JPH0434798B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal transmitting device for transmitting a signal to the earth's surface from a transmitter placed deep below the earth's surface.

In the drilling carried out in the exploration of oil beds,
In practice, it is often necessary to transmit information about the pressure at the bottom, mud density, temperature or other useful parameters to the plant control room at the surface, supplied by sensors placed at the bottom of the borehole. There's a problem.

[Prior Art] To solve this problem, sensors are connected in the drill collar of the drilling tube string, i.e. in the drill collar supporting the drill bit, and for transmitting the information collected by them to the surface. It has already been proposed to place transmitters that can be applied to

In the known device, the transmitting antenna consists of a metal member insulated from the drill collar, connected to the drill collar by a mechanical connection made of an insulating material and formed by a portion of the actual drill collar. .

Thus, for example, in the paper submitted by Mr. Clarisse to the University of Lille in 1969, it was proposed that at the level of the last drill collar they be separated by a bridge made of insulating material and that an alternating current potential difference of a particular frequency is formed between them. It was proposed to divide the perforation tube string into two parts, in which case the lower part of the drill collar formed the antenna, and the upper part, threadedly connected to the upper perforation tube, was placed at the bottom of the drill hole. It constitutes an axis that guides electromagnetic waves toward the ground that allow remote transmission of the signals provided by the telemetry sensor.

This type of device was described in an article entitled "The Next Generation MWD Tool" published on February 21, 1983 in a magazine called "Oil and Gas Journal," especially in that magazine. It is also published in the last paragraph of page 86.

A significant drawback of this device is that in order to form an insulating connection between the two metal parts of the drill collar, an insulating ring or bridge is required which reduces the mechanical strength of the drill collar, which, as is known, is subjected to considerable torsional and shear forces. It is necessary to use it.

Furthermore, such devices are of no use when information needs to be transmitted from a drill collar that is immersed in oil drilling mud which is essentially itself insulating.

Problems to be Solved by the Invention The present invention overcomes these drawbacks and at the same time provides information from the bottom of the drilled hole by means of a special type of electromagnetic radiation mechanism supported by the drill collar. This is achieved without any mechanical weakness of the drill collar, allowing the signal to be transmitted from the bottom of the drilled hole even when the drill collar is immersed in an oil mud which is itself insulating. It is set as.

Another object of the invention is to provide an antenna that makes it possible to measure the resistance of the formation at the bottom of an oil well.

According to the invention, the device for transmitting signals to the surface of the earth is for transmitting electromagnetic waves electrically connected to a transmitter arranged in a known manner in the drill collar together with a sensor supplying the transmitted aperture parameters. A drill collar forming an antenna member, and a cylindrical metal sleeve having a larger diameter and shorter length than the drill collar, the metal sleeve being coaxially disposed on the drill collar, and the end portion of the metal sleeve The metal sleeve is separated from the drill collar by an insulating layer surrounding the drill collar to a distance from the drill collar.

According to a feature of the invention, the insulating layer surrounding the drill collar is longer than the cylindrical metal sleeve forming the transmitting antenna member.

According to another feature of the invention, the cylindrical metal sleeve is split on the side adjacent to the bit to form a metal ring of slight height in the lower part of the drill collar, the metal ring being such that the transmitter itself is cylindrical. electrically connected to the transmitter only when electrically isolated from other parts of the shaped metal sleeve.

This small height metal ring makes it possible to measure the resistance of the terrain at the bottom of a substantial oil well, which hitherto was practically impossible.

In the embodiment shown in FIG. 1, as a result of the wear and tear that the cylindrical metal sleeve undergoes in the well due to the circulation of rock debris and frictional debris in the walls of the well, there is a risk of damage to the extent that the cylindrical sleeve will fail. is therefore more important than failure of the cylindrical metal sleeve, since in some cases this results in a reduction or even cessation of the circulation of the drilling mud or, in extreme cases, immobilizes the drilling tube string. The disadvantage is that the drilling itself presents problems.

