CN1044286C - Radioactive energy spectrum tracing water uptake section well logging method - Google Patents

Abstract

The present invention provides a radioactive energy spectrum tracing water uptake section well logging method, which belongs to the radioactive logging field of geophysical prospecting for petroleum. Radioactive energy spectrum gamma-ray tracer agents with sufficient width are injected into a water injection well; radioactive energy spectrum logging downhole instruments which are processed by scales, are provided with a plurality of energy spectrum analyzers and pass through oil pipes are arranged into the well; counting rate energy spectrums which are transmitted by measuring tracer agents make the measured energy spectrums and standard scale energy spectrums compared; according to spectral hardening theory, the residue position of the tracer agents in a perforation channel can be distinguished, and the tracing can be also recognized whether lies in the contamination state or the leakage loss state. Accordingly, the radioactive energy spectrum tracing water uptake section well logging method provides reasonable and reliable correction for water uptake section curves, and the accuracy of the tracing water uptake section well logging method is greatly increased.

Description

Radioactive energy spectrum tracing water uptake section well logging method

The invention belongs to geophysical prospecting for oil well logging field, especially for the radioactive tracer measuring method of water injection well in oil fields intake profile.

When oil-field development, for improving recovery ratio, a large amount of waterflooding methods of using with water displacing oil.By near the water injection well water filling of producing well, boring, make water enter the water accepting layer that communicates with pay sand, drive crude oil from the producing oil well output.Axis with water injection well serves as that axle has a steel water injection pipe (often being called as oil pipe), is with a steel sleeve pipe outside it, and is fixed with cement between this sleeve pipe and the stratum, forms a cement mantle.To the sleeve pipe and the cement mantle perforation at water accepting layer position, make the water that injects by oil pipe enter water accepting layer thus, then should not intake without the stratum of perforation.For developing oil fields scientifically and rationally, be exactly the water-intake capacity of measuring each water accepting layer in the water injection well as far as possible exactly.This operation is called as water uptake section well logging.The water uptake section well logging method of current use is a radioactive tracer isotope injection profile well logging method.This method easy steps is as follows, and (commonly used has with the radioactive isotope that is prepared into particulate emission gamma ray ¹³¹Ba, ¹³¹I and ^113mIn) inject well with water, these radioactive particulates are just collected at surface of stratum by filter when water enters the stratum.The radioactive isotope that the stratum many more filters of suction collect on it is just many more.Put down an instrument (often being called the oil pipe radioactivity logging device) of measuring the gamma ray count rate by oil pipe, successively record gamma ray count rate behind intrinsic natural gamma rays counting rate in each stratum and the filter collection radioactive isotope with it, obtain the total gamma-ray count-rate logging trace of this well.Think that the net added value of gamma ray count rate on each stratum is directly proportional with the water absorbing capacity on this stratum, thereby extrapolate going up of stratum water absorbing capacity by the total gamma-ray count-rate logging trace.But aforementioned radioactive tracer isotope injection profile well logging method exists " contamination " and shortcomings such as " leakages ".So-called " contamination " is meant at oil pipe or casing coupling, eccentric water distributor, packer and be stained with dirt such as crude oil, wax deposition or the internal surface of sleeve pipe and the oil pipe inside and outside wall place of corrosion are arranged are directed at the unusual high gamma ray count rate that records because of having adsorbed tracer isotope.According to statistics, the ratio of well that this type of abnormal occurrence occurs is up to 92.6%, wherein serious contamination the and the ratio that can't calculate water absorbing capacity is 16.4%.To this a kind of improvement way of implementing is to adopt surfactant and well-flushing, can reduce contamination, but can not deal with problems fully.The Vol14 of " geophysical well logging " magazine of publishing in nineteen ninety, No.6 has published the article that is entitled as " control and the bearing calibration of staiing in the isotope injection profile well logging " of Lv Zhiqiang in P.405-414.Method in this article has provided correction coefficient separately to dissimilar contaminations.Before doing correction, at first to select corresponding correction coefficient for use, resulting stratum relative injectivity is revised according to different contamination types and degree.In this way, as long as stain the type correct judgment, generally can draw relative injectivity more accurately.But when judging that contamination type and degree thereof are had any problem, the error of the method is just very big.So-called " leakage " is meant in some duct greater than the stratum of isotopic tracer particle diameter, and tracer agent may flow into earth formation deep rather than filter collects on the surface via macropore.Though this stratum water absorbing capacity is very big, the gamma ray count rate that records presents low value abnormally.Zhao holds up greatly in the article that is entitled as " analysis of big particle diameter isotope injection profile well logging test " and has proposed a solution, and this article is published in " logging technology " Vol.16 in 1992, No.1, P.66-70 in.The main point of this scheme is to adopt big particle diameter tracer agent, and it can improve the leakage to input tracer agent to a certain extent, and reduces the error of measured result, but still can not reach gratifying effect.

