Block 09/05 covers 355 square kilometres in water depths of four to ten metres and lies 50km south-east of Tianjin.
Under the terms of the contract, Roc Oil (Bohai) Company will collect 3D geological data and drill wells on the 09/05 oilfield during the exploration period, said CNOOC.
The contract entitles CNOOC to have a maximum 51% stake in any commercial oil and gas operations in the oilfield block.
Alan Linn, ROC chief executive officer, said the award of this under-explored block in a prolific basin is an exciting addition to Roc’s portfolio.
"With success, we expect to leverage our existing operating strengths within Bohai to accelerate the development and production of any commercially attractive discoveries," Linn added.
The block exhibits sag zone characteristics with stacked clastic reservoir potential, similar to the producing multilayered sands at its Zhao Dong field about 15km to the north.
Previous exploration activity within the block included wide-spaced 2D and limited 3D seismic acquisition, plus two exploration wells were drilled on the block prior to 3D seismic processing.
Roc’s minimum work commitment for the first phase of exploration will include drilling of exploration wells. Upon completion of the first phase, the company will carry out two further optional two-year exploration periods with additional commitments.