FORMATION TESTER Russian patent published in 1997 - IPC

FIELD: mining industry; applicable in testing of promising horizons in course of drilling without lifting of drill bit with remote measurement of bottom hole parameters. SUBSTANCE: formation tester has packer with body, switching mechanism, sub and gas chamber. Packer has radial pressure and equalizing holes. Hollow rods are installed movably in axial sealed hole of packer, hollows of switching mechanism and sub. Body sub of switching mechanism accommodates bushing with shaped stepped recess engageable with rods and fixing the rods in several working positions. Braking spring is installed on the rod in sub hollow. Gas chamber hollow accommodates differential piston separating gas chamber into high-pressure and atmospheric-pressure chamber. Rod has seat for seating and sealing of removable valve device. Formation tester has circular pressure channel and axial channel used also as equalizing channel. Rod upper part has fixing mechanism of removable valve device in form of retaining balls. There is a compensator of volume and pressure. It is run into pipes on logging cable. EFFECT: higher quality and reliability of well testing in course of well drilling. 2 cl, 6 dwg