YZ1斜井定向井小井眼侧钻技术OA

YZ1 inclined well is the first risk exploration well located in the northern slope zone of the Nanwu Sag in the South Yellow Sea Basin.After drilling to 3 588 m,there was no footage in the 215.9 mm section of YZ1 deviated well.However,the drill bit was found to have fallen into the well when tripping out to the wellhead.After multiple unsuccessful attempts to salvage,it was decided to drill a window behind the 200 m cement plug in the open hole section.The sidetracking operation is difficult due to deep drilling points,high formation strength,complex formation lithology,and complex well conditions.By reducing the number of stabilizers and selecting the Shengli Tiangong S323 PDC drill bit with 5 blades and strong attack,combined with a 1.5 °screw motor drilling tool combination,during pressure control,drilling,grooving,and bench building were carried out,overcoming the difficulties of deep sidetracking position,complex well condi-tions,and high formation strength in this section,one-time successful sidetracking was completed.The sidetracking process and new wellbore trajectory are smooth,the new is smooth,and the wellbore deviation is reduced.