CN1015674B - Well lagging tool with accelerator neutron source - Google Patents
Well lagging tool with accelerator neutron sourceInfo
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- CN1015674B CN1015674B CN 86104825 CN86104825A CN1015674B CN 1015674 B CN1015674 B CN 1015674B CN 86104825 CN86104825 CN 86104825 CN 86104825 A CN86104825 A CN 86104825A CN 1015674 B CN1015674 B CN 1015674B
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Abstract
The present invention relates to a porosity neutron logging instrument which is in a disclosed illustrative embodiment. The present invention comprises a D-T neutron accelerator, a fast neutron monitor, a near epithermal neutron detector, a far epithermal neutron detector and a thermal neutron detector, wherein the fast neutron monitor is used for monitoring the output of the accelerator; the near epithermal neutron detector and the far epithermal neutron detector are mainly used for the measurement of porosity; the thermal neutron detector is far and provides thermal neutron absorption properties of stratum configuration around a well hole; corresponding to a neutron source of the accelerator, epithermal neutrons are shielded and separated to cause the instrument to obtain optimal response to the stratum porosity. Thus, the instrument provides accurate sensitivity in the whole meaningful porosity range.
Description
The present invention relates to a kind of well logger, be used to study drilling well stratal configuration on every side, measure the feature of stratal configuration.More particularly, the present invention relates to utilize accelerator neutron generator, can accurately determine formation porosity and other characteristics, such as the well-logging probe of macroscopic capture cross section.
To the drilling well understanding of the factor of porosity of stratal configuration on every side, very important in petroleum industry, be used to differentiate oily gentle Production Regional, calculate maximum oil-producing capacity index and other important parameters on stratum.The general known well logger that is used for measuring factor of porosity uses chemical neutron source, for example Cf
252, Am-Be or Pu-Be neutron source, and placing two or more neutron detectors from source different distance place.Such well logger all has a detailed description in the United States Patent (USP) 3,566,117 of the M.Tixier that the United States Patent (USP) of the S.Locks that announces on Dec 9th, 1969 was announced on February 23rd, 3,483,376 and 1971.
Yet chemical neutron source exists serious problems such as processing, transportation and storage, and this has seriously hindered their use.Really, consider radiation safety and the reason that control is used to chemical source, just restriction and then their use of possibility total ban more.In addition, chemical source has the limit of output intensity, is typically per second 4 * 10
7The magnitude of individual neutron or lower.Even using bigger chemical source may do under the design conditions restriction of well logger obtains also only can making radiation safety problem noted earlier even more serious.
Various types of accelerator neutron generators also may be applicable in the well logger, such as accelerator neutron generator based on deuterium-tritium (D-T) reaction, it can produce the neutron of 14Mev, accelerator neutron generator based on deuterium-deuterium (D-D) reaction, can produce the neutron of 2.5Mev, produce the spectrum of a 1-10Mev based on the accelerator of deuterium-deuterium alpha reaction, the neutron average energy is near 5Mev, the United States Patent (USP) 3 of the A.Frentrop that announces on November 27th, 1973,775, in 216, the example of a D-T accelerator neutron generator has been described.(this part application has transferred the application's assignee)
Because accelerator neutron generator can be controlled by switch (switching on and off by desirable), the radiation problem that occurs when using chemical source in accelerator neutron generator, has just no longer existed.Another advantage of accelerator neutron generator is to improve neutron source strength.The sort of per second 5 * 10
8Individual neutron output or higher output obtain easily, and this is than the big order of magnitude of chemical source.Because the neutron output intensity is bigger, accelerator neutron generator can improve statistical accuracy, can also make test operation carry out more hurry up.
In addition, higher neutron source strength has increased the dirigibility about configuration design between the shielding between the different detectors and configuration and special detector and the neutron source.Therefore, can improve the performance of sniffer.For example, the spacing of big detector just can cause less boring influence.
