Based on the knowledge for deep reservoir physical property in Songnan and the potential damage pattern & degree with conventional drilling technology, analysis was made on action principles of protection technologies of well drilling and completion in each stage and the corresponding reservoir protection schemes were made. Research practices show that the technology requirement of reservoir protection are satisfied in well drilling and completion through the pressure sealing with temporary shielding plugging by underbalanced drilling and the improvement on the property of filtrate invaded reservoir with high quality noninvasive drilling fluid and completion fluid system.