Chevron Corp. (NYSE: CVX), the second-largest U.S.-based oil and gas major behind ExxonMobil (NYSE: XOM), is doing its part to demonstrate the increasing importance of the South China Sea among the Big Oil companies.

The company has acquired operating interests in three oil and gas exploration blocks in the Asian waters from Devon Energy (NYSE: DVN). At the same time, BP (NYSE: BP) has gained permission from Chinese authorities to take a portion of one of the blocks. Terms were not announced, as was the case with Chevron's acquisition of three deepwater concessions offshore Liberia this week.

BP bought Devon's assets in three worldwide venues earlier this year. BP this week released its report on the April 20 Deepwater Horizon oil rig explosion and ensuing oil leak in the Gulf of Mexico. BP and Transocean (NYSE: RIG), along with Halliburton (NYSE: HAL), were completing the deepwater Macondo well when the explosion occurred.

Under the new agreement announced by Chevron and China's CNOOC (NYSE: CEO), Chevron is retaining 59.18% of block 42/05 from Devon, with BP taking the remainder. That split appears to constitute at least something of an imprimatur among foreign governments regarding BP's continued participation in their acreage holdings. Further, the acquisition indicates renewed attention among the majors to the South China Sea, following decades of disinterest in the area.

Block 42/05 lies in Baiyun Sag at the mouth of the Pearl River basin in the eastern portion of the sea. It covers almost 2,700 square miles, with water depths ranging from 650 feet to 6,500 feet. The other two blocks, 64/18 and 53/30, in which Chevron will acquire 100% interests from Devon, are in the Qiong Dong Nan Basin in the western South China Sea. CNOOC will be able to participate up to 51% in any commercial discoveries made by the Western companies.

As my Foolish colleague Toby Shute noted earlier this year, Devon sold BP all of its deepwater assets in the Gulf of Mexico, Brazil, and Azerbaijan for $7 billion, as part of a decision to concentrate onshore in North America. The Oklahoma City company concurrently paid $500 million for 50% of BP's interest in the Kirby oil sands project in Alberta, Canada.

I'm an energy price bull -- at least given a two-year time frame -- so I'm also a believer that Fools' portfolios should include ample representation in the sector. And while I'm most intrigued by Chevron's increasingly active approach to its business, I'd be sheepish about attempting to talk you out of any of the companies named above.

Chevron is a Motley Fool Income Investor recommendation., and CNOOC is a Motley Fool Global Gains selection.  The Fool owns shares in ExxonMobil and Devon Energy.  Try any of our Foolish newsletter services free for 30 days. True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community.

Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned in this article. The Motley Fool has a disclosure policy.