CN204327065U - For the front-end circuitry of Compensated Neutron Log Tool - Google Patents
For the front-end circuitry of Compensated Neutron Log Tool Download PDFInfo
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- CN204327065U CN204327065U CN201420638988.XU CN201420638988U CN204327065U CN 204327065 U CN204327065 U CN 204327065U CN 201420638988 U CN201420638988 U CN 201420638988U CN 204327065 U CN204327065 U CN 204327065U
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Abstract
The utility model relates to a kind of front-end circuitry for Compensated Neutron Log Tool, it is characterized in that comprising: charge amplifier, be coupled that the charge signal exported by described probe is transformed into voltage signal via the first capacitor with the probe in described Compensated Neutron Log Tool; Differentiating amplifier, to be coupled with charge amplifier via the second capacitor and to amplify described voltage signal to obtain the first medium voltage with differential, wherein said first medium voltage is proportional with the time rate of change of described voltage signal and have and contrary the meeting of described voltage signal U; Comparator, for more described first medium voltage U1 and adjustable threshold voltage to obtain pulse signal, the described pulse signal tool vicissitudinous time cycle; And pulse shaper, for carrying out shaping to described pulse signal to obtain the identical pulse signal of width, the pulse signal that described width is identical is sent to control circuit board in described Compensated Neutron Log Tool for subsequent treatment.
Description
Technical field
The utility model relates to the electric wire section for acquisition and processing signal in oil well logging instrument, relates more specifically to the front-end circuitry for Compensated Neutron Log Tool.
Background technology
Well logging, is also geophysical log or oil well logging, and being called for short well logging, is the geophysical property such as electrochemical properties, conductive characteristic, acoustic characteristic, radioactivity utilizing rock stratum, measures the method for geophysical parameters, belongs to one of applied geophysics method.In oil field prospecting and development process, well logging is one of the important means determining and evaluate oil, gas-bearing formation, is also the important means solving a series of geological problem.During oil drilling, all must log well getting into after planned well is spent deeply, also known as completion logging, to obtain various petroleum geology and engineering data, i.e. the information such as reservoir depth, thickness, as completion and the firsthand information that develops oil fields.
Well logging can directly for petroleum geology and engineers and technicians provide every data and data.As required, various logger is developed if acoustic logging instrument, induction log tool and dipmeter tool etc. and various auxiliary well logging pipe nipple are to obtain petrophysical parameter and the Engineering technical parameters on various stratum.These loggers due to be operated in high temperature, high pressure adverse circumstances under (such as, when the down-hole degree of depth to 7000 m, temperature can reach 175 DEG C, and pressure reaches 140 MPa) and high temperature resistant, high voltage bearing performance must be had.
Compensated Neutron Log Tool is the one of radioactive logging instrument.It has the probe of the thermal neutron-epithermal neutron of two different spacings, is determined the degree of porosity on stratum by the count rate ratio of long and short spacing detector.
Specifically, compensated neutron probe section loads the Am-Be neutron source of 16 Curie, and kind per second is by generation 4 × 10
7individual fast neutron, these fast neutrons inject stratum, collide with the material in stratum.According to collision theory, the energy loss in neutron collision is with relevant with angle of incidence by the quality of collision object.It is maximum that the material that fast neutron is suitable with quality collides the energy that (elastic collision) lose.Through collision rift several times, fast neutron will be decelerated, and average energy decays to 0.25eV from 5.6MeV, become thermal neutron.These thermal neutrons some enter probe, clash into He
3core, causes nuclear reaction, produces H
3(tritium) and proton, this proton makes other a part of He
3ionization, produces charged ion and electronics.Now, under high voltage electric field effect, electronics anode is moved, and produce a negative pulse, this pulse is amplified by electronic circuit and recorded.Because the quality of hydrogen atom and neutron are suitable, so the quantity that probe accepts thermal neutron just reflects the quantity of hydrogen atom in stratum.Therefore, the logging instrument be made up of probe and electronic circuit thereof can measure the hydrogen content in stratum.
But current electric wire section exists problems to the collection of detector signal and transmission, the low and resistance to elevated temperatures of such as poor stability, signal to noise ratio is weak etc.Therefore, due to the work under bad environment of down-hole, there is the demand to the front-end circuitry improving Compensated Neutron Log Tool.
Utility model content
The purpose of this utility model is to provide a kind ofly to be measured accurate, easy to operate and is convenient to the front-end circuitry for Compensated Neutron Log Tool of fixing a breakdown.This front-end circuitry has the narrow and small advantage of high temperature high voltage resistant, anti-vibration and space structures.
