CN202832520U - System and acoustic logger capable of eliminating interference of direct waves during acoustic logging - Google Patents
System and acoustic logger capable of eliminating interference of direct waves during acoustic logging Download PDFInfo
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- CN202832520U CN202832520U CN 201220208110 CN201220208110U CN202832520U CN 202832520 U CN202832520 U CN 202832520U CN 201220208110 CN201220208110 CN 201220208110 CN 201220208110 U CN201220208110 U CN 201220208110U CN 202832520 U CN202832520 U CN 202832520U
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Abstract
The utility model relates to a system and a logger capable of eliminating interference of direct waves during acoustic logging, wherein a transmission energy converter of the acoustic logger transmits logging acoustic waves to two or more receiving transducers, and the logging acoustic waves are collected by the receiving transducers. For each receiving transducer, scanning is carried out in time domain and slowness domain so that time slowness correlation coefficients of the logging acoustic waves are obtained. Therefore, time slowness correlation coefficient spectrums are formed. The time slowness correlation coefficient spectrums are searched, and slowness of each pattern wave of stratums is confirmed by seeking of peak values. The time that each pattern wave is transmitted to the receiving transducers for the first time is confirmed according to the slowness so that analysis data for logging is provided. Due to the fact that uniformity of direct waves received by each receiving transducer is damaged, correlation coefficients of the direct waves are lowered, and therefore reliability and accuracy of the logging data are achieved.
Description
Technical field
The utility model relates to the system of eliminating direct-wave jamming in a kind of acoustic logging utilizing acoustic logging instrument to carry out, wherein launch well logging sound wave from the transmitting transducer of acoustic logging instrument to two or more receiving transducers, gather described well logging sound wave by described receiving transducer, for each receiving transducer, by scanning the time slowness index of correlation of asking for described well logging sound wave in time-domain and slowness domain, formation time slowness spectrum of correlation coefficient thus, search for described time slowness spectrum of correlation coefficient, search the slowness of determining each mode wave of stratum by peak value, determine oil reservoir and geologic feature according to described slowness.In addition, the utility model also relates to a kind of corresponding acoustic logging instrument that is applied to this system.
Background technology
Acoustic logging method is the acoustic properties for rock on the record well profile, such as velocity of sound harmony wave amplitude attenuation law, and then judgement lithology, estimate the Elastic properties of porosity of sandstones and rock stratum, understand the character of Around A Borehole rock stratum and the distribution of fluid, a kind of logging method of the problems such as research drilling geology section, judgement cementing quality.Acoustic logging instrument is exactly the observation instrument of realizing the method.Acoustic logging instrument has a variety of, but basic principle is similarly, and Fig. 1 is the measuring principle figure of common array acoustic well logger device.
As shown in Figure 1, logger is placed in the well between two parties, and it has 1, two sound wave receiving transducer 3 of a soic wave transmitting energy converter and 5.Be provided with sound insulation groove 2,4 between each transducer 1,3,5.Theoretical according to geometrical acoustics, when sound wave passes mud and arrives the surface of stratum of the borehole wall again from transmitting transducer 1, if sound wave in the spread speed on stratum faster than the spread speed of sound wave in mud, under some critical incident angles, sound wave can continue to propagate forward along surface of stratum with a kind of form of slide wave, turns back at last also received transducer 3,5 receptions in the mud again.
As shown in Figure 2, simultaneously record at a distance of two receiving transducers 3 with different spacings (referring to that transmitting transducer is to the distance of receiving transducer) and 5 acoustic signals that receive of L.This twice ripple is because spacing is different, so sound wave arrives the moment difference of receiving transducer.Calculate the then difference △ T of twice ripple, by the spacing difference L of known two receiving transducers, just can calculate the acoustic wave propagation velocity V on sound wave corresponding stratum between receiving transducer 3 and 5:
V=L/△T
At logging community, often use slowness S, namely the inverse of acoustic wave propagation velocity V is described the Acoustic Wave Propagation speed on stratum:
S=△ T/L, wherein this slowness value is larger, and the expression acoustic wave propagation velocity is slower, otherwise faster.
The key of this algorithm is to find sound wave to arrive first the time (usually being referred to as first arrival time) of receiving transducer.For finding this first arrival time, most popular method is a threshold method, as shown in Figure 3.
In Fig. 3, by Well Logging Engineering teacher scene also i.e. sound window starting point among the figure of Mintrop wave search zero-time A(is set), Mintrop wave search termination time B(is i.e. sound window terminating point among the figure also), the low door of a first wave amplitude threshold value C(also is low threshold), the threshold value D(of first wave amplitude wealthy family also is high threshold).By software for calculation from time A search start signal, until time B stops.In this time range, find first crest, if its amplitude be greater than at least low door threshold value C(can be simultaneously greater than the D value represent that signal is enough strong) begin to search for forward from this crest again, find a point, its amplitude is 30%(or other factor of proportionality of the peak value of this crest), namely shown in the small circle among the figure, it namely can be considered to Mintrop wave and arrive.
