TDW successfully isolates sections of the Chad-Cameroon pipeline

With the completion deadline of the massive Lom Pangar dam construction project looming on the horizon, a leading Italian construction firm has been hard at work in the jungles of Cameroon modifying sections of the Chad-Cameroon pipeline. The necessary modifications had to be made well before the pipeline is submerged in the reservoir when the dam becomes operational later this year.

Described by Michael Ngako Tomdio, Minister of Energy and Water for Cameroon, as the “keystone in the arch of the Cameroonian electric system," the Lom Pangar Dam will generate electricity for industry and millions of residents throughout Cameroon. In preparation for constructing the dam, extensive environmental assessments and studies were carried out, revealing that two sections of the pipeline would be flooded in the reservoir when the dam is completed, so they would have to be modified.

Protected wildlife reserve demands care and vigilance

It was essential that there be minimal impact on the surrounding environment, which is a semi-deciduous rainforest and the home of Cameroon’s Deng Deng National Park. The park is a wildlife-protected zone that boasts a rich variety of wildlife, including primates, so it was critical that every precaution be taken to ensure that the pipeline modifications be carried out flawlessly.

The Chad-Cameroon pipeline extends 1080 km from Chad to Kribi, Cameroon on the Atlantic coast. It transports oil from Chad through Cameroon’s coastal port, where it is exported. The two 13 km pipeline sections in need of modification lay in partial jungle terrain east-northeast of Douala. The objectives of the modification program were to re-route and strengthen the two pipeline sections to ensure that they would be capable of supporting 20 m water columns that would eventually be installed upon completion of the dam.

Tasked with executing the entire pipeline modification project, the construction firm retained T.D. Williamson (TDW), specialising in pipeline intervention and pressure isolation services, to isolate the live pipelines so that repair or modifications could be made safely, without disrupting product flow.

Working in the jungle heat, the TDW team, consisting of four technicians based on-site throughout the operation, carried out more than 30 hot tap and plugging operations to isolate pressure in the two sections. TDW used the tandem STOPPLE® pipeline pressure intervention method to achieve a Double Block and Bleed isolation, which makes it possible to cut, plug and safely isolate pressure from the sections without shutting them down, which would have resulted in disruption to flow.

While the lines were safely isolated, providing a safe working environment, the necessary modifications to the lines were made so that they could be re-routed. Each line was safely isolated for approximately 20 days while the tie-ins were completed. The entire pipeline intervention operation, from deployment to completion of the final intervention, was completed by TDW well within the four month timeframe.

The isolation made it possible for TDW’s customer to connect the existing pipeline to new pipeline, safely and efficiently. Maintaining product flow throughout this complex operation was critical, so TDW’s ability to make that possible was key.

Operating in the remote jungle, in such hot and humid conditions, called for detailed planning in logistics and operational safety. In addition, given that the pipelines were located in jungle terrain, TDW worked closely with the construction firm to plan every move very carefully, especially in terms of personnel safety and transporting equipment and materials.

“We worked very closely with this construction firm which, like TDW, has vast experience in executing pipeline operations in remote, harsh environments, “ said Alexandre Flamand, Project Manager – Europe/Africa/Middle East for TDW. “As a result, our joint efforts and shared commitment to careful planning and high levels of safety led to a successful result: the timely completion of the tie-ins, with an absolute minimal impact on the environment,” he added.

Adapted from press release by Hannah Priestley-Eaton

Read the article online at: https://www.worldpipelines.com/business-news/17062014/tdw_successfully_isolates_sections_of_the_chad_cameroon_pipeline/