Secondary Well Control
When primary well control measures cannot maintain control of the well during either drilling, completion, or production operations, the process used for bringing the well under control is called secondary well control. Secondary well control comprises specific procedures and equipment. Blow-out prevention (BOP) equipment and particular methods such as the driller method, wait and weight, lubricate and bleed, and bull heading are used as part of the secondary well control process to regain control of the well.