NOVEL CALCULATION METHOD OF THE ACID LEAK-OFF CONSIDERING THE EFFECT OF ACID WORMHOLE

Compared with the matrix acidizing,wormhole is formed inevitably during the process of high pumping rate acid fracturing treatment,which leads to serious acid leak-off and short acid penetration distance and leads to a bad effect on the carbonate stimulation,or even brings the treatment into failure.Therefore,the acid wormhole propagation mechanism study and the novel calculation model for the acid leak-off in the acid fracturing is very important.In this paper,a novel model has been developed to analysis the initiation and propagation mechanisms of wormhole and the acid leak-off mechanisms during the process of the acid fracturing.The model can simulate the propagation process of wormhole,and also can shows the changes of propagation process and leak-off of acid with pumping rate and time.