METHOD FOR SIMULTANEOUS REPLACEMENT OF WELLHEAD MASTER VALVES UNDER PRESSURE (EMBODIMENTS) AND DEVICE FOR IMPLEMENTATION THEREOF (EMBODIMENTS)

摘要

The invention is related to oil-and-gas producing industry. The essence of the vertical valve replacement method: on the upper flange of the swab valve, a hydraulic unit body with an inserted packoff assembly is mounted through an adapter, the packoff assembly including a packer with a sealing collar, a threaded sleeve and a clutch, a hollow mounting rod having a two-step outer surface, and a packing rod. Two posts of composite drive screws are connected on two diametrically opposite sides of the cross member in parallel with the axis of the valve and of the hydraulic unit body. The foundation plate is mounted on the posts providing alignment of the plate central bore with the axis of the hydraulic unit body and the valves by screwing a sliding stop nut on the hydraulic unit body until seating in the central bore of the foundation plate, and the posts are fixed on the plate. A hollow packer drive screw is screwed into the hydraulic unit body until it touches a step of the hollow mounting rod, composite drive screws are installed and fixed on the foundation plate, after which an additional plate is mounted on the composite drive screws until touching the end of the mounting rod. Screw couplings are fixed on the additional plate. After that, the failed central valve and the swab valve are opened in turn, and the presence of pressure in the inside cavity of the hydraulic unit body is checked. By rotating the packer drive screw, the hollow rod with the packing rod is entered in the bores of the valves to the depth of the packer seating. The sealing collar is mounted by means of the packing rod. After blocking of the wellhead valve line bores, excess pressure in the inside cavity of the hydraulic unit body is reduced. If there is no fluid leaks from the well through the packer, the mounting rod is fixed, and the plate is pressed by tightening the nuts, after which the hydraulic unit body with the valves joined to it is lifted above the wellhead equipment to mount a guard flange for maintaining the sealing state of the packer in the wellhead borehole. The hollow rod and the packing rod are disconnected and withdrawn from the failed valve borehole, after which the failed valve is replaced by a new one. Then a reverse process is performed ended by the packer withdrawal from the wellhead borehole, closure of the central valve and dismantling of the valve replacement device. The method of wing valve replacement differs from the first version by using trolleys running along a cargo monorail constituting a part of the composite drive screw for replacement of the upper master valve and the central valve to be replaced. The technical result consists in provision of a high-technology method for simultaneous replacement of failed vertical and wing borehole valves of the wellhead equipment.