CN104074501B - A kind of fission neutron well logging modification method - Google Patents

Abstract

The present invention relates to a kind of fission neutron tool calibration modification method, comprise the following steps: 1, obtain the correction counting rate of neutron monitor in tested wellhole；2, water correction factor is obtained；3, the borehole wall is leaned on after obtaining tested WIH correction and along borehole axis neutron count rate；4, by the borehole wall with along borehole axis neutron count rate after acquisition was revised by the epithermal neutron life-span in well logging；The present invention can directly measure uranium content, compares with drill core sampling chemical analysis results, and deviation is less than 10%；The present invention has the most objectively reacted uranium ore grade, especially in the location that U Ra equilibrium is destroyed, in conjunction with conventional γ-ray logging, on-the-spot can determine the U Ra equilibrium coefficient of boring ore deposit section, decrease boring sample quantity, reduces uranium resource ex-ploration cost；The present invention can accurately measure Uranium extraction rate in mining using leaching technology, it is to avoid the environmental pollution caused because of blindly excess fluid injection during mining using leaching technology and cost waste, to soak with improving adopt smelting efficiency, reduce cost, protection environment has important practical significance.

Description

A kind of fission neutron well logging modification method

Technical field

The invention belongs to core and radiation environmental monitoring metering field technical field, be specifically related in a kind of fission Sub-logging instrument adopts, for uranium exploration reserves and ground leaching, the modification method that smelting residue uranium resource amount calculates.

Background technology

Fission neutron logging technique belongs to the logging technique directly surveying uranium, and this technology starts from last century 70 years In generation, including prompt neutron logging technique and DFN technology.To middle nineteen seventies the most Prompt neutron logging instrument and deferred neutron logging instrument are widely used in uranium exploration, the sensitivity of its detection uranium Reach 10^-4G/g, reached that in-situ leachable uranium deposit reconnoitres minimum adopts production-grade.

Current the most often use γ-ray logging carries out uranium resource exploration and reserves calculate, and γ-ray logging is to be contained by measurement radium Amount calculates uranium content indirectly.The fission neutron logging technique directly surveying uranium still belongs to the starting stage, and Fission neutron logging instrument in use, along with loss and the natural radioactive decay of tritium, the neutron tube of neutron tube The neutron population produced gradually reduces, and the different time in same ore deposit section is measured, and the epithermal neutron number recorded is also Can reduce.And, when in wellhole anhydrous time, well diameter to fission neutron well logging have no significant effect； But when there being water in wellhole, the protium in water is significant on the impact of fission neutron well logging response value, And this impact is relevant to hole diameter size；The counting rate of thermal neutron or epithermal neutron is decided by the deceleration energy of water Power, the accuracy of fission neutron well logging is had the impact can not ignore, this impact to need to use water correction by water Coefficient eliminates.Not yet there is the modification method that fission neutron is logged well at present, it is impossible to realize fission neutron moisture Effective correction of well, brings impact to accurately calculating of uranium resource amount.

Summary of the invention

It is an object of the invention to reconnoitre and ground leaching is adopted at in-situ leachable uranium deposit for directly surveying uranium logging technique Application in smelting provides a kind of modification method, it is achieved the scene of field boring uranium content is quickly, accurately measure.

The present invention is achieved in that a kind of fission neutron logging instrument modification method, comprises the following steps:

Step one, obtain the correction counting rate of neutron monitor in tested wellhole

Gathered respectively in tested wellhole along borehole axis with by the neutron count rate S1 during borehole wall by fission neutron instrument And S2, and gather respectively in tested wellhole along borehole axis with by two neutrons supervision of fission neutron instrument during the borehole wall The difference △ M of the neutron count rate of device MON1 and MON2 record₁With △ M₂；At fission neutron logging module In standard set-up, gather respectively along borehole axis with by two neutron monitors of fission neutron instrument during the borehole wall The difference △ M of the neutron count rate of MON1 and MON2 record₀With △ M₀ ^'；

Obtain neutron monitor in tested wellhole respectively according to formula (1) and (2) and along borehole axis and lean on the borehole wall Time neutron monitor correction neutron count rate DS1 and DS2；

$\mathrm{DS}1=S1\·\frac{{\mathrm{\ΔM}}_0}{{\mathrm{\ΔM}}_1}---\left(1\right)$

$\mathrm{DS}2=S2\·\frac{{\mathrm{\ΔM}}_{0^{\′}}}{\mathrm{\Δ}{M}_2}---\left(2\right)$

Step 2, acquisition water correction factor

1, the diameter D of tested wellhole is gathered_K, the test tube diameter D of fