FIELD: oil and gas industry.
SUBSTANCE: invention can be used for sealing the mouth of oil and gas wells in the sequential run-in into the well of a two-lift assembly of downhole equipment with a parallel arrangement of columns during oil, gas and water show (OGWS). A method is claimed for sealing a wellhead when running a two-lift column with a parallel suspension of strings during oil and gas production, including installing and fastening a preventer on the support flange of a wellhead valve with studs and nuts and successively lowering and securing two pipe strings. In this case, first, a short pipe string equipped with downhole equipment is run through the preventer bore diameter. If there are signs of OGWS, the wellhead is sealed with pipe rams of the preventer, for which a short string of pipes is suspended on a casing pick-up elevator. After the liquidation of OGWS, a short string of pipes is continued to be run into the well. After lowering a short pipe string into the well, a pipe holder is screwed onto its upper end, and the short pipe string is run into the well with the pipe hanger installed in the support flange of the wellhead valve. After that, a long pipe string equipped with downhole equipment is lowered through the preventer bore diameter and the hole in the pipe hanger. If there are signs of OGWS, a support sub is screwed onto the upper end of the long pipe string and the long pipe string is run in until the support sub stops in the pipe holder. The preventer may comprise pipe slips and a gate valve or two levels of slips – tubular and blind slips, and sealing of the mouth when the long string is run in by a gate valve or blind slips.
EFFECT: reduced complexity of the process of running in a two-lift column in case of OGWS.
2 cl, 10 dwg
