Manifa: A feat in offshore engineering

Manifa: A feat in offshore engineering
Published: 2 June 2019 - 9:15 a.m.
By: Carla Sertin

Working offshore requires the right mix of finesse and durability, environmental awareness and operational efficiency.
The field was first discovered in 1957, a six-reservoir field 45km long and 18km wide, in water 15m deep. It sits in a delicate environment of seagrass and coral reefs, home to sea snakes, crabs, dolphins, sea turtles and more. With valuable resources so close under the water, the environment was a clear concern, as conventional drill rigs for shallow water could harm the habitat.

“The challenge was the reach the oil without destroying the environment, so the team had to think outside of the box and come up with a radical solution,” says Faisal Nughaimish, drilling general supervisor at Saudi Aramco, according to a written statement on its website.

In 2006, the company invested $10bn into the project to find out how it could extract hydrocarbons from the reservoir without harming the delicate marine ecosystem.

Saudi Aramco says that its new approach required a multidisciplinary team of engineers, environmental protection officials, scientists, geologists and marine specialists, as well as “technology that didn’t exist yet.”

Essentially, the company turned an offshore environment into onshore fields, developing 27 man-made islands, each as large as 10 soccer pitches, made using 45mn cubic metres of sand from the seabed. The islands became onshore drill sites for the offshore field.

The islands are linked by a 41-km causeway. Originally meant to extend across the bay’s coast, research found that water circulation was important to maintain the environment and to allow marine life to move freely. Openings were put in between the causeway and coastline, meaning that 13 bridges were added to the project.

All of this work meant 4mn hours were spent on the design phase, and more than 136,000 engineering drawing and plans were made to create this engineering feat—27 islands, 13 bridges, 13 offshore platforms, 15 onshore drill sits, 350 wells, injection facilities, pipelines and a 420-megawatt heat and electricity plant.

“There was a lot of innovation,” says Mohammed Abdulkarim, manager of the Manifa Project Department at Saudi Aramco. “We looked at ways and means to challenge ourselves, and the program was accomplished under budget.”
The six reservoirs are stacked on top of one another, adding another challenge to extracting hydrocarbons from Manifa. In response, Saudi Aramco built its nuclear magnetic resonance tool to create real time 3D profiles of the different layers. Using this technology, geologists could “accurately tap into reserves at extreme distances, through a heavy layer of tar, from wells on the surface.”

It wasn’t until 2013 that oil production began, three months ahead of schedule and more than $1bn under budget. In July 2013, Manifa produced 500,000bpd, and in 2017 it reached its target of 900,000bpd.

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