FR2570818A1 - METHOD AND APPARATUS FOR TRANSMITTING ELECTRICAL AND ELECTRO-OPTICAL SIGNALS FOR TELEMETRY - Google Patents

Abstract

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

Description

2570818.-

  The present invention relates to a telemetry method and apparatus for drilling apparatus

  used for example in oil fields.

  The usual practice of drilling uses sections of boreholes of standard dimensions, each section having a thread at one end and a complementary thread to the other. When the drilling depth increases, additional sections are attached to the "drill string" .- The drilling operation is such that

  the hole has a diameter greater than that of the drill string.

  During drilling, mud is pumped along the drill string and back into the outside borehole.

  of the drill string, with drilling detritus entrainment.

  It is very desirable that the operator can control

  the operation of the drill head at the bottom of the hole.

  It should be noted that the working conditions of the drilling and

  the surrounding conditions are normally extremely hostile, and the implementation of telemetry from the drill head to the drilling rig is

difficult.

  It has already been proposed a limited form of telemetry by using ultrasonic devices only; The drilling mud pumped along the train at one

  considerable pressure can be modulated by the pressure

  which creates systolic "impulses" that go back into the drill string. These pulses come from. the

  region of the drill head and are detected on the surface: -

  The analysis and interpretation of the signals give a

  information on the drilling activity, although it

be limited .. -.

  The present invention relates to a method and

  a device for transmitting electronic signals

  metrices created by an instrument cluster placed behind the drilling site, including a broadband transmission, along the SocCOSSIS sections of tubes and VerS wellheads, so that dynamic measurements can be performed on a number of parameters during a

2570818.

actual drilling operation.

  An apparatus according to the invention for transmitting

  telemetric signals in a section of pipe,

  takes a cylindrical coating intended to be housed in the hole of the tube and placed substantially over the entire length of the tube, the coating comprising two annular end portions connected by an intermediate portion, the intermediate portion comprising signal conductors which are embedded therein and starting from a first end

  towards each other, each end

  positive high-frequency transceivers, circuits

  interface to connect the transmitting devices

  signal-conducting receivers and a power supply for supplying electrical power to the transceiver devices and the interface circuits, all of which

elements being incorporated.

  The invention also relates to a method for transmitting

  telemetric signals in a section of pipe,

  taking the reception of high frequency signals at a

  first end of the section, regeneration and trans-

  formation of high frequency signals into signals intended to

  to be transmitted by drivers joining the other former

  pipe end and retransform the signals

. -._ .. ..

  in high-frequency signals intended to be retransmitted

  to an adjacent section of pipe.

  The expression "signal conductor used.

  in this specification means any guided route of propagation

  signaling: such as electrical conductors or.

  optical fibers.-.--, - - -; ? ':: -

  Other. characteristics and advantages of the invention

  tion will become more apparent from the following description,

  made with reference to the appended drawing in which:

  FIG. 1 is a cross-section of a tube section; FIG.

drilling; - -

- .. -

  Figure 3 shows a detail of the part of ex-

tremity of the coating; and

2570818.

  Figure 4 shows a detail of the wall of the coating. When drilling an oil well, the drill head is carried at the lower end of a rotating drill string. This drill string consists of identical sections of tube 1 (FIG. 1) each having, at one end, a collar 2 welded and having a tapered thread, and at the other end, a collar 3 having a thread

  complementary taper. When the drilling operation pro-

  gresse and when the upper end of the last added section approaches the level of the floor of the drilling rig, the rotation of the drill-rod is interrupted., a new section is screwed to the upper part of the drill string and the rotationh of the drill string resumes. Of the

  mud is pumped along the drill string as described above.

  cédemment. The present invention is implemented in the hy

  o stent where the drill head has. a set of instruments

  able to measure various parameters such as pressure and temperature, and to create

  low power frequency that correspond to them.

