PACKER FOR DRILLING WITH DUAL DRILLING STRING Russian patent published in 1999 - IPC

FIELD: bore-hole drilling equipment. SUBSTANCE: packer has body in the form of sleeve and hollow plunger which is seated in body. Openings are made in their upper part. Circular bore is made in external surface of plunger. Seated in this bore are spring-biased wedges with external tapers and through-slots. Sealing member is made in the form of flexible cylindrical jacket. Installed on its external surface is set of pads. Located on internal surface according to number of pads is set of wedges with internal taper and keys. External pipe of string moves plunger and set of wedges. Plunger closes openings. Flexible jacket and pads are extending. This ensures hermetization of bore-hole bottom-hole. On completion of drilling, plunger with wedges is lifted. Sets of wedges are removed from closing position. Jacket returns to its initial diameter. Drilling string is lifted. Application of aforesaid embodiment of packer helps improve operational reliability. EFFECT: higher efficiency. 2 dwg