Key Drilling Technologies for Increasing ROP in Ultra-Deep Well Yuanshen 1

Well Yuanshen 1 is a key exploration well located in the gentle structural belt of northern Sichuan. The drilling process encountered several technical challenges, including complex formation pressure systems, borehole collapse, drilling fluid loss, strong terrestrial formation abrasiveness, and high risk of well control, etc. Based on the geological characteristics and drilling experiences of adjacent wells, a series of drilling technologies were implemented to increase the rate of penetration (ROP). Foam drilling technology was utilized to improve the ROP in large boreholes within shallow formations. For the highly abrasive terrestrial formations, the technologies of “turbodrill+impregnated diamond bit”and“rotary percussion drilling rig+hybrid drilling bit”were employed to enhance ROP. The combination of high-temperature, leak-proof drilling fluid with “high-efficiency polycrystalline diamond compact (PDC) bit+high torque screw” technology enabled safe and rapid drilling in the complex formations of the marine multi-pressure system. The microcore PDC bit was used to drill into the target zone, enhancing drilling efficiency while meeting the needs of cuttings logging. The well was successfully drilled to a depth of 8 866.00 meters, setting a Sinopec’s record for the deepest vertical well in the Sichuan Basin. This achievement provided technical experience for ultra-deep well drilling in the Sichuan Basin.