CN1016649B - Induction logging sonde with metallic support - Google Patents

Abstract

The present invention relates to an induction logging instrument which comprises transmitting and receiving solenoid coils and a supporting frame, wherein the coils arranged on the supporting frame are axially separated from each other; the supporting frame made of an electric conducting material comprises at least one first longitudinal cylinder and second longitudinal cylinders distributed at both sides of the first cylinder, and the coils are installed on the first longitudinal cylinder. At least the first cylinder has a basically continuous and axially symmetric outer surface helpful to the flow of an eddy current surrounding the surface to basically eliminate an electric field on the surface.

Description

Induction logging sonde with metallic support

The present invention relates to the well logging apparatus by wellhole investigation stratigraphic structure character, specifically it relates to a kind of induction instrument.

Induction instrument comprises a transmitting coil and a receiving coil substantially.They all are contained on the support, along wellhole direction axially-spaced.The transmitting coil frequency of utilization is generally 20 kilo hertzs alternating current driver, and the magnetic field of generation formation induction around goes out an eddy current, and this electric current flows with wellhole is coaxial, and the conductance on strength of current and stratum is proportional.Electromotive force of generation is responded in the magnetic field that these eddy current produce again in receiving coil.With suitable method to handle the conductance that just can measure stratigraphic structure from the signal of receiving coil.

The support of coil is (to consult U.S. Patent No. 3,179,879, TANGUY with what the epoxy resin that electrically non-conductive material such as glass fibre strengthen was made the tubular core shape shaft in traditional induction instrument; 3,147,429, MORAN; With 3,706,025 REGAT).Everybody thinks always, because the information from receiving coil is very weak, so the utmost point need reduce near the existence of the conductive material coil, in order to avoid parasitic current flows near coil, cause the composition that looks genuine (" well logger error "), consult SPE publication S.P.E12 167, " electromagnetic wave resistance MWD instrument ", P.F.RODNEY ET AL work, explain and publicise in the 58th technology in 5-8 day San Francisco in October nineteen eighty-three and the exhibition annual meeting, the 1st page, left hurdle, second section.Using a tangible disadvantage of synthetic resin frame is in use to be easy to fragmentation.In several different well logging apparatus, induction instrument is the easiest fragmentation.But, must be contained in steel (or other high-strength materials) and be with within it around the drill collar of drilling mud owing to survey device while boring, if say, so for the survey device just can not use induction tool while boring by above-mentioned S.P.E publication.

Be noted that it is impossible getting rid of metallic object near coil fully, because must come energy to be provided and to transmit information with electric wire from receiving coil for transmitting coil.The lead that uses in traditional induction instrument is hard withstand voltage multilayer coaxial cable, and cable contains the coaxial metal " layer " of mutual insulating.Its internal layer transmits information as conductor, and skin provides due physical strength, and becomes the shielding of conductor.These cables and be in the emission electromagnetic field in uncontinuity and produce eddy current when existing with coil connectors, and produce the output signal error thus.Under the low stratigraphic structure situation of conductance, this error may be same magnitude with useful signal.In addition, this error is subjected to the influence of temperature drift to a great extent, differ greatly at ambient temperature with under the wellhole environment of temperature up to 150 ℃, this further error also can change along with the time limit of equipment, for example because synthetic resin aging and influence the bending etc. of support.

United States Patent (USP) 3,249,858(GOUILLOUD) suggestion uses metal frame to increase physical strength.This patent is also talked about in order to make metal frame produce parasitic current less as far as possible, should bore radial direction through hole on the whole length of metal frame.This patent points out that also coil should be that circular wire turn is formed, and connects with the linear conductance sheet between the wire turn, and its intermediate point is positioned on the sagittal plane in hole.But, it is also noted that boring makes that increasing physical strength is restricted on support, and does not refer to owing to there is the problem that produces in electric wire.

United States Patent (USP) 3,408,561 relate to a kind of resistivity logging system of measuring simultaneously in drilling well.Different with the present invention, this system has used toroidal transmitter coil and the annular receiver coil of installing along conductive core pole, and its electric current is to produce in stem stem owing to exciting of toroidal transmitter.

