressure of caprock with highest pressure of reservoir are the best pressure matching types to form large and medium gas fields with high and middle gas reserves abundance.

Key words: large and medium gas fields, caprock, reservoir, pressure matching type, gas reserves abundance