Abstract:

The T₃X² gas reservoir in the Xinchang structural belt, Sichuan Basin, suffers a lot of challenges such as widespread water production, complex water production characteristics, unclear water invasion patterns, and a lack of effective water control strategies, affecting the stable production. Based on geological data and production performance from the gas reservoir, and using the theories/techniques of gas reservoir engineering, orthogonal experiments and development practices, the water production characteristics of the gas reservoir were analyzed, typical water invasion patterns were clarified, and water control strategies for gas wells were proposed. The results show that the T₃X² gas reservoir has 5 types of water production which can be identified by plotting charts. The water invasion patterns are classified into: rapid water channeling along fractures and slow water advancing. The degree of fracture development and the scale of fracturing treatments are the key factors influencing water invasion pattern. For the pattern of rapid water channeling along fractures, controlling pressure difference and balancing water drainage are critical, while for the pattern of slow water advancing, rationalizing production system and localized water blocking are recommended.

Key words: T₃X² gas reservoir, fractured and watered gas reservoir, water production type identification, water invasion pattern, water control strategy