Study on Wall Stability Period and Anti-Instability Countermeasures of Shallow Drilling Well in Bozhong Area of Bohai Basin
In the process of early exploration well operation in Bozhong X Oilfield,the wellbore wall instability was relatively serious,and the drilling safety of subsequent shallow extended reach wells was facing huge risks.In order to reduce the complications occur-rence of subsequent drilling and provide technical support for on-site operations in time,rock mechanics experiment and numerical simulation analysis were used to study the wellbore stability period and anti-instability countermeasures for the shallow water-sensi-tive clay mineral shale and weakly consolidated sandstone and other unstable formations.The results show that the main influencing factors of wellbore stability period are wellbore orientation,ion concentration and density of drilling fluid.The drilling fluid with ap-propriate density and ion concentration can maintain wellbore stability for 65 h,40 h and 93 h respectively in the vertical well,the minimum principal stress direction and the maximum horizontal principal stress direction.Accordingly,the targeted countermeasures against wellbore instability are proposed.The research results provide technical guidance for maintaining the wellbore stability and re-ducing the drilling complexity during the drilling process of the extended reach well in Bozhong X Oilfield,and finally play a good ap-plication effect.
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维普
