DOWNHOLE TRACTOR FOR WORK IN CASED WELLS Russian patent published in 2019 - IPC E21B23/14 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and is intended for transportation of field geophysical instruments. Invention is controlled by program-controlled logging system including power supply and control unit of well tractor. Invention consists of electronic unit and two main driving sections with possibility of connection of third and fourth. They are interconnected electrically through three-contact geophysical connector and mechanically by means of coupling nut. Seat is sealed by rubber O-rings. There is a transit electric wire, in a point of connections of moving sections connected by connectors. Each section has two driving wheels. Through gear transmission they are connected with power electromechanical drive. Rotation of electric motor is transmitted to wheels and when these wheels are pressed to inner wall of casing pipe downhole tractor is moved. Wheel clamp implements clamping mechanism consisting of electromechanical drive and power assembly-activator, which pushes or shifts drive wheels relative to axis of housing of downhole tractor. At that, the clamp is made through a power spring. Centralizers on rollers are installed at ends of well tractor. Lower centralizer is terminated by docking assembly for connection of downhole geophysical instruments with cable head. Plug is fitted in transport position. Upper centralizer at the inlet has a head for connection of a cable lug with a three-contact geophysical connector. Electron unit of the downhole tractor consists of a controller, a power supply unit, a modem, a control system of electric drives, switches of wires switching and a sensor unit containing a tension sensor on the cable head, accelerometers and a temperature sensor.

EFFECT: increased speed of movement of the downhole tractor and traction force, as well as increased reliability of the device and quality of electric divergent logging.

1 cl, 2 dwg