OML58- Upgrade: Rejuvenating a 40 year old oilfield onshore Nigeria through Heavy Simultaneous Production and Construction Operations.

Abstract It is a unique situation amongst the fields operated by Total that has recently taken place on the OML58 Oil and Gas facilities located in the Niger Delta area of Nigeria. Major financial investments over 4 years, and more than 4000 workers at peak on the different locations of the field, for a total of more than 20 millions worked hours, were necessary to complete the first phase of the transformation of an oil producing site into a gas producing site. Eventually, the field will have its life extended for another 30 years, but if it is mainly oil that has been produced so far, 80 % of the future production will be gas. These few figures illustrate what is at stake in a region where Total has been operating for over 45 years and has confidence to go further and bring the installations to their full production capacity. Right from the beginning, it was decided that Simultaneous Production and Construction Operations (SIMOPS) would be the mode of operations. Large scale SIMOPS on remote existing aging facilities, spreading over years, is definitely not a usual challenge. It is even more difficult when it takes place on running installations where gas under high pressure circulates almost everywhere. Therefore, a dedicated organization allowing a strict control of the SIMOPS was implemented. The paper will describe the advantages of a transversal approach where production operations teams and construction teams are aligned on common shared objectives. It will also show how a challenging operating approach in a difficult context (unknown underground conditions, aging facility challenges, etc) can lead to a significant reduction of production short-falls without compromising safety. Furthermore, the case will also highlight how such a big project can positively impact the development of local communities and participate to their sustainable development.