Yet, have been found that in a known factor of porosity sniffer, directly replace chemical neutron source with accelerator neutron generator, a feasible well logger can not be provided.The response that its reason is known factor of porosity proving installation mainly by be transported near the detector high-energy neutron and by the degradation of energy collision, the neutron that local slowing down can be surveyed when more low-yield decides.By near detector, the total cross-section that detects neutron is different with energy, the source neutron energy can influence the response of factor of porosity, to a D-T source that can produce the 14Mev neutron, the ground layer cross section that neutron suffered from is very different with the situation of typical chemical source (is 4Mev as Am-Be source neutron average energy).Because factor of porosity changes the influence to neutron detector, and the output signal of detector, all is different for D-T accelerator source and chemical source.Such as, directly replacing the distinct disadvantage of a chemical source with a D-T accelerator source is the insufficient sensitivity of factor of porosity, almost surpasses 25% factor of porosity.
Therefore, to using the porosimeter of accelerator neutron generator, must eliminate and the relevant radiation problem of the chemical neutron source of use.Meanwhile, also to provide accurate factor of porosity sensitivity, in logging Application, reach whole significant scopes.Also will use a high-intensity accelerator neutron generator for the factor of porosity tester, this source can provide reasonable statistical accuracy, and test faster improves the dirigibility in the design, and can make preferably, is subjected to drilling well to influence less porosity determination.
According to the present invention, for satisfying the above-mentioned of prior art and other requirements, can realize by a kind of well logger, this well logger comprises an accelerator neutron generator, a neutron source monitor, a nearly epithermal neutron detector and a distance hyper-thermal neutron detector, for the special neutron shield of nearly epithermal neutron detector and distance hyper-thermal neutron detector, may also have a thermal neutron detector.
The purpose that the neutron source monitor is set is, its mainly neutron without slowing down to sending from the source, also is those neutron sensitivities of not having an effect with stratum or drilling well.Then, the neutron source monitor produces a signal that is proportional to the neutron source output intensity.
Nearly epithermal neutron detector is placed on and closes on the neutron source place.To the shielding of nearly epithermal neutron detector, preferably, bring up near 10ev with its low energy neutron detection threshold, keep sensitivity simultaneously than high-energy neutron.Best, around nearly epithermal neutron detector, form a ring with degraded neutron one intercept neutrons material.Such arrangement, in whole significant scopes (0%-40%), the sensitivity that has improved factor of porosity.Best, between neutron source and nearly epithermal neutron detector, do not place the high density shielding, can make nearly epithermal neutron detector, the source there is very close spacing.Close like this source-detector pitch, the sensitivity that helps to improve the ratio factor of porosity.
Owing to improved the average detection energy of nearly epithermal neutron detector, just reduced sensitivity sharp to formation porosity.But be still sensitive for the effect of drilling well surrounding environment and instrument " far " effect.Therefore, when determining sensitivity with proportional technique or crossplot technique, this tester can be used to proofread and correct the influence and instrument " far " effect of drilling well surrounding environment.Their each technology has detailed discussion in the back.
The position of distance hyper-thermal neutron detector will face toward neutron source, in order that make this detector keep enough sensitivities, and preferably more partially, adopt shielding to formation porosity, so that further improve its sensitivity, reduce sensitivity to the drilling well neutron to the stratum.
Thermal neutron detector is more farther from neutron source than distance hyper-thermal neutron detector from neutron source, but very near, measures statistical accuracy so that improve.Thermal neutron detector preferably inclined to one side put and in one side conductively-closed towards drilling well so that reduce the influence of drilling well surrounding environment.Mensuration that thermal neutron detector just makes stratum characteristic is set in this well logger can depend on the absorption of thermal neutron, such as the capture cross-section ∑ on stratum, and still has good factor of porosity sensitivity and statistical degree of accuracy.
Although the accelerator neutron generator of other types also can be used, preferably use the D-T source.Suitable neutron detector is helium-3(
3He) proportional counter tube, rely on recently with two such detectors and neutron source, just near epithermal neutron detector and distance hyper-thermal neutron detector, they each wrap up with a thin cadmium layer that energy is lower than the neutron of about 0.5ev is insensitive so that they become.