On the other hand, because the small-signal of neutron detector can be amplified by front-end circuitry of the present utility model, become measurable pulse signal after treatment, monitoring to front-end circuitry is provided simultaneously, thus the debugging maintenance difficulty of the front-end circuitry of Compensated Neutron Log Tool can be reduced, the questions and prospect of easy position nose Circuits System, reduces cost of labor.
According to one side of the present utility model, a kind of front-end circuitry for Compensated Neutron Log Tool is provided, it is characterized in that comprising: charge amplifier, be coupled that the charge signal exported by described probe is transformed into voltage signal via the first capacitor with the probe in described Compensated Neutron Log Tool; Differentiating amplifier, to be coupled with charge amplifier via the second capacitor and to amplify described voltage signal to obtain the first medium voltage with differential, wherein said first medium voltage is proportional with the time rate of change of described voltage signal and have and contrary the meeting of described voltage signal U; Comparator, for more described first medium voltage U1 and adjustable threshold voltage to obtain pulse signal, the described pulse signal tool vicissitudinous time cycle; And pulse shaper, for carrying out shaping to described pulse signal to obtain the identical pulse signal of width, the pulse signal that described width is identical is sent to control circuit board in described Compensated Neutron Log Tool for subsequent treatment.
According to one side of the present utility model, described front-end circuitry also comprises: supervisory circuit, is arranged in monitor described first medium voltage in real time between described differentiating amplifier and described comparator, thus the failture evacuation in auxiliary described front-end circuitry.
According to another aspect of the present utility model, described front-end circuitry also comprises: power module, for the charge amplifier of described front-end circuitry, differentiating amplifier, comparator and pulse shaper provide 5 volts or 12 volts of direct currents.
According to another aspect of the present utility model, described front-end circuitry also comprises: high-pressure modular, is coupled with described first capacitor and described probe, and wherein said first capacitor is used for isolated high-voltage.
According to another aspect of the present utility model, between the positive and inverting input of described charge amplifier, be connected in series the first resistor and a diode to prevent high-voltage arc to the infringement of described charge amplifier, wherein said first capacitor is connected to described inverting input and positive input end grounding via described first resistor.
According to another aspect of the present utility model, the first resistor and two diodes are connected in parallel to prevent high-voltage arc to the infringement of described charge amplifier between the positive and inverting input of described charge amplifier, wherein said two diode reverse are connected in parallel, and wherein said first capacitor is connected to described inverting input via described first resistor, and positive input end grounding.
According to another aspect of the present utility model, described probe comprises the first probe and the second probe.
According to another aspect of the present utility model, the 3rd capacitor and the second resistor is connected in parallel between the inverting input and output of described charge amplifier, described output is connected to the inverting input of described differentiating amplifier via described second capacitor and the 3rd resistor, and wherein said voltage signal is relevant to described 3rd capacitor.
According to another aspect of the present utility model, described differentiating amplifier inverting input be at least connected the 4th resistor between output, wherein said first medium voltage and described second capacitor, the 3rd resistor are relevant with the 4th resistor.
According to another aspect of the present utility model, described adjustable threshold voltage is obtained from described power module by resistor divider mode.
According to another aspect of the present utility model, described pulse shaper is made up of monostable flipflop, is wherein regulated the width of described pulse signal by the 5th resistor that connects at the pin place of monostable flipflop and the 4th capacitor.
Read detailed description of the invention below in conjunction with the drawings, feature and advantage of the present utility model can be understood better.
Accompanying drawing explanation
Embodiment of the present utility model is explained now with reference to accompanying drawing.It should be noted that these embodiments are for illustrating general principle, making only to illustrate to understand general principle and those required features.Accompanying drawing not in scale.In addition, similar label represents similar features in the whole text in the accompanying drawings.
Fig. 1 is the schematic diagram of the front-end circuitry for Compensated Neutron Log Tool according to an embodiment of the present utility model.
Fig. 2 A is the schematic diagram of the charge amplifier comprised according to the front-end circuitry of an embodiment of the present utility model.
Fig. 2 B is the schematic diagram of the charge amplifier comprised according to the front-end circuitry of another embodiment of the present utility model.
Fig. 3 A is the schematic diagram of the differentiating amplifier comprised according to the front-end circuitry of an embodiment of the present utility model.
Fig. 3 B is the schematic diagram of the differentiating amplifier comprised according to the front-end circuitry of another embodiment of the present utility model.
Fig. 4 A is the schematic diagram of the comparator comprised according to the front-end circuitry of an embodiment of the present utility model.
Fig. 4 B is the schematic diagram of the test signal waveform of the comparator comprised according to the front-end circuitry of an embodiment of the present utility model.
Fig. 5 is the schematic diagram of the pulse shaper comprised according to the front-end circuitry of an embodiment of the present utility model.
Fig. 6 is the schematic diagram of the supervisory circuit comprised according to the front-end circuitry of an embodiment of the present utility model.