One object of the present invention is to provide a kind of induction instrument with superior mechanical intensity and durability.

Another object of the present invention is to provide a kind of low, stable and induction instrument predictable well logging error.

Another object of the present invention is to provide a kind of can removing to use the multilayer coaxial cable induction instrument of connecting coil back and forth.

Another object of the present invention is to provide a kind of induction instrument, and this well logger can insert on any position of logging tool composite set.

Another object of the present invention is to provide a kind of induction instrument of surveying operation while boring that is applicable to.

According to the present invention, induction instrument comprises that the solenoid coil of microscler, a common cylindrical conducting metal frame, at least one emission usefulness and at least one receive the solenoid coil of usefulness.This two coil is coaxial and is spaced from each other with respect to the relation of support.It is irrelevant with medium effect basically that the frequency of operation of transmitting coil will make that institute generates an electromagnetic field, and suitable frequency range is 10 to 400 kilo hertzs, is limited to about 20 kilo hertzs under the best, is limited on the best about 200 kilo hertzs.Support, the part in its adjacent coils has continuous basically, a preferably axially symmetrical outside surface at least, is beneficial to eddy current annularly flow on every side on this surface.

Support preferably has one with the high metal of conductance, the outer sleeve that is made of such as copper and the material that physical strength is higher with conductance is lower, the inner core of making as stainless steel.

Consult below in conjunction with the description of the drawings, will be readily appreciated that the present invention.

Fig. 1 is the synoptic diagram of induction instrument embodiment of the present invention and the uphole equipment that is connected with it;

Fig. 2 is the enlarged detail of coil unit among first embodiment of Fig. 1;

Fig. 3 is the enforcement illustration after the coil unit improvement;

Fig. 4 is one to be suitable for while boring surveying the induction instrument of the present invention of operation;

Fig. 5 is the partial longitudinal section of induction instrument preferred example;

Fig. 6 is the sectional view of Fig. 5 V-V line.

Fig. 1 has expressed according to of the present invention to investigate by the induction instrument of wellhole 12 frazzled stratigraphic structures 11, be full of drilling mud 13 in the wellhole, instrument plays with multiconductor cable 14, on winch 16, winch is the part with the matching used uphole equipment of downhole logging instrument to cable through pulley 15.Uphole equipment is powered and the transfer operation control signals to downhole hardware 10 by cable 14, and receives metrical informations from downhole hardware 10.Uphole equipment comprises the system 17 that handles and write down these information.Sensor 17a is in order to the working condition of monitoring cable.The information that sensor 17a sends indicates the instant degree of depth of downhole hardware, feeds back to disposal system, carries out degree of depth coupling with metrical information.

Downhole hardware 10 has an electronic cartridge 18, and it is connected with cable by cable end 19.A remote measurement box 20 is arranged in the box 18, and the message of sending from uphole equipment that downhole hardware is produced converts the program that is fit to the cable transmission to.

Downhole hardware 10 also has a microscler support 30, and its upper end and electronic cartridge 18 fix.A coil system is housed on the support 30, and this coil system comprises that transmitting coil 31 and 32, two coils of receiving coil are coaxial and spaced-apart at the longitudinal direction of support 30.Transmitting coil 31 is energized the back and produces a magnetic field.This magnetic field is responded to the eddy current that forms and is done coaxial flowing around support shaft in stratigraphic structure.The magnetic responsiveness that receiving coil produces these eddy current, the output information of the conductance of stratigraphic structure is represented in generation.The frequency of operation of transmitting coil depends on that can its magnetic field in stratigraphic structure be divided into " quasistatic " electromagnetic field, and in other words, frequency of operation is to accomplish that displacement current can ignore, and conduction current is occupied an leading position.Suitable frequency is greatly between 10 kilo hertzs and 400 kilo hertzs.Surpass 400 kilo hertzs, it is important that displacement current can become, and output information not only is sensitive to the conductance of stratigraphic structure, and is sensitive to its dielectric constant, and this is undesirable to purpose of the present invention.Best upper frequency limit is about 200 kilo hertzs, is limited to about 20 kilo hertzs down.

