SU1550070A1 - Method of constructing wells in friable saturated uncemented rock - Google Patents

Abstract

The invention relates to the mining industry and is intended for the construction of wells. The goal is to prevent the collapse of the borehole walls of the main part of the trunk. To do this, drill the trunk under the conductor and install it in the well, followed by cementation. After the cement hardens, the well is drilled with a smaller diameter to the design depth. In the lower part of the well, the barrel is expanded to a size greater than twice the diameter of the barrel. Expansion is carried out at a height from the bottom not exceeding the tripled bore diameter. The well is then washed with a mud solution, the drilling tools are removed, the lid is welded to the top of the conductor and the well is left for later use for hydrogeological purposes. A conductor with annular carburization prevents rocks from sliding down from the surface. 1 hp f-ly, 1 ill.

Description

The invention relates to the mining industry, in particular to methods for the construction of wells.

The purpose of the invention is to prevent the collapse of the borehole walls of the main part of the trunk.

The drawing shows a well constructed in a new way and conserved, longitudinal section.

The well is fixed by a guide conductor 1 with annular carburization 2. At the completion of drilling, the part of the conductor 1 projecting above the surface is closed by a cover 3 in welding 4. The well is drilled through sandy 5 and clay 6 wells. Sands 5 is flooded, their static water level is 7, SST is smaller than internal pipe diameter 4,

the hole is drilled after fastening the latter. This diameter 8 is maintained only at the time of drilling and at the bottomhole completed by drilling a well. At a distance of 14 due to the redistribution of the intensity of the array of sand-clay rocks caused by weight; overlying layers, borehole diameter

reduced to the minimum diameter d ,. At a height of 1, a fracture 9, caused by the disparity of radial strength at the bottom and in the middle part of the wellbore, moves from expansion upwards to a cylindrical vertical position. At a distance of 1, a somewhat longer distance 1i, an extension of 10 wellbore was made. The diameter of the recess. exceeds the diameter d of a cylindrical, part of the crack.

ate

Example. Drill the barrel under the guide pipe - jig. Install the latter with annular cementation. After the cement hardens, drilling with a smaller diameter d is continued until the bottom hole. Then the expansion is made in the previously drilled hole at a height from the bottom 1, equal to 3.0-5.0 diameters of SC, diameter d4, large double diameter dj. After that, the well is washed with a mud solution, the drilling tool is removed, welded (4) to the pipe - the conductor 1 on top of the cover 3 and left the well for subsequent use in hydrogeological purposes. During storage, a discontinuous crack develops at the contact of the flat bottom of the bottom and the cylindrical part of the well bore, which after turning into a cylindrical part stops so its development up. The fractured portion of the wellbore is peeled off, decompressed, and slides down below the top — recesses. The rest of the trunk remains intact. The slipping of rocks from above from the surface prevents

pipe - conductor 1 with annular carburization 2. If necessary, cover 3 is opened, the production string with a water catching device, for example, a filterless well with a lateral water inlet, is lowered into the well.

Claims (2)

1. A method of constructing wells in detrital water-cut non-cemented rocks, including drilling a well for a conductor, installing 5 of the conductor, followed by cementation and further drilling of the well with a smaller diameter to the design depth, which is distinguished by the fact that, in order to prevent 0 the collapse of the borehole walls of the main part of the trunk; in the lower part of the well, the borehole is expanded to a size exceeding twice the bore diameter, five 2. The method according to claim 1, wherein the expansion is carried out at an elevation from the bottom not exceeding three times the diameter of the trunk.