Roc Oil has begun production from its first appraisal well drilled on the Zhanghai block in Bohai Bay, offshore China.

The company started drilling well ZD CP2N-H-1 from the Zhao Dong C4 platform and encountered 310m of a horizontal reservoir section.

Production through existing C4 facilities started at an initial rate of 3,546 barrels of oil per day.

Roc said PetroChina exercised its rights under the production sharing contract to participate with a 51% interest in the new Zhao Dong blocks on the commencement of completion activities and the commercial development of the well.

This resulted in the reduction of Roc’s interest in the new blocks from 80% to 39.2% and that of joint venture partner Sinochem from 20% to 9.8%.

The company will drill a second appraisal well during 2012 and will bear an 80% cost obligation on a dry-hole basis.