The factor of porosity on stratum can be by the signal from nearly epithermal neutron detector, to ratio from the signal of distance hyper-thermal neutron detector, promptly determine with proportional technique, or pass through by the normalized signal of neutron source supervisory signal from nearly epithermal neutron detector, with by the signal from distance hyper-thermal neutron detector of the signal normalization of neutron source monitor, the curve of comparing, promptly crossplot technique is determined.With any technology in the two,, can be equivalent to or be better than the mensuration that existing chemical source well logger is provided to the mensuration of factor of porosity.Meanwhile, the safety that interrelates with the prior art well logger and the restriction of intensity have but been avoided.
Objects and advantages of the present invention from below in conjunction with the detailed description of accompanying drawing to embodiment, can better be understood, among the figure:
Fig. 1 is a well logger sectional view of the present invention;
Fig. 2 is the sectional drawing of well logger shown in Figure 1 along the 2-2 line, and illustrates thermal neutron detector and its shielding;
Fig. 3 is the sectional drawing of well logger shown in Figure 1 along the 3-3 line, illustrates distance hyper-thermal neutron detector and shielding thereof;
Fig. 4 is the synoptic diagram of this well logger detector signal treatment circuit;
Fig. 5 is the function curve of the comparison factor of porosity of closely superthermal and distance hyper-thermal neutron detector counting rate.
Fig. 6 is with regard to the parent rock of various stratum, and the distance hyper-thermal neutron detector counting rate is to the function X plot of nearly epithermal neutron Detector count rate.
One be based upon on the principle of the invention basis specific embodiment as shown in the figure, wherein, identical label is represented same parts.Fig. 1 represents that a well logger that is used for studying the factor of porosity of stratal configuration around the drilling well promptly pops one's head in 10.This device comprises 12, one neutron source monitors of an accelerator neutron generator, 16, one distance hyper-thermal neutron detectors 18 of 14, one nearly epithermal neutron detectors and a thermal neutron detector 20. Shielding 22,24 and 26 is used for shielded probe 16,18 and 20 respectively, and shielding 28 places between nearly epithermal neutron detector 16 and the distance hyper-thermal neutron detector 18.
Probe 10 in case of necessity, can provide bending spring or other conventional equipment as shown in the reference numeral 11 to this instrument as a kind of sidewall instrument, and this instrument is pushed to against borehole wall.Although this instrument gives meter and is mainly used in the test of opening hole, also can be used for the sleeve pipe hole, and when needing, it can use also in siphunculus with certain specification.
Neutron accelerator 12 can be any suitable type, is output as 5 * 10 but preferably have
8The neutron source of neutron/second or bigger D-T type 14Mev is so that improve statistical counting and test speed.Although do not show among Fig. 1, still can understand the accelerator assembly and comprise necessary high-voltage power supply and the starting circuit that is used for operating accelerator, and these circuit also can be conventional.By purpose of the present invention, accelerator operation can be continuously (d.c) mode, also can be pulsed.If use a kind of mode in back, the accelerator assembly also should comprise necessary pulsing circuit certainly.Be further appreciated that also tackling instrument 10 provides suitable power supply (not shown), to drive detector 16,18 and 20 and other well logging electrical equipment.
In a most preferred embodiment, neutron source monitor 14 comprises a scintillator 30, (plastics preferably, certainly other types also can be used), it is used for surveying the fast neutron that is sent by described source, also has a photomultiplier 32 in addition, and it is used for amplifying the signal that scintillator 30 produces.This neutron source monitor is that application serial is the sort of structure that United States Patent (USP) disclosed of No508623 and the monitor of size, and this United States Patent (USP) is be entitled as " the neutron source strength monitor of being applied for by P.Albats ".Suitable part is merged among the application in the Albats application.
