Effective Utilisation of Underbalanced Perforation with Electrical Submersible Pump's Boost Oil Production of Mature Oil Field in Western Desert of Egypt: Case Study

Abstract

Conventionally, the transition from completion to production often requires the well to be killed immediately after perforation is completed, thus exposing the formation to potentially damaging killing fluid. To obtain a perforation tunnel with maximum productivity, this transition requires an optimal clean-up and removal of the perforation damages. Underbalance perforation through Tubing Conveyed Perforating (TCP) system is one of the best practices to ensure less damage to the perforation tunnels (perforating skin) leading to increased well productivity. However, it is very challenging in cases of completions with Electrical Submersible Pump's (ESP) to maintain productivity with undamaged reservoir by preventing any contact between reservoir and completion fluid and achieve the above simultaneously with safe well control during ESP deployment. Otherwise, the alternative solution is to run TCP string in single run then kill the well after perforation in order to install the ESP completion. As a result of the increasing emphasis on reducing operating costs, maximizing well productivity, and minimizing wellbore clean-up time, an integrated solution was designed and successfully implemented for perforating artificially lifted wells in static underbalanced condition and installing ESP completion in single run without killing the well. It combines the use of TCP system equipped with automatic release gun hanger. TCP gun string has been set by Electric Line against the required intervals, then the ESP has been separately installed and the guns has been activated through an electronic firing head for a shoot-and-drop operation. The static underbalance condition has been created by the ESP thanks to the programmed delayed firing time. After this operation, the well has been directly lined up to production flowline with minimal wellbore clean-up time. The combination of static underbalanced perforation with deep penetration charges which is able to bypass invasion zone, can create a clean perforation tunnel, and significantly reduce the post-perforating damage by killing fluid, and finally maximize the well productivity. Despite the challenging reservoir conditions (Depth= 16,500 FT, Pressure=6250 Psi, Temperature= 285 deg. F, Porosity = 8%), the Productivity Index (PI) of the wells were three times compared to the offset wells. Five jobs have been performed by Agiba Petroleum Company, one of the main operators in Western Desert of Egypt, employing this combined TCP-ESP technique which has resulted in significant savings in rig time and increased operating efficiency. This paper summarizes the practical experiences gained during the development and deployment of this integrated technique, in addition to an evaluation of the impact compared to the conventional perforation techniques through ESP downhole sensor data and well modelling.