Above-mentioned door threshold method is used very extensive, remains at present the main force in logging community low side well logging market.Its benefit is that apparatus structure is simple and reliable.Shortcoming is: in case formation variation is violent, because stratum of different nature is widely different to the attenuation of sound wave amplitude, first wave amplitude meeting big ups and downs, and for inclined to one side soft formation, noise is suitable with the first wave amplitude value, Mintrop wave more is difficult to find, and shows that the log of final output can acutely be beated, and causes indeterminacy.
What the instrument of higher-end used now is another kind of method, i.e. time slowness correlation method STC.This method need to arrange more receiving transducer, and 4 at least, 8 of many persons or more.These transducers equidistantly distribute, and synchronous acquisition receives signal.
Because the STC algorithm is more stable, reliable than traditional door threshold method, is applied at some high-end array instruments gradually.Yet the characteristic of STC itself has determined that it is more responsive to the signal correlation between the passage, and not too responsive to the energy of signal itself.Even very faint signal if the correlation between the passage is enough good, also can be detected.Therefore, the method very easily is subject to the interference of the interfering signal of good relationship.In this interfering signal, typically be exactly direct-path signal, this signal is not through the propagation on stratum and directly arrive receiver.
In actual applications, the receiving transducer array can either receive the sound wave that arrives by the stratum, also can receive the sound wave that arrives by acoustic isolater.The instrument that spacing is short, because the limited space of cutting, the signal amplitude of the direct wave of propagating by shell often is lower than formation wave, but it still has higher signal to noise ratio, the physical attribute that adds outer rigid housing is stable, propagates the direct wave of coming, interchannel good relationship by it.In the judgement of STC correlation peaks, it is formation wave that this direct wave is mistaken as sometimes, and this situation is particularly evident at soft formation.This has just limited the stratum accommodation of short space instrument, but the array acoustic instrument of short space has again its compactness, the advantage that signal energy is high.Because the amplitude of direct wave is often also little.When the correlation on stratum is weaker than the correlation of direct wave, will cause erroneous judgement.
The utility model content
The technical problems to be solved in the utility model just is, reduces in acoustic logging or eliminates direct wave to the impact of well logging data analysis, improves authenticity and the accuracy of well logging data analysis.
According to an embodiment, the utility model proposes a kind of system for eliminate direct-wave jamming in acoustic logging, comprising:
Acoustic logging instrument, it comprises transmitting transducer (1) and two or more receiving transducers (3,5), and described transmitting transducer is used for to described receiving transducer emission well logging sound wave, and described receiving transducer (3,5) is used for gathering described well logging sound wave,
STC algorithm array instrument is used for for each receiving transducer by scanning the time slowness index of correlation of asking for described well logging sound wave in time-domain and slowness domain, formation time slowness spectrum of correlation coefficient thus,
Searcher is used for searching for described time slowness spectrum of correlation coefficient, and searches the slowness of determining each mode wave of stratum by peak value,
Output device is used for output and can partly reflects the oil reservoir of different well depths position and the slowness value line of geologic feature, thereby the log analysis data are provided,
Wherein because the uniformity of the direct wave that each receiving transducer receives is destroyed, and the index of correlation of direct wave is lowered, formation wave information then is highlighted.
Wherein because the index of correlation of direct wave is lowered, the time of asking for described well logging sound wave does not comprise the index of correlation of direct wave during the slowness index of correlation.
Wherein because the index of correlation of direct wave is lowered, the time of asking for described well logging sound wave does not comprise the index of correlation of direct wave during the slowness index of correlation.
Wherein the index of correlation of direct wave is lower than the index of correlation of each mode wave of stratum.
Wherein there are differences the uniformity of destroying the direct wave that each receiving transducer receives by the cutting between each receiving transducer sound window of described acoustic logging instrument.
Wherein the cutting between each receiving transducer sound window there are differences the cutting number difference that refers between each receiving transducer sound window.
Wherein the cutting between each receiving transducer sound window there are differences the cutting shape difference that refers between each receiving transducer sound window.
Wherein there is not cutting between the part receiving transducer sound window.
Wherein adopt Finite Element Method for each the different cutting modes between the receiving transducer to be carried out modeling, analog computation goes out time-delay and the amplitude fading that cutting causes, and then the correlation of calculating direct wave array signal, find the cutting combination of an index of correlation minimum as last preferred version.