Press the announcement of Albats, this monitor 14 can be made up of 0.5 inch long plastic scintillant (NE102A), and its diameter is 0.5 inch.Neutron source monitor 14 should be placed to such an extent that it is preponderated to the response without the high-energy neutron of slowing down that comes from the source, and scattered neutron and gamma-ray influence then are reduced to minimum.Preferably this monitor 14 nestles up or just on the radius distance of accelerator neutron generator 12, makes scintillator 30 face toward target 34 positions of accelerator 12.But because device is tied (space constraint), monitor may be had to and neutron source is coaxially settled, such as being placed in some collar aperture tube proving installation.When not having strong the shielding between source 12 and the monitor 14, scintillator 30 may be placed in from source 30cm at a distance, just as what describe in detail in the Albats application.
Through suitably selected size and location, neutron monitor is mainly in response to the neutron without slowing down, be those neutrons above neutron source is directly incident on it, thereby can measure the variation of source 12 output intensities reliably, and the influence that not changed by drilling well or stratum characteristic.So as will be explained hereinafter, the output signal of neutron source monitor 14 can be used for the output signal of epithermal neutron detector 16,18 and thermal neutron detector 20 is carried out normalizing to the intensity fluctuation in source.Monitor 14 has good intrinsic gain stability, but just like in the Al-bats application and described in Fig. 4, if it is used in the high-voltage power supply FEEDBACK CONTROL circuit of monitor photomultiplier, the stability of gain is also bigger.
Represented nearly epithermal neutron detector 16 and distance hyper-thermal neutron detector 18 helium-3(preferably among Fig. 1
3He) proportional counter, it has the thin cadmium layer shielding of 0.02 inch (0.51cm) to be wrapped in, and this can make detector for having below the superheated region, and the neutron that also promptly is lower than about 0.5ev is insensitive.These detectors provide main porosity measurement.
The sensitive volume of nearly epithermal neutron detector or active zone are positioned at extremely close 12 places, source, and best (though this not necessarily) do not insert the high density screen layer.Such as, for a diameter is 1 inch (2.5cm), the so typical detector size of cylindrical detector of long 3 inches (7.6cm), the suitable interval between the target of the center of sensitive volume and a D-T accelerator should be 8 to 10 inches (20.3 to 25.4cm) magnitudes.Approaching like this source-detector pitch is compared with the detector than long spacing that inserts shielding, has improved the sensitivity of ratio factor of porosity.Therefore, be appreciated that best source-detector pitch can be along with some factors vary, i.e. suchlike factors such as detector size, pressure, source strength, accelerator type.
The shielding 22 that is used for nearly epithermal neutron detector 16 preferably annular and around the sensitive volume of nearly epithermal neutron detector.As described, shielding 22 is intended to the low energy neutron detection threshold is brought up near 10ev.Along with shielding 22 has such consideration, nearly epithermal neutron detector places the local of very close source again and does not insert the high density shielding therebetween, nearly epithermal neutron detector changes relatively say it is insensitive for the factor of porosity on stratum, because neutron energy that those and stratum react generally is the low energy neutron detection threshold that is lower than this detector.But, this nearly epithermal neutron detector still keeps sensitive for the influence of drilling well surrounding environment and instrument away from effect, because those neutron energies of having an effect with the thing in the drilling well generally surpass 10ev.Therefore, can compensate the signal of other detectors at the drilling well surrounding environment influence by the signal of nearly epithermal neutron detector output.The device and the technology that are used for this purpose are No300 in application serial, record to some extent in 418 the United States Patent (USP), and this part patent is to be applied for by people such as Ellis on September 9th, 1981, the existing patent No. is No4,423,323; At application serial No405, also on the books in 391 the United States Patent (USP), this part patent is to be applied for by Scott August 5 nineteen eighty-two, existing patent No. No4, and 524,274, part suitable in these documents is included into the application.About profile, spacing and the effect of nearly detector 16 and to shield 22 the further details of structure be No508 in application serial, disclose to some extent in 622 the United States Patent (USP), this application is that S.Antkiw applies for that to be entitled as " the neutron porosity pen recorder that uses the accelerator source " relevant portion of this application also is merged among the application.