In the synoptic diagram of Fig. 1, well logger has only a transmitting coil and a receiving coil as can be seen, but later on will be clear, each coil system can have plural coil, such as one or several transmitting coil, several receiving coils, and and the compensating coil that links of receiving coil to eliminate between transmitting coil and the receiving coil directly coupling effect.Well logger can also comprise several coils, is distributed in each position.

Support 30 is generally tubulose, makes with metal material, preferably adopts the high nonmagnetic metal of conductance.The metal that is fit to comprises copper, aldary and stainless steel.

Support comprises several sections vertical barrel portions 33, its outer wall 34 with extraneous as drilling mud contact and its external diameter less than vertical barrel portion 35 of 33 external diameters.The groove 35a that right cylinder 35 forms thus is in order to admit coil 31 and 32, both and right cylinder 35 coaxial and mutual insulatings.Fig. 1 example contains a such groove, and each groove is adorned a coil, but understands that in the future a column body 35 also can be adorned a whole coil system, and promptly groove 35a can admit the coil of a plurality of axially spaced-aparts.The internal diameter of mediate cylindrical 33 is more preferably greater than right cylinder 35, and the boundary becomes space 36 in.In Fig. 1 example, right cylinder 33 is connected by lateral part 37 with 35, and the wall thickness of right cylinder 33 must be enough to bear the hydrostatic pressure of wellhole.

Lead 38 closing coil 31,32 and electronic cartridges 18 in the support.

Because the holder part of adjacent coils is a high conductive material make and a symmetric outside surface of continuous axial is arranged, so it almost is equivalent to an ideal conductor.This helps to produce eddy current when the electromagnetic field of transmitting coil exists, and this eddy current flows around rack surface.As a result, the tangent electric field of rack surface is forced zero, and the confined space that internal stent forms does not have electromagnetic field.Thereby support has become a highly effective electromagnetic screen.For example, frequency of operation is 20 kilo hertzs, and conductance is 5.8 * 10s/m(copper) time, 5 millimeters thickness are represented 10 skin depths.Like this, between conductor and the coil directly the ghost effect that produces of coupling be eliminated, also can use the holocentric lead and needn't use common multilayer coaxial cable.

And owing to eliminated the tangent line electric field basically at rack surface, the well logger error of being brought by the eddy current that flows at a frame peripheral can be very little.Have been found that the well logger error is the decreasing function of timbering material conductance and frequency to the metal support of axial strict symmetry.The mathematical notation formula of this variation is:

${\mathrm{E\; =\; k\; ·\; \rho }}^{-\frac{1}{2}}\mathrm{·\; f}{}^{-\frac{3}{2}}$

E represents the well logger error,

ρ represents conductance

F represents frequency

K represents coefficient

Find out that thus if adopt the high metal of conductance, the well logger error will diminish.The typical well logger error amount that such metal support is measured in air is 2 milli Siemenss, and the output information that obtains in this and the most high resistance stratigraphic structure is the same order of magnitude.In addition, a very important advantage of the present invention is that this well logger error has low temperature drift and is predictable.Therefore, from output information, deduct the well logger error, can correct the influence of metal support at an easy rate output information.

Coil is contained in this fact on the metal cartridge, has reduced the sectional area of the magnetic flux that is received by coil 31 emissions and coil 32, and its surface area depends on the space between coil and the cylinder 35.This has also reduced the sensitivity of measuring.But, design an appropriate coil, for example, increase some wire turns than the conventional coil that adopts non-conductive support more, this problem just can be compensated at an easy rate.