Detailed description of the invention
The following specifically describes and relate to accompanying drawing, these accompanying drawings are shown by diagramatic way can implement detail of the present utility model and embodiment.These embodiments of abundant specific descriptions are to enable those skilled in the art to implement the utility model.Other embodiment can be utilized and structure, logic and electricity can be carried out and change and do not depart from scope of the present utility model.Various embodiment may not mutual exclusion, because some embodiments can combine to form new embodiment with one or more other embodiment.
In the following detailed description with reference to the accompanying drawing of a part for this detailed description of formation, the mode in the drawing by illustrating shows wherein can put into practice specific embodiment of the utility model.In this respect, the direction term at " top ", " end ", "front", "rear", " head ", " tail " etc. is employed such as with reference to the orientation of described accompanying drawing.Assembly due to embodiment can be positioned in several different orientation, and therefore described direction term is used to the object of explanation and limits anything but.It being understood that and can utilize other embodiments when not deviating from scope of the present utility model and the change that structure or logic can be made.Therefore, detailed description is not below considered as restrictive, sense, and scope of the present utility model is defined by the appended claims.
It being understood that as in this manual the term " coupling " that adopts and/or " being electrically coupled " not meaning that mean as described in element must direct-coupling together; Intermediary element can be provided between the element of " coupling " or " being electrically coupled ".As in this manual the term " connection " that adopts and/or " electrical connection " not meaning that mean as described in element must direct-coupling together; Intermediary element can be provided between the element of " connection " or " electrical connection ".
It being understood that except non-specific Stated otherwise further, otherwise the feature of each exemplary embodiment as described herein can combination with one another.It should be understood that the embodiment only unrestricted the technical solution of the utility model in order to explanation.Although be described in detail the utility model with reference to embodiment, but those of ordinary skill in the art is to be understood that: still can modify to the utility model or equivalent replacement, and do not depart from spirit and scope of the present utility model, and claims are intended to contain these amendments or equivalent replacement of falling into the utility model spirit and scope.
Next, embodiment of the present utility model explained by concrete reference accompanying drawing.
Fig. 1 is the schematic diagram of the front-end circuitry 100 for Compensated Neutron Log Tool according to an embodiment of the present utility model.As shown in Figure 1, Compensated Neutron Log Tool generally at least comprises probe such as neutron detector 50(such as He
3probe), front-end circuit treatment system 100 and rear end master control borad or control circuit board 80.According to an embodiment of the present utility model, Compensated Neutron Log Tool comprises the high-voltage power module 70 that the electric charge for producing probe accelerates alternatively, and this high-voltage power module 70 can such as be arranged between neutron detector 50 and front-end circuit treatment system 100.
As is further illustrated in figure 1, this front-end circuit treatment system 100 can comprise charge amplifier 200, differentiating amplifier 300, comparator (also referred to as comparing differentiation device) 400 and pulse shaper 500.Whether this front-end circuit treatment system 100 also can comprise optional supervisory circuit 600 normal with the signal evaluated probe and gather for the output of monitoring differentiating amplifier 300 in real time.
Fig. 2 A is the schematic diagram of the charge amplifier 200 comprised according to the front-end circuitry 100 as shown in Figure 1 of an embodiment of the present utility model, particularly for the electronic circuit connection diagram of the charge amplifier 200 of HA2620-2 type.From figure, probe 50 such as neutron detector 50 is connected to capacitor C1 via the node 2 shown in Fig. 2 A, and wherein capacitor C1 such as can have 0.1-10nF, is preferably 1nF.
As shown in Figure 2 A, high voltage output module 70 can by power supply V4, the capacitor C4 in parallel with power supply V4, the resistor R3 connected with capacitor C4 forms, and be also connected to above-mentioned node 2, wherein power supply V4 can have such as 500-2000V, is preferably 1000V; Capacitor C4 such as can have 0.1-10nF, is preferably 4.7nF; And resistor R3 can such as have 0.1-10M Ω, is preferably 3.9M Ω.High voltage output module 70 provides high direct voltage for neutron detector 50, makes charged particle under high voltage electric field effect, produces negative pulse.
According to an embodiment of the present utility model, probe 50 can be connected to the inverting input of amplifier U1 via capacitor C1 and resistor R1 and the normal phase input end of amplifier U1 such as can ground connection, wherein resistor R1 such as can have 1-1000 Ω or 10-500 Ω, is preferably 100 Ω.As shown in Figure 2 A, described amplifier U1 can have the type of HA2620-2.Alternatively, described amplifier U1 can also have the type of OPA211-HT and LMC6061AIM.Further, the diode of contact resistance device R2 and two Opposite direction connection between the inverting input and normal phase input end of described amplifier U1, wherein resistor R3 can such as have 0.1-10M Ω, is preferably 1M Ω; Such as, and the diode of shown two Opposite direction connections can have identical or different type, has IN4148 model.