The object of the present invention is to provide a kind of radioactive tracer water uptake section well logging method.This method can judge that measured gamma ray count rate is normally or unusual, if judge unusually again be stain or leakage due to, and identify and stain type and leakage degree, provide more accurately and proofread and correct.To improve the precision of radioactive tracer water uptake section well logging.

The present invention realizes as follows.

Radioactive energy spectrum tracing water uptake section well logging method of the present invention comprises following several steps.The first step drops into radioisotope tracer to water injection well to be measured, and this tracer agent can be launched at least two enough gamma rays away from energy peak.Second step will cross oil pipe radioactivity well logging down-hole instrument and insert and wait to log well, the total gamma-ray count-rate that residual tracer agent is launched on the purpose well section in this well of continuous coverage, the counting rate signal is changed into electric signal, transfer to the ground instrument and write down it recording signal then, form the gross-count rate curve at last.The used mistake in the instrument of oil pipe radioactivity well logging down-hole has the multiple tracks energy spectrum analysis device of twice at least, multiple tracks energy spectrum analysis device by predetermined can spectral coverage segmentation record separately can spectral coverage the gamma ray count rate and produce corresponding curve.The scale that the aforementioned well logging down-hole instrument that the energy spectrum analysis device arranged will carry out in the master scale well is in advance handled.The 3rd step separated spectrometry with each measured counting rate curve application gamma spectra and carries out the power spectrum interpretation process, according to explanation results the gross-count rate curve was revised then.The 4th step was calculated the relative injectivity of various places layer according to corrected gross-count rate opisometer.

Scale treatment step described in aforementioned second step is as follows.

(a) calibration well that sets up standard, calibration well oil pipe, calibration well sleeve pipe, calibration well cement mantle and simulated formation that this well is installed by the outside coaxial order intussusception from the lining are formed jointly, and the inside is full of water;

(b) on certain position of calibration well sleeve pipe, outwards radially penetrate calibration well oil pipe, calibration well sleeve pipe, calibration well cement mantle and simulated formation and make analogue perforation from the lining;

(c) will treat that scale well logging down-hole instrument is lowered in the calibration well oil pipe, and make down-hole instrument detecting head crystal, and the energy spectrum analysis device road number of establishing wherein is m near analogue perforation;

(d) in analogue perforation, insert suitable tracer agent or available alternative radioactive source;

(e) move tracer agent along analogue perforation, stop on n the position that makes it to set in the foundation accuracy requirement, and measure m road gamma ray count rate simultaneously in each stop place, an aforementioned n position can be in calibration well oil pipe inside and outside wall, calibration well sleeve pipe inside and outside wall, calibration well cement mantle outer wall, the stratum;

(f) with measured gamma ray count rate by the in addition normalization of down-hole instrument outer wall, so-called normalization is exactly with the counting rate in each road and the ratio of the counting rate sum in all roads, has so just obtained n and has opened m road standard spectrum.Wherein the port number m of power spectrum should be greater than or equal to the tracer agent stop place and count n.

The concrete steps that gamma spectra described in aforementioned the 3rd step is separated spectrometry are as follows.

