CNOOC announced on 8 December 2017 to confirm a medium-size gas field discovery, BZ 19-6, in Bohai offshore, Bohai Gulf Basin.  BZ 19-6-1, discovery well, completed in April 2017 and has a TD of 4,180 m. During drilling the well penetrated 25 m oil pay and 348 m gas pay in the pre-Tertiary buried hill reservoir. The following appraisal well, BZ 19-6-2 and BZ 19-6-3, achieved average testing rate of 1,000 b/d of oil and 6.4 MMcf/d of gas.  BZ 19-6 field discovery demonstrates the good prospects of buried hills for future gas exploration in this area of Bohai offshore. Currently most fields in the Bohai area have reservoir in the Tertiary, few fields has reservoir in buried hill, and also no significant gas field has been found in Bohai offshore.  Bozhong 19-6-1 (BZ 19-6-1), a new-field wildcat, is drilled in the Bozhong Depression in 20 m of water. The well is located in the east of BZ 19-4 field and drilling target is mainly at the Upper Tertiary Minghuazhen and Guantao formations. âBohai 4â J/U is used for drilling operation. Â  BZ 19-6-1 was spudded in December 2016 and completed in April 2017. It was reported as discovery well in the company 2017 mid-year review in August 2017. Â Â  Background information The BZ 19-4 fields is comprised of three fault blocks, BZ 19-4, BZ 19-4N and BZ 19-4S. The discovery of the field actually can be traced back to 2003 when BZ 19-4-1 tested oil flow from the Dongying Formation of the Lower Tertiary. In 2005, BZ 19-4N-1, north of the BZ 19-4-1, tested oil from the Guantao and Minghuazhen formations of the Upper Tertiary, the following appraisal well BZ 19-4N-2D confirmed the reservoir. Again in 2005, BZ 19-4S-1, south of the BZ 19-4-1, tested oil from the Guantao and Minghuazhen formations as well. The field overall holds about 300 MMbbl of oil in place.  BZ 19-4 block was first put on stream in 2010 and followed by BZ 19-4N and BZ 19-4S. The whole field produced at a rate of 8,000 b/d of oil.  BZ 19-4 is jointly developed by CNOOC US supermajor Chevron. Operator CNOOC holds 83.8% interest, while Chevron holds the remaining 16.2% interest.  Â 
China (Bohai Gulf B.) ? op. by CNOOC TJ (100.0%) in Bozhong block