Further as shown in Figure 2 A, capacitor C2 and resistor R4 is connected in parallel between the inverting input (i.e. the pin two of amplifier U1) and output (being designated " NODE1 ") of amplifier U1, wherein capacitor C2 such as can have 0.1-10pF, is preferably 4pF; And resistor R4 can such as have 0.1-20M Ω, is preferably 10M Ω.
In addition as shown in Figure 2 A, in order to make amplifier U1 carry out normal operating, the different pins of amplifier U1 can be applied in supply voltage V1 and V2, and the pin 4 of such as amplifier U1 can be applied in-12V and the pin 7 and 8 of amplifier U1 can be applied in+12V.According to an embodiment of the present utility model, supply voltage V2 is preferably coupled to the pin 8 of amplifier U1 via capacitor C3, wherein capacitor C3 such as can have 0.1-100pF, is preferably 10pF.
It is noted that the number range of above-mentioned capacitor, resistor and supply voltage can as required or actual carrying out regulate or revise, run more well to make whole electronic circuit system.In addition, also show optional test branch road in fig. 2, this optional test branch road is included in the oscillograph that the test input of charge amplifier 200 and node 2 are connected with between its output and NODE1, so just can test this charge amplifier 200 individually, thus simplify and facilitate failture evacuation.In this case, only need apply test waveform V3 between node 2 and ground, the voltage of such as test waveform V3 is 0V ~ 0.5V and its cycle 0.01msec(millisecond) to 0.1msec.
Again, the function of the critical piece shown in Fig. 2 A and requirement are summarized as follows: capacitor C1 needs to select 3KV high-voltage capacitance, plays isolated high-voltage; The effect of resistor R1 is by the output impulsive quarantine of high voltage source 70 with probe 50; And R2, D1, D2 are used for preventing high-voltage arc to the infringement of amplifier amplifier U1.
In sum, the effect of charge amplifier 200 is that charge Q probe being exported pulse accumulation is transformed to corresponding voltage pulse, and wherein C2 plays coupling electric charge, and the voltage exported at " NODE1 " place is V=Q/C2.
Fig. 2 B is the electronic circuit connection diagram of the charge amplifier 200' comprised according to the front-end circuitry 100 as shown in Figure 1A of another embodiment of the present utility model.
With Fig. 2 category-A seemingly, from Fig. 2 B, probe 50 such as neutron detector 50 is connected to capacitor C1 via the node 2 shown in Fig. 2 B, and wherein capacitor C1 such as can have 0.1-10nF, is preferably 1.25nF.As shown in Figure 2 B, high voltage output module 70 can by power supply V4, the resistor R5 connected with power supply V4, the capacitor C4 in parallel with the series circuit of power supply V4 and resistor R5, the resistor R3 connected with capacitor C4 forms, and be also connected to above-mentioned node 2, wherein power supply V4 can have such as 500-2000V, is preferably 1000V; Capacitor C4 such as can have 0.1-10nF, is preferably 1.25nF; Resistor R3 can such as have 0.1-10M Ω, is preferably 3.9M Ω; And resistor R5 can such as have 0.1-100M Ω, is preferably 10M Ω.
According to an embodiment of the present utility model, as shown in Figure 2 B, probe 50 can be connected to the inverting input of amplifier U1 via capacitor C1 and resistor R1 and the normal phase input end of amplifier U1 such as can ground connection, wherein resistor R1 such as can have 1-5000 Ω or 100-2000 Ω, is preferably 1k Ω.As shown in Figure 2 B, described amplifier U1 can have the type of OPA211-HT.Alternatively, described amplifier U1 can also have the type of HA2620-2 and LMC6061AIM.Further, between the inverting input and normal phase input end of described amplifier U1, connect a diode, this diode can have and such as have IN4148 model.
Further as shown in Figure 2 B, capacitor C2 and resistor R4 is connected in parallel between the inverting input (i.e. the pin two of amplifier U1) and output (being designated " NODE1 ") of amplifier U1, wherein capacitor C2 such as can have 0.1-10pF, is preferably 4pF; And resistor R4 can such as have 0.1-20M Ω, is preferably 1M Ω.
