RU2278256C1 - Bottomhole telemetric system with electromagnetic communication channel - Google Patents

Abstract

FIELD: well drilling, particularly to change bottomhole characteristics during well drilling.

SUBSTANCE: telemetric system comprises land-bases receiving and processing equipment, electric string separator, alternating current generator installed below the separator and downhole equipment with measuring sensors and with electronic transmission unit. Electronic transmission unit is linked to the alternating current generator from above through electrical connector for power cable. Self-contained power supply module and measuring downhole equipment modules are connected to the generator by low-power wires through lower electric connector.

EFFECT: simplified structure and increased reliability of bottomhole telemetric system.

1 dwg

Description

The invention relates to the field of geophysical exploration and is intended for measuring downhole parameters of a well during directional and horizontal drilling.

Known downhole telemetry system ZIS-4, containing ground receiving and processing equipment, an alternating current generator with a hydraulic turbine, a borehole module with measuring primary transducers, an electronic transmitting unit and an electric column separator that performs the functions of a dipole. The generator is located at the bottom of the system, and the inclinometric module is located at the top of the borehole module (Molchanov A.A., Lukyanov E.E., Rapin V.A. “Geophysical surveys of horizontal oil and gas wells”, St. Petersburg, 2001, p. 98-102).

Placing the generator at the bottom of the system necessitates the use of an additional non-magnetic insert to separate the inclinometer from the magnetic masses. Inclinometric sensors in such a system are located above, so the point of measurement of the zenith angle is removed from the bit, which leads to inaccuracy in determining its location.

A downhole telemetry system is known, comprising ground receiving and processing equipment, an electric generator, and downhole equipment located inside the electrical separator with measuring sensors and an electronic transmitting unit. The generator has electrical connectors for power cables on both sides. Downhole equipment is connected to the lower part of the generator (certificate of the Russian Federation for utility model 15911, IPC 7 E 21 V 47/02, 2000).

The known design has the following disadvantages. The placement of downhole equipment inside the electric separator of the column, which is one of the weakest places in the structure, reduces the reliability of the telemetry system. The presence of several electrical connectors for power cables complicates the design of the generator and reduces its reliability.

The aim of the invention is to simplify the design and increase the reliability of the downhole telemetry system with an electromagnetic communication channel.

This goal is achieved by the fact that in the telemetry system the alternator and downhole equipment are installed below the electric separator of the column, the electronic transmitting unit of the downhole equipment is connected to the generator from above through an electrical connector for the power cable, and the autonomous power supply module and measuring modules of the downhole equipment are connected to the generator by low-current wires through the lower electrical connector.

The drawing shows a General view of the downhole telemetry system with an electromagnetic communication channel.

The telemetry system contains an electrical separator of the column 1, an alternating current generator 2, an electronic transmitting unit 3, connected to the generator through the upper electrical connector 4 under the power cable. Behind the generator, a sealed self-contained power supply module 5, made in the form of a battery system, and measuring modules 6 are installed. The downhole equipment is connected to the generator and the electronic transmission unit through the lower low-current electrical connector 7. The electrical separator of the column forms a dipole, to the upper electrode of which a power electric cable leads 8.

Downhole telemetry system with an electromagnetic communication channel operates as follows.

The drilling fluid drives the rotor of the generator 2, which provides energy to the electronic modules of the downhole telemetry system. The generated electric current through the connector 4 via power cables enters the electronic transmitting unit 3, is modulated and transmitted through the power cable 8 to the upper electrode of the dipole. Downhole parameters data obtained in the downhole equipment are received in the electronic transmitting unit 3 through a low-current connector 7 in the lower part of the generator via information wires located in the hollow shaft of the generator. Then, information signals are transmitted via an electromagnetic communication channel to a ground receiving device.

Due to the fact that the generator and the downhole equipment are located below the electric separator of the column and only one power cable passes through its cavity, it became possible to increase the wall thickness of the electric separator and thereby increase its strength.

Placing the electronic transmitting unit on the upper side of the generator made it possible to reduce the number of electrical connectors for power cables, simplify the design, and increase the reliability of the telemetry system.

Claims (1)

Downhole telemetry system with an electromagnetic communication channel, containing ground receiving and processing equipment, an alternating current generator, an electric column separator, downhole equipment with measuring sensors and an electronic transmitting unit, characterized in that the alternating current generator and downhole equipment are installed below the electric column separator, electronic the downhole equipment transmitting unit is connected to the generator from above through an electrical connector under the power cable, and the tone supply and measuring modules of the downhole equipment are connected to the generator by means of low-current wires through the lower electrical connector.