Be noted that the axial spacing e between coil terminal and the adjacent transverse cylinder 37 will suitably surpass predetermined numerical value.When along the well logger outer surface measuring, opposite with coil, the vertical response of measuring instrument has a cliffy summit value, and the mean breadth of peak value is equivalent to about a diameter of coil separately.In order to prevent the variation of well logger response, the spacing of coil terminal and adjacent transverse cylinder equals the diameter of this coil at least.If a plurality of coils are arranged in groove 35a, the spacing between the coil terminal of each horizontal cylinder and contiguous this cylinder should equal the diameter of this coil at least so.In other words, the support right cylinder that a coil or whole winding system are housed must surpass coil or coil system at the axial dimension of coil or each side of coil system, equals the diameter diameter of end coil (or in the coil system) of coil at least.

As mentioned above, best support is that the cylinder appearance surface of adjacent coils is very axially symmetrical and continuous, and still, design does not always reach this best requirement.But this still belongs to scope of the present invention, as long as the swirl flow of a frame peripheral does not have much influences, for example, but also can use the similar ring section that differs from, and also can adopt as polygonal cross section.Can also on support, bore aperture, allow lead pass and be connected, can seriously not change flowing of eddy current with coil.On the other hand, the cannelure of support can hinder the shield effectiveness of flowing of eddy current and infringement support.

The other advantage of metal support is to improve the physical strength and the durability of well logger, and the cylinder 33 of support itself just can be withstand voltage.

Space 36 in the right cylinder 33 can be used in some circuit of placing well logger.Like this, all coils needn't all be placed in the box 18, as shown in Figure 1, the launch-box that links to each other with transmitting coil 31 can be placed on 36 li in the space on this coil next door, and the receiving box that links to each other with receiving coil output can be with near 36 li in the space that is contained in quadrat method this receiving coil.

Should also be noted that because the possibility that can put lead in the physical strength of support 30 and the support above-mentioned induction instrument can be dissimilar with one or more (sound, nuclear), and well logging apparatus combines, and is contained in the bottom of induction instrument.Fig. 1 label is 40 dotted portion a kind of device that comes to this, and the lead that connects this device and remote measurement box through the internal stent space has also dotted out in Fig. 1, is numbered 41.Therefore, induction instrument of the present invention can be contained in any position of well logging apparatus assembly, and the induction instrument of common non-metal frame can only be contained in the bottom of assembly.

Fig. 2 is than the example of expressing coil 31 and 32 in more detail.The structure of each coil is all identical with coil device 50, and with insulating sleeve 51, as right cylinder 35 insulation of stupalith sleeve and support, sleeve 51 has been adorned several rings 53 and several ring 54 by selling 52 such mode and right cylinders 35 and fixing on the sleeve 51.Use screw-driving on tubular sleeve 51 in the coil device both sides, with fixing in place coil device.

Coil device is a coil box, is generally circular by insulating material by two, forms as the toroidal frame member 56,57 of the formation of pottery, and two members are formed a rectangle cross section together, formed annular in space 58.The wire turn 60 of space 58 receiving coils, the coaxial placement of axle of wire turn 60 and support 30, a lot of leads 61 wrap in around member 56 and 57 by the shape of annular, and every lead all cuts off, make it can not form the loop of sealing, all leads are all received among the figure with on the ground ring with expression not.Like this, all obtain same earth potential gesture.Lead 61 has formed an electrostatic screening, prevent separately coil and other coils or several coil or drilling fluid between produce electrostatic coupling.This method is understood in the application that another awaits the reply jointly in more detail.The exercise question of this application: " well logging is with shielding solenoid coil ", sequence number No.551,239, the assignee who has transferred the application.Here give with reference to the property introduction.

Fluid-tight sleeve 62 is to use electrically non-conductive material, and the epoxy resin that strengthens as glass fibre is made, and pressure seal 62a is equipped with at two ends.Sleeve 62 is enclosed within on the coil device in case the principal vertical line coil apparatus contacts with mud, and ring 53 and 54 supports sleeve 62 from inside surface, makes it can bear the pressure of mud, aperture is arranged as 63 on the support right cylinder 37.The lead that connects in order to the transference coil passes from aperture.

