DIRECTIONAL DRILLING TECHNIQUE FOR DOUBLE TARGET DEEP WELLS WITH SOPHISTICATED FORMATION

Well Clzhu-1 is a double target, long lateral displacement and directional deep well of main exploration Changxing reef and Carboniferous system on Chuandong high-steep structural belt with the "five section system" well profile. The final depth is 5625m, the lateral displacement is 1235. 70m. The drilling technology for the top formation, hole trajectory controlling technique and safe drilling technology under rough conditions were introduced in detail. The following difficulties were overcome:high dip angle formation, serious collapse, tough formation, deep burial depth of producing zones, long horizontal displacement, long-section coring operation, deepening design depth half way and having drilled six rare vugular lost circulation zones and so on. The double targets were hit precisely with high quality wellbore.