In addition as shown in Figure 2 B, in order to make amplifier U1 carry out normal operating, the different pins of amplifier U1 can be applied in supply voltage V1 and V2, and the pin 4 of such as amplifier U1 can be applied in-12V and the pin 7 and 8 of amplifier U1 can be applied in+12V.According to an embodiment of the present utility model, supply voltage V2 is preferably coupled to the pin 8 of amplifier U1 via capacitor C3, wherein capacitor C3 such as can have 0.1-100pF, is preferably 10pF.Equally, also show optional test branch road in fig. 2b, this optional test branch road is included in the oscillograph that the test input of charge amplifier 200' and node 2 are connected with between its output and NODE1.According to an embodiment of the present utility model, can apply test waveform V3 between node 2 and ground, the voltage of such as test waveform V3 is 0V ~ 0.5V and its cycle 0.01msec(millisecond) to 0.1msec.
Fig. 3 A is the schematic diagram of the differentiating amplifier 300 that the front-end circuitry 100 according to Fig. 1 of an embodiment of the present utility model comprises.
As shown in Figure 3A, output NODE1 from the amplifier U1 of Fig. 2 A is connected to the differentiating amplifier 300 of Fig. 3 a, its interior joint NODE1 is connected to the inverting input of amplifier U2 via capacitor C5 and resistor R5 and the normal phase input end of amplifier U2 such as can ground connection, wherein resistor R5 such as can have 0.1-100k Ω or 1-10k Ω, be preferably 6.2k Ω, and capacitor C5 such as can have 10-1000pF, is preferably 560pF.As shown in Figure 3A, described amplifier U2 can have the type of HA2620-2.Alternatively, described amplifier U1 can also have the type of OPA211-HT and LMC6061AIM.Further, between the inverting input and normal phase input end of described amplifier U2, connect capacitor C8, wherein capacitor C8 such as can have 10-100pF, is preferably 91pF.
Further as shown in Figure 3A, contact resistance device R6 between the inverting input (i.e. the pin two of amplifier U1) and output (being designated " NODE2 ") of amplifier U2, wherein resistor R6 can such as have 0.1-10M Ω, is preferably 1M Ω.
In addition as shown in Figure 3A, normal operating is carried out in order to make amplifier U2, the different pins of amplifier U2 can be applied in supply voltage V5 and V6, and the pin 4 of such as amplifier U1 can be applied in supply voltage V5(such as-12V) and the pin 7 and 8 of amplifier U1 can be applied in supply voltage V6(such as+12V).According to an embodiment of the present utility model, supply voltage V6 is preferably coupled to the pin 8 of amplifier U2 via capacitor C7, wherein capacitor C7 such as can have 0.1-100pF, is preferably 10pF.
Equally, similar with Fig. 2, also show optional test branch road in figure 3 a, this optional test branch road is included in test input and node 20(or NODE1 of differentiating amplifier 300) oscillograph that is connected with between its output and NODE2, so just can test this differentiating amplifier 300 individually, thus simplify and facilitate failture evacuation.In this case, only need apply test waveform V1 between node 20 and ground, the voltage of such as test waveform V1 is 0V ~ 0.5V and its cycle 0.01msec to 0.1msec.
Thus, the voltage U at output at differentiating amplifier 200 and NODE2 place can be obtained according to formula below
o:
U
o＝-R
6/R
5×C
5×dU
20/dt
Wherein U
20represent the voltage at node and NODE1 place, but mean the output of amplifier U2 and the voltage time rate of change at NODE1 place proportional meet contrary.
Fig. 3 B is the another kind of connection diagram of the differentiating amplifier 300 that the front-end circuitry 100 according to Fig. 1 of another embodiment of the present utility model comprises.
As shown in Figure 3 B, output NODE1 from the amplifier U1 of Fig. 2 A is connected to the differentiating amplifier 300' of Fig. 3 B, its interior joint NODE1 is connected to the inverting input of amplifier U2 via capacitor C5 and resistor R5 and the normal phase input end of amplifier U2 such as can ground connection, wherein resistor R5 such as can have 0.1-100k Ω or 1-10k Ω, be preferably 3.3k Ω, and capacitor C5 such as can have 10-100MF, is preferably 47MF.As shown in Figure 3 B, described amplifier U2 can have the type of HA2620-2.Alternatively, described amplifier U1 can also have the type of OPA211-HT and LMC6061AIM.
Further as shown in Figure 3 B, capacitor C1 and resistor R6 is connected in parallel between the inverting input (i.e. the pin two of amplifier U1) and output (being designated " NODE2 ") of amplifier U2, wherein capacitor C1 such as can have 0.1-100pF, is preferably 20pF; And resistor R6 can such as have 0.1-10M Ω, is preferably 100k Ω.
In addition as shown in Figure 3 B, normal operating is carried out in order to make amplifier U2, the different pins of amplifier U2 can be applied in supply voltage V5 and V6, and the pin 4 of such as amplifier U1 can be applied in supply voltage V5(such as-12V) and the pin 7 and 8 of amplifier U1 can be applied in supply voltage V6(such as+12V).According to an embodiment of the present utility model, supply voltage V6 is preferably coupled to the pin 8 of amplifier U2 via capacitor C7, wherein capacitor C7 such as can have 0.1-100pF, is preferably 10pF.
