SHANGHAI/HONG KONG, March 31 (Reuters) - CNOOC Ltd , China's top offshore oil and gas producer, plans to raise about 35 billion yuan ($5.5 billion) next month in what will likely be China's 10th-biggest listing, to fund oil and gas extraction as Beijing prioritizes energy security amid rising geopolitical tensions.

State-owned CNOOC, which is blacklisted by Washington, said in a prospectus on Thursday it plans to sell 2.6 billion shares on April 12 and list thereafter on the Shanghai Stock Exchange.

CNOOC is taking advantage of soaring global oil prices as Russia's war on Ukraine pushes up already high inflation. CNOOC expects first-quarter profit to jump 62%-89% from a year earlier and its Hong Kong-listed shares hit two-year highs on Wednesday.

The oil giant said it would use the share sale proceeds to fund one gas and seven oilfield projects in China and overseas, and to replenish capital.

The company said in September it aimed to raise up to 35 billion yuan, potentially making the share sale China's 10th largest on record, trailing China Railway Construction Corp's 2008 initial public offering, according to Refinitiv data.

"China's demand for oil and gas has been steadily rising, and its dependency on oil and gas imports increases every year .... The supply-demand situation is very grave," CNOOC said in its prospectus on Thursday.

"With China's demand for oil and gas rising, and the government's high attention to energy security, we expect Chinese investment in oil and gas exploration will increase further."

CNOOC said it had no business in Ukraine, but its 10% stake in the Arctic LNG 2 project in Russia could be vulnerable to financial sanctions triggered by Russia's military operations.

CNOOC, whose U.S. shares were delisted by the New York Stock Exchange in October after Washington added it to an economic blacklist, said it could face additional sanctions.

"We cannot predict if the company or its affiliates and partners will be affected by U.S. sanctions in future, if policies change," CNOOC said.

CNOOC is preparing to exit one of the North Sea's largest field in a strategic shift of focus to newer oil and gas developments and away from Western assets, banking and industry sources told Reuters.

($1 = 6.3489 Chinese yuan renminbi) (Reporting by Shanghai Newsroom Editing by Stephen Coates and Mark Potter)