DEVICE FOR CONSTRUCTION OF WELLS Russian patent published in 1998 - IPC

FIELD: drilling of deep wells for water, oil and gas, in particular, for increase of tightness and strength of permeable rocks. SUBSTANCE: device is made in the form of centralizer mounted directly above jet drilling bit. Centralizer blades are combined with bit legs. Nozzles are located in centralizer blades in planes square to axis of central channel. Point of intercrossing of axes of nozzles are located at boundary of initial section - at the beginning of transition sections of jets flowing from nozzles mounted in blades directly above pit. Point of intercrossing of axes of nozzles installed in upper row of centralizer blades is located at a distance of not more than 4 d_n from nozzle ends, where d_n is nozzle diameter. With the same pressure differential across bit and nozzles of the device (at fixed deliveries of mud pumps), low row has nozzles forming round jets of small diameter. In the upper row, nozzles form flat jets, including square ones whose equivalent diameter equals to diameter of low row nozzles, or used in upper row are nozzles forming the flat jets including square ones whose equivalent diameter is less than that of nozzles of lower row. EFFECT: reduced time taken for establishment of low-permeable (impervious) barrier inside rocks, and fuller utilization of hydraulic power supplied to bits. 5 cl, 3 dwg