(a) standard spectrum that records on the j scale position is represented with a column vector Aj who is made of the m row element, j=1～n, n scale position can get n and open standard spectrum altogether, and n column vector also arranged, thereby constitute m * n matrix A, be referred to as the spectrometer response matrix, its matrix element is designated as aij, i=1～m, j=1～n, i represents the Taoist monastic name composed, and j represents the standard clef, i.e. tracer agent scale location number in the calibration well;

(b) scale is good well logger is logged well on the spot by preceding method, on each well logging position, can not done the m road counting rate spectrum of normalized, represents i=1～m with a column vector B who is made of m row element bi;

(c) aforementioned measured count rates spectrum B is the result that possible remain in the common contribution of tracer agent of each position on a certain perforation path radially of well, if the tracer agent that retains on the j of position is xj to the contribution portion of B, j=1～n has then produced the column vector X that the n row element is arranged that xj constitutes;

(d) aforementioned three column vector A, X and B satisfy following equation:

A X=B (1) formula (1) is the system of linear equations that comprises n unknown number xj that m linear equation constitutes, and available general mathematical method for example least square method is found the solution wherein unknown number xj;

(e) each xj that step (d) is tried to achieve on the foundation, and to impinging upon the physical meaning of the locus of each j that invests in the scale treatment step, just can judge the contamination situation, to sleeve pipe with the interior locational xj of each j during if any remarkable numerical value, then contamination has taken place in decidable on this well logging position, equally for the locational xj of each j on the stratum during if any remarkable numerical value, decidable has to miss on this well logging position and has taken place;

(f) for judgement the well logging position that leakage takes place and stain is arranged, from this locational gross-count rate numerical value, because of staiing the share of being brought, augment the share that is caused because of leakage, continue aforementioned the 4th step then by the numerical value subduction of xj.

Advantage of the present invention is as follows.

The principle of " spectral hardening " can take place when having utilized the radioactivity gamma ray to propagate in material in the radioactive energy spectrum tracing water uptake section well logging method of the present invention, be that the gamma ray of different-energy is when passing in material, its relative intensity can change, it is slow that the decling phase of high-energy rays contrasts low-yield ray, utilize the single-valued relationship of the ratio of the two with distance, in the scale process, " remember " this relative intensity ratio, can instead release the relative position of the space retention of this tracer agent if any the point of same ratio in the reality well logging, thereby the counting rate value of judging this point is to stain, any situation among leakage or normal filter are long-pending is perhaps calculated the proportionate relationship that they do to contribute.Thereby provide more reasonable more reliable means for revising the gross-count rate curve, also just improved the degree of accuracy of radioactive tracer water uptake section well logging.

Description of drawings.

Fig. 1 is the enforcement view of radioactive energy spectrum tracing water uptake section well logging method of the present invention.

Fig. 2 is the theoretical calculation model figure of well logging method of the present invention institute foundation.

Fig. 3 is the structural representation of water injection well in the well logging method of the present invention.

Fig. 4 is the main composition partial circuit block scheme of the down-hole instrument that uses in the well logging method of the present invention.

Fig. 5 is well logging method of the present invention counting rate curve reduced graph of surveying when implementing well logging.

Fig. 6 is scale model well and the calibration results corresponding diagram that well logging method of the present invention uses when scale.

Bottom reaches embodiment in conjunction with the accompanying drawings the present invention is described in detail.

The structure of water injection well described in the radioactive tracer water uptake section well logging method as shown in Figure 3, wherein, well (6) is arranged in the stratum (1), the center of well (6) was oil pipe (4), cross and be with sleeve pipe (3) outside the oil pipe (4), between stratum (1) and sleeve pipe (3), be solidified with cement mantle (2), water injects from well head, enter the down-hole through oil pipe (4), enter the suction stratum (1-1) of perforation along the operation of direction shown in the arrow, and not entering the not non-suction stratum (1-2) of perforation, tracer agent used in the well logging moves in the lump with water injection well.

