PROCESS FOR CONSTRUCTING WELL FOR EXPLOITING RESERVOIR UNDER SEA-BED OR OCEAN-BED Russian patent published in 2018 - IPC E21B7/12 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of well construction at a large and very large depth. Method for constructing well (1) for developing an oil or gas field, comprising steps of: drilling a formation submerged by a water head, at least 3,600 m deep or more, reaching the formation from the surface of the water with drilling riser (7) and a drilling tool which passes internally through the drilling riser; installing a production string, also referred to as production casing (300E), in the formation; evacuating through drilling riser (7) at least one of the following: circulating drilling fluid, oil or natural gas coming from the formations and the resulting drilling materials. Production casing (300E) has an outer diameter of at least 7 inches (177.8 mm). Drilling riser (7) has an external diameter equal to or smaller than 17 (431.8 mm) inches and reaches wellhead (3) having an internal diameter equal to or smaller than 18.75 inches (476.25 mm), and positioned on or close to the seabed submerged which covers the formation.

EFFECT: wider operational limits for increasing the depth and for existing equipment.

11 cl, 3 dwg