It is true that the wall thickness of the cylindrical metal sleeve acting as an antenna member can be increased and formed in the form of a hollow cylinder of considerable thickness, which can be in the range of up to 1 cm. However, in order to maintain the same outer diameter for the cylindrical metal sleeve it is necessary to reduce the wall thickness of the drill collar supporting the cylindrical metal sleeve, and this reduces bending and compression with respect to the drill collar. resulting in a decrease in resistance to
It therefore presents other risks and disadvantages.

If the cylindrical metal sleeve is made of mesh, it is electrically connected to a transmitter housed within the drill collar by means of a conductor insulated from the drill collar at the point where it passes through the wall of the drill collar. It is important to have strength and electrical properties equal to those of a simple metal plate sleeve connected to the metal plate sleeve.

The present invention provides a sufficient solution to this problem and eliminates the need to complicate the structure for connecting the cylindrical metal sleeve to the insulating layer forming the dielectric between the cylindrical metal sleeve and the drill collar. There is no
The object is to provide an advantageous embodiment of an antenna member for a transmitting device which is easy and inexpensive to manufacture and which, in the event of wear and tear, is easily supported along with, rather than preventing, the removal of rock fragments resulting from the perforation. .

According to the basic feature of the embodiment of the electromagnetic radiation-emitting metal sleeve of the antenna element according to the invention, the metal sleeve is flush with the cylindrical outer surface of the drill collar when its manufacture is completed.

The ends of the drill collar are formed to be protective stops on the outer surface of the metal sleeve.

According to another feature of the invention, the metal sleeve consists of a cylindrical sheet of mesh formed from helical springs combined parallel to each other by adjacent windings, the mesh being formed in an annular groove formed in the drill collar. It is embedded in an electrically insulating material consisting of, for example, a curable material or an epoxy resin marketed by Civer-Geigy, Basel, under the trademark "Araldite", which is advantageously attached to the bottom of the base.

In order to ensure that the spring is maintained at a sufficient distance from the bottom of the annular groove formed in the drill collar, according to another feature of the invention, the insulating layer is applied in two stages, one of which is It is used to hold and secure the mesh pressed against it before it is fully installed.

In order to ensure a good electromagnetic wave transmission of the metal sleeve formed by a mesh of overlapping helical springs, a cylindrical sheet of helical springs is placed on the first layer and completely within the covering second layer. After being embedded, the shell face of the drill collar protrudes over approximately one-third of the shell thickness, said shell face bordering an annular groove provided in the drill collar for receiving the metal sleeve and its insulating layer.

In order to ensure a good connection between the first layer and the drill collar, the epoxy resin used to construct the first layer for this purpose advantageously incorporates a mesh of glass fibers.

This results in a good adhesion of the first layer on the bottom of the annular groove provided in the drill collar. Advantageously, this occurs in the same way for fixing the mesh on the first layer which is not yet completely hardened.

Thus, according to another feature of the invention, before the mesh in the form of a helical spring is fully embedded in the second insulating layer, which is made of epoxy resin, the mesh is advantageously made of helically woven glass fibers or other A still soft first insulating material by means of a binder made from synthetic fibers.
It is held in layers.

This creates a reinforcement that facilitates the adhesion of the second layer surrounding the drill collar and helical spring type mesh arrangement.

In order to bring the metal part of the embedded mesh forming the metal sleeve into contact with the outside, according to another feature of the invention, the second resin layer is provided such that, after curing, the mesh is separated from the metal part of the drill collar. The drill collar is machined flush with the shell surface of the drill collar bordering the annular groove disposed on the first layer of insulating material.

This results in an insulating layer on the surface of which appears a number of cross sections of the spring winding, achieving the same effect as a metal sleeve.

In other features of the invention, to achieve electrical continuity of the mesh embedded within the insulating resin layer,
The mesh is provided with weld points that connect the windings of two adjacent helical springs to each other at their intersections.

