Since the ultra-deep well YS1 in western Sichuan has several drilling difficulties such as complex geological conditions, soft and hard staggered upper continental strata, poor drillability, high temperature and high pressure of marine stratum, hydrogen sulfide gas, etc., the designers optimized the setting position, recommended the four casing scheme and reserved five casing scheme; compound drilling and vertical drilling and other techniques were selected to increase drilling speed; high-efficiency drill bits were optimized, and the drilling fluid system and performance were improved in deep well sections. The drilling engineering design and technique plan were adapted scientifically which lead to an average penetration rate 2.39 m/h and the average drilling operation time 356.45 d, creating the shortest record of drilling to 6,000 m depth in western Sichuan. The successfully completed well provides important references for 7,000 m ultra-deep wells in the same area
论文详情