The synoptic diagram of the well logging duty of radioactive energy spectrum tracing water uptake section well logging method of the present invention as shown in Figure 1.By stratum (1), cement mantle (2), sleeve pipe (3) is crossed oil pipe (4), in the well that well (6) is formed, in crossing oil pipe (4) down-hole instrument (5) is arranged, by cable (7) down-hole instrument (5) is suspended in the well (6), signal energising cable (7) transfers to ground instrument (8), circuit block diagram such as Fig. 4 of down-hole instrument (5), scintillation crystal (9) is wherein arranged, multiple tracks energy spectrum analysis device (10), and the common composition of amplifier (11).

The physical principle of well logging method of the present invention institute foundation is as follows.The gamma ray that sends from radioactive isotope has all different energy, and when these gamma rays passed material, their absolute strength all can be because of the absorption of material to them weakens, and its relative intensity also can change simultaneously.Have two kinds of main variation tendencies this moment, one, in the low energy range, the penetration capacity of high-energy ray is stronger than low energy ray, make pass same material after, the relative intensity of high-energy ray increases and the low energy part weakens relatively, and so-called " spectral hardening phenomenon " takes place.Its two, the part high-energy ray can weaken the spectral hardening phenomenon to a certain extent because of the Compton scattering effect becomes the low ray of energy.In general, select the suitable gamma ray beam of energy, the material density that passes is big more, and the Z value is high more, and material thickness is thick more, and its spectral hardening phenomenon is obvious more.And the steel sleeve pipe in the water injection well of oilfield is all bigger with density and the Z value of crossing oil pipe, and is apparent in view by the spectral hardening phenomenon that they cause.By measurement to the spectral hardening degree, just may judge whether ray does not pass oil pipe, perhaps only passed oil pipe, perhaps pass oil pipe and sleeve pipe simultaneously, just can judge whether input tracer agent is to stain in oil pipe inside and outside wall and internal surface of sleeve pipe.Pass oil pipe and sleeve pipe but do not go deep into the stratum if judge ray, then tracer agent is normal filter collection.Also can judge also just so-called leakage equally for the tracer agent that gos deep into the stratum certain depth.

For the measurement result of well logging method of the present invention, can find the solution with approximate algorithm.Replace situation in the real well with the barrel surface source model, Fig. 2 is the sketch of this model.A three-dimensional rectangular coordinate system wherein being arranged, represent borehole axis with the Z axle, is R at a radius, and high is the radioactive source that distributing equably on the garden abridged table face of H.The gamma ray of launching in the unit interval on the unit area in this face source adds up to Q, and wherein energy is that the shared share of gamma ray of E is designated as q (E).

Be the coaxial annulus medium of multilayer in the barrel surface source, the thick of each medium is Δ ri, and it is that the linear absorption coefficient of the gamma ray of E is μ j (E) to energy.

Cylinder center's point has one to survey scintillation crystal, and it is that the intrinsic conversion efficiency of the gamma ray of E is η (E) to energy.

Through the infinitesimal analysis computing, obtain at last by energy be E without the direct projection gamma ray of scattering with survey the counting rate N (E) that the scintillation crystal effect produces, its expression formula is:

N(E)=Qη(E)q(E)F(R,E) (1)

In actual conditions, also have gamma ray to enter crystal detection, therefore to formula (1) through scattering.Should add scattering modifying factor B (r, effect E) obtains following formula:

N (E)=Q η (E) q (E) B (r, E) F (R, E) (2) are in formula (2): $F(R,E)={\∫}_0^{\mathrm{tg}\frac{-1H}{2R}}{e}^{-b(R,E)\mathrm{Sec\θ}}\mathrm{d\θ}-----\left(3\right)$

And the b in the formula (3) (R, E)=∑ Δ ri μ i (E) (4)

And in the formula (4): ∑ Δ ri=R (5)

∑q(Ej)=1 (6)