Furthermore, in order to enhance the electrical conductivity of the entire mesh of the antenna, diagonal metal connecting wires, preferably of tin, are welded approximately every 10 meshes of the mesh, said connecting wires being connected to the C-shaped wire sections. All rows are held electrically connected to each other, and the tips of the C-shaped wire pieces are machined such that the second resin layer is flush with the outer surface of the drill collar or lies within the groove of the drill collar. When the second resin layer is removed, the outer surface of the second resin layer is exposed.

According to another feature of the invention, the metal wire connecting the metal sleeve to the transmitter arranged in the drill collar is welded to one or more of the metal connection wires or connecting the metal sleeve to the transmitter. Therefore, the connecting line itself is closest to the electrically insulated passage opening provided in the drill collar.

[Embodiments] The accompanying drawings showing embodiments of the present invention will be described in detail below.

In the known measurement-while-drilling device (MWD) shown in FIG. They are screwed together and support a bit 2 schematically shown together with a perforating roller 3 at the bottom thereof.

In this device, a drill collar 1 is divided into an upper part 4 and a lower part 5, which are mechanically connected to each other by an annular component 6 made of insulating material. In this embodiment, the overall number is 7.
and 8 are held in position in the lower part 5 of the drill collar by a metal member 9, which provides an electrical connection between the modulating transmitter E and the part 5 forming the antenna. Form.

The modulation transmitter E is connected to the drill collar 1 by means of a metal ring 10 arranged corresponding to the axis of the metal member 9.
The upper part 4 of the drill collar 1 is electrically connected to the rest of the drilling tube string, and the modulating transmitter E is likewise connected to a power supply indicated at 11. ing.

Such an embodiment is very fragile, since the component 6, which has to be electrically insulated, has to be formed only of a material that cannot guarantee sufficient strength of the drill collar, and the lower part of the drill collar used as an antenna. As a result of the parts being subjected to wear, the drill collar has to be completely replaced, which involves considerable removal costs and a considerable loss of time.

This drawback does not exist in the device according to the invention, which is carried out in a uniform manner with respect to mechanical stress and whose antenna can be easily replaced at low cost.

In a first embodiment of the device according to the invention, shown by way of simple example in FIG. 2 of the accompanying drawings, which can be shown schematically in block form and consisting of various parts, the transmitter E is mounted on a ring such as 17. It is housed in a drill collar 12 which is wedged and is a leak-proof cylindrical case through which drilling mud can circulate. The actual electromagnetic wave transmitting member of the antenna of this device consists of a cylindrical metal sleeve 13 that emits electromagnetic waves. wear and tear, etc.)
The sleeve 13 is mounted coaxially with respect to the drill collar 12 and is interposed between the drill collar 12 and the sleeve 13. Since the insulating liner 14 is fixedly disposed on the outer surface of the drill collar 12, it is never subjected to the resistance of the drill collar 12.

The metal sleeve 13 is rigid and can be made of one or more pieces of perforated or scored sheet metal, wire mesh with metal rings, etc., and includes an insulating liner 14 surrounding the drill collar 12. It can be partially or completely embedded inside.

The insulating liner 14 is made of a suitable and sufficiently resistive material;
For example, it is made of silicone rubber, elastomer or synthetic resin reinforced with glass fibers, for example.

This insulating liner 14 is mechanically secured to the outer surface of the drill collar 12 .
are themselves suitably adjusted for this purpose by any suitable means that ensure complete adhesion.

According to a feature of the invention, each of the drill collar 12 and the insulating liner 14 has a cylindrical metal sleeve 13 acting as an antenna member attached to the drill collar 12.
It has at least one through hole which accommodates the passage of a conductor connecting to the output of a transmitter E incorporated in the cavity.

At the location of this through hole, the insulating liner 14
As shown in an enlarged view in FIG. 3, the insulating member 15 that penetrates into the drill collar 12 is reinforced to the thickness of the drill collar 12, and the sealed body is
The conductor 16 connecting with the transmitter E transmitting the signals from the sensors associated with C ₁ and C ₂ is represented by the arrow F ₁ .

