PetroChina â Liaohe achieved significant gas flow in the Bohai Gulf Basin on 7 May 2020. Jiatan 1, a NFW, tested 11.5 MMcf/d of gas through an 8 mm choke from volcanic rock (Basalt) in the Tertiary Shahejie 3 Formation at an interval between 4,360 and 4,396 m.   Jiatan 1 is located in the East Sag of the Liaohe Depression, the Bohai Gulf Basin. The well has a PTD of 4,800 m and reached a TD of 4,428 m. During the midway test in drilling operation, the well also tested gas at shallower interval of 3,904 to 4,000 m in another volcanic rock (Diabase).    The success of Jiatan 1 indicated a volcanic gas play fairway of 146 sq km in Jiazhangsi-Taoyuan-Dapingfang area in the East Sag with potential geological gas resources of 4 Tcf.   PetroChina made discovery in the Tertiary volcanic in 1971 when Re 24 tested commercial oil and gas in the East Sag. There have been several fields with reservoir in the Shahejie 3 Formation Volcanic rock in this area, such as Oulituozi, Rehetai and Qinglongtai. Key exploration risk for this play is reservoir quality and effective seal.   For the last 10 years, PetroChina has made success in this volcanic reservoir exploration in the Liaohe Depression since Hong 22 tested oil and gas in 2007, followed by Hong 23, Hong 24 and Hong 28.   In 2016 Jia 33 tested 490 b/d of oil from volcanic in Shahejie 3 Formation.  In 2017 Jia 34 tested 311 b/d of oil and 250 Mcf/d of gas from a volcanic rock interval in the Shahejie 3 Formation.   Background Information  PetroChina has operated in the Liaohe Depression for more than 45 years. By end 2018 the company had found 40 fields with 17 billion bbl of oil in place and produced cumulative 3.2 billion bbl of oil. The main reservoir is the Tertiary clastic rock, the Ordovician and pre-Cambrian basement are also important reservoir. In past few years the company achieved exploration success in the Mesozoic play, which has added additional reserves and production.   PetroChina reached a peak production rate of 310 Mb/d of oil from the Liaohe Depression in 1995. For the last few years the company maintained production at 200 Mb/d of oil. In 2019 the company produced at a rate of 201 Mb/d of oil and 60 MMcf/d of gas.
Jiatan-1 nfw E. sag of the Liaohe Depression, onshore Bohai Gulf Basin, TD 4,428m, on 7 May '20 tested 11.5 MMcfg/d on an 8mm choke from Tertiary Shahejie 3 fm volcanics between 4,360-4,396m. Gas was also tested between 3,904-4,000m, rates n/a.