Bui Viet Duc; Ngo Van Tu; Bui Trong Khai; Dang Cua; Bui Viet Phuong; Vu Van Hung; Hoang Hong Linh; Bui Van Thom; Nguyen Xuan Thao. Research and Field-Trial of “KCl-Protex Sta” Drilling Mud System and Using Protex Sta in Combination With CFL-AKK-KCl-PAG, KGAC Drilling Mud Systems to Improve Well Drilling Efficiency . PVJ 2019, 4, 23-29.