CORE BARREL Russian patent published in 1996 - IPC

FIELD: mining; equipment for coring. SUBSTANCE: core barrel has sub, body inner barrel with radial holes and hollow bushing in it at upper end with seats for dropping valves. Bushing and inner barrel are fastened by shear pins. Inner barrel has core catcher with catching teeth on lower end. Secured to body is core bit with water courses and circular protrusion engageable with core catcher. Core drilling bit is detachable and has circular coupling movable in axial direction and covering water courses which are stepped. Hollow of core drilling bit is covered with inserted drilling bit assembly having central water course and located in coupling hollow. Drilling bit assembly, coupling and core drilling bit are joined by shear pins. Drilling bit assembly has branch pipe with jet nozzle and seat for dropping valve. In full-hole drilling down to producing formation, core drilled out by core drilling bit is destroyed by inserted drilling bit assembly. When it is required to have core, valve-ball is dropped in core barrel hollow to close single channel of flow of drilling mud to bottom hole, as a result, pressure rises in hollow of barrels and pins are sheared which connected inserted drilling bit assembly with core drilling bit and circular coupling. Then, dropped into barrels hollow is value-ball which closes hollow of inner barrel to stop drilling mud. Upon completion of coring, the third valve-ball having the largest diameter is dropped to close the core barrel control channel due to which drilling mud pressure shears pins connecting inner barrel with sub, and bushing with inner barrel, and they move down. In this case, the core catcher teeth are bent inside barrel to catch core coming there, and moving down bushing opens radial holes for flow of drilling mud from the hollow of drill pipes to well during lifting the core barrel filled with core from well. EFFECT: higher efficiency. 4 dwg