FIELD: means of oil and gas wells.
SUBSTANCE: means for sealing the mouth of oil and gas wells during tripping operations (TO) in wells equipped with a double-row pipe string. In particular, the claimed method of successively lowering two pipe strings with downhole equipment into the well includes installing and fastening a preventer on the support flange of the wellhead valve with the help of studs and nuts, lowering and securing two pipe strings. A preventer with large bore diameter is fixed onto the support flange of the wellhead flange, then the first pipe string is lowered into the well, after the first pipe string is lowered into the well, a pipe holder is screwed onto its upper end, then the first pipe string is allowed into the well and the pipe holder is installed in the support flange of the wellhead valve. On the top flange of the preventer, with the help of studs and nuts, the lower flange of the additional preventer with a smaller bore diameter, made with eccentricity, is fastened, then through the smaller bore diameter of the additional preventer, and then the second pipe string is lowered. After lowering the second pipe string into the well, its upper end is fixed in the pipe holder, after which the preventer and the additional preventer are dismantled, and the upper flange of the wellhead valve is installed on its support flange. A device for implementing said method is also claimed.
EFFECT: simplification and provision of successive running of TO with two strings of pipes with downhole equipment without dismantling the preventer between TOs with two strings of pipes of different diameters.
2 cl, 4 dwg
