1. The No. 12 Oil Production Plant of Changqing Oilfield Company, PetroChina, Qingyang 745400, Gansu, China
2. Downhole Operation Company, CNPC Bohai Drilling Engineering Co., Ltd., Renqiu, Hebei 062552, China
3. Technical Center of the First Oil Production Plant of Qinghai Oilfield, Mangya, Qinghai 816400, China
4. COSL-EXPRO Testing Services (Tianjin) Co., Ltd., Tianjin 300457, China
5. The King’s School, BP1560, Bujumbura, Burundi