In order to obtain bigger stratum sensitivity, far detector 18 preferably is placed on a side of this probe 10, makes it towards the stratum by shielding, and as shown in Figure 3, the shielding 24 that is used for far detector is cylindrical, and its inside has groove 36, and far detector 18 is placed in the groove.Shielding 24 makes the sensitive volume of far detector obtain shielding, prevents that just the neutron there on stratum incides above it dorsad from this probe towards drilling well over there.Erect image will recognize like that, this biasing of far detector and dorsad the result of screen layer reduce the sensitivity of far detector to the drilling well surrounding environment influence, improve its response to the formation porosity variation.
Spacing between source 12 and the far detector 18 is longer, just causes 18 pairs of source neutrons of detector relatively to say it is insensitive.Also can between nearly detector 16 and far detector 18, add an additional mask layer 28, so that further reduce the sensitivity of far detector to source neutron.
The sensitive volume of thermal neutron detector 20 is set at the source of leaving than the 18 farther places of leaving far detector, and it is so near in fact preferably putting from far detector, so that counting rate reaches maximal value.As the epithermal neutron detector, the position of thermal neutron detector can be along with some factors vary, such as the size of workspace and the pressure of detector etc.The size of sensitive volume can adapt with the counting rate statistics that will reach, and is that 2.25 inches (5.7cm) length is 4 inches (10.2cm) such as diameter.Best, thermal neutron detector is offset in the groove as far detector 18, towards the stratum here.
As described in Fig. 2, shielding 26 makes the sensitive volume of thermal neutron detector obtain shielding, and the drilling well neutron of avoiding facing toward from probe over there incides above it, and this is the same situations with above-described shielding 24 shielding far detectors 18.Because the cause of this biasing and screen layer 26, thermal neutron detector is less to the remolding sensitivity of drilling well surrounding environment influence, to formation characteristics, as the variation of formation macro capture cross-section ∑ bigger sensitivity is arranged.Shielding 26 preferably one thin, as the cadmium layer shielding of 0.020 inch (0.51cm), it has the curved arch shape that is close to 180 ° of arcs, if but select for use other neutron absorbing material and other shape also to be fine.
Shielding 22,24 and 28 can be made with any suitable material or combined material, and they should have the performance of degraded neutron and intercept neutrons two aspects.For the slowing down fast neutron, just those seldom with the interactional neutron in stratum, need neutron moderator.In order to absorb thermal neutron, just those by slowing material or by thing in the drilling well or stratum thermalization neutron, need neutron-absorbing material.(application serial No508622) contrasts and comprehensively discusses in the Antkin application that the acting on of shielding material quoted from the front.Though not necessarily necessary, best three screen layers 22,24 and 28 use same shielding material.
A kind of suitable shielding material is exactly boron carbide (B
4C), its disperse is in epoxy resin or in other hydrogeneous constraint media, such as the B that 65% weight is arranged in epoxy resin
4C.As selected shielding material, screen layer 22,24 and 28 each layer thickness all should be enough to satisfy necessary requirement, such as shielding 22, if use above-mentioned 65%B
4The C-epoxide resin material is made, and then its rough thickness should be 1 inch (2.5cm), has now found that this is gratifying for the low energy neutron detection threshold of described nearly detector is brought up near 10ev from 0.5ev.
Along with neutron source monitor 14 and neutron detector 16,18 and 20 have suitable spacing and shielding, just can improve determining to formation porosity.Just as previously described, because nearly detector 16 is relatively said smaller for the sensitivity that factor of porosity changes, bigger to drilling well surrounding environment influence and instrument away from effect sensitivity, the sensitivity that 18 pairs of factor of porosity of far detector change is relatively said greatly, so can the proportion of utilization technology or nearly detector 16 draw to make with the friendship of far detector 18 counting rates factor of porosity determined to improve, handing over draws is that the counting rate of each detector is come normalization with the ionization meter of neutron source monitor.With the exception of this, because the response to factor of porosity comes compared with the epithermal neutron detector, thermal neutron detector is relatively said not too sensitivity for drilling well size and instrument away from effect to the response of factor of porosity, so its output can be in order to derive the measurement of an additional factor of porosity.It can be the measurement of particular value that a kind of like this thermal neutron proosity is measured, and in the middle of this, the response of thermal neutron detector is not subjected to stratum and drilling environment that neutron is absorbed this material impact.Have, the output of thermal neutron detector makes that macroscopic capture cross section ∑ and other stratum entrapment properties can obtain with the measurement of epithermal neutron factor of porosity measuring together in same instrument again.
