China National Offshore Oil Corporation is offering some prime frontier deep and ultra-deepwater acreage as part of the country’s latest batch of blocks up for grabs, mainly in the company’s current focus area for deepwater exploration and development, the South China Sea.

The company is inviting foreign companies to bid on 25 oil and gas blocks covering 102,577 sq km, with 15 of the blocks in the Eastern and Western sectors of the South China Sea. The other blocks in shallower waters are located in the East China, Yellow and Bohai seas. The deadline for bids is set for 30 April, 2014.

There are 10 deepwater blocks in the South China Sea’s eastern waters:

• Block 29/31 – located in Baiyun Sag in the Pearl River Mouth Basin, with water depths ranging from 700-1,000 m (2,296-3,281 ft) and covering an area of 1,170sq km. Up to now, says CNOOC, there is full coverage of 3D seismic data over the block, where one well has been drilled.

• Block 29/27 – located also in Baiyun Sag in the Pearl River Mouth Basin, with water depths again ranging from 700-1,000 m and covering an area of 740 sq km. Once more there is full 3D seismic coverage over the block, although no wells have been drilled so far.

• Block 29/24 – another located in the Baiyun Sag area of the Pearl River Mouth Basin, with similar waters depths to the blocks above, and covering an area of 2,271 sq km. There is 3D seismic coverage over the block, with no wells drilled so far.

• Block 42/08 – this is located in Yunkai Low Uplift of the Pearl River Mouth Basin, with water depths ranging from 1,000-1,500m (3,281-4,921 ft) and covering 1,608 sq km. Up to now, there are 2,580km of 2D and 630 sq km of 3D seismic data over the block, with one well having been drilled.

• Block 30/19 – this lies in the cross area between Dongsha Massif and Southern Massif Belt of the Pearl River Mouth Basin, with water depths ranging from 700-1,000 m and covering an area of 2,274 sq km. Up to now, there are 2,166km of 2D seismic data shot in the block, with no well drilled thus far.

• Block 42/19 – located in the Southern Massif Belt of the Pearl River Mouth Basin, with water depths ranging from 1,000-1,500 m, and covering an area of 3,304sq km. Up to now, there are 5,212km of 2D seismic data over the block. No well has been drilled in this block.

• Block 55/03 – this is located in the Southern Massif Belt of the Pearl River Mouth Basin, with water depths ranging from 700-2,000 m (2,296-6,562 ft), and covers an area of 6,009 sq km. There are 3,280km of 2D seismic data shot in the block, with no well yet drilled.

• Block 55/12 – this block lies in the Heshan and Changchang Depression of the Pearl River Mouth Basin, with water depths ranging from 1,500-3,000 m (4,921-9,843 ft) and covering an area of 6,498 sq km. Up to now, there are 2,454 km of 2D seismic data over the block, where no well drilled at present.

• Block 44/07 – this is located in Xingning Sag of the Pearl River Mouth Basin, with water depths again ranging from 1,500-3,000 m and covering an area of 5,366sq km. Up to now, there has been 2,165km of 2D seismic data shot over the block, with no well yet drilled.

• Block 30/01 – this block lies in Dongsha Massif and Chaoshan Depression of Pearl River Mouth Basin, with water depths ranging from 500-700 m and covering an area of 5,102 sq km. There have been 2,602 km of 2D seismic data shot in the block, with no wells drilled.

There are a further five deepwater blocks in the west of the South China Sea:

• Block 64/17 – this lies in the southern slope of Lingshui Sag of Qiongdongnan Basin, with water depths ranging from 1,000-1,600m (3,281-5,250 ft) and covering 1,656 sq km. Up to now, there are about 2,157 km of 2D and 1,100sq km2 of 3D seismic data in the block, with one gas well drilled there.

• Block 64/03 – located in the centre of the Lingshui Sag and Songnan Low Uplift of Qiongdongnan Basin, it has water depths ranging from 200-1,300 m (656-4,265 ft) and covers an area of 2,237sq km. Up to now, there are about 2,700 km of 2D and 800 sq km of 3D seismic data over the block, with one well drilled with gas shows.

• Block 64/26 – lying in the north of the Lingnan Uplift of Qiongdongnan Basin, with water depths ranging from 700-1,200 m, this covers an area of 592 sq km. There are about 1,442 km of 2D seismic data and 513 sq km of 3D seismic data shot over the block, where no well has yet been drilled.

• Block 53/32 – this is located in the southern slope of Baodao Sag and part of Songnan Uplift of Qiongdongnan Basin, with water depths ranging from 1,500-2,000 m and covering an area of 1,756 sq km.

• Block 53/36 – this block lies in the Changchang Sag of Qiongdongnan Basin, with water depths ranging from 1,500-2,200 m and covering an area of 1,982 sq km.