Three dimensional (3-D) simulation of wormhole propagation is crucial for predicting stimulation effects of acidizing or acid fracturing in carbonate reservoirs.This paper presented a 3-D multiple-scale wormhole propagation model built based on the double-scale model

and its solving details.Meanwhile

geological modeling method was used to establish the geology model of porosity correlation distribution in 3-D space

which deals with the saltation of porosity successfully and makes the simulation results more realistic and reliable.Through the simulations

we found that the injection rate is the key factor affecting wormhole patterns.With the increase of the injection rate

five dissolving patterns may be observed

namely face dissolution

conical wormhole

dominant wormhole

ramified wormhole and uniform dissolution.When the convection and dispersion are comparable

the dominant wormhole may form with a thick root and a thin tip.The do-minant wormhole propagation can be divided into the following successive four stages

including competition stage

dominant stage

breaking stage and broadening stage.Most importantly

we found that the wormhole propagation pathway is highly correlated with the spatial correlation of porosity

since the wormhole breaks the core through those large pores with well connectivity.Finally

the field simulation results verified that the models and methods proposed in this paper are feasible and reliable for wormhole simulation of acidizing and acid fracturing in carbonate reservoirs.Those works could provide theoretical support for fine simulation and prediction in the relevant research areas.