7/27/2019 Nigerian pipeline completed through swamp, rock and forest

1/2

3 PiPelines international digest | deCeMBer 2011

key ProjeCts

The project involves construction of an 18 inch diameter

pipeline, which will transport 172 MMcf/d of natural gas

at a pressure of 70 bar from the existing Obigbo ALSCON

Pipeline at Ukanafun, Akwa Ibom state, to Mfamosing, near

Calabar in Cross River state.

A local inuenceEHGC ensured that local companies were involved in the

project, creating jobs in the local community.

The pipeline was designed and engineered by Zishan

Engineering Nigeria Ltd with indigenous rm Oilserv Nigeria Ltd

appointed as main construction contractor.

Major aspects of the project were subcontracted to local

operators, such as horizontal directional drilling awarded to

Enikkom and swamp pipeline construction awarded to MJD

Oil Services.

EHGC also engaged the services of Solewant/Kema Coating

Nigeria Ltd a NACE-certied indigenous rm to execute the

application of corrosion coating of the bends and their girth welds.

Host communities were educated on the environmental, health

and safety impact assessment of the project through several

enlightenment sessions that EHGC held.

Saety frstOando Gas and Power which is ISO 9001:2000 certied

ensured that the design and construction of the pipeline

project was compliant with the American Society of Mechanical

Engineers 31.8 standard.

Oando Gas and Power is committed to world-class operations

with strict adherence to safety, quality, health and environment

standards, said Oando Head of Upstream, Gas and Power

Projects John Alamu.

Nigerian pipeline completed

through swamp, rock and forestOando Gas and Power's subsidiary East Horizon Gas Company (EHGC) recently completed a 128 km pipeline to supplynatural gas to industrial areas operating heavy-duty power engines and equipment in southeast Nigeria, overcomingvarious terrain challenges along the way.

The gas pipeline under construction.

http://-/?-

7/27/2019 Nigerian pipeline completed through swamp, rock and forest

2/2

4 PiPelines international digest | deCeMBer 2011

key ProjeCts

To mitigate the social and environmental impact of

conventional, open-cut river crossing construction, all seven river

crossings were constructed using horizontal directional drilling.

Procedures and job hazard analyses were developed for all

activities with barriers, controls and recovery measures clearly

identied.

The end facilities were also tted with pressure relief valves set

at 10 per cent below the pipelines maximum allowable operating

pressure.

A challenging pipeline routeThe pipeline route traversed various challenging terrains

through swamp, forest and built-up areas, as well as throughundulating and extremely rocky topography.

The swampy nature of the right-ofway (RoW), and the

seasonal and reoccurring ooding of the land area presented

some civil engineering and logistic challenges, said Mr Alamu.

Mr Alamu described some of the initiatives which were

deployed to overcome these challenges.

In the extended swamp segment, the swamp constructions

were executed using anchor blocks in order to provide negative

buoyancy on the welded pipeline and to avoid oating.

The soil cover after pipe burial was also increased from 1.2 m to

2 m from the top of the pipe, said Mr Alamu.

In the forest and built-up areas, the pipeline network was

categorised at Class 2 HD, which necessitated the installation of

line break valves at intervals as prescribed by applicable codes.

The pipeline was located at the centre of a 15 m wide RoW.

Thrust-bore technology was also used to pull welded spools

across major roads. This innovation allowed for the preservation

of the roads integrity and structure.

Mr Alamu said that community shrines and sacred lands were

avoided; however, some cultural heritage sites were unavoidably

located in the pipeline RoW.

Relevant parties were adequately compensated for these sitesprior to their relocation. Landowners were also compensated as

required by the State Government for all farmlands and trees that

were aected.

In September 2011 just under three years after Oilserv Nigeria

rst mobilised to site in November 2008 the pipeline reached

technical completion.

Pre-commissioning was completed in October 2011, gas was

introduced into the pipeline by the end of October, and the

system was nally stabilised on the 3 November 2011.

Oando Gas and Powers city gate facility for its recently completed gas pipeline.

http://-/?-