Wellbore geometry variations including casing ovality, corrosion pits, and wear grooves challenge seal stack effectiveness as seals must conform to irregular surfaces. Adequate seal length and element flexibility allow stacks to bridge minor irregularities while maintaining sealing contact, though severe casing damage may require repair before reliable sealing is achievable. https://linkingbookmark.com/story20902764/replacement-api-6a-wellhead-seals-oem-quality-oil-gas-gaskets