Horizontal flow drilling requires focus on well control

Horizontal wells drilled underbalanced or while flowing must have surface equipment and a blow-out preventer stack specially designed for circulating operations. Functional well control methods for drilling horizontal wells have been developed in specific regions worldwide. Special safety equipment and procedures, however, are still required in most horizontal development applications. The challenge for horizontal drilling development and underbalanced drilling is to overcome the obstacles of government regulation, reduce pollution dangers, and improve personnel and equipment safety. Well control techniques tailored to the demands of each field can help overcome these challenges. Several well control elements must be addressed carefully on each horizontal well: drilling fluid requirements, well control procedures and equipment, and surface equipment and special considerations for handling hydrocarbons produced while drilling. The paper discusses each of these elements for underbalanced horizontal drilling.