Cold hydraulic expansion of oil well tubulars

The cold hydraulic expansion of two concentric tubulars is analysed with emphasis on the applications to oil and gas casings. Theories of elasticity and plasticity are used to develop a model relating the hydraulic pressure, the geometric dimensions of the tubulars and the residual contact pressure between the pipes. Nonlinear finite element analysis is used to validate the theoretical results and to investigate the effects of end support conditions. Hydraulic expansion experiments are conducted on tubulars and the measured evolution of the deformation and residual contact pressure are compared with the corresponding theoretical predictions and finite element solutions. There is a good agreement between the experimental results and predictions from the theoretical analysis and numerical simulations. The implications of the results for the design of casing hangers and patch repairs of oil and gas tubulars are discussed.

► The cold expansion of concentric tubulars is studied.
► Analytical, numerical and experimental solutions of the interface pressure are presented.
► The residual interface pressure increases with increasing radial clearance.
► Fixed end constraint reduces the residual interface pressure.