The invention relates to a bellows type adjustable casing. A subsea assembly for producing fluids froth a well having a casing string in the well supported with a hanger on an upper end. Cement is in a portion of an annulus between the casing string and walls of the well, thereby leaving segment of the casing string unsupported in the well. A motion compensating element is coaxially provided in the unsupported segment of the casing string to absorb axial expansion and/or contraction that may occur in the unsupported segment of the casing string.