Metal sleeve 13 acting as an antenna member
a conductor 16 electrically connecting the output of the transmitter E to
As for the insulating member 15, which serves to house the insulating member 15, the insulating member 15 is either integral with the insulating liner 14 or has the form of a rivet and is welded between the conductor 16 and the metal sleeve 13 forming the transmitting antenna member. It can be formed from a separate mounting member in the form of a bush incorporating a receptacle in which a connection can be made.

The insulating member 15 constituting this mounting member can be formed, for example, from a ceramic material that resists shock, vibration and wear.

The insulating liner 14, together with the sleeve 13 formed with a relatively small thickness, does not increase the outer diameter of the drill collar 12 too much and does not interfere with the circulation conditions of the drilling mud, whether oily or not. It must be made thin enough so that

As mentioned above, the length of the insulating liner 14 must be less than or equal to the length of the drill collar 12 in order to provide a gripping and tightening tool abutting portion at the end of the drill collar 12.

Since the standard length of the drill collar 12 is 9 m, the difference in length between the drill collar 12 and the insulating liner 14 is approximately 4% of the total length of the drill collar 12.
and 10%, these values are merely indications and are in no way limiting, as a function of the conditions experienced in operating the perforated tube string and as a function of the insulating liner 1.
4 can be varied as a derivative-specific function.

As explained above, the cylindrical metal sleeve 13 acting as an antenna member leaks at the end of the cylindrical sleeve 13 forming the antenna member.
It is formed shorter than the insulating liner 14 in order to avoid interference and to prevent interference.

A preferred embodiment is obtained with a cylindrical metal sleeve 13, for example 5 m long and 1 to 2 mm thick, centered on an 8 m long insulating liner 14. This means that there is a length between the edge of the insulating liner 14 and the edge of the cylindrical metal sleeve 13, especially in the lower part.
Leave an exposed zone of insulating material over 150 cm.

This cylindrical metal sleeve 13 is attached to the drill collar 12.
It may be the same as or different from the metal composing it,
Made from metal that resists impact and wear. Exposed portions of insulating material must precisely provide high resistance to abrasion. The distance d is shown in FIG.

In order to create an insulating liner that resists abrasion, the insulating liner 14 is preferably made of an elastomer or resin reinforced with glass fibers, for example.

FIG. 4 shows a modification of the device shown in FIG. 2, in which the metal sleeve 13 is mechanically and electrically connected to two cylindrical sections 13' and 13'' of unequal length. It is subdivided into sleeve 1
3'' forms a resistance measuring mechanism for measuring the resistance of the formation at the bottom of the drilled hole near the transmitter and insulating liner 14 near the bit, i.e. at the drilling level achieved by the bit.
It consists of a narrow metal ring placed as low as possible on top.

The transmitter E, which is not shown in Figure 4 for clarity, is the electromagnetic wave transmitting member of the antenna (arrow F ₁ ).
It can be electrically coupled either to the sleeve 13' forming the 13' or to the lower insulating metal ring 13'', the function of which will be explained in more detail below.

In FIG. 5 showing the equivalent electric circuit of this device,
The transmitter E transmits a low-frequency alternating current via its internal resistance Rg on the one hand to the conducting wire of the perforated tube string with impedance Zc and on the other hand to the cylindrical sleeve 13 whose impedance with respect to the formation at the bottom of the perforation is denoted by Ra. Send, as already explained,
The resistance Ra is the leakage resistance of the current passing directly through the drilling mud between the drill collar 12 and the cylindrical sleeve 13 over the exposed portion of the insulating liner 14 along the length d.

It is important to minimize these losses and obtain the best current injection by giving the highest possible value to the distance d, i.e. it is important to maximize the height of the cylindrical metal sleeve. A solution is found between the maximum dimensions of the cylindrical metal sleeve and the minimum leakage current.