Several coils of saying in the above are contained under the situation in the same right cylinder 35, and the ring that also has some to be similar to ring 53 is placed on the space between the coil in addition, makes coil stationary on the position of oneself, and stop sleeve 62, has sealed the groove 35a between the coil.

It can also be seen that from Fig. 2 right cylinder 35 and 33 is distinct parts,, after coil device is loaded onto right cylinder 35, support could be assembled by means of the screw thread 64 that is used for right cylinder 35 is fixed on horizontal right cylinder 37 at right cylinder 35 two ends.

Should also be noted that the material about support, right cylinder 33 can be used stainless steel as right cylinder 33 with different materials, right cylinder 35 usefulness copper or aldarys with 35.

Fig. 3 is an embodiment after the improvement.Coil 70 is enclosed in and is similar among Fig. 2 in the coil box 71 by member 56 and 57 structures that constituted.Multiple-grooved cylindrical elements 72 is to make with a kind of conductive material, has filled up insulating material in the groove 73, plays the electrostatic screening effect of coil.Similar to the above embodiments, coil box is to be fixed on the position by the ring that is tightened on the sleeve, and these rings tightly engage with multiple-grooved element inwall again, prop up the pressure of fluid in the wellhole.

Improvement to top example is to give the inside pressure boost of the groove of placing coil device, with the pressure of fluid in the opposing wellhole.The circuit of fluid is to flow to groove from support 30 inside, receives a UP compensation system.In this case, fluid-tight electric wire will pass the groove walls connection.

Fig. 4 expresses and is applicable to the induction instrument of the present invention of surveying operation while boring.

Well logger 80 is on the top of drill bit 82, and the part of drill collar 83 is used as coil brace, and drill collar 83 is steel pipe fittings, is connected with the bottom of drill string usually, so that be contained in drill bit top.During drilling operation, drilling mud is by 84 circulations of drill collar center pit.Drill collar is very thick so that exerted pressure suitable weight on the drill bit when drilling well in the past.

Fig. 4 only expresses two coils, a transmitting coil 85 and a receiving coil 86.But fine understanding was explained above, and a compensating coil that does not show cooperates with receiving coil, and well logger can have several different coil arrangement methods with the transmitting coil spacing, and all these coils are all pressed the method for coil 85 and 86 and arranged.

Drill collar 83 has several positions external diameters to shrink, thereby forms the annular groove 87 that can place coil in it, and each coil all embeds in order in the sleeve of being made up of rubber or similar material 88 that fills up groove.The filling of rubber will make the outside surface of sleeve 88, and right cylinder 89 outside surfaces of drilling rod 83 with the contact wellbore fluid are the same flat basically.The central cylinder 90 that it is D that each groove 87 all has an external diameter, its external diameter are less than the outer diameter D of right cylinder 89, and coil is contained in respectively around the central cylinder, cut the conical right cylinder 91 of body central cylinder 90 and drill collar right cylinder 89 are coupled together.Suitable axial dimension approximates the diameter of coil separately to cut the body cone.

Be added on transmitting coil and receive the information of coming from receiving coil and all pass through wire spread, lead does not show, and they all are arranged on the drill collar outside surface in the formed cannelure, are filled into appropriate insulation and protective material again.These leads are connected with an electronic cartridge.Do not show among the figure, electronic cartridge is contained in the drilling rod that is positioned at above the induction instrument.

In a most preferred embodiment, the central cylinder 90 of each groove has an aspect 92 made from copper or the high material of other conductances, and a surface that conductance is high is just arranged near coil like this.Drilling rod 83 as above be that steel is made pointing out.

Fig. 5 is the part sectioned view of induction instrument most preferred embodiment of the present invention.

