SINOPEC Group owns 458 rigs, including 49 SCR rigs, 114 rigs with a drilling capacity deeper than 5,000 m with 4-1/2" DP, provided with 1,021 blowout preventers and 35 top drive systems. They are leading the way nationwide in drilling of directional wells, cluster wells, horizontal wells, casing sidetrack wells, ultra-deep wells, wells penetrating salt-gypsum beds and low-permeable reservoirs with high pressure, well control, lost circulation prevention, plugging, well completion and seal coring. Well Zhong 4,the deepest land well in China, drilled by 70835JS Team of Jiangsu Drilling Company in December, 2003, was completed, reaching a total depth of 7,220 m.. SINOPEC Group owns various multi-job-purposed workover rigs with drawworks of 250-900HP. SINOPEC Group has developed advanced and sophisticated workover techniques which enable services' range from casing sidetracking, casing replacement in open-hole, casing patching, casing reshaping by explosion, casing cutting, plugging, drill pipe or tubing string back-off by explosion, stuck testing, unstucking, fishing, milling and over-milling, etc. Workover depth is up to 6,500 m.
Drilling of Horizontal Wells
China's long eastern coastline is abundant in petroleum resources on&offshore. Shengli Petroleum Administrative Bureau applies horizontal drilling technology with the horizontal displacement as long as 3,000 m and controlled up to more than 600 km2 of offshore proved oil-bearing area without construction of platforms. Well CB21-H1 was completed with the total depth of 4,837.40 m, and its horizontal displacement reached 3,167.34 m, the longest horizontal displacement onshore China.
Drilling of Cluster Wells
The cluster He 50 in Shengli Oilfield, the largest land cluster in China, consists of 42 wells in 6 rows within an area of 110 m?84 m.
UBD is conducted by using a rotating control head and a closed degassing and circulating system. While drilling, kicks are very helpful to discover and protect the oil or gas reservoirs. Shengli Petroleum Administrative Bureau achieved great results by this in protecting oil and gas, bringing up production and solving problems of drilling in complicated conditions.
The First Scientific Investigation Well in China
The first scientific investigation well in China is being drilled by Zhongyuan Petroleum Exploration Bureau for the Chinese Academy of Science after winning the bid among many other companies.
SINOPEC Group owns 11 offshore rigs, among them 3 are bottom supporting rigs, 6 are jack-ups and other 2 are semi-submersible rigs. They are provided with all necessary vessels and facilities. Operation water depth ranges from 0 to 40 m for the bottom supporting and jack-up rigs with maximum drilling capability of 9,000 m, and for semi-submersible rigs the operation water depth up to 600 m with drilling capability 6,000-7,500 m.