The transmitter described above can operate in an oil mud, which circulates at the bottom of the perforated hole forming the dielectric of the cylindrical capacitor, the inner arrangement of which is the sleeve 13 and the outer arrangement of which is located in the surrounding area. be.

This example specifically measures the resistance (resistivity) of the formation at the level achieved by the bit with the sleeve 13'' (FIG. 4) and obtains important information from this for carrying out the drilling operation. enable.

This resistance force can be measured from the impedance of the cylindrical metal sleeve given by the following equation.

Ra=ρLogL/2R/2.L Here, ρ is the resistance force of the stratum, r is the radius of the cylindrical shape forming the cylindrical metal sleeve, and L is the length of the cylindrical metal sleeve.

Therefore, in order to accurately measure the resistance force over a small thickness of the formation, it is advantageous to "focus" the measurement over a narrow band, which means that the metal sleeve 13'' is as short as possible. This is why the embodiment shown in FIG. Since it is electrically isolated, its impedance to ground, Ra, can be easily measured by connecting it.

The metal sleeve 13 can be split at the lower part to form a metal sleeve 13'';
When the metal sleeve 13'' is electrically isolated,
It is used to measure the resistance of the area of the formation achieved by the bit at the bottom of the borehole.

However, according to another feature of the invention, the metal sleeve 13, which fastens the drill collar 12 to the insulating casing 14, can be manufactured from a plurality of cylindrical rings or collars arranged next to each other at a short distance from each other. is possible, and the output of the transmitter is
A programmable switching device can connect one or more of the rings to provide the desired capacitance measurement.

Thus, by connecting only one of these rings at each time to a device that measures the resistance of the terrain, such measurements can be carried out at several positions of the actual height of the drill collar.

The embodiment shown in FIG. 6 includes a cylindrical metal sleeve 1 of mesh intended to constitute an antenna element 17 which can be seen in FIGS. 9 and 10.
A partial plan view of No. 3 is shown. As clearly shown in FIG. 7, the mesh forming the cylindrical metal sleeve consists of a plurality of superimposed helical springs 18 with intertwined windings 19.

As can be seen in the enlarged view of Figure 10,
These windings 19 are welded, for example with tin, at their intersections, such as 20. In order to ensure good electrical conductivity of the structure and to strengthen the stability of the cylindrical metal sleeve 13 consisting of the spring 18, the winding 19 is fitted with its welded metal wires 21, for example in 10 rows. and are connected to each other (see FIGS. 6 and 7).

The mesh metal sleeve 13 is incorporated in an electrically insulating material, for example made of a synthetic material or an epoxy resin whose curing time can be conveniently adjusted.
3 (FIG. 10). A first layer 24 of epoxy resin, advantageously reinforced by a network or sheet of glass fibers 25, eg spirally wound to form a ring, is initially placed within this annular groove 22.

In FIG. 10, the seat of the helical spring 18 is placed relatively close to the edge of an annular groove 22 formed in the drill collar 23, but it does not incorporate the insulating layer filling said annular groove 22. This is suitable when the net protrudes considerably on both sides of the net.

The sheet of helical spring 18 is then fully cured by a sheet or ribbon of glass fibers 26 woven and knitted to enhance the penetration of the mesh forming the annular metal sleeve 13 into the still soft first layer 24. The drill collar 23 is then completely covered by a second layer 27 of epoxy resin which is placed on top of the first layer 24 of uncoated epoxy resin and which protrudes to the outside of the drill collar 23.

This second layer 2 covering the mesh metal sleeve 13
7 is completely cured and is made of epoxy resin.
When integrated with layer 24, the outer surface 28 of drill collar 23 made in this manner is machined;
The windings 19 of the mesh metal sleeve 13 are flush with the outer surface 28 of this drill collar.

By flattening to the position of the solid line 29 shown in FIG. 10, that is, to the height of the outer surface of the drill collar 23, the portion shown by the broken line in the figure is removed.