In aforementioned expression formula (2), η (E) depends on the detection scintillation crystal, and q (E) depends on tracer agent, they and media independent.After well logger and tracer agent caused, they no longer changed, and (R E) is the very sensitive function of the product of dielectric thickness Δ ri and linear absorption coefficient μ i (E) to F.When gamma energy during in 100kev order of magnitude scope, the approximate and E of μ i (E) ^0.8Be inversely proportional to, thus the integration F of exponential function (R, E) value reduces with ray energy and diminishes rapidly.(R E) has described the spectral hardening phenomenon to F quantitatively, and its value can be by quite accurately calculating in theory.(r, E) relevant with the surrounding environment and the ray energy of crystal detection, their influence is far from, and (R, E) remarkable like that, (r E) has described weakening effect to the spectral hardening phenomenon to B to F to scattering modifying factor B quantitatively, generally needs to measure in the experiment.

Actual measurement profile such as Fig. 5 of checking this method, use therein radioactive source is ¹³¹Ba, in order to express clearly two curves that only drawn among Fig. 5, transverse axis is the energy of gamma ray, and the longitudinal axis is a relative count rate, curve A is that radioactive source is placed tube inner wall, and curve B is the relative count rate spectrum curve that records when radioactive source is placed sleeve outer wall.From the variation of curve as can be seen: curve A differs very little near counting rate peak value the 100kev and near the peak value 500kev, and 2 peak value difference is very big in the curve B, obviously observes out the spectral hardening phenomenon.Curve A is the spectrum curve of measuring when gamma ray source places tube inner wall, does not at this moment have steel pipe or stratum to separate between gamma ray source and crystal detection; And curve B is the spectrum curve of measuring when gamma ray source is put sleeve outer wall, at this moment is separated with two-layer steel pipe between source and the crystal.

Well logging method according to the present invention is made the calibration results as Fig. 6, for making things convenient for contrast that the half of situation of the well of calibration well (17) is drawn in bottom accordingly through simplifying with the result, wherein calibration well (17) is by the calibration well oil pipe (13) from the outside coaxial package in lining, calibration well sleeve pipe (14), calibration well cement mantle (14), simulated formation (16) is common to be constituted, and the inside is full of water (12), and there is well logging down-hole instrument (5) at the center.Represent the scale stop place of tracer agent with j among the figure at the model calibration well.Here enumerate 8 positions:

I down-hole instrument outer wall

The II tube inner wall

The III oil-pipe external wall

The IV internal surface of sleeve pipe

V sleeve outer wall (perforation part)

VI sleeve outer wall (not perforation part)

VII cement mantle outer wall

VIII enters stratum 150mm

The abscissa of curvillnear coordinate is the well radius among Fig. 6, and ordinate is the ratio of high low-energy peak.The high low energy peak area ratio that calculates of curve a, curve b is the high low energy peak area ratio of experiment gained, curve c is the high low energy road counting rate ratio of experiment gained.Each calibration results is to the normalization of instrument outer wall.

Embodiment.With reference to accompanying drawing 1 to accompanying drawing 6.

The first step drops into radioisotope tracer to water injection well to be measured (6), with radioactive isotope ¹³¹Ba is as the gamma-ray bursts source material in the radioisotope tracer.Radioactive isotope ¹³¹The low peak energy section of Ba is 100kev～150kev, and high peak energy section is 450kev～550kev.

Second step at first was ready to oil pipe radioactivity well logging down-hole instrument (5), it is 128 that m is counted in the power spectrum road of the multiple tracks energy spectrum analysis device (10) that wherein contains, to cross oil pipe radioactivity well logging down-hole instrument (5) and carry out the scale processing in master scale well (17), the scale step is as follows:

(a) calibration well (17) that sets up standard, calibration well oil pipe (13), calibration well sleeve pipe (14), calibration well cement mantle (15) and simulated formation (16) that this calibration well (17) is installed by the outside coaxial order intussusception from the lining are formed jointly, and the inside is full of water (12).

(b) on certain position of calibration well sleeve pipe (14), outwards radially penetrate calibration well oil pipe (13), calibration well sleeve pipe (14), calibration well cement mantle (15) and simulated formation (16) and make analogue perforation from the lining.

