Investigation of the origins of rapid gas-water contact rise and excess water production in naturally fractured reservoirs: a case study

Efficient gas production management is an important task for oil and gas companies. Water production is a critical problem in gas reservoirs which may result in early abandonment of many wells, reservoir and low recovery factor. In Homa gas field, since 2012, a rapid increase in water-gas contact of 20 meters per year has been observed, so that in 2018, an average of 40 to 50% of the reservoir area has become water invaded. The calculations indicated an approximate amount of 1.5 to 2.37 Trillions of standard cubic feet of trapped gas in the reservoir. This phenomenon is of great importance in the reduction of reservoir recovery. In this study, an integrated approach is proposed for determination of source of water production in gas production wells of a fractured reservoir in the south of Iran. This study showed a water encroachment from highly fractured aquifer with high-speed invasion in fracture networks and considerable bypassed gas in matrix blocks that highly reduces recovery factor and it was not early detectable by classical methods. The proposed approach can be applied for new fields under development in the region.