PROCESS OF DRILLING OF ADDITIONAL SHAFT OF WELL Russian patent published in 2002 - IPC

FIELD: oil industry. SUBSTANCE: invention refers to technology of drilling of wells, specifically, to running additional shafts from key shaft of well. It can be used to drill multiface wells. Casing string including casing tube with window cut in advance and closed with bushing of easy-to-drill material is run in well, column is pressure grouted, cement bridge is installed in area of window, cement bridge and bushing are drilled out and drilling tool comes outside casing string. In this case adapters are placed at angles of (180^°-α^°) and α^° to longitudinal axis of tube in front and after casing tube in plane of longitudinal cut of tube. EFFECT: enhanced operational efficiency, reduced time of drilling. 2 dwg