For this purpose, from
3He detector 16 and 18 output signal can be amplified and counted with any proper method, thereby derive for the counting rate (N) of nearly detector 16 with for the counting rate (F) of spy device 18 far away.For example, picture as shown in Figure 4, can deliver to charge- sensitive preamplifier 35 and 37 from the detector signal of detector 16 and 18, give pulse amplifier 38 and 40 more therefrom, from each detector, deliver to a forward position discriminator 42 and 44 again through the burst spectrum that amplifies, their output drives scaler 46 and 48.Scaler output is added on the signal processing circuit 50, this circuit can suitably digital machine, microprocessor or other data processing devices of programming be formed by one, can obtain the ratio N/F of nearly detector calibration device counting (N) from this circuit, as an indication of factor of porosity to far detector scaler counting (F).This indication is subjected to the influence and the instrument of surrounding environment (mud, drilling well size etc.) but relatively smaller away from effect, and it can provide a kind of accurate, reliable porosity measurement.Ratio signal N/F can be added on conventional record/drawing apparatus 52, with its record as the function of the probe degree of depth and in addition.
Fig. 5 represent to get 8 inches long one section drilling wells lime rock stratum is recorded factor of porosity be 0,13.2%, 29.3% and 40.6% o'clock near/more than the response of (N/F).Just as will be understood, ratio N/F has good sensitivity in whole 0 to 41% factor of porosity scope.
If desired, can also utilize the X plot of nearly detector and far detector counting rate to determine factor of porosity.As understandable, crossplot technique can be used to revise surrounding environment influence.
Fig. 6 is near-(N-F) X plot far away of 0 to 41% factor of porosity in sandstone, ls and rauhkalk stratum, and it demonstrates the influence that geology changes.The data of painting corresponding 8 inches long uncased drill holes.
When crossplot technique being used for determine factor of porosity, N counting rate and F counting rate at first will be used the output normalization of neutron flux monitor 14.For this reason, each all will remove counting rate (intensity) output signal (window A) of monitor 14 detector calibration device 46 and 48 output signal, thus obtain as Fig. 4 represented, the output A/N and the A/F of signal processing circuit 50.In this method, apply at aforesaid Albats that by intensity output signal A and related circuit thereof that monitor 14 produces (relevant portion of application serial (No508623) all has sufficient description, need not repetition here.The application of Albats has also been described and has been made monitor circuit obtain stable parts (unit 54 to 61 among Fig. 4), for this reason, has produced window B counting rate signal.
By normalized far detector counting rate F the factor of porosity sensitivity of height is arranged also, and can be used to derive the information of factor of porosity.But, it and N/F compare surrounding environment influence sensitive a little, but this sensitivity can reduce by the accelerator of use higher-strength and bigger source-detector pitch.
The output signal of thermal neutron detector can be exaggerated, differentiates and calibrate (unit 62 to 68 among Fig. 4) equally, and a calibration output counting rate T about thermal neutron detector 20 is provided.This signal is preferably also used monitor output signal A normalization, and is used to derive the measurement of formation macro capture cross-section ∑.It can also be individually or with one or more normalization epithermal neutron Detector count rate signal A/N and A/F be used to derive factor of porosity information or differentiate the influence that neutron absorbs in porosity determination.Any part or all of these functions can be achieved in signal processing circuit 50 in any suitable manner and easily.
Although be here describe with specific embodiment of the present invention, but be appreciated that it all is possible need not to change the improvement of the inventive concept that is disclosed and changing, and for example replaces all being fine with boron fluoride (BF) detector or other type neutron detector without helium-3 detector.Also have, also can use the source-detector pitch, the detector size that are different from here to be disclosed.All these improvements and changes have been comprised in the appended claims.