According to another embodiment, the utility model provides a kind of acoustic logging instrument for eliminate direct-wave jamming in acoustic logging, comprising:
Transmitting transducer (1),
Two or more receiving transducers (3,5),
Wherein, described transmitting transducer is used for to described receiving transducer emission well logging sound wave, and described receiving transducer (3,5) is used for gathering described well logging sound wave,
Cutting between each receiving transducer sound window of wherein said acoustic logging instrument there are differences.
Wherein the cutting between each receiving transducer sound window there are differences the cutting number difference that refers between each receiving transducer sound window.
Wherein the cutting between each receiving transducer sound window there are differences the cutting shape difference that refers between each receiving transducer sound window.
Wherein there is not cutting between the part receiving transducer sound window.
Description of drawings
Specific embodiment of the utility model is described with reference to the accompanying drawings.Among the figure:
Fig. 1 is the measuring principle figure of conventional arrays acoustic logging instrument.
Fig. 2 is the schematic diagram of the acoustic signals that receives of two receiving transducers.
Fig. 3 utilizes door threshold method search first wave of sound to arrive the method schematic diagram of receiving transducer.
Fig. 4 utilizes time slowness index of correlation (STC) method to measure the schematic diagram of array acoustic.
Fig. 5 is the acoustic isolater of acoustic logging instrument and the schematic diagram of acoustic wave propagation path.
Fig. 6 is the schematic diagram of axle and shell in the acoustic isolater of acoustic logging instrument of prior art.
Fig. 7 is prior art STC result index of correlation contour map.
Fig. 8 is the perspective view of prior art STC result index of correlation on the slowness axle.
Fig. 9 shows the contrast of structure of the logging instrument shell of the utility model and prior art.
Figure 10 shows the sound insulation property the results of the sound insulation section of 1.1 feet length.
Figure 11 shows the waveform that passes through the given viewpoint that analog computation obtains of cutting scheme shown in Figure 10.
Figure 12 shows 0.5 foot cutting scheme between the long receiver.
Figure 13 shows the respective waveforms of cutting scheme shown in Figure 12.
Figure 14 shows direct wave and the stratigraphic model ripple STC figure of the instrument of cutting scheme shown in Figure 12.
Figure 15 shows the direct wave waveform that five receiving transducers of prior art receive.
Figure 16 shows the direct wave waveform that five receiving transducers according to an embodiment of the present utility model receive.
Reflected among Figure 17 that the shell of prior art and an embodiment of the present utility model is to the contrast of the inhibition ability of direct wave.
Figure 18 is the block diagram that the utility model is eliminated the method and system of direct-wave jamming.
The specific embodiment
Time meta-slowness-index of correlation (STC) method of at first introducing in conjunction with Fig. 4 that the utility model uses.The cardinal principle of this STC method is exactly to utilize similar this characteristic of waveform shape of same mode wave in the array sonic log signal to come the computation schema wave slowness.Shown in the STC principle of operation figure of Fig. 4, when carrying out the STC computing, from selected time T, use the time window T of certain-length
WPair array acoustic logging waveform signal scans in time-domain and slowness domain, and calculates respectively index of correlation.Index of correlation is larger, is that the waveform possibility of same mode wave is just larger in the corresponding time window.Can to the time meta-slowness-spectrum of correlation coefficient carry out peak value and search the slowness that obtains each stratigraphic model ripple.Window has represented mode wave then in the position of time shaft, and the slope of window is relevant with the slowness of mode wave propagation.The formula of the similitude of the interior waveform of window computing time has two: one is Semblance formula (Kimball and Marzetta, 1986):
Another one is Nth power root formula (Mc-Fadden etc., 1986):
In formula (1) and (2),
Be the waveform of m receiving transducer in the array of N receiving transducer, d is the receiving transducer spacing,
Long for the time window window, in a general desirable 2-3 cycle, s is the slowness variable, and T is time variable.In Nth power root formula (2), n is power exponent, is generally 4.Comparatively speaking, Nth power root formula (2) is more sharp-pointed than the peak value of the correlation function that Semblance formula (1) obtains, so slowness resolution ratio is higher.The computational speed of Semblance is then faster.In theory, the correlation coefficient ρ (s, T) of above-mentioned expression similitude is to represent that similitude was 100% at 1 o'clock, is to represent that similitude was zero at 0 o'clock.
Next analyze the acoustic isolater of logging instrument to the impact of different acoustic slowness derivation algorithms.
The acoustic isolater of logging instrument generally includes interior axle acoustic isolater and shell acoustic isolater.Interior axle acoustic isolater normally utilizes the obvious especially combination of materials of acoustic impedance difference to intercept the acoustic propagation path of interior axle, and this mode defening effect is often fine; The shell acoustic isolater often adopts on outer rigid housing the mode of cutting to reach and eliminates straight line acoustic propagation path, increase the acoustic propagation path, sound wave is caused the purpose of decay.But be subject to the restriction of mechanical strength and spacing length, defening effect is limited.
