Method and device for producing a cased string bore

Abstract

In a method for producing a cased string bore (5) extending from a well shaft (1) in the horizontal direction for the installation of a filter string, a starter drill pipe (13) and subsequently further drill pipes are driven into the rock mass (6) surrounding the well shaft through an opening (4) in the wall (2) of the well shaft (1) using a drive means (11) arranged in the well shaft. Arranged in the starter drill pipe (13) is a hydraulically driven drill motor (18) which drives in rotation a drilling tool (19) protruding from the leading end of the starter drill pipe (13) and is supported in the starter drill pipe (13) by means of a clamping device (21, 22) so as to be fixed against rotation and axial displacement, a partition sealing the starter drill pipe (13) being formed by means of the clamping device (21, 22). Pressurized water is supplied to the drilling tool (19) via a flushing pipe (29) penetrating the clamping device (21, 22) and the drillings, which are separated by the drilling tool (19), are conveyed away toward the surface through a conveying pipe (25) which opens out in the center of the drilling tool (19) and is guided rectilinearly through the clamping device (21, 22) to the well shaft (1). On reaching the final depth of the string bore (5) the drilling tool is retracted into the starter drill pipe by axial movement of the clamping device (21, 22) and the free space between the drift face of the string bore (5) and the starter drill pipe (13) is filled and sealed by injection of a quick-setting, expanding filling compound. Afterwards the clamping device (21, 22) is disengaged and removed, together with the drill motor (18) and the drilling tool (19), from the drill pipes.

Dependencies are inferred from the claim text.