Claims (15)
1, a kind of well-logging probe that is used to study stratal configuration around the boring, its composition is:
-one accelerator neutron generator that constitutes by the D-T source of monoenergetic 14 Mev neutrons in fact,
-neutron source monitoring arrangement mainly to from described neutron source, is directly incident on its and goes up neutron sensitivity without slowing down, is used for the output of surveillance source, and the sensitive volume of described monitoring arrangement places the outside near neutron source,
-the first neutron detection device, be used for surveying epithermal neutron, this sniffer has one with the sensitive volume of some distance of neutron source and in fact it is insensitive for the neutron that energy is lower than about 0.5ev, the sensitive volume of described this sniffer nestles up neutron source, but there is not highdensity screen layer between them
-can degraded neutron and first shield assembly of intercept neutrons, it is used for shielding the sensitive volume of the first neutron detection device, reaches at least near 10ev to improve the low energy neutron detection threshold of this device, to make,
-be used for surveying the second neutron detection device of epithermal neutron, this device has a sensitive volume, this district is far away than the sensitive volume from the described first neutron detection device from accelerator neutron generator, and one side of deflection well, the described second neutron detection device is actually insensitive to the neutron that energy is lower than about 0.5ev
-have the secondary shielding device of degraded neutron and intercept neutrons performance, be used to shield the sensitive volume of the described second neutron detection device, shielding projects the neutron above it from away from well logger on one side.
2, well-logging probe according to claim 1, wherein said first shield assembly, basically ringwise, be placed on the first neutron detection device around, constitute by a kind of hydrogenous material that can degraded neutron, the inside disperse has the material of intercept neutrons.
3, as well-logging probe as described in the claim 2, wherein the material of intercept neutrons is a boron carbide.
4, well-logging probe according to claim 1, wherein said secondary shielding device is made of a kind of hydrogenous material that can degraded neutron, and disperse has the boron carbide of intercept neutrons in this material.
5, well-logging probe according to claim 1, described first and the described second neutron detection device between the 3rd additional shield assembly is housed, it is made of a kind of hydrogenous material that can degraded neutron, disperse has the material of intercept neutrons in this material.
6, as well-logging probe as described in the claim 5, wherein the material of intercept neutrons is a boron carbide.
7, well-logging probe according to claim 1, wherein said neutron source monitoring arrangement comprises an organic scintillator, constitutes described sensitive volume and a photomultiplier, described scintillator and said photomultiplier be optical coupled together.
8, as the said well-logging probe of claim 7, wherein said scintillator is a plastic scintillant.
9, well-logging probe according to claim 1, the wherein said first and second neutron detection devices, each is all by a thin cadmium cover of band
3The He proportional counter tube is formed.
10, use the well logger of probe according to claim 1, it is subsidiary to have the output signal that is used for deriving the described first neutron detection device of indication to the ratio of the output signal of the described second neutron detection device telltale as the formation porosity indication.
11, use the well logger of probe according to claim 1, it also comprises and is used for deriving the first ratio signal display device of described neutron source monitoring arrangement to the ratio of the output signal of the described first neutron detection device, and is used for deriving the device of the described neutron source monitoring arrangement of representative to second ratio signal of the ratio of the output signal of the described second neutron detection device.
12, well logger as claimed in claim 11, it also comprises and is used for making up described first and second ratio signal, to draw the device of indication formation porosity signal.
13, a kind of well-logging probe that is used to study stratal configuration around the boring comprises:
-one accelerator neutron generator that constitutes by the D-T source of monoenergetic 14Mev neutron in fact,
-one neutron source monitoring arrangement, it mainly to directly from neutron source, project above it without the neutron sensitivity of slowing down, be used for the output of surveillance source, the sensitive volume of described neutron source monitoring device places the outside near neutron source.
-the first
3The He proportional counter tube, it is placed on close neutron source but a distance is arranged, and does not insert highdensity screen layer therebetween, and it is insensitive that this pipe is lower than about 0.5ev neutron actual to energy.
