Mechanical Analysis For Well Completion Casing In Bridge Plug Staged Fracturing Operation In Long Horizontal Well

Xinjiang Oilfield Company start to explore bridge plug fracturing technology in Jimusar block in recent years.During bridge plug fracturing operation,well completion casing deform and damage is founded and it has a severe effect on fracturing operation and oil extraction progress.Have a research on this problem and avoid it's happen will have a good significance on field application.In consideration of different factors that will have an effect on the length of the free section of the casing,a mechanical analysis was made.And from it,a model for axial force of free section of the casing is made,the normal work conditions of the free section of the casing material in fracturing operation is discussed and finally a triaxial yield model is built.Based on these analysis,a conclusion is obtained that with different working conditions in fracturing operation the risk point of the free section of the casing is different.And the security coefficient of tri-axial stress yield strength and extension strength should also be checked in the fracturing operation.Based on former analysis and for the convenient of field use a software is made.ABAQUS is used to simulate the deformation of the casing cemented in horizontal section under different conditions.And a living model is built to verify the deformation of the casing.The numerical analysis draw the conclusion that the inhomogeneous extension of the cracks in the formation and the reduction of mechanical properties in the fracturing area is key factors that case casing deformation.The non-uniform of the mechanical properties of formation and the original stress condition should be considered in the division of the fracturing section in order to reduce the non-uniform of fracturing zone.