(c) will treat that scale well logging down-hole instrument (5) is lowered in the calibration well oil pipe (13), and make the close analogue perforation of detecting head crystal (9) of down-hole instrument.

(d) in the simulation hole, insert described radioisotope tracer in the first step.

(e) move tracer agent along analogue perforation, make it to rest on 8 positions as shown in Figure 6, n=8 just, and while measures 128 road gamma ray count rate on each stop place.

(f) with measured gamma ray count rate by in addition normalization of down-hole instrument outer wall (I), so-called normalization is exactly with the counting rate in each road and the ratio of the counting rate sum in all roads, these must 8 128 road standard spectrums, so far scale is finished dealing with.

Again the aforementioned ready oil pipe radioactivity well logging down-hole instrument (5) of crossing is inserted in the water injection well to be measured (6), penetrating property of the gamma gross-count rate of residual tracer agent on the purpose well section in this well of continuous coverage, the counting rate signal is changed into electric signal, transfer to ground instrument (8) and write down it recording signal then, form the gross-count rate curve at last.

The 3rd step was revised gross-count rate Qu Jinhang.

At first measured each counting rate curve is used gamma-ray spectrometry and separate spectrometry processings that make an explanation, gamma-ray spectrometry separates spectrometry and the correction step is as follows.

(a) standard spectrum that records on the j scale position is represented with a column vector Aj who is made of 128 row elements, j=1～8,8 scale positions can get 8 standard spectrums altogether, 8 column vectors are also arranged, they constitute 128 * 8 matrix A, be referred to as the spectrometer response matrix, its matrix element is designated as a _IjI=1～128, j=1～8, i represents the Taoist monastic name composed, j represents the standard clef, i.e. tracer agent scale location number in the calibration well.

(b) each well logging of well logging can get the counting rate spectrum that normalized is not done in 128 roads on position on the spot, with one by 128 row element b _iThe column vector B that constitutes represents i=1～128.

(c) aforementioned measured count rates spectrum B is the result that possible remain in the common contribution of tracer agent of each position on a certain perforation path radially of well.If the tracer agent that retains on the j of position is xj to the contribution portion of B, j=1～8 have then produced the column vector X that 8 row elements are arranged that xj constitutes.

(d) aforementioned three column vector A, X and B satisfy equation, AX=B, this equation be 128 linear equations constitute comprise 8 and do not know x _jSystem of linear equations, available general mathematical method is found the solution, and can be least square method.

(e) each xj that tries to achieve according to step (d) to impinging upon the physical meaning of the locus of each j that invests in the scale treatment step, just can judge the situation of staiing and missing.

(f) have for judgement and take place to stain and the well logging position of leakage, from this locational gross-count rate numerical value, because of staiing the share of being brought, augment the share that is caused because of leakage by the numerical value subduction of xj.

The 4th step was calculated the relative injectivity of various places layer according to the gross-count rate opisometer of revising.

Claims (1)

1. radioactive energy spectrum tracing water uptake section well logging method, by following poly-composition the in each step:

The first step drops into radioisotope tracer to water injection well to be measured (6);

Second step will cross oil pipe radioactivity well logging down-hole instrument (5) and insert in the water injection well to be measured (6), the total gamma-ray count-rate that residual tracer agent is launched on the purpose well section in this well of continuous coverage, the counting rate signal is changed into electric signal, transfer to ground instrument (8) and write down it recording signal then, form the gross-count rate curve at last;

The 3rd step was revised the gross-count rate curve;

The 4th step was calculated the relative injectivity of various places layer according to corrected gross-count rate opisometer;