This results in a cylindrical metal sleeve surface having the appearance shown in FIG. 11, in which the small circles designated 30 are embedded in the first layer 24 and the second layer 27 of epoxy resin. C of winding 31
Indicates the end of the shaped part.

Prior to assembly, the cylindrical metal sleeve is of course electrically connected to a transmitter (not shown) housed in the drill collar 23 by means of a metal connection line designated 16 in FIGS. 3 and 4. .

It goes without saying that the device is not limited to the embodiments described merely by way of example, and that various detailed changes may be made to the embodiments described above without departing from the scope of the invention.

Therefore, instead of a net, a smooth perforated slit or a thin metal plate of this kind as schematically shown in FIG. 8 is arranged in the annular groove 22 of the drill collar 23, and the resistance force at different values of the drilled hole is measured. For this purpose, several continuous grooves can be provided to accommodate either cylindrical metal sleeves in the form of several rings or a single cylindrical metal sleeve.

[Brief explanation of drawings]

1 is a longitudinal sectional view of a known device for transmitting signals from the bottom of a drilled hole, FIG. 2 is a longitudinal sectional view of the device according to the invention, and FIG. 3 shows a cylindrical metal sleeve acting as an antenna element and an arrow An enlarged cross-sectional view showing the electrical connection between the transmitter output shown in Figure 4, specifically for measuring the resistance of the terrain at the depth achieved during drilling of an oil well housed in a drill collar. A longitudinal cross-sectional view of another embodiment of the device shown in FIG. 2 with a subdivision of the cylindrical metal sleeve to form a metal ring in the lower part which can be connected to the device; FIG. Equivalent electrical circuit diagram of the device whose leakage resistance depends on the length d shown in Fig. 2, Fig. 6 a partial plan view of a cylindrical metal sleeve in the form of a mesh with diagonal metal wires connecting the windings. figure,
Figure 7 is a sectional view taken along the - line in Figure 6, and Figure 8 shows how the cylindrical metal sleeve forming the antenna member is installed in the annular groove of the drill collar with the conductor connecting the antenna member to the transmitter. FIG. 9 is a partial illustration similar to FIG. 8 schematically showing a mesh in the form of a helical spring used as a cylindrical metal sleeve; Figure 10 has a mesh section in place;
A partial cross-sectional view of the lower part of the drill collar showing the portion shown in dashed lines that is removed by machining to complete the antenna; FIG. 11 is a C-shape welded together as shown in FIG. 10; FIG. 3 is a schematic diagram showing the surface of a completed cylindrical metal sleeve allowing the ends of the sections to be seen; In the figure, 1 is a drill collar, 2 and 3 are bits, 12 is a drill collar, 13 is a metal sleeve,
13' is another part of the sleeve, 13'' is a metal ring, 14 is an insulating liner, 15 is an insulating member, 16
is a conductor, 18 is a spiral spring, 19 is a winding wire, 20 is a welding point, 21 is a metal wire, 22 is an annular groove, 23 is a drill collar, 24 is a first layer, 25 and 26 are glass fibers, 27 is a second layer layer, 29 is a solid line, 30 is a small circle, 3
1 is a winding, and E is a transmitter.

Claims (1)