As shown in Figure 5, to (the shortest spacing is 3 feet usually, and minority reaches 1.5 feet) between the nearest receiving transducer, the acoustic propagation path generally includes at transmitting transducer:
1, transmitting transducer---mud---stratum---mud---receiving transducer, namely the path among the figure 1.,
2, transmitting transducer---mud---acoustic enclosure---mud---receiving transducer, namely the path among the figure 2.,
3, transmitting transducer---mud---sound insulation in axle---mud---receiving transducer, namely the path among the figure 3.,
4, transmitting transducer---mud---receiving transducer, i.e. so-called " mud wave ", it is a kind of mode wave of intrinsic existence, and is relevant with spacing, and the acoustic isolater performance is irrelevant, is not emphasis of the present utility model, so do not mark here.Among Fig. 5,50 expression transmitting transducers, the nearest receiving transducer of 51 expressions, 53 expression sound insulation cutting shells, axle in the 54 expression sound insulation.
Axle designs comparatively easily in the sound insulation, because the acoustic impedance between each impedance dissimilar material has analytical expression to follow on the impact of sound wave amplitude, it is convenient to calculate.And the inventor finds in the practice, and the defening effect of axle is often all good in the sound insulation, is not the main cause that causes direct-wave jamming.
The sound insulation mode of cutting on the acoustic enclosure, particularly rigid body, design is complicated, can follow without analytic expression, often needs to utilize finite element/finite difference theory to carry out analog computation.The sound amplitude fading harmony carryover effects that different cutting shapes obtains is not identical.No matter in analog computation and practical application, no matter but what cutting shape the inventor finds to adopt, its sound insulation effect all can not reach the defening effect of interior axle, although its direct wave amplitude is very weak, but because shape is fixed, material is fixed, and the direct wave that each receiving transducer receives often has very strong correlation.This shows that the STC coefficient is still higher, and this is because the shape similarity relation of STC algorithm and signal is very large, and and the relation of the difference between the signal amplitude be not to cause especially greatly.Normalization STC algorithm particularly, the very weak direct wave of amplitude still has good STC coefficient.This is especially obvious in the situation of soft formation (the stratum echo is weak) partially, and its can cause interference to STC coefficient peak-seeking, and may cause sometimes direct wave to be mistaken as is the stratum echo, and the slowness of direct wave is marked into formation slowness.
For this reason, the utility model proposes a kind of software and hardware combining method for designing, can shield the direct-wave jamming under the extreme case.The characteristics of direct wave be then stablize, slowness is stable, amplitude is substantially measurable.As indicated above, the utility model is only paid close attention to the direct wave propagated along acoustic enclosure to the impact of stratum echo.Because shape and the Material Processing of acoustic enclosure are changeless, it is indefinite to ponder so unlike formation variation, thus the slowness value of shell direct wave and then (refer in particular to here direct wave that the nearest receiving transducer of spacing receives then) can measure.Under this environment that does not have external interference such as stratum of anechoic tank,, the two can be measured.Again according to then with the relation of slowness it being rejected from the echo of stratum.
As mentioned above, the impact of direct wave often is reflected in direct wave that the receiving transducer of different spacings receives to has preferably on the correlation, rather than its amplitude.Add the time-lag action of acoustic isolater, the direct wave that amplitude is very low often is submerged in the echo of stratum, so the impact of direct wave often can be ignored in door threshold method, this namely why low side logger (what often adopt is exactly that door threshold method is surveyed a slowness) be not easy on the contrary to be subject to the impact of direct wave.And the novel array instrument of use STC algorithm, it more pays attention to the correlation between the array signal, but not signal amplitude, so the in fact easier impact that is subject to direct wave of array instrument is higher to the designing requirement of acoustic enclosure.Below in conjunction with Fig. 6 analyze respectively the array instrument direct wave then with the decisive factor of slowness.
