LOSS OF AXIAL STABILITY OF CASING IN PERMAFROST PRODUCTION WELLS WITH A LATERAL SUPPORT ON THAWING ICERICH GROUND
Rzhanitsyn's general method for calculating the stability of an axially loaded column embedded into an elastic medium has been used to develop a calculation scheme and to estimate the critical load that leads to buckling of production well casing supported laterally by thawing ice-rich ground. In the suggested model, casing deforms within a thin layer of ice-rich ground with enhanced deformability under thawing; thawing ground resists elastically. The critical load depends on the thickness of the ice-rich layer, the stiffness of unfrozen ground, and the ﬂexural rigidity of casing. The minimum critical load is a complex function of ice-rich layer thickness, while buckling can be either symmetrical or anti-symmetrical. Symmetrical buckling has been detected instrumentally in an accidental well at the Yamburg gas-condensate ﬁeld. Using of the well casing with higher rigidity of its construction is suggested to optimize well completion designs and reduce buckling risks in areas of deep bedding of permafrost.