DRILLING SYSTEM WITH BARREL EXPANSION UNIT Russian patent published in 2020 - IPC E21B7/28 E21D1/06 

FIELD: soil or rock drilling; mining.

SUBSTANCE: invention relates to a drilling system for drilling, in fact, vertical wells or shafts. Drilling system comprises a bore expansion unit comprising a hollow column adjacent to the lower end of the drilling system, a first cutting head coupled to the hollow column with possibility of rotation, drill head assembly connected to the functionally lower end of the string, and a gripping device assembly connected to the hollow column. First cutting head comprises the first driving device intended for rotation of the first cutting head relative to the hollow column so that to drill the well having the diameter corresponding to the diameter of the first cutting head in the downward direction. First cutting head comprises support housing accommodating structure with blades and rotatably connected to said string. Structure with blades comprises multiple blades extending from support case. Each blade is equipped with multiple first cutting elements or comprises them, where each blade is inclined in direction upwards and from support housing so that to form, in fact, V-shaped cutting profile. Drill head assembly connected to the lower functional end of the string is terminated by the second cutting head with the second drive to actuate the second cutting elements of the drilling head for drilling of the advanced well at continuation of drilling downward by the drilling system. Gripping device assembly is located at operation under the first cutting head and above the drill head assembly around the column so as to substantially surround the column, and is configured to reliably capture the advance well drilled by the second cutting head so as to lock the drilling system in the position within the drilled hole. At that, the gripping device assembly is connected to the drive unit attached to the column and made with possibility to move the gripping device assembly in axial direction along the string length, to facilitate general movement of the downward expansion device.

EFFECT: possibility of drilling wells of relatively large diameter and with possibility of drilling relative to drill cuttings removal without the need to wash out drilled rock.

34 cl, 28 dwg