Pearl River Mouth Basin

Asset overview - Block 03/33

Pearl River Mouth Basin, South China Sea, offshore China

One development area around the HZ12-7 & HZ12-5 discoveries, totalling 40km2 in approx. 114m water depth.

Operator Roc Oil (China) Company
JV partners and interests

Block 03/33

Development Area
Roc Oil (China) Company 
CNOOC Limited 50%
CNOOC has the right to participate in up to 51% of ROC's interest in any development. If exercised in full, CNOOC's interest would be 75.5% and ROC's interest would be 24.5% in development, following FID.

Development feasibility studies are in progress.


ROC and CNOOC signed Petroleum Contracts for two blocks on 19 August 2015; blocks 03/33 and 16/07, with ROC 100% interest and operator.

In 1H 2018, ROC drilled the HZ12-5-1 exploration well in block 03/33 which was plugged and abandoned as an oil discovery.  

CNOOC subsequently farmed into the blocks for 50% interest..

In 2019, two exploration wells drilled in block 16/07 were dry and the block was relinquished in August.

In 1Q 2021, CNOOC and ROC drilled the HZ5-1-1d exploration well in block 03/33 which was plugged and abandoned as a dry hole.

The third well in block 03/33, HZ12-7-1, was jointly drilled by ROC and CNOOC in 2022.  The well discovered oil in the Enping with a total of nearly 50m net vertical oil pay and flowed oil from a single zone on a drill stem test (DST) at a rate of over 1,000 barrels per day by natural flow.  This is the first commercial-scale discovery in the block.

Potential STOOIP resources for the HZ12-7 and HZ12-5 discoveries were accepted by the relevant Chinese governing body in December 2022.  The JV is working on subsurface studies and development feasibility studies, with an aim of a final investment decision on development to be made in 2026.

Following review of remaining exploration prospectivity in the block is in 2023, a decision was made to relinquish all exploration areas, retaining only a development area around the discoveries.