According to Reuters, the pair have kicked off a simultaneous sale of offshore natural gas assets in the southern UK and Dutch North Sea.
The news agency quoted three industry and banking sources.
Jefferies has allegedly been hired to run the sales process, which could yield over $2 billion.
Launched earlier this month, it comes after Shell and Exxon ran initial sales processes for their British and Dutch assets.
Shell, Exxon and Jefferies declined to give a comment to Reuters.
The sale of UK assets contains Shell and Exxon’s stakes in their “British southern North Sea gas hub”, including the Clipper Leman Alpha complex, as well as the Bacton terminal in Norfolk, Reuters said.
In July, the pair begun the process of selling their 50-50 NAM joint venture in the Netherlands.
It operates the Groningen gas field and is one of Europe’s largest and oldest natural gas production companies.
NAM has also launched the sale of its offshore assets independently, one of the sources quoted by Reuters said.
According to the news agency, the sale of the Southern North Sea and offshore NAM assets are separate, allowing for a single or multiple buyers.
They form part of the oil giants drive to remove ageing oil and gas initiatives from their portfolios in favour of new projects.