The left side of Fig. 6 and right side show respectively the interior axle of acoustic isolater of acoustic logging instrument and the schematic diagram of shell.67 expression D profile shaft acoustic isolaters among Fig. 6, the single transmitting transducer of 60 expressions, 68 expression A profile shaft acoustic isolaters, axle acoustic isolater in 69 expressions, 61 expression 1# receiving transducers, 62 expression 2# receiving transducers, 63 expression 3# receiving transducers, 64 expression 4# receiving transducers, 65 expression 5# receiving transducers, 66 expression 6# receiving transducers.At first study the reason that direct wave produces according to Fig. 6.When axle was obtained better defening effect in sound insulation, the performance of acoustic enclosure had determined directly whether direct wave can be received transducer array and receive.If the acoustic emission time is T
0, the time that first receiving transducer was propagated, arrived to direct wave along acoustic enclosure is T
1, the time that arrives second receiving transducer is T
2For more other receiving transducer, the rest may be inferred.Supposing to transmit and receive spacing is L
Tr, the spacing between each receiving transducer of receiving transducer array is L
Rr, detected by the STC algorithm and the direct wave estimating to obtain then is
, slowness (or time difference) is
Then have:
" the equivalent slowness " that can further calculate Acoustic Wave Propagation in the sound insulation section between transmitting transducer and the first receiving transducer is
It has reflected that this section acoustic enclosure is to the delay effect of direct wave between transmitting transducer and the first receiving transducer.Equivalence slowness value is larger, and expression acoustic enclosure carryover effects is better, otherwise poorer.
In a lot of instruments of reality, also be carved with the sound insulation groove between the reception of different receiving transducers and the reception.Suppose that the reception of different receiving transducers and the sound insulation section between the reception are duplicate, the direct wave slowness that the estimation of STC algorithm obtains
What reflect is the delay effect of the acoustic enclosure between the receiving transducer array.
It reflected the reception of different receiving transducers and receive between this section acoustic enclosure to the delay effect of direct wave.Equivalence slowness value is larger, and the expression delay effect is better.If can allow
The formation slowness of deviation instrument is measured the scope of range (for example 40 μ s/feet to 180 μ s/feet(microsecond/feet)) outside, just can make direct wave can not estimate to impact to formation slowness.But in order to pursue preferably depth of stratum resolution ratio, the spacing between the receiving transducer is often very little, approximately 0.5feet (foot).This limited space, common cutting are difficult to obtain desirable effect, and this has just caused
Often drop within the range ability, in case the Echoes correlation on stratum weak (for example soft formation), the correlation of direct wave will appear within the range, causes the formation slowness misjudgment.This disadvantageous situation is shown in Fig. 7 and 8.
Although the direct wave amplitude a little less than because its propagation medium stable (the outer rigid housing characteristic does not change with environmental change substantially) so the correlation of the direct wave that different receiving transducer receives is fine, has affected the in length and breadth detection of ripple of stratum.In order to address this problem, a kind of method that the utility model proposes is to reduce the peak value of direct wave index of correlation, makes it significantly to be lower than the in length and breadth index of correlation of ripple isotype ripple of stratum, allows direct wave detect not out.For example, can take non-homogeneous cutting mode to reduce the index of correlation of the direct wave that receiving array receives.
Figure 18 shows the block diagram that the utility model is eliminated the method and system of direct-wave jamming.At first, two or more receiving transducers 3,5 by acoustic logging instrument gather the well logging sound wave that sends from transmitting transducer.For each receiving transducer, by STC algorithm array instrument from selected time T, use the time window Tw pair array acoustic logging waveform signal of 2-3 wave period for example to scan in time-domain and slowness domain, to ask for the time slowness index of correlation of described well logging sound wave, thus formation time slowness spectrum of correlation coefficient.Then search for described time slowness spectrum of correlation coefficient by searcher, search the slowness of determining each mode wave of stratum by peak value.And then, by the line of output device according to the described slowness value that can partly reflect oil reservoir and geologic feature that obtains in different well depth position measurements, thereby provide the log analysis data.Wherein take non-homogeneous cutting mode to reduce the index of correlation of the direct wave that receiving array receives, make it significantly to be lower than the in length and breadth index of correlation of ripple isotype ripple of stratum, allow direct wave detect not out.
The common cutting mode of constructional drawing 9A that Fig. 9 A shows the logging instrument shell of prior art adopts transverse horizontal groove (hereinafter being called the A scheme), the cutting shape is not limited to the transverse horizontal groove shown in the figure, but its thought is consistent, be exactly to prolong the time that direct wave is delivered to receiving array as far as possible, reduce simultaneously the energy of direct wave.90 expression transmitting transducers among Fig. 9,91 expression R1 receiving transducers, 92 expression R2 receiving transducers, 93 expression R3 receiving transducers, 94 expression R4 receiving transducers, 95 expression R5 receiving transducers.We analyze the sound insulation property of this groove as example take the level trough of Fig. 9 A.From this figure as seen, this instrument source distance is 3 feet, the spacing that is transmitting transducer and receiving transducer bottom is 3 feet, spacing between the receiving transducer is 0.5 foot, cutting scheme and the cutting scheme between the receiver between it transmits and receives are consistent, are horizontal cutting, 3 millimeters of groove widths, 16 millimeters of cannelure spacings, circumferential slot spacing 80 degree.The first slowness namely is decided by the delay effect (i.e. " equivalent slowness " mentioned above) of this section acoustic isolater between transmitting transducer sound window and first receiving transducer sound window, utilize finite element method that a bit of in this section acoustic isolater carried out modeling, then extrapolate the direct wave first slowness value of this type instrument.
