Research on the Design Method of Exploration Well Bore Structure in Xihu Sag of the East China Sea

In the process of using the exploratory well bore structure in Xihu Sag of the East China Sea, there are many complex situations caused by the inappropriate design of the well bore structure. Most of them are due to the failure to effectively separate the abnormal pressure formation in the lower part, resulting in pressure leakage in the upper part of the lower well section. In order to solve this problem, the well structure design in Xihu Sag of the East China Sea is optimized from the view of design method. The new design method can not only seal the complicated formation pressure, but also ensure the casing diameter to be large enough to meet the requirements of follow-up operation.