Study and application of wellbore stability methods in BZ13-1 Oilfield

When exploration wells were drilled in BZ13-1 Oilfield in the central part of Bohai Sea, many problems appeared, such as overflow, leakage and pipe stuck, which have a great influence on the drilling rate.Based on drilling data, well logging and other data, the mechanical method for analysis of wellbore stability is used to analyze the distribution of the format ion pressure, in-situ stress and strength parameters, by calculating collapse pressure and fracture pressure with proper strength criterion, the fluid density window for safety drilling has been obtained finally.According to wellbore stability analysis for Well BZ13-1, the location of high pressure zone, thief zone and collapse zone have been obtained, and the casing program has been designed based on the study result s.Good results have been achieved in development well drilling, and the complex drilling problems have been reduced.