Equally, with Fig. 3 category-A seemingly, also show optional test branch road in figure 3b, this optional test branch road is included in test input and node 20(or NODE1 of differentiating amplifier 300') oscillograph that is connected with between its output and NODE2, so just can test this differentiating amplifier 300' individually, thus simplify and facilitate failture evacuation.In this case, only need apply test waveform V1 between node 20 and ground, the voltage of such as test waveform V1 is 0V ~ 0.5V and its cycle 0.01msec to 0.1msec.
Fig. 4 A is the schematic diagram of the comparison differentiation circuit 400 that the front-end circuitry 100 according to Fig. 1 of an embodiment of the present utility model comprises.
As shown in Figure 4 A, output NODE2 from the amplifier U2 of Fig. 3 A is connected to the comparison differentiation circuit 400 of Fig. 4 a, its interior joint NODE2 is connected to one end of comparator U3 via capacitor C10 and the other end of comparator U3 connects adjustable threshold voltage, wherein capacitor C10 such as can have 10-1000nF, is preferably 100nF.According to an embodiment of the present utility model, capacitor C10 can be connected to ground via resistor R9, and wherein resistor R9 can such as have 0.1-100k Ω, is preferably 10k Ω.According to an embodiment of the present utility model, adjustable threshold voltage can be obtained from supply voltage V8 dividing potential drop by resistor R7 and R8, and wherein resistor R7 such as can have 10-200k Ω, is preferably 130k Ω; And resistor R8 such as can have 0.1-100k Ω, be preferably 10k Ω.
As shown in Figure 4 A, described comparator U3 can have the type of LM11H.Alternatively, described comparator U3 can also have the type of LM211-EP.
In addition as shown in Figure 4 A, normal operating is carried out in order to make comparator U3, the different pins of comparator U3 can be applied in supply voltage V1, V8 and V9, the pin 4 of such as comparator U3 can be applied in supply voltage V8(such as-12V), the pin 8 of comparator U3 can be applied in supply voltage V1(such as+12V), and the pin 7 of comparator U3 can be applied in supply voltage V1(such as+5V).
Further as shown in Figure 4 A, the output of comparator U3 is represented by node NODE3.Equally, similar with Fig. 3, also show optional test branch road in Figure 4 A, this optional test branch road is included in the oscillograph that the test input that compares differentiation circuit 400 and NODE32 are connected with between its output and NODE3, so just can test comparing differentiation circuit 40 individually, thus simplify and facilitate failture evacuation.In this case, only need apply test waveform between node NODE2 and ground, such as shown in Figure 4 B, wherein Fig. 4 B is the schematic diagram of the test signal input and output waveform of the comparator comprised according to the front-end circuitry of an embodiment of the present utility model.
Specific works process is as follows: the in-phase input end of comparator LM111 is coupled in the output pulse of the amplifier U2 in Fig. 3 A and 3B by capacitor C10, and it outputs signal the ground end being taken from it; The resistance value of R7 and R8 can determine the threshold voltage of comparator, and such as voltage threshold can be set as about-0.8V; R11 is load resistance.When the negative pulse from amplifier U2 exceedes comparator threshold level, comparator U3 exports the positive pulse of 5V, and when the negative pulse from amplifier U2 is lower than comparator threshold level, comparator U3 does not export pulse.As shown in Figure 4 B, curve 410 is input waveform to simulation waveform, and this input waveform can be the sine wave of frequency 10KHz, amplitude 10V; And curve 420 is output waveform such as square wave.
Fig. 5 is the schematic diagram of the pulse shaper 500 that the front-end circuitry 200 according to Fig. 1 of an embodiment of the present utility model comprises.
According to embodiment of the present utility model, in normal well logging situation, the output NODE3 of comparator U3 is pulse signal, the described pulse signal tool vicissitudinous time cycle.In order to the needs of subsequent conditioning circuit process (such as counting), the pulse signal that the cycle that maybe advantageously converted to by the pulse signal of the period of change exporting NODE3 place is fixing.
As shown in Figure 5, shaping pulse chip U5 can adopt the type of CD4528.According to an embodiment of the present utility model, show in Figure 5 for+5V at the pin one of shaping pulse chip U5 and VDD() between be connected in parallel capacitor C13 and C14, wherein capacitor C13 such as can have 0.01-1uF, is preferably 0.1uF; And capacitor C14 such as can have 0.1-100uF, be preferably 10uF.According to an embodiment of the present utility model, shaping pulse chip U5 pin one be connected capacitor C15 between pin two, wherein capacitor C15 such as can have 100-1000pF, is preferably 820pF.
