DEVICE FOR APPLYING DEPRESSION TO BED Russian patent published in 1994 - IPC

FIELD: development of oil wells. SUBSTANCE: device comprises packer with diaphragm 2 installed in tubing 1. Packer is made up of upper movable 3 and lower stationary 4 stops. Upper stop 3 has circular groove 10 with holes 11 and sealing member 6 therebetween. Said member 6 has spring 8 inside. Upper space of member 6 has through holes 9 which connect internal space of seal with well. As diaphragm 2 is fractured, surplus pressure forces annulus liquid into tubing 11. Hydrostatic pressure of said annulus liquid covers this space with sealing member 6 thus setting up a pressure difference in the above-packer and under-packer zones. Hydrostatic pressure in drill string-borehole annulus acts on stop 3 through holes 11,9 on circular groove while sealing member 6, on internal cavity 7 of packer. Spring 8 compresses while walls of sealing member 6 are pressed against internal surface of casing string and isolator completely intrastring space from annular space. Stop 3 moves down through tubing 1. As a result, deep vacuum is applied to bed. EFFECT: improved design. 2 dwg