RU2707610C1 - Downhole tractor for work in cased wells - Google Patents

Abstract

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

Description

The field of technology.

The invention relates to the oil and gas industry and is intended for the transportation of field geophysical instruments, electric divergent logging tools and technological repair arrangements in directional sections and horizontal ends of cased oil and gas wells having an internal diameter of 73 mm to 245 mm, with upper values of temperature inside the well up to 150C and hydrostatic pressure up to 105 MPa.

A device is known for delivering devices to a horizontal well (RF Patent No. 2175374, ЕВВ 23/14, 10.27.2001), consisting of a cylindrical body pivotally mounted in the body of wedging supports having guide rods and a driving device made in the form of four bushings, in pairs connected by proppants, while in each pair the movable sleeve has a running nut and is mounted with the possibility of movement, and the other sleeve is fixedly mounted on the guide rods installed in the respective housings, in each of which an electric motor with a reduction gear and a lead screw is installed with a step excluding its self-braking.

The disadvantage of this device is the low productivity due to the small linear movement of the device, limited by the distance between the bushings and the long cycle time of the operation.

The closest analogue of the claimed device is a device for delivering devices to a horizontal well (RF patent No. 2487230, ЕВВ 23/14, 05/03/2011), containing a cylindrical body with an electric motor installed in it, articulated proppants, and at least one section with a mover made in the form of wheels installed in the casing with a radius of curvature equal to the radius of the investigated well, according to the invention is equipped with a pump driven by an electric motor and a hydraulic motor with a chain drive to the wheels, as well as tivatorom propping supports.

In addition, an additional electric motor can be installed in the housing of the downhole tractor for the proppant activator.

The disadvantage of this device is the lack of on-board sensors for monitoring the movement of the downhole tractor, navigation and other parameters, the absence of centering devices - centralizers allowing the tractor to maintain a stable position in the well.

The invention is designed to work with a load-bearing three-core geophysical cable, up to 4000 meters long, as well as with downhole geophysical instruments with an external diameter of 40 mm. up to 170 mm., working with one or three working cores of a cable, autonomous geophysical instruments and repair technological layouts. The invention is controlled by a software-controlled logging system, which incorporates a power unit and a downhole tractor control.

A downhole tractor for working in cased wells is a modular cylindrical structure containing two wheeled moving sections 3 and 5 pressed to the well wall by an activator motor located in the activator block 4 and 6, respectively, an electronic block 2, two centering devices - lower centralizer 7 and upper centralizer 1 (shown in General view - Fig. 1).

The objective of the invention is reliable and high-quality delivery to directional oil or gas wells, or horizontal shafts of similar wells of geophysical field devices operating on a load-bearing geophysical cable, or autonomous geophysical devices, electric divergent logging equipment, as well as technological repair arrangements for capital well repair.

This goal is achieved by the fact that brushless DC motors are used in the downhole tractor (the main motor responsible for moving the tractor and the activator motor responsible for opening and closing the clamping mechanism of the driving wheel group of the downhole tractor), with high power and efficiency, which can significantly increase the speed and traction of the downhole tractor and minimize interference to the transit wires.

Also, unlike other known devices for transporting downhole tools, this invention uses an electronic control unit made in a modular design on reprogrammable logic integrated circuits (FPGA), connected via a modem and information core of a geophysical cable with an electronic computer (computer) , a land logging system equipped with a program for controlling the movement of a downhole tractor and recording parameters from a block of sensors placed in an electronic unit the tractor, namely accelerometers, a tension sensor on the cable head and a temperature sensor, it is possible to connect field geophysical instruments and read data from them in real time into a logging system.

 The operation of the device is as follows, before starting work, at the wellhead, the well tractor is assembled from one or more moving sections and an electronic unit on the surface, connected to a ground logging system, by connecting a geophysical cable, testing without equipment or technological layouts, then after testing a complete assembly of devices or arrangements with a downhole tractor, the device is launched into the well. The descent control is carried out using the depth gauge block of the logging system installed on the shaft of the winch of the geophysical elevator, as well as using the sensors on the descent of the electronic unit of the downhole tractor, as well as using geophysical instruments in conjunction with the downhole tractor.

In the intervals of the well adjacent to the intervals where the geophysical cable should not be used as a means of delivery (the zenith angle of the well is more than 40 degrees) for safety reasons, the speed of lowering the bundle of equipment or devices is reduced for descent, together with the downhole tractor.

Upon reaching the design interval where further transportation on the geophysical load-bearing cable is not possible, a downhole tractor is launched. The control unit for the downhole tractor is activated, the electromechanical drives are turned on, which provide the wheels are pressed against the well wall through the operation of the activator engines, rotation is transmitted to the wheels through the gear transmission and when these wheels are pressed against the inner wall of the casing (shown in Fig. 2), the downhole moves tractor.

The pressure of the wheels carries out the clamping mechanism. It consists of an electromechanical drive and a power unit that extends and moves the drive wheels.

In the process of transporting devices or technological arrangements in the well, you should carefully monitor the recording of parameters on the logging system that characterize the fact of the device’s movement.

The downhole tractor uses an electronic unit made in a modular design using reprogrammable logic integrated circuits (FPGA), connected via a modem and information core of a geophysical cable with an electronic computer (PC), a land logging system equipped with a program for controlling the movement of the downhole tractor and recording parameters from a block of sensors located in the electronic unit of the tractor, namely accelerometers, a tension sensor on the cable head and a temperature sensor In addition, it was possible to connect field geophysical instruments and read data from them in real time into a logging system.

Record of parameters in the intervals of interest can be made when the device moves, both in the direction of the "face", and in the direction of the "mouth".

Having reached the final interval of work, we close the clamping mechanism with wheel pairs, using the activator engine and record when lifting the downhole tractor, with a bunch of geophysical instruments, on the geophysical cable. Observing the lifting speed characteristic of not more than 1000 m / h.

The technical result obtained by solving the task is to increase the speed of movement of the downhole tractor and the traction force of the device and, as a result, increase the reliability of the device and improve the quality of electric divergent logging and other methods of geophysical research of wells in horizontal and directional sections of oil and gas wells, as well as improving the reliability of the delivery of repair and technological arrangements for the overhaul of wells.

Claims (2)

1. A downhole tractor for working in cased wells, consisting of two wheeled driving sections, pressed against the casing wall by an activator motor located in the activator block of each section, and having lower and upper centralizers, providing a stable position, characterized in that it uses an electronic unit made in a modular design on reprogrammable logic integrated circuits (FPGA), connected via a modem and information core of a geophysical cable with electronic an electronic computer (computer), a land logging system equipped with a program for controlling the movement of a downhole tractor and recording parameters from a block of sensors located in the electronic block of the tractor, namely accelerometers, a tension sensor on the cable head and a temperature sensor, the possibility of connecting field geophysical instruments and reading data from them in real time into the logging system. 2. A downhole tractor for working in cased wells according to claim 1, characterized in that in its moving sections, brushless DC motors are used to clamp the wheels to the casing and set the borehole tractor in motion, providing the device to move and clamp the wheels to the casing wall columns engine-activator.

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