According to an embodiment of the present utility model, show in Figure 5 for+5V at the pin two of shaping pulse chip U5 and VDD() between contact resistance device R13, wherein resistor R13 can such as have 1-100k Ω, is preferably 39k Ω.The pin 3 and 5 of shaping pulse chip U5 is connected to supply voltage VDD(and shows in Figure 5 for+5V), and the pin one of shaping pulse chip U5,12 is connected ground GND with 15.In addition, the pin 6 of shaping pulse chip U5 is connected to ground GND via resistor R14, and wherein resistor R14 can such as have 1-1000k Ω, preferably 10-500k Ω, is more preferably 100k Ω.
In addition, the output NODE3 of comparator U3 is fed to the pin 4 of shaping pulse chip U5 and the pin 6 of shaping pulse chip U5 is output signal OUT, wherein can realize output pulse width t by tune R13 and C15
wadjustment, wherein pulse width t
w∝ R
13× C
15× log
10(VDD-VSS), wherein VDD equals 5 volts and VSS equals 0 volt in this example.In addition, other pin of shaping pulse chip U5 can be unsettled.
Alternatively, according to an embodiment of the present utility model, shaping pulse chip U5 also can adopt the type of MC14528.By above-mentioned pulse shaper 500, can obtain the pulse signal that width is identical, the control circuit board (control circuit board 80 as shown in Figure 1) that the pulse signal that described width is identical is sent in described Compensated Neutron Log Tool such as counts for subsequent treatment.Such as, when root system of the present utility model has the probe of thermal neutron-epithermal neutron of two different spacings, the degree of porosity on stratum is determined by the count rate ratio of long and short spacing detector.
Fig. 6 is the schematic diagram of the supervisory circuit 600 that comprises of the front-end circuitry 100 according to Fig. 1 of an embodiment of the present utility model and peripheral circuit thereof.
According to embodiment of the present utility model, in order to monitor the working condition of the front-end circuitry 100 shown in Fig. 1 in real time, alternatively, in front-end circuitry 100, add an A/D supervisory circuit 600, the effect of this A/D supervisory circuit 600 comprise monitoring high voltage source whether high pressure is applied to probe and described high pressure size, whether successfully acquire charge signal etc.
As shown in Figure 6, the pulse signal that the differentiating amplifier U2 shown in Fig. 3 a and 3b exports can pass through filter circuit (not shown in figure 6) and be imported into A/D supervisory circuit 600, and it exports JAout is the data signal of 0 ~ 65535.According to an embodiment of the present utility model, this A/D supervisory circuit 600 can such as adopt chip AD7656.
As seen from Figure 6, the output NODE2 of amplifier U2 is imported into pin 36 or the SIGNAL1 of chip AD7656, and corresponding data signal exports from the pin one 1 of chip AD7656 or AD_SCK.It is noted that above input and output pin is only schematic, channel position and the quantity of corresponding input and output can be adjusted according to actual needs.
Space relative terms such as " below ", " below ", D score, " on ", " on " etc. is employed to explain that an elements relative is in the location of the second element for ease of illustrating.Except being different from the orientation of those orientations described in the drawings, the difference that these terms are intended to contain device is directed.In addition, such as " first ", " second " etc. are also used to describe various element, region, part etc. term, and also and not intended to be restrictive.Run through manual, the element that similar term reference is similar.
As used herein, term " has ", but " containing ", " comprising ", " comprising " etc. indicate the existence of element or the feature stated do not get rid of other element or the open-ended term of feature.Article " one ", " one " and " being somebody's turn to do " are intended to comprise plural number and odd number, unless context clearly separately has instruction.
Although illustrate and describe various exemplary embodiment of the present utility model above with reference to accompanying drawing, clear can making will be realized the various change of some advantages of the utility model and amendment and does not depart from spirit and scope of the present utility model by those skilled in the art.Therefore, as long as these amendments of the present utility model, modification and replacement belong within the scope of claims of the present utility model and equivalent technical solutions thereof, then the utility model is also intended to comprise these amendments, modification and replacement.In addition, with regard to describe in detail or use term " to comprise " in claims, " having ", " with " or their other variants, such term intention is inclusive " to comprise " similar mode with term.
In addition, term " exemplary " only means as an example, instead of the best or optimum.Also will recognize, feature described here and/or element are for simple and understandable object with shown in specific dimensions relative to each other, and actual size may be significantly different from size shown here.
This area rational technique personnel will understand, suitably can replace with other parts performing identical function.Even if it should be mentioned that in those situations not yet clearly mentioning this point, with reference to the feature specifically scheming to explain can with the Feature Combination of other figure.Be intended to be covered by claims to the amendment of utility model concept like this.
