HOUSTON, June 21 (Reuters) - Exxon Mobil Corp (XOM.N) and Guyana are in talks over which unexplored offshore areas will be returned to the government, people close to the discussions said, as the nascent oil nation seeks to attract new operators to the country. The Exxon-led consortium that controls offshore production in Guyana this year was required to return 20% of unexplored acres, under the original 2016 production contract. Reuters Graphics Reuters GraphicsCONTRACT FORCE MAJEUREThe relinquishment deadline for the 20% unexplored portion of the Stabroek block is due in October, one of the people said. Guyana plans to hold its first competitive oil blocks auction in August, which it expects to attract new operators to the country. It will offer 14 offshore blocks outside the Exxon group's domains.

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Persons: Hess, Sabrina Valle, Lincoln Organizations: Exxon Mobil Corp, Exxon, HK, Reuters Graphics Reuters, Guyana's Energy Ministry, Thomson Locations: Guyana, U.S