For this embodiment, the sound insulation property the results of the sound insulation section of 1.1 feet length as shown in figure 10.In analog computation, the right lower end surface place of supposing this structure 10 the point-like sound sources that equally spaced distributing, 10 points of observation are equally spaced placed in its left upper end end, the waveform of the given viewpoint that point-like sound source and analog computation obtain is (Figure 11 illustrates the sound source that is positioned at model one end and is positioned at the waveform of the reception signal of the model other end) as shown in figure 11, transverse axis is the time, the longitudinal axis is acoustic pressure, the crest of the point-like sound source of one of them is positioned at the 0.05ms place, and first crest of 10 points of observation overlaps at the 0.22ms place substantially.
The above results is the result of 1.1 feet acoustic isolater, if spacing is 3 feet, except near the about 0.3 foot not cutting section falling tone window, the length of acoustic isolater can be accomplished about 2.7 feet usually.Adopt so the first slowness of the instrument of this kind cutting scheme, namely equivalent slowness is about 142 μ s/ feet.
If between receiving transducer sound window, carve same groove, Figure 12 is 0.5 foot cutting scheme between the long receiver, and result of finite element is (Figure 13 illustrates the sound source that is positioned at model one end and is positioned at the waveform of the reception signal of the model other end) as shown in figure 13.Among Figure 13, first crest is sound-source signal, 1.1*10
-4Near second 10 almost overlapping crest be uniformly-spaced to observe at ten to point out the direct wave Mintrop wave that observation obtains.
0.5 foot of this acoustic isolater length, the simulation result from figure can be calculated direct wave after being received by two adjacent receiving transducers respectively by this acoustic isolater, and near 115 μ s/ feet, this i.e. the second slowness value greatly for the slowness value that calculates.
At last, the direct wave of the instrument of this cutting scheme and stratigraphic model ripple STC figure as shown in figure 14.
Dotted line is depicted as direct wave, other be the stratigraphic model ripple.What obviously direct wave and stratum shear wave leaned on is very near, severe jamming the detection of formation wave.
In order further to calculate the direct wave index of correlation, we do following analog computation.
We describe with A scheme above:
Receiving transducer R1 is to the acoustic enclosure defening effect between the R2: sound amplitude fading A
12, time-delay τ
12
Receiving transducer R2 is to the acoustic enclosure defening effect between the R3: sound amplitude fading A
23, time-delay τ
23
Receiving transducer R3 is to the acoustic enclosure defening effect between the R4: sound amplitude fading A
34, time-delay τ
34
Receiving transducer R4 is to the acoustic enclosure defening effect between the R5: sound amplitude fading A
45, time-delay τ
45
If the direct wave that nearest R1 receiving transducer receives is s
1(t)=and s (t), then have:
The direct wave that the R2 receiving transducer receives is s
2(t)=A
12S (t-τ
12),
The direct wave that the R3 receiving transducer receives is s
3(t)=A
12A
23S (t-τ
12-τ
23),
The direct wave that the R4 receiving transducer receives is s
4(t)=A
12A
23A
34S (t-τ
12-τ
23-τ
34),
The direct wave that the R5 receiving transducer receives is s
5(t)=A
12A
23A
34A
45S (t-τ
12-τ
23-τ
34-τ
45).
By analog computation, the time-delay that the acoustic enclosure of A type cutting scheme causes is 57.5 microseconds, and amplitude fading is 0.29; If not cutting, the time-delay that the rigid body shell causes self are 28.5 delicate.
So have for A type scheme:
Receiving transducer R1 is to the acoustic enclosure defening effect between the R2: sound amplitude fading A
12=0.29, time-delay τ
12=57.5 μ s;
Receiving transducer R2 is to the acoustic enclosure defening effect between the R3: sound amplitude fading A
23=0.29, time-delay τ
23=57.5 μ s;
Receiving transducer R3 is to the acoustic enclosure defening effect between the R4: sound amplitude fading A
34=0.29, time-delay τ
34=57.5 μ s;
Receiving transducer R4 is to the acoustic enclosure defening effect between the R5: sound amplitude fading A
45=0.29, time-delay τ
45=57.5 μ s.
Then the direct wave waveform that receives of five receiving transducers as shown in figure 15.
Because we when doing correlation analysis, often will do normalized preliminary treatment with the amplitude of array signal, so can not consider amplitude fading (unification is set to 1), the impact of a computation delay.
