Successful First Offshore Fully Retrievable ESP System Installation in Congo
Authors: Rizza G. , Pilone S. , Bespalov E. , Drablier D. , Okassa F.D. , Tita G.E. 
Published: March 2015

The world's first offshore Rigless Fully Retrievable Electric Submersible Pump (RFR-ESP) system has been successfully installed in the eni Congo Foukanda Field (Republic of the Congo). The project was developed between eni Milan and eni Congo as an Innovation Technology Application (ITA), and it is the world's first offshore RFR-ESP system. The RFR-ESP technology provided by ZEiTECS allows the rigless deployment and retrieval of a conventional Electric Submersible Pump (ESP) system through tubing by means of standard oil field wireline, rod or coil tubing technology. The RFR-ESP system technology is based around a specially designed oilfield wet connector system. This "plug and play" connector design permits the use of any ESP manufacturer's equipment, allowing ESP optimization to match changing well conditions and replacement of failed ESPs without rig interventions; thereby providing an opportunity for OPEX savings, a significant reduction in workover costs and deferred production due to limited rig availability. The success of the first RFR-ESP completion and the positive results achieved to date are encouraging in the pursuit of extending this innovative and valuable ESP completion philosophy to eni Congo wells where ESP failures are primarily related to pump or motor and workover cost are high. The paper describes the technical features of the new RFR-ESP completion, the experience acquired on the Foukanda well and shows, via theoretical study, the economic implications of applying this new ESP philosophy in all the eni Congo high OPEX wells.

Introduction

Electric Submersible Pumps (ESPs) have become a reliable and important tool in today's global oilfield. ESP technology itself has evolved to meet new, more challenging, operating environments but, nevertheless, the vast majority of ESP deployments use techniques developed decades ago. ESP systems are still installed using jointed pipe, lowered with a pulling unit, drilling or workover rig while power cable is secured to the tubing by means of metal clamps or bands. Even acknowledging the fact that the reliability of ESPs has increased tremendously since their first introduction, some form of remedial work will be required multiple times during the life of a producing field. If that work requires a pulling unit, a drilling or workover rig, the economics of field development may become unfavorable. Eni is looking at reducing its ESP operating costs and, in doing so, decided to evaluate the relative merits of "alternative" ESP deployment options. The RFR-ESP provided by ZEiTECS was selected for an offshore test installation in one of the eni Congo fields. The RFR-ESP technology represents a step change in ESP operating philosophy. ESP replacement without a hoist reduces operational disruption, reduces OPEX and deferment in production but, moreover, has profound safety and cost advantages with elimination of a number of the heavy offshore well interventions. To gain confidence in the new technology and in its new deploying mode, eni selected the well FOKM 101, located on the eni Congo offshore Foukanda platform.