Rubber
| Sat 30 May 2026
Beijing, May 30 -- Daqing Drilling Eng Co Ltd and China National Petroleum have applied Chinese patent for Calculation Method for Predicting Service Life of Packer Rubber Sleeve. Wang Bo, Zheng Dianfu, Wang Kan, Zhang Hao, Kou Zhihui, Zheng Ruiqiang, Wu Lei, Wang Hongchao, Yu Xiaobo, Wan Faming, Wang Chunhua, Wang Guiru and Yang..