METHOD FOR ADVANCE DRILLING OF PILOT SHAFTS DURING CONSTRUCTION OF WELLS ON SHELF Russian patent published in 2024 - IPC E21B43/01 E21B7/132 B63B35/44 

FIELD: well drilling.

SUBSTANCE: invention relates to a method for advance drilling of pilot boreholes during construction of wells on the shelf. Method involves advance drilling of a pilot borehole to the depth of the conductor lowering of 500–600 m using an equipped geological engineering vessel. First, engineering surveys are carried out at locations of wells by remote geophysical methods. For complete elimination of risks results of remote methods are confirmed by direct method—pilot borehole positioning. Drilling of a pilot shaft is carried out using an engineering geological vessel using a dynamic positioning system without using anchors and blowout prevention equipment and without core sampling. Method also includes lowering the bottom frame with a pipe clamp. Drill string is also assembled. Besides, remote controlled unmanned underwater vehicle is lowered with its fixation at well head. Drilling string bottom assembly includes tools for logging and recording of technical parameters in real time of pilot well drilling. Control over gas inflow at the wellhead is carried out using a remotely controlled unmanned underwater vehicle during the entire drilling cycle of the pilot well. Besides, a system of gas analyzers is installed on the drilling deck; after reaching the design bottom, cementing and liquidation of the drilled well are performed.

EFFECT: prevention of accidents during drilling of prospecting, exploration and production wells on promising areas of shelf and deposits.

2 cl