METHOD AND DEVICE FOR DRILLING LARGE-SIZED WELLS Russian patent published in 1995 - IPC

FIELD: vertical workings; drilling. SUBSTANCE: working tool is disposed onto surface of face which breaks rocks by rotation to form pulp with different sizes of grains. Annular flux of washing liquid is applied to face being twisted before entering input of tool case, after the flux leaves the case it opens to form reduced speed area at central part of the flux. Zone of circulation currents is formed to produce rotating cone of water-supplied solid particles at central part of surface of the face. Pulp is lifted onto the surface from the cone by means of injection through reduced speed zone. Annular flux of washing liquid is applied and twisted by means of vortex generator inside cavity of drill pipe string. Pulp is lifted inside internal cavity of drill pipe string along unloading branch pipe till achieving tee-joint. After that pulp is removed to space behind the pipe and slime is separated to small- and large-sized particles by gravitation method. Small-sized particles are brought up the surface by ascending current and large-sized particles are gathered at collection zone of space behind the pipe. After the space is filled completely with large-sized particles, the drilling is stopped. Assembly is lifted onto the surface and zone of collection of large-sized slime is unloaded. After that the assembly is lowered into the face and the cycle should be repeated. Device for drilling wells has drill pipe string connected with working tool through tee-joint. Working tool has case and roller bit chisel mounted onto the case, encapsulating gland ring and units for twisting flux. Device has unloading branch pipe disposed in axial within pipe string. Lower end of the branch is mounted no lower than lower end of output hole in case of working tool. Top end is made in form of tee-joint which has edges to be cut in walls of adapter diametrically. Members for twisting annular flux are made in form of flux vortex generator. Case of the generator made in form of drill pipe is connected with one its end with the case, and the other end is connected with adapter and has cassette onto its internal surface. Cassette has removable blades for twisting flux; the blades enclose unloading branch pipe. Support clamp with centering rods is mounted above the cassette on the loading branch. EFFECT: improved efficiency. 3 cl, 3 dwg