Ideally, the direct wave normalizated correlation coefficient that utilizes formula (1) to calculate should be 1.The connecting line of the Mintrop wave of per pass ripple is straight line among Figure 15.
We analyze Type B (Fig. 9 B) acoustic enclosure again, here consideration sound amplitude fading no longer:
Receiving transducer R1 is to the acoustic enclosure defening effect between the R2: time-delay τ
12=57.5 μ s;
Receiving transducer R2 is to the acoustic enclosure defening effect between the R3: time-delay τ
23=28.5 μ s;
Receiving transducer R3 is to the acoustic enclosure defening effect between the R4: time-delay τ
34=57.5 μ s;
Receiving transducer R4 is to the acoustic enclosure defening effect between the R5: time-delay τ
45=28.5 μ s.
Then the direct wave waveform that receives of five receiving transducers as shown in figure 16.
As can be seen from Figure 16, at this moment because the then difference between the array signal is no longer even, and the line of the Mintrop wave of the direct wave that each receiver receives no longer is straight line, and has become broken line, also just significantly reduced the correlation between the array signal.
The Type B shell direct wave normalizated correlation coefficient that utilizes formula (1) to calculate is 0.59, much smaller than the index of correlation 1 of the even cutting of Type B shell.In the STC graphics relevant peaks of direct wave can become flat, and this has reduced it to the interference of stratigraphic model ripple relevant peaks.
Reflected among Figure 17 that A type and Type B shell are to the inhibition ability of direct wave.Solid line represents the direct wave situation that obtains according to the non-homogeneous cutting scheme of Type B shell, and dotted line represents the even cutting scheme of A type.
The method of cutting has a lot, and the triangle profile groove is arranged, and level trough is arranged, and can carve 4 road grooves between the receiving array, also can not cutting or only carve together or twice groove or three road grooves, for example C among Fig. 9, D and E scheme.We can be by the preferred scheme of the method for analog computation.Can at first adopt Finite Element Method to each to the cutting Method Modeling between the receiving transducer, the time-delay that analog computation goes out to cause and amplitude fading; And then calculate the correlation of these direct wave array signals, find the cutting combination of an index of correlation minimum as last preferred version.
Also can manufacture experimently out the experiment shell, without measuring its direct wave in the environment of acoustical reflection, calculate the correlation of direct wave array signal under water, also can optimize a kind of non-homogeneous acoustic enclosure of direct wave index of correlation minimum.
In a word, according to the utility model, the slowness value of direct wave is decided by the cutting method between the window, because the cutting space is very limited between the sound window, it is (normally very difficult outside the 40us/feet～180us/feet) to want to allow the direct wave slowness drop on the well logging range.Know that according to the STC principle direct wave STC coefficient is decided by the uniformity of the direct wave that each receiver receives, if can destroy this uniformity, just can reduce the STC coefficient, we can adopt above-mentioned non-homogeneous cutting method, in many cutting mode permutation and combination, by finite element simulation calculation, perhaps actual measurement can optimize a kind of acoustic enclosure of optimum, the direct wave index of correlation of this moment is minimum, and is also just minimum on the impact of stratum wave measurement.
Claims (12)
1. system that is used for eliminating in acoustic logging direct-wave jamming comprises:
Acoustic logging instrument, it comprises transmitting transducer (1) and two or more receiving transducers (3,5), and described transmitting transducer is used for to described receiving transducer emission well logging sound wave, and described receiving transducer (3,5) is used for gathering described well logging sound wave,
STC algorithm array instrument is used for for each receiving transducer by scanning the time slowness index of correlation of asking for described well logging sound wave in time-domain and slowness domain, formation time slowness spectrum of correlation coefficient thus,
Searcher is used for searching for described time slowness spectrum of correlation coefficient, and searches the slowness of determining each mode wave of stratum by peak value,
Output device is used for output and can partly reflects the oil reservoir of different well depths position and the slowness value line of geologic feature, thereby the log analysis data are provided,
Wherein because the uniformity of the direct wave that each receiving transducer receives is destroyed, and the index of correlation of direct wave is lowered, formation wave information then is highlighted.
2. the system as claimed in claim 1, wherein because the index of correlation of direct wave is lowered, the time of asking for described well logging sound wave does not comprise the index of correlation of direct wave during the slowness index of correlation.
3. the system as claimed in claim 1, wherein the index of correlation of direct wave is lower than the index of correlation of each mode wave of stratum.
4. the system as claimed in claim 1, wherein the cutting between each receiving transducer sound window of described acoustic logging instrument there are differences, and destroys thus the uniformity of the direct wave that each receiving transducer receives.
5. system as claimed in claim 4, wherein to there are differences the cutting number that refers between each receiving transducer sound window different for the cutting between each receiving transducer sound window.
