Abstract: Located in the central part of Bonan sub-sag in Jiyang depression,Yi 171-Xie 16 VF well is a non-conventional well in Bonan area,and the main target layer is lower Sha-4 member.Sandstone of Sha-1 member in the area was well developed with sensitive formation pressure,while Sha-3and Sha-4 member was of abnormal high pressure,of obvious pressure contradictions and narrow safety window.During the drilling process when the drilling fluid pressure exceeds its bearing capacity,it is easy to fracture formation and form fractures in traps,and then case complexities such as pumping,no leakage.Therefore by taking appropriate construction measures,good drilling effects have been achieved.