SU255883A1 - TELEMETRIC SYSTEM FOR GEOPHYSICAL RESEARCHES OF WELLS IN THE PROCESS OF DRILLING - Google Patents

Description

The invention relates to the field of geophysical surveys of wells during their drilling, in particular, to telemetry systems with the transmission of electrical signals along a string of drill pipes.

Geophysical measurements made after a minimum period of time after the formation has been opened, provide sufficient zero and reliable information about the section to make the appropriate technical solution. As a matter of fact, to transmit information about rocks to the surface, a wireless electric communication channel through drill pipes is used, a non-resistive current electric machine serves as a transmitter.

Since the basic parameters of the transmitter generator are calculated from the average data for wells of certain sections and conditions, reliable communication with the wellhead can only be carried out in cases where the well conditions do not have significant differences from the calculated ones. Moreover, even when drilling the same well, the possibility of alternating formations with very low and relatively high electrical resistances is not excluded, therefore in some sections of the section the output resistance of the generator does not correspond to the external load. Everything

This significantly reduces the range of the channel, noise immunity and versatility of the system.

In the proposed system, discrete automatic adjustment of the value of the internal resistance of the generator is ensured by switching sections of its winding (low-resistance and high-resistance) relay device, which operates depending on the value of

external load, which makes it possible to reconcile the non-redundancies with one or another section.

The control circuit of the repair equipment is connected to the output of an additional measuring device.

The latter contains an alternating voltage generator connected through the primary winding of the transformer to the bottomhole shell, and a series-connected rectifier whose input is connected to the secondary winding of the transformer, and a threshold device whose output is connected to the control circuit of the relay.

A 1chem telemetry system consists of a downhole projectile and a ground device for locating, extracting and recording depth measurement data with reference to the depth of the well. The ground equipment is composed of well-known standard units.

instrumental copteyner and turbogeneperator unit.

The geophysical probe contains a separator / for electrically disconnecting the drill string and an insulated tube 2 with probe electrodes A and M. A sealed instrumentation container 3 is provided with measuring equipment and a matching circuit of the transmitter generator with an external load in the communication channel. The measuring apparatus consists of a probe current generator 4, a measuring amplifier 5, a control unit 6, a modulator 7, and a relay unit 8.

The transmitter matching circuit includes a generator 9, a current transformer 10, a rectifier 11, a threshold device 12 and a relay device 13.

The turbogenerator unit contains a hydro turbine 14, a sealing gland 15, a three-phase generator 16 with a power 17 and transmitting windings. The transmission winding consists of a high resistance 18 and a low resistance 19 sections. The winding 17 of the three-phase generator 16 and the rectifier 20 serve to stabilize the power supply to the electronic projectile system.

Works depth apparatus as follows.

In the presence of washing in the well, a turbine 14 drives a three-phase generator 16, generating an alternating current with a frequency equal to the frequency of rotation of the turbine.

The relay unit 5, which controls the pulse-width modulator 7, switches the signals in the communication channel by connecting or disconnecting the transmitter winding of the generator for certain periods of time, with the pause length being determined by the value of the corresponding parameters measured by the amplifier 5, for example (KC) and ( JS); the difference in the duration of the current parcels 4 or is used to separate the channels.

The control unit 6 performs a sequential polling of the channels and controls the modulator during the formation of the current parcel. A semiconductor probe current generator 4 generates a measuring electrical field.

The relay device 13, controlled by the threshold device 12, automatically connects to the communication channel a high resistance 18 or low resistance 19 section of the generator's transmitter winding, depending on the external load, which is determined mainly by the ground resistance of the drillstring column.

The earthing resistance of the column is determined by the generator 9 connected to the communication channel and operating at a frequency different from the frequency of the current of the generators 4 and 16. Since

the generator 9 and the transmitting winding of the generator 16 are loaded at the same price, the current in the circuit of the generator 9 will characterize the load of the non-destructive winding of the generator 16 and the degree of its coordination with it.

The voltage from the current transformer 10, rectified by the rectifier 11, is supplied to the threshold device 12 which is sensitive to the change in current at the value of the measuring generator (for example, the Schmitt trigger) and operates depending on its magnitude.

Subject invention

Telemetry system for geophysical

well drilling studies using a galvanic communication channel and consisting of a downhole shell containing geophysical sensors, channel transducers, electrical column separator,

an electric machine generator with a power and transmission winding, a stabilized power source, and a ground-based device for receiving, selecting I1I and recording data of depth measurements, characterized in that

In order to increase the range and noise immunity of the system, the generator winding contains low-resistance and high-resistance sections, alternately connected, depending on the external load, to the communication channel.

relay device, the control circuit of which is connected to the output of an additional measuring device, containing an alternating voltage generator, connected through the primary winding of the transformer to the bottomhole shell, and connected in series with an inverter, the input of which is connected to the secondary winding of the transformer, and the threshold device, output which is connected to the control circuit of the relay.