Well productivity improvement using extreme overbalanced perforating and surging-case history

This paper describes overbalanced perforating and surging operations as a pretreatment to hydraulic fracturing for the Romeo interval at Prudhoe Bay. Operation conditions are presented and discussed, as well as surface and bottomhole pressure measurements. Well productivity and the amount of proppant placed are compared to results in offset wells where the technique was not applied. The paper shows how the use of the technique allows placement of small, highly conductive fractures in intervals that were not previously considered fracturing candidates due to the close proximity to the gas/oil contact (GOC). The paper also shows pressure transient analysis affirming the technique as a stand-alone stimulation. It is shown that the use of extreme overbalanced perforating and surging treatments prior to hydraulic fracturing produces a substantial increase both in the success rate and the efficiency of the hydraulic fracturing operation and in the production rate of the wells that are pretreated. Finally, a comparison between pressure data and a new radial fracture propagation model shows a good match. The model demonstrates that high-energy treatment can significantly increase the extension and the height of the fracture; this was corroborated by downhole pressure measurements recorded during one overbalance treatment and by well logs.