-one has first shield assembly of moderation of neutrons and absorptive character, is used for shielding described first
3The He proportional counter tube so that improve the threshold value that this pipe is surveyed low energy neutron, reaches near 10ev at least.
-one second
3The He proportional counter tube, it is placed on leaves described neutron source ratio and leaves described first
3The He proportional counter tube is the distant place slightly, and described second
3The He proportional counter tube, one side of deflection well-logging probe, the neutron that energy is lower than 0.5ev is actually insensitive.
-one has the secondary shielding device of moderation of neutrons and absorptive character, is used for shielding described second
3The He proportional counter tube is on one side shielding is from the neutron that scatters to away from well-logging probe on the pipe.
-Di three
3The He proportional counter tube, it is placed on leaves described neutron source ratio and leaves described second
3The He proportional counter tube is the distant place slightly, and is partial to described well-logging probe one side, and uses the intercept neutrons material, in the side shielding away from well-logging probe.
14, use well logger as probe as described in the claim 13, it comprises that also the neutron source monitoring arrangement is to the described the 3rd
3The device of first ratio signal of the ratio of He proportional counter tube output signal and described neutron source monitoring arrangement are to the second ratio signal device of the ratio of the output signal of described the 2nd He proportional counter tube.
15, as well logger as described in the claim 14, it also comprises and is used for making up described first and second ratio signal, with the device of the macroscopic capture cross section signal of deriving the indication stratigraphic structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86104825 CN1015674B (en) | 1986-06-07 | 1986-06-07 | Well lagging tool with accelerator neutron source |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86104825 CN1015674B (en) | 1986-06-07 | 1986-06-07 | Well lagging tool with accelerator neutron source |
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| CN86104825A CN86104825A (en) | 1987-12-16 |
| CN1015674B true CN1015674B (en) | 1992-02-26 |
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| CN 86104825 Expired CN1015674B (en) | 1986-06-07 | 1986-06-07 | Well lagging tool with accelerator neutron source |
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| CN100561377C (en) * | 2004-11-12 | 2009-11-18 | 佳能株式会社 | Imaging device |
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|---|---|---|---|---|
| CN100497885C (en) * | 2006-05-24 | 2009-06-10 | 中国石化集团胜利石油管理局钻井工艺研究院 | Deuterium-deuterium controllable compensating neutron well logging instrument during drilling |
| US7633058B2 (en) * | 2007-12-04 | 2009-12-15 | Schlumberger Technology Corporation | Hermetically sealed packaging and neutron shielding for scintillation-type radiation detectors |
| CN101598017B (en) * | 2008-06-04 | 2012-10-31 | 中国石油集团钻井工程技术研究院 | Device for measuring porosity of azimuth neutrons during drilling |
| US8242436B2 (en) * | 2010-11-30 | 2012-08-14 | Sondex Limited | Neutron porosity logging tool using microstructured neutron detectors |
| CN102359370B (en) * | 2011-07-04 | 2013-08-14 | 中国石油化工股份有限公司 | Intelligent tester |
| CN103527181B (en) * | 2012-07-05 | 2016-12-21 | 中国石油天然气集团公司 | A kind of with boring controllable source neutron well logging method and instrument |
| CN104747179A (en) * | 2013-12-31 | 2015-07-01 | 中国石油化工集团公司 | Stratum density measuring while drilling instrument based on deuterium-tritium accelerator neutron source |
| CN109893780B (en) * | 2019-04-19 | 2021-07-23 | 兰州大学 | Epithermal neutron flux detector for BNCT |
| CN112259265B (en) * | 2020-10-21 | 2023-11-07 | 中国核动力研究设计院 | Off-stack high-sensitivity neutron detector and layout system |
-
1986
- 1986-06-07 CN CN 86104825 patent/CN1015674B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100561377C (en) * | 2004-11-12 | 2009-11-18 | 佳能株式会社 | Imaging device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN86104825A (en) | 1987-12-16 |
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