In Fig. 5 embodiment, transmitting coil is contained in 100 position.Solenoid coil has a lot of ranking methods, and each coil comprises a receiving coil and a compensating coil, and their design and position arrangement will make the direct coupling effect that can eliminate transmitting coil and receiving coil.The receiving coil that different spacing is arranged with transmitting coil is as shown in 101 and 102 position, respectively the compensating coil that matches with receiving coil as shown 101 ' and 102 ' the position.All coils all is contained on the central cylinder 105, and right cylinder 105 is cylindrical outer surfaces of ring section, sees too clearly from the section of Fig. 6.Diameter become big end right cylinder 106 and 107 be fixed on the two ends of support 105.Glass fiber reinforced epoxy resin sleeve 108 is overlapping coil, and the protection coil does not touch wellbore fluid.Sleeve 108 between two termination right cylinders 106 and 107, external diameter and theirs is identical.Form free annular space 110 between center bearing bracket 105 and the sleeve 108 and filled with compressed oil.For this purpose, a pressure compensation element must be installed, on 111 positions of contiguous bottom right cylinder 107.Pressure compensator 111 is ingredients of common well logger, is used for the pressurization of the oil in the annular space 110 make the pressure of a little higher than wellbore fluid of pressure, thereby the pressure reduction of sleeve 108 is very little.

Fig. 6 is the sectional view of center bearing bracket 105 most preferred embodiments, support comprises two parts, a part is the outer sleeve made from the high metal of conductance such as copper or aldary 115, another part is the interior fuse made from high mechanical properties metal such as stainless steel 116, fuse outside in outer sleeve is enclosed within, cooperating very loosely, mainly is to consider that copper has different thermal expansivity with steel.There is the cannelure 117 of much putting lead interior fuse 116 outsides, as shown in Figure 6, have adorned lead 118 in the groove 117, and lead 118 pierces into 119 li of tubular shieldings.Though each groove can hold the couple of conductor that is contained in the shielding, the just shielding of a band lead that Fig. 6 only expresses.The purpose of shielding 119 is in order to reduce the interference between the adjacent slot inside conductor as far as possible.Shielding can be adopted ferromagnetic material such as hiperloy.Except groove 117, inner core also has longitudinal center hole 120, is used to put supply lines and the lead that links to each other with other well logging apparatus on the induction instrument of the present invention.Groove 117 links to each other with annular space 110 by the radial hole that does not show among the figure with center pit 120, so also filled with in the groove and the identical oil of annular space 110 pressure.The manufacture method of inner core is to push with suitable mold.

Coil can be the same structure with the coil device introduced among Fig. 2, and receiving coil and the compensating coil that links are installed on the same ceramic insulation sleeve, as the coil among the figure 101 and 101 ', its sleeve is 122.Perhaps they also can be contained on the different sleeves, as coil 102 and 102 ', on the outer sleeve 115 of support radial hole is arranged, the lead that is connected with compensating coil with receiving coil passes from the hole, and another root lead 124 links up every pair of coil mutually.

Annular space 110 between the coil has filled up filling material 125, as epoxy resin, so that the pressure oil consumption that provided by compensation system 111 and the length of this table apparatus to be provided.

Transmitter need be joined electronic cartridge 130 and could be worked, and as shown in the figure, electronic cartridge is a pressure diaphragm 131 between compensation system 111 and electronic cartridge 130 near the bottom of well logger.The electronic cartridge 132 that is connected with receiving coil is near the well logger upper end, and is same, is pressure diaphragm 133 between electronic cartridge 132 and the well logger coil.Fig. 5 also expresses the top and bottom right cylinder of well logger coiler part.In the right cylinder of lower end, in two semicircular ring 135 and 136 are stuck in the fuse termination above, the circumference of interior fuse has a groove 137, the flange 138 of semicircular ring imbeds in the groove.Two semicircular ring screw mutually with bolt near the termination of copper sleeve, do not show among the figure, and like this, they have just formed a rotary sleeve in support core termination.Sleeve 140 and two semicircular ring screw by screw, by the key 141 that inserts in the keyway on support and the sleeve 140 sleeve can not be rotated around support mandrel 116.Sleeve 140 reduced diameter is arranged part 142, just in time allow outer sleeve 108 entangle.Compensation system shell 145 couples together with sleeve 140 usefulness swivel nuts 148, and swivel nut 148 is threaded with the latter between sleeve 140 and shell 145 bottoms.Swivel nut 148 usefulness retainers 149 are tightly fixed, and make swivel nut 148 and sleeve 140 not do displacement to axial.Unclamp swivel nut with special-purpose plank, shell can be done displacement to axial with sleeve 140, also promptly coil brace is done axial displacement.In addition, groove 117 is connected with the inclined tube 121 that leads to center pit 120 at two ends.

