With the announcement Monday that it would pay up to $2.2 billion for a one-third stake in Chesapeake Energy assets, CNOOC lays claim to a share of properties that eventually could produce up to half a million barrels a day of oil equivalent.

It also might pick up some American know-how about tapping the hard-to-get deposits trapped in dense shale rock formations, analysts said…

“From the Chinese perspective, this is a golden opportunity for them. They have identified shale resources in China, but they don’t have the knowledge or technical expertise to go after those resources,” said Ken Medlock, a fellow at Houston’s Baker Institute and adjunct professor in Rice University’s economics department.