CNPC
CHN ENERGY
Yanchang Petroleum
Yu'neng Group（榆能集团）
CNOOC
BCIG
Shaanxi Coal and Chemical Industry Group Co., Ltd.
SINOCPEC
SINOCHEM GROUP
Hengyi Petrochemical
Rongsheng Petrochemical Co., Ltd.
ZPC
Shandong Dongming Petroleum & Chemical Group Co., Ltd.
CNNC
Shandong Chambroad Holding Group Co., Ltd.
Yitai Group（伊泰集团）
Hengli Group（恒力集团）
Web：www.osguni.com
E-mail：info@osguni.com
Address:Room 205, Unit C, 2/F., Kwong On Bank, Mongkok Branch Bldg, 728-730 Nathan Rd, Mong Kok, Hong Kong.
