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19/03/2015 News

New Technology on the Ofon Facility

The Ofon Phase 2 Project develops technical innovations to deliver industry success

  • Eliminating Gas Flaring
  • Driving Local Industrial Development
  • The Ultra-Filtration Package
  • Waste Heat Recovery Units (WHRU)
  • Habtag and Mobtag Solutions

Eliminating Gas Flaring

Ofon Phase 2 has monetized associated gas as an energy source and will eliminate the flaring of three million cubic meters per day when all twenty-four new Ofon2 wells are on stream. This is a major step forward in reducing Greenhouse Gas emissions on the Project.

Consistent with applicable Nigerian legislation and Total's stringent safety regulations, this example of sound environmental stewardship is helping Total to uphold its commitment to reduce the amount of associated gas flared on its operated sites. Indeed, the cessation of flaring on OML102 accounts for a 10% reduction in overall E&P flaring by the Group. 

Associated gas from Ofon is being piped more than 70 kilometers to the Amenam offshore gas hub. From there, the gas is exported to the onshore Bonny LNG plant and fed into Nigeria's natural gas distribution grid. Total is the first to achieve flare-out in its offshore operations in Nigeria.

Driving Local Industrial Development

The Phase 2 field development project marked a new chapter in the growth of Nigerian local content and in Total's support for host communities.

Before Ofon Phase 2, never had so many components of a Total project been manufactured locally in Nigeria. Total brings international contractors together with local businesses and communities to accelerate technology transfer, training and the hiring of local workers.

Five of the seven main Engineering, Procurement and Construction (EPC) contracts for the project were awarded to Nigerian businesses. For example, the piping and topsides to retrofit the existing facilities were fabricated locally. More importantly, the Ofon Living Quarters, providing safe and comfortable accommodation for staff working on the site, was wholly built in-country. This achievement is a first in Nigeria.

The Ultra-filtration Package

The ultrafiltration package filters seawater to remove suspended particles as small as 0.01 microns. The seawater is then piped to the deaeration tower before being routed to the water-injection systems for injection into the reservoirs. At a working production rate of 1668m3/hr under vacuum, the seawater deaerator removes dissolved oxygen (to a level of only 20 ppb).

The availability of the seawater treatment system is essential for Ofon field water injection. If water injection is shut down, oil production will be directly affected by the resulting reduction in reservoir pressure. The removal of dissolved O2 by the deaeration tower and by O2 scavenger injection makes reservoir souring less likely; failure of the de-aeration system can therefore promote bacterial activity which will negatively impact the reservoir. Sodium hypochlorite injection and periodic biocide treatment both help to prevent the growth of bacteria and other organisms in the seawater system and should be constantly maintained.

Waste Heat Recovery Unit

An ingenious solution that contributes decisively to the 'greening' of our industrial processes.

Total is significantly curbing energy consumption and Greenhouse Gas emissions offshore by reusing the heat from gas turbine exhaust gases. Waste heat recovery is an innovative technology used for the first time for shallow offshore oil facilities in Nigeria.

Ofon Phase 2 is synonymous with energy efficiency. The three Waste Heat Recovery Units (WHRU) on the new process platform will capture waste heat from the exhaust gases of the three gas turbines. The temperature of the exhaust gas stream can reach as much as 500°C, and this thermal energy will be recovered to heat water to a temperature of 170°C for use in separating associated gas from the crude oil produced.

These Waste Heat Recovery Units have two major advantages over conventional separation technologies deployed by Total to date. For a given separation performance, recycling this heat allows a lasting reduction in fuel requirements and therefore in energy costs. Waste heat recovery also eliminates the need to generate additional electricity to heat the crude oil.

Moreover, recovering heat from the combustion exhaust gases at the turbine outlet substantially reduces emissions, as it limits the need for combustion or thermal electric generation, both of which are significant aggravating factors in the Greenhouse Effect. It is an ingenious solution that contributes decisively to the 'greening' of Total's industrial processes.

Habtag and Mobtag Solutions:  Initiative to reduce accidents

To achieve the Ofon Phase 2 Project's objectives of flare-out and increased production, the Ofon field underwent large-scale Simultaneous Operations (SIMOPS) for more than 24 months. During this period, the Personnel On Board figure reached a maximum of 1,400 pax, with four or five accommodation barges present during peak activities.

Basically, the HABTAG and MOBTAG concepts were developed to ensure that a population of more than 1,400 personnel, working for multiple contractors in many different disciplines, could all understand and follow the same Total safety principles in a way that is practical, efficient and enforceable.

The two concepts offer a way to ensure that the “shopfloor workers” understand and can react instinctively to Total's safety rules. They offer a way to transfer many volumes of procedures into pragmatic, efficient and workable methods. They offer a way to tag, track and control safe behaviour on site that can be sustained during prolonged SIMOP durations (more than two years).