The Eagle Ford shale just keeps getting hotter.

In the fossil-fuel-rich South Texas region's latest deal, Marathon Oil (NYSE: MRO) paid $3.5 billion on Nov. 1 to the private equity firm Kohlberg Kravis Roberts & Co. and closely held Hilcorp Energy Co. for 141,000 Eagle Ford acres.

That's $21,000 an acre, compared to the $1.55 billion, or $16,000 per-acre, which Korea National Oil paid in March. That payment essentially served as an entry fee for the Korean company's joint venture with Anadarko Petroleum (NYSE: APC).

In November, China's CNOOC (NYSE: CEO) cut a deal with Chesapeake (NYSE: CHK) to ultimately fork over $1.27 billion for a one-third interest in Chesapeake's 600,000 net acres -- the largest position in the play -- plus a 75% "carry" for Chesapeake's future drilling costs.

Marathon's Eagle Ford deal occurs as the company is preparing to spin off its refining and sales business from its exploration and production unit. The deal should close by the end of this month. Shareholders will receive one share of the new downstream company, Marathon Petroleum, for every two shares they hold of Marathon Oil.

The two companies will operate completely separately following the spinoff. While Marathon Oil will remain in Houston, Marathon Petroleum will be headquartered in Findlay, Ohio. It will include the company's six current refineries, with a combined capacity of 1.1 billion barrels per day, along with the marketing and pipeline transportation operations. It is expected to be listed on the New York Stock Exchange under the symbol "MPC."

Regarding the newly announced deal with KKR and Hilcorp, Marathon CEO Clarence P. Cazalot said, "This transaction enhances our already strong North American position." Marathon Oil produced 412,000 barrels of oil equivalent per day last year. Cazalot believes the new company will increase that figure by 5% to 7%, up from a prior expectation of 3% to 5%. Along with such other companies as ConocoPhillips (NYSE: COP) and Repsol (NYSE: REP), Marathon has halted its operations in Libya, where it produced about 46,000 barrels per day in 2009.

In considering the planned acreage acquisition at Marathon, my recommendation to Fools is twofold: I would add Marathon Oil to your watchlist, but avoid acquiring shares until the dust settles from its pending changes. At the same time, I'd ascertain that Chesapeake, which maintains larger positions in virtually all the nation's shale plays -- along with an integrated structure that includes oilfield services capabilities -- also enjoys a watchlist position.

Motley Fool newsletter services have recommended buying shares of Chesapeake Energy. Try any of our Foolish newsletter services free for 30 days.

We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Fool contributor David Lee Smith doesn't own shares in any of the companies named above. The Motley Fool has a disclosure policy.