[Claims] 1. A drill collar extending in the axial direction is provided, a transmitter is disposed within the drill collar, and a cylindrical metal sleeve forming an antenna member for transmitting electromagnetic waves is provided around the drill collar. The cylindrical metal sleeve has a diameter larger than the diameter of the drill collar and a length shorter than the length of the drill collar, and a cylindrical metal sleeve is provided between the cylindrical metal sleeve and the drill collar. places an insulating layer, makes the insulating layer shorter than the length of the drill collar, provides a resistance measuring mechanism for measuring the resistance of the formation at the bottom of the drilled hole near the transmitter, and connects the resistance measuring mechanism to the insulating layer. comprising a metal ring surrounding the cylindrical metal sleeve, the metal ring being shorter than the length of the cylindrical metal sleeve, the metal ring being disposed between the cylindrical metal sleeve and the end of the drill collar to which the drill bit is attached; A transmission at the bottom of a drilled hole, characterized in that the cylindrical metal sleeve and the metal ring are connected to the transmitter by a coupling mechanism for selectively connecting either the cylindrical metal sleeve or the metal ring to the transmitter. A signal transmitter that transmits signals from the aircraft to the ground. 2. A drill collar extending in the axial direction is provided, a transmitter is disposed within the drill collar, a cylindrical metal sleeve forming an antenna member for transmitting electromagnetic waves is disposed around the drill collar, and a transmitter is disposed within the drill collar. the cylindrical metal sleeve is larger than the diameter of the drill collar and shorter than the length of the drill collar, an insulating layer is provided between the cylindrical metal sleeve and the drill collar, and the insulating layer is shorter than the length of the drill collar, an annular groove is provided on the outer peripheral surface of the drill collar, an insulating layer and a cylindrical metal sleeve are disposed in the annular groove, and the outer peripheral surface of the cylindrical metal sleeve is approximately the same as the outer surface of the drill collar. The cylindrical metal sleeves are of the same diameter, the cylindrical metal sleeves are made of mesh, the mesh is formed from superimposed helical springs, each helical spring is assembled parallel to the adjacent helical spring, and the mesh is made of hardenable plastic. Or a signal transmitting device for transmitting a signal from a transmitter at the bottom of a bore hole to the ground surface, characterized in that it is embedded in an annular groove using epoxy resin. 3 The insulating layer consists of a first layer of insulating material attached to the bottom of the annular groove and a second layer of insulating material applied on the net, and the first layer and the second layer of insulating material form the net into the annular groove. 3. The signal transmitting device according to claim 2, wherein the signal transmitting device is embedded in a. 4. The end of the helical spring is arranged along the outer surface of the second layer of the insulating layer, and the end is made up of a portion of the remaining helical spring embedded in the insulating layer after machining the outer surface of the second layer. The signal transmitting device according to claim 3, characterized in that: 5. The signal transmitting device according to claim 3, wherein a glass fiber network for reinforcing the first layer is knitted in the first layer. 6 A patent characterized in that a strip made of glass fibers is wound helically over the first layer of the insulating layer in order to isolate the screen from the drill collar when the screen is applied to the still soft first layer of the insulating layer. The signal transmitting device according to claim 3. 7. The signal transmitting device according to claim 2, wherein adjacent helical springs are connected to each other by a large number of welding points, and the welding points are points where the helical springs overlap each other. 8. The signal transmitting device according to claim 3, wherein the network includes at least one metal connection wire welded to a plurality of helical springs to maintain electrical contact between the helical springs. . 9. The signal transmitting device according to claim 3, wherein the helical spring forming the cylindrical metal sleeve is electrically connected to the transmitter by at least one connecting wire. 10 Providing a drill collar extending in the axial direction,
A transmitter is disposed in the drill collar, and a cylindrical metal sleeve forming an antenna member for transmitting electromagnetic waves is disposed around the drill collar and is electrically connected to the transmitter. The diameter of the drill collar is larger than the length of the drill collar, an insulating layer is placed between the cylindrical metal sleeve and the drill collar, the insulating layer is shorter than the length of the drill collar, and the hole is drilled near the transmitter. providing a resistance measuring mechanism for measuring the resistance of the stratum at the bottom of the hole, the resistance measuring mechanism comprising a number of metal rings surrounding an insulating layer, the metal rings being arranged at regular intervals along the axial direction; A signal from a transmitter at the bottom of the borehole to the surface, characterized in that a metal ring is coupled to the transmitter by a programmable switch device for making a capacitance measurement to determine a desired level of resistance at the bottom of the borehole. A signal transmitting device for transmitting.