chevron completes subsea engineering feat in africa
August 18, 2015 – Chevron recently achieved a technological feat in the depths of one of the world's largest underwater canyons. With vital right-of-way permits approved by the governments of the Democratic Republic of the Congo and Angola, Chevron has completed the drilling of a well intersection conduit beneath the Congo River submarine canyon, part of the Congo River Canyon Crossing pipeline project.
To create the intersection, two wellbores were drilled simultaneously from shallow water platforms located on each side of the canyon. One of the platforms is located in the Democratic Republic of the Congo while the other platform is located in Angola. The wellbores transitioned from vertical to horizontal, and then intersected almost midway beneath the canyon, approximately 2,000 feet (610 m) beneath the seabed, where the water depth is one-half mile (0.8 km).
"The Congo River well intersection is a major engineering feat," said Ali Moshiri, president of Chevron Africa and Latin America Exploration and Production Company. "And with the drilling platforms and subsea structures having been fabricated in-country, this project is another prime example of Chevron's commitment to helping fuel Angola's economic development."
The Congo River crossing is Chevron's largest-ever well intersection and it is the most technically challenging aspect of the pipeline project. The well intersection provided the most secure method of crossing the canyon and connecting to the pipeline at the platforms located on each side of the canyon.
"This was the most unique well intersection project of its kind ever undertaken by Chevron—and the very first in the industry performed offshore," said Ben Leonard, project drilling manager for Chevron's Southern Africa strategic business unit. "Other intersection projects have involved drilling under highways or riverbeds, but this one is more than 10 times the length of a routine crossing."
Several innovative technologies and processes were employed during the drilling of the well intersection. For example, an active magnet ranging technology was used to direct the drilling assembly so that the wellbores merged precisely on a target roughly the size of a basketball. This involved a magnetic sensor in the drill string on one side and a powerful magnet, located behind the drill bit, on the other side.
An additional challenge for the project team was to install the two offshore platforms in an area close to the mouth of the Congo River where there are strong currents.
The pipeline will transport natural gas from Angola's offshore Blocks 0 and 14 to the Angola Liquefied Natural Gas (LNG) Plant, the country's first LNG project. When completed, the pipeline will be approximately 87 miles (140 km) in length and initially transport up to 250 million cubic feet of natural gas per day.
Published: August 2015