Liner Pressure Test Buckling Generation and Influences on Running String and Cement Quality of Previous Casing in Vertical Wells

Buckling occurrence during liner pressure test represents a challenge, in addition to running string deformation; previous casing cement quality may be severely affected. Practically, running string placed straightly on the top of liner. Consequently, buckling pressure limit will surely reached while rising pressure. In order to investigate column performances during testing, drill pipe elongation, bending and buckling are all considered. Buckling influences on pipe quality, based on helical springs under compression theory will revisited. The examination of contact pressure generated and their influences on previous casing cement sheath is the main purpose, via interface continuity conditions and stress analysis method. Results show that minimum yield shear stress could achieved at high casing pressure test. Conversely, contact pressure, radial and hoop stress, for both interfaces casing-cement and cement-formation confirm that DP has more influences on cement sheath compared to casing. Simulations and well registrations presented to confirm buckling occurrence and their impacts.