China National Offshore Oil Corp (CNOOC), China's largest offshore oil producer, said that its $15.1 billion acquisition of Canadian oil and gas company Nexen Inc is worth the money, in response to widespread concern that the deal may be overpriced, the Shanghai Securities News reported Tuesday.

"The one-year acquisition process was filled with hardships. Its success has big significance and value to the company," Wang Yilin, chairman of CNOOC, told the newspaper.

Wang said that CNOOC targeted Nexen because of its huge shale gas resources in Canada. "The asset is in accordance with CNOOC's long-term strategy, and the price also conforms to the level of the industry, so we did not overpay for it, but rather we paid the right price," Li Fanrong, CEO of CNOOC, told the newspaper.

The deal, sealed on February 26, was the largest overseas acquisition by a Chinese company so far, but as part of the takeover CNOOC will also absorb Nexen's $4.3 billion in debt, causing analysts to worry that the debt-burdened firm came at too high a price. 

CNOOC has a very low debt ratio, so adding Nexen's $4 billion debt will not increase the debt ratio past 30 percent, said Zhong Hua, CFO of the company.