In addition, the scope of the application be not intended to be limited to describe in manual process, machine, manufacture, material composition, device, method and step specific embodiment.As those of ordinary skill in the art from of the present utility model open easily recognize, according to the utility model can utilize perform function identical in fact with corresponding embodiment described herein or realize result identical in fact, current existence or later process leaved for development, machine, manufacture, material form, device, method or step.Accordingly, claims are intended within the scope of it, comprise these processes, machine, manufacture, material composition, device, method or step.
Claims (11)
1., for a front-end circuitry for Compensated Neutron Log Tool, it is characterized in that comprising:
With the probe in described Compensated Neutron Log Tool, charge amplifier, is coupled that the charge signal exported by described probe is transformed into voltage signal via the first capacitor;
Differentiating amplifier, to be coupled with charge amplifier via the second capacitor and to amplify described voltage signal to obtain the first medium voltage with differential, wherein said first medium voltage is proportional with the time rate of change of described voltage signal and have and contrary the meeting of described voltage signal U;
Comparator, for more described first medium voltage U1 and adjustable threshold voltage to obtain pulse signal, the described pulse signal tool vicissitudinous time cycle; And
Pulse shaper, for carrying out shaping to described pulse signal to obtain the identical pulse signal of width, the pulse signal that described width is identical is sent to control circuit board in described Compensated Neutron Log Tool for subsequent treatment.
2. front-end circuitry according to claim 1, is characterized in that described front-end circuitry also comprises:
Supervisory circuit, is arranged in monitor described first medium voltage in real time between described differentiating amplifier and described comparator, thus the failture evacuation in auxiliary described front-end circuitry.
3. front-end circuitry according to claim 1, is characterized in that described front-end circuitry also comprises:
Power module, for the charge amplifier of described front-end circuitry, differentiating amplifier, comparator and pulse shaper provide 5 volts or 12 volts of direct currents.
4. front-end circuitry according to claim 1, is characterized in that described front-end circuitry also comprises:
High-pressure modular, is coupled with described first capacitor and described probe, and wherein said first capacitor is used for isolated high-voltage.
5. front-end circuitry according to claim 1, it is characterized in that being connected in series the first resistor and a diode between the positive and inverting input of described charge amplifier to prevent high-voltage arc to the infringement of described charge amplifier, wherein said first capacitor is connected to described inverting input and positive input end grounding via described first resistor.
6. front-end circuitry according to claim 1, it is characterized in that being connected in parallel the first resistor and two diodes between the positive and inverting input of described charge amplifier to prevent high-voltage arc to the infringement of described charge amplifier, wherein said two diode reverse are connected in parallel, and wherein said first capacitor is connected to described inverting input via described first resistor, and positive input end grounding.
7. front-end circuitry according to claim 1, is characterized in that, described probe comprises the first probe and the second probe.
8. the front-end circuitry according to claim 5 or 6, it is characterized in that being connected in parallel the 3rd capacitor and the second resistor between the inverting input and output of described charge amplifier, described output is connected to the inverting input of described differentiating amplifier via described second capacitor and the 3rd resistor, and wherein said voltage signal is relevant to described 3rd capacitor.
9. front-end circuitry according to claim 8, it is characterized in that described differentiating amplifier inverting input be at least connected the 4th resistor between output, wherein said first medium voltage and described second capacitor, the 3rd resistor are relevant with the 4th resistor.
10. front-end circuitry according to claim 3, is characterized in that, described adjustable threshold voltage is obtained from described power module by resistor divider mode.
11. front-end circuitry according to claim 1, it is characterized in that, described pulse shaper is made up of monostable flipflop, is wherein regulated the width of described pulse signal by the 5th resistor that connects at the pin place of monostable flipflop and the 4th capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420638988.XU CN204327065U (en) | 2014-10-30 | 2014-10-30 | For the front-end circuitry of Compensated Neutron Log Tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420638988.XU CN204327065U (en) | 2014-10-30 | 2014-10-30 | For the front-end circuitry of Compensated Neutron Log Tool |
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| Publication Number | Publication Date |
|---|---|
| CN204327065U true CN204327065U (en) | 2015-05-13 |
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|---|---|---|---|
| CN201420638988.XU Expired - Fee Related CN204327065U (en) | 2014-10-30 | 2014-10-30 | For the front-end circuitry of Compensated Neutron Log Tool |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105545293A (en) * | 2014-10-30 | 2016-05-04 | 中国石油集团长城钻探工程有限公司 | Compensated neutron logging device front end circuit |
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2014
- 2014-10-30 CN CN201420638988.XU patent/CN204327065U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105545293A (en) * | 2014-10-30 | 2016-05-04 | 中国石油集团长城钻探工程有限公司 | Compensated neutron logging device front end circuit |
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Granted publication date: 20150513 |