Oando Gas & Power’s 128 km pipeline project involves the construction of an 18 inch diameter pipeline from the existing Obigbo – ALSCON Pipeline at Ukanafun, Akwa Ibom state, to Mfamosing, near Calabar in Cross River state.

The pipeline is being constructed to supply natural gas to industrial areas in the southeast of Nigeria. In addition to the 100 km gas pipeline distribution network the company has constructed in Lagos, the project will service over 100 companies.

The foundation customer is United Cement Company which is estimated initially to offtake 22 MMcf/d to fuel to its new cement plant at Calabar.

Upon completion, expected in the first quarter of 2011, the transmission pipeline will deliver 100 MMcf/d of gas.

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Pipeline construction

Zishan Engineering completed engineering and design work on the pipeline, and construction began on the pipeline in November 2008.

Oilserv Nigeria Ltd is the primary construction contractor on the project. The scope of work under the contract includes right-of-way (RoW) survey; pipeline trench excavation; stringing and welding of the pipes; non-destructive testing of the welded joints; field-joint coating; flushing, hydrotesting and drying; and, execution of the associated civil works.

East Horizon Gas Company (EHGC) also subcontracted major aspects of the project, including horizontal directional drilling (HDD) and swamp pipeline construction, to local contractors Enikkom and MJD Oil Services respectively. In addition, EHGC engaged the services of NACE-certified Solewant/Kema Coating Nigeria Ltd to undertake corrosion coating of the field bends and their girth welds.

Oando Gas & Power is committed to safety, quality, health and environment standards. The pipeline design and construction is compliant with the ASME B31.8 standard, and the pipeline is fitted with pressure relief valves set at 10 per cent below the pipeline maximum allowable operating pressure.

The pipeline is built to the Nigerian standard of Class 2 Human Density. This category necessitates the installation of automatic line-break valves located at intervals prescribed by the applicable codes, and at the banks where the pipe crosses a waterway.

Challenges

The pipeline route is characterised by undulating and rocky topography. The RoW also has swampy areas, and the seasonal and recurring flooding along the route also presents some civil engineering and logistical challenges.

Pipeline construction in swamp areas were executed using anchor blocks to create required negative buoyancy for the welded pipeline, and to avoid flotation of the line. The trench backfill was also increased from 1.2 m to 2 m in these areas.

HDD was deployed at all the seven river crossings as opposed to the traditional ‘open-cut’ practice. This technique was chosen to mitigate the social and environmental impacts of the river crossing construction.

Thrust boring was also used for pulling the welded spool under major roads without affecting their integrity and structure.

EHGC held a number of ‘awareness sessions’ to educate host communities on the environmental, health and safety impact assessment of the project. Landowners whose farmland and trees were affected by the RoW clearing were duly compensated at levels determined by state government. In addition, community shrines and sacred areas were avoided, and cultural heritage sites along the pipeline RoW were also adequately compensated prior to relocation.

Oando investing in Nigeria’s pipeline future

In October 2010 Oando Chief Executive Officer Yomi Awobokun said the company will build 120 km of gas pipelines every 18 to 24 months as part of its plans to develop a gas grid that will feed power plants.

“We hope to reach all parts of the country with the gas grid in the coming years,” said Mr Awobokun.

“We have built a network in Lagos. We are doing the same in the east of the country, and very soon we shall start work in the west.”

The company also aims to replicate the success of the Greater Lagos natural gas distribution scheme in other parts of Nigeria and West Africa by making significant investments in pipelines and related infrastructure to ensure a reliable supply of natural gas.

The 128 km pipeline project is being completed to supply natural gas to industrial areas in the southeast of Nigeria.