The upper end of coiler part is a sleeve 160, and screw thread 161 is arranged on the sleeve 160, and with the screw-threaded engagement on the adjacent supports mandrel 116, sleeve has the part 163 of one section reduced, and outer sleeve 108 just in time overlaps.Sleeve 160 usefulness and swivel nut 148 similar swivel nuts 166 join with the shell 165 of pressure diaphragm 133, and with sleeve 160 threaded engagement with prevent to do displacement to axial with shell 165.

Pressure diaphragm is represented with 170 in the drawings, itself is in the common part in the well logger equipment axial tube that penetrates the resistance to compression lead that does not show among the figure to be arranged, and the two ends of resistance to compression lead are connected with conductor.At pressure diaphragm 170, be intermediate tubular part 171 between sleeve 160 and the coil brace termination 172, termination 172 reduced diameter of support mandrel 116, cooperate with the annular groove of intermediate tubular part 171, spirality pressure spring 173 produces an elastic force in the centre of intermediate tubular part 171 with support termination 172 to pressure diaphragm.Intermediate tubular part 171 and sleeve 160 all have axial passage 175,176, and the lead that is connected with coil passes in these passages, passage 176 by be fixed on the support and have the parts 178 of the radially sulculus that a lot of live wire use to be connected with groove 117 on the support.

Claims (18)

1, a kind of induction instrument is applicable to displacement in being full of the wellhole of fluid, by horizontal wellhole investigation stratigraphic structure, it is characterized in that it comprises:

At least one firing solenoid coil is used to launch and produces the electromagnetic field that basically with medium effect have nothing to do of frequency for about 10-400KHz scope, and this electromagnetic field produces induction current in stratigraphic structure;

At least one receives solenoid coil, with the transmitting coil axially-spaced, is used to respond the electromagnetic field that is induced by induction current, produces the signal of the conductance of an expression stratal configuration;

A kind of microscler have at least one first longitudinal component and second longitudinal component of the first longitudinal component both sides, in order to coil with coaxial and spaced-apart dress support thereon, this support is to make with conducting metal, at least described first has a continuous exterior surface basically, helping by described around the flowing of this surperficial caused eddy current of electromagnetic field, and described second portion is used for bearing the pressure of wellhole fluid; And

The electrostatic screening device is in order to prevent the electrostatic coupling between described each coil.

According to the well logger of claim 1, it is characterized in that 2, the external diameter of described support second portion is greater than the external diameter of first.

According to the well logger of claim 2, it is characterized in that 3, first and second parts of support connect with a lateral part, the spacing of this lateral part and adjacent windings termination equals the diameter of this coil at least.

According to the well logger of claim 2, it is characterized in that 4, the internal diameter of described support second portion is greater than the internal diameter of first.

According to the well logger of claim 1, it is characterized in that 5, described support is made with copper or aldary.

6, a well logger that is fit to the survey while boring of the signal that the stratigraphic structure conductance that expression records by horizontal wellhole can be provided that connects with drill string is characterized in that, comprising:

At least one firing solenoid coil, in order to emission and produce the electromagnetic field that basically with medium effect have nothing to do of frequency for about 10-400KHz scope, this magnetic field produces induction current in stratigraphic structure;

At least one receives solenoid coil, with the transmitting coil axially-spaced, is used for response by faradic induction field, produces the signal of an expression stratigraphic structure conductance;

The elongate tubular support be connected with drill string with conducting metal being fit to of making, this support contains and is applicable to part coaxial and that the mode that is spaced from each other is installed coil, this part has a continuous exterior surface basically, to help by described flowing around this surperficial caused eddy current of electromagnetic field; And

The electrostatic screening device is in order to prevent the electrostatic coupling between described each coil.

