Sinopec, the parent of Hong Kong-listed Sinopec Corp , gave no financial details of the transaction of block D, which is awaiting approval from regulators, nor did it give any estimate of the reserves.
The block, over which Sinopec acquired full exploration rights in 2004 from Myanmar Oil and Gas Enterprise, sprawls over 12,000 sq. km near Myanmar's second-largest city of Mandalay.
There have been three oil and gas discoveries at the six exploration wells drilled in the onshore block, CPC said on its website.
Last month, CNPC, the parent of PetroChina, entered a joint exploration pact with CPC to hunt for oil in Niger, as well as a long-term crude supply deal.
State-run CNOOC, parent of offshore oil and gas specialist CNOOC Ltd, also agreed last month to supply the Taiwanese firm liquefied natural gas.