It is characterized in that the tracer agent described in the aforementioned first step can be launched at least two enough gamma rays away from energy peak; There is the multiple tracks energy spectrum analysis device (10) of twice at least oil pipe radioactivity well logging down-hole instrument (5) lining of crossing described in aforementioned second step, multiple tracks energy spectrum analysis device (10) is by the predetermined spectral coverage segmentation writing down the gamma ray count of each self energy section and produce corresponding curve, and the scale that the aforementioned well logging down-hole instrument (5) that energy spectrum analysis device (10) arranged will carry out in the master scale well (17) is in advance handled; The correction in aforementioned the 3rd step should be each measured counting rate curve application gamma spectra to be separated spectrometry carry out the power spectrum interpretation process,, according to the interpretation process result gross-count rate curve is revised then;

Scale treatment step described in aforementioned second step is as follows:

(a) calibration well (17) that sets up standard, calibration well oil pipe (13), calibration well sleeve pipe (14), calibration well cement mantle (15) and simulated formation (16) that this well is installed by the outside coaxial order intussusception from the lining are formed jointly, and the inside is full of water (12);

(b) on certain position of calibration well sleeve pipe (14), outwards radially penetrate calibration well oil pipe (13), calibration well sleeve pipe (14), calibration well cement mantle (15) and simulated formation (16) and make analogue perforation from the lining;

(c) will treat that scale well logging down-hole instrument (5) is lowered in the calibration well oil pipe (13), and the detecting head crystal (9) that makes down-hole instrument (5) is near analogue perforation, and the road number of establishing energy spectrum analysis device (10) wherein is m;

(d) in analogue perforation, insert suitable tracer agent or available alternative radioactive source;

(e) move tracer agent along analogue perforation, stop on n the position that makes it to set in the foundation accuracy requirement, and simultaneously in each measurement m road, stop place gamma ray count rate, an aforementioned n position can be oil pipe inside and outside wall (I, an II), sleeve pipe inside and outside wall (IV, V), cement mantle outer wall (VII) is in the stratum (VIII);

(f) with institute turbid the gamma ray count rate by in addition normalization of down-hole instrument outer wall (I), so-called normalization is exactly with the counting rate in each road and the ratio of the counting rate sum in all roads, this just obtains n and opens m road standard spectrum, wherein the port number m of power spectrum should be greater than or equal to the tracer agent stop place and count n, and so far scale is finished dealing with;

The concrete steps that gamma spectra described in aforementioned the 3rd step is separated spectrometry are as follows:

(a) standard spectrum that records on the j scale position is represented with a column vector Aj who is made of the m row element, j=1～n, n scale position can get n and open standard spectrum altogether, and n column vector also arranged, they constitute m * n matrix A, be referred to as the spectrometer response matrix, its matrix element is designated as aij, i=1～m, j=1～n, i represents the Taoist monastic name composed, and j represents the standard clef, i.e. the scale location number of the tracer agent in the calibration well;

(b) scale is good well logging down-hole instrument (5) is logged well on the spot by preceding method, on each well logging position, can obtain the counting rate spectrum that normalized is not done in the m road, represents i=1～m with a column vector B who is made of m row element bi;

(c) aforementioned measured count rates spectrum B is the result that possible remain in the common contribution of tracer agent of each position on a certain perforation path radially of well, if the tracer agent that retains on the j of position is xj to the contribution portion of B, j=1～n has then produced the column vector X that the n row element is arranged that xj constitutes;

(d) aforementioned three column vector A, X and B satisfy following equation:

AX=B (1) formula (1) is the system of linear equations that comprises n unknown number xj that m linear equation constitutes, and available general mathematical method is found the solution;

(e) each xj that step (d) is tried to achieve on the foundation, and to impinging upon the physical meaning of the locus of each j that invests in the scale treatment step, just can judge the situation of staiing and missing, to sleeve pipe (3) with the interior locational xj of each j during if any remarkable numerical value, then contamination has taken place in decidable on this well logging position, for the locational xj that remarkable numerical value is arranged of each j in stratum (1), decidable has leakage to take place on this well logging position equally;

(f) have for judgement and take place to stain and the well logging position of leakage, from this locational gross-count rate numerical value, because of staiing the share of being brought, augment the share that is caused because of leakage by the numerical value subduction of xj.

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