Well jet device for well-logging operations and the operating method thereof

A method of operating a well jet device for well-logging operations, comprising:

• assembling a pipe string by installing a jet pump and a packer on a pipe string, lowering the assembled unit into a well and releasing the packer, lowering a sealing unit on a logging cable with a logging instrument attached to the cable via a cable head, the sealing unit is installed on the mounting seat in the jet pump step-like channel, and the logging instrument is arranged in the area of a producing formation, during lowering background values of rock physical fields, in particular those of thermal fields, are recorded along the well bore, then pressure drawdown on the producing formation is created by supplying with a jet pump an active working medium to the active nozzle along the pipe string annular space and, thus, the producing formation is drained, then, when the jet pump is operated, current values of rock physical fields and a formation fluid coming to the well are recorded;
• while recording, the logging instrument being moved along the well bore, including the producing formation, with the use of the logging cable;
• then the jet pump is stopped, and the pipe string inner cavity above the jet pump together with the annular space above the packer is separated from the pipe string inner cavity under the jet pump together with the under-packer space by using a return valve, maintaining a reduced bottom-hole pressure under the packer, then the logging instrument is slightly raised with the use of the logging cable and the step-like piston is pressed by the cable head for moving it up, and, thus, the under-packer space of the well is brought in communication with the pipe string inner cavity through the openings in the sealing unit body wall and the lateral openings in the jet pump body, and, due to this, pressures above and below the packer are equalized, after which the logging instrument together with the sealing unit is removed from the well.