6. system as claimed in claim 4, wherein to there are differences the cutting shape that refers between each receiving transducer sound window different for the cutting between each receiving transducer sound window.
7. wherein there is not cutting in system as claimed in claim 5 between the part receiving transducer sound window.
8. system as claimed in claim 4, wherein adopt Finite Element Method for each the different cutting modes between the receiving transducer to be carried out modeling, analog computation goes out time-delay and the amplitude fading that cutting causes, and then the correlation of calculating direct wave array signal, find the cutting combination of an index of correlation minimum as last preferred version.
9. acoustic logging instrument that is used for eliminating in acoustic logging direct-wave jamming comprises:
Transmitting transducer (1),
Two or more receiving transducers (3,5),
Wherein, described transmitting transducer is used for to described receiving transducer emission well logging sound wave, and described receiving transducer (3,5) is used for gathering described well logging sound wave,
Cutting between each receiving transducer sound window of wherein said acoustic logging instrument there are differences.
10. acoustic logging instrument as claimed in claim 9, wherein to there are differences the cutting number that refers between each receiving transducer sound window different for the cutting between each receiving transducer sound window.
11. acoustic logging instrument as claimed in claim 9, wherein the cutting between each receiving transducer sound window there are differences the cutting shape difference that refers between each receiving transducer sound window.
12. wherein there is not cutting in acoustic logging instrument as claimed in claim 10 between the part receiving transducer sound window.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220208110 CN202832520U (en) | 2012-05-10 | 2012-05-10 | System and acoustic logger capable of eliminating interference of direct waves during acoustic logging |
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| CN 201220208110 CN202832520U (en) | 2012-05-10 | 2012-05-10 | System and acoustic logger capable of eliminating interference of direct waves during acoustic logging |
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Cited By (8)
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| CN104343443A (en) * | 2013-07-26 | 2015-02-11 | 中国石油集团长城钻探工程有限公司 | Method for eliminating direct coupling signal in three-dimensional array induction logging instrument |
| CN104712324A (en) * | 2014-12-11 | 2015-06-17 | 杭州丰禾石油科技有限公司 | Novel sound insulator well logging device for acoustic logging instrument and optimization design method |
| CN105637177A (en) * | 2013-10-31 | 2016-06-01 | 哈利伯顿能源服务公司 | Acoustic signal attenuator for LWD/MWD logging systems |
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| CN108035708A (en) * | 2017-11-20 | 2018-05-15 | 中国石油天然气股份有限公司 | Method and device for removing stratum interface reflected waves |
| CN110067554A (en) * | 2019-06-06 | 2019-07-30 | 中油奥博(成都)科技有限公司 | Three-component sound wave far detects well logging apparatus and its measurement method in well |
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| CN104343443A (en) * | 2013-07-26 | 2015-02-11 | 中国石油集团长城钻探工程有限公司 | Method for eliminating direct coupling signal in three-dimensional array induction logging instrument |
| CN105637177A (en) * | 2013-10-31 | 2016-06-01 | 哈利伯顿能源服务公司 | Acoustic signal attenuator for LWD/MWD logging systems |
| CN104712324A (en) * | 2014-12-11 | 2015-06-17 | 杭州丰禾石油科技有限公司 | Novel sound insulator well logging device for acoustic logging instrument and optimization design method |
| CN104712324B (en) * | 2014-12-11 | 2018-01-19 | 杭州丰禾石油科技有限公司 | Novel sound body well logging apparatus and Optimal Design Method for acoustic logging instrument |
| CN105891817A (en) * | 2016-06-08 | 2016-08-24 | 中国人民解放军海军航空工程学院 | Distributed passive radar target detection method under direct wave-free condition |
| CN107143333A (en) * | 2017-07-12 | 2017-09-08 | 黄河勘测规划设计有限公司 | Acoustic isolater for hydraulic engineering full wave train acustic logging inserting tube |
| CN108035708A (en) * | 2017-11-20 | 2018-05-15 | 中国石油天然气股份有限公司 | Method and device for removing stratum interface reflected waves |
| CN108035708B (en) * | 2017-11-20 | 2021-04-30 | 中国石油天然气股份有限公司 | Method and device for removing stratum interface reflected waves |
| CN110067554A (en) * | 2019-06-06 | 2019-07-30 | 中油奥博(成都)科技有限公司 | Three-component sound wave far detects well logging apparatus and its measurement method in well |
| CN110067554B (en) * | 2019-06-06 | 2024-03-29 | 中油奥博(成都)科技有限公司 | Well three-component acoustic wave remote detection logging device and measurement method thereof |
| CN114645708A (en) * | 2020-12-18 | 2022-06-21 | 航天科工惯性技术有限公司 | Well drilling tubular column and noise reduction structure |
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