According to the well logger of claim 6, it is characterized in that 7, the part of described installation coil has reduced diameter to be used to lay coil with the part that forms groove.

According to the well logger of claim 7, it is characterized in that 8, coil is embedded in the rubber type of material.

According to the well logger of claim 7, it is characterized in that 9, the part of described installation coil has a matallic surface layer, its conductance is than support height.

According to the well logger of claim 9, it is characterized in that 10, said support is to make with stainless steel, said superficial layer is made of copper.

11, a kind of induction instrument is applicable to displacement in wellhole, by horizontal wellhole investigation stratigraphic structure, it is characterized in that it comprises:

At least one firing solenoid coil is used to launch and produces the electromagnetic field that basically with medium effect have nothing to do of frequency for about 10-400KHz scope, and this electromagnetic field produces induction current in stratigraphic structure;

At least one receives solenoid coil, with the transmitting coil axially-spaced, is used to respond the electromagnetic field that is induced by induction current, produces the signal of the conductance of an expression stratal configuration;

A kind of microscler in order to coil with coaxial and spaced-apart dress support thereon, this support is to make with conductive material, at least near the outside surface coil is continuous basically and axial symmetry, to help by described flowing around this surperficial caused eddy current of electromagnetic field; And

The electrostatic screening device is in order to prevent the electrostatic coupling between described each coil.

According to the well logger of claim 11, it is characterized in that 12, outside surface longitudinal extension continuous basically and axial symmetry exceeds corresponding coil-end, exceeds the diameter that the coil both sides are at least a coil.

13, according to the well logger of claim 11, it is characterized in that, said support comprises the outer sleeve made by first kind of high conductive material and has the inner core that the material of high mechanical properties is more made by second kind than first kind of material that the external diameter of inner core equals the internal diameter of outer sleeve substantially.

According to the well logger of claim 13, it is characterized in that 14, said outer sleeve is to make with copper or aldary, inner core is to make with stainless steel.

According to the well logger of claim 13, it is characterized in that 15, said inner core has groove longitudinally on around it, these grooves and outer sleeve inside surface form passage, and lead can pass support in these grooves.

According to the well logger of claim 15, it is characterized in that 16, said inner core also has a longitudinal center hole.

17, a kind of induction instrument is applicable to and passes wellhole,, it is characterized in that it comprises so that detect the stratigraphic structure of horizontal wellhole with the method for electromagnetism:

One high-intensity, conduction, have an in fact microscler support of continuous exterior surface, to help flowing of eddy current;

One coaxial and by the insulating sleeve of its support with described support;

At least one is coaxial and by the firing solenoid coil of its support with described sleeve, be used to launch and produce the electromagnetic field that basically with medium effect have nothing to do of frequency for about 10-400KHz scope, this electromagnetic field induces electric current in the stratum, and induces the eddy current around the surface on the surface of described microscler support;

One coaxial and arranged by first receiver of its support with described sleeve, and it has an elementary receiver solenoid coil that is first longitudinal separation that is configured in described transmitter solenoid coil one side;

One coaxial and arranged by second receiver of its support with described sleeve, it have one be configured on the described transmitter solenoid coil, arrange the elementary receiver solenoid coil that is second longitudinal separation of that relative side of a side with described first receiver is housed, and described second at interval at interval greater than described first; And

The electrostatic screening device is in order to prevent the electrostatic coupling between described each coil.

18, according to the well logger of claim 17, it is characterized in that, during described first and second receivers are arranged each also comprises a secondary receiver solenoid coil, their its corresponding elementary receiver solenoid coils are connected in series, but winding direction is opposite, and between described transmitter solenoid coil and corresponding elementary receiver solenoid coil, so that the signal that causes owing to the coupling that interacts from the transmitter solenoid coil in described elementary receiver is arranged is balanced basically.

Images