  Each section of tube has inside. a thin coating (Figure 2) for ensuring the communication of signals between the drill head. and the platform. The coating essentially comprises annular portions 4, 5 of upper and lower ends connected by an intermediate portion 6 with a thin wall. The coating is preferably formed of a flexible material and has dimensions

  allowing him an adjustment in the tube section. normally

  welded collars 2, 3 form a small step in the hole of the pipe and these steps are used to

  the pesitioning of the coating in the pipework. An issue

  high-frequency receiver-receiver 7 (Figure 3) and

  8 signal conversion systems that communicate with buried electrical conductors or optical fibers 9

  in the thin-walled intermediate part of the coating -

  are coated at each end portion. The end portions 4, 5 may also contain local circuit supplies and regeneration circuits 11.

data where appropriate.

  Each section of tube having a coating as described is in fact an autonomous segment of a broadband communication system, in a similar manner.

  to the general behavior of biological systems.

  We now consider the data coming from any source, below a given given segment,

  communication from one side to the other of the connector being

  radio transmission. The techniques used

  can be microwave, by modulation of

  frequency, digital and intermediate frequency to zero.

  The transmitted signal propagates in the mud and is received -

  by the receiver and regenerator circuit placed at the lower end of the preceding section. The distance to be traveled rarely exceeds one meter. The receiver then causes the

  transmission of regenerated information through -

  - conductors buried in the wall of the ma-

  This is because the transmitter at the upper end of its own section is modulated, the high-frequency transmission operation repeating itself. Thus, the data transmitted, after several regenerations, -rrive without deformation to the

  wellhead, regardless of the depth of the bit.

  The presence of accumulator batteries has been

  placed in the end portions 4, 5 of the cover

  is lying. Of course, batteries or electric batteries

  have a limited period of use before replacement or.

  refill. In an advantageous embodiment, the food

  is formed of accumulator batteries and each

  end portion 4, 5 further has piezoelectric devices

  electrical, that is to say sensitive to pressure. Mud

  pumped to the lower part of the drill string is normally

  badly subjected to frequent pressure variations.

  Piezoelectric devices are sensitive to these

  pressure and create electricity that is

  used for charging-batteries3accumulators.

25708 18

  When pressure variations are insufficient norrm--

  Sludge pumping can be cyclically and regularly pulsed using a device at the wellhead so pressure sensitive devices can generate enough electrical energy to accumulator batteries remain in the state

  operating for long periods.

  The coating, as well as its end portions, is made of a sufficiently flexible material to allow easy introduction into the piping and, when in place, accommodates mud pressures of up to 700 bars. The material shall have a low coefficient of friction so that it has a surface with minimal friction against the sludge.

  drilling normally used. Similarly, the devices

  capsules which are embedded in the end parts must be able to withstand the high pressures exerted

by the mud.

257081.8.

Claims (6)

  Apparatus for transmitting electrical signals or electro-optical telemetry in a pipe section, characterized in that it comprises a cylindrical coating intended to be housed in the hole of the tube and arranged practically over the entire length thereof, the coating having two end annular portions (4, 5) connected by an intermediate portion (6), the latter containing, in the form of a coating, conductors (9) for transmitting signals from an end portion to the other, each   end portion having, in the form of a coating,   high-frequency transceivers, circuits   interface devices intended for the transmission of   receivers to signal conductors, and a power supply   intended to supply electrical energy to transmitters   receivers and interface circuits 2. Apparatus according to claim 1, characterized in that at least one end portion (4, 5) further comprises a signal regeneration device so well   that the signals transmitted in the conductors (9) are regu- néré. -   3. Apparatus according to one of claims 1 and -   2, characterized in that the power supply is   stored by a battery, and sensitive devices. at the pressure create electrical energy from recharging the battery.   Apparatus according to any of the claims   1 to 3, characterized in that the signal conductors (9)   coated in the intermediate part (6) of the coating are ---   optical fibers, the interface circuits comprising light sources and photodetectors for transmitting data signals in the drivers   of signals formed of optical fibers.   5. A method of transmitting electrical or electro-optical telemetric signals in a tube tronton, characterized in that it comprises the reception of signals - at a high frequency at a first end of the section, the 257081'8.   regeneration and transformation of signals to iJau-this fre-   quencc eÄn signals intended to be transmitted by c-. duc-   signal transducers joining the other end of the tube, and the inverse transformation of the signals into high-frequency signals so that they are re-transmitted to an adjoining section of tube.   6. Method according to claim 5, characterized in that the high frequency signals are transformed   in optical signals so that they are transmitted from a first   first end of the tube to the other by the optical fibers.