DEVICE FOR THE DYNAMIC UNDER BALANCE AND DYNAMIC OVER BALANCE PERFORATING IN A BOREHOLE

摘要

According to a preferred embodiment, a dynamic underbalance device has a longitudinally extending tool string including an underbalance part. A first overbalance part is above the underbalance part and a second overbalance part below the underbalance part. Upon application of underbalance from the underbalance part and overbalance from the overbalance part, the overbalance and underbalance interact to isolate the underbalance.