Abstract: In view of the shortage of effective approach for calculating the critical production and predicting the water coning in fracturedvuggy layered reservoirs with bottom water when drilling inside vugs, a method for domain decomposition is adopted, considering the different flow mechanical characteristics and flow variation between inside and outside of vugs, a calculating formula is put forward to describe the water coning shape under critical production based on binomial and linear flow models. The method for getting the key parameters from steady well test data at early stage of development is presented, of which the critical production can be calculated with trial method. The case study indicates that the water coning inside vugs forms peak shape nearby well bore and quickly declines outward as flat shape. The water coning shape outside vugs is obviously different from the inside, whose shape is in gradual flat from the inside to the outside.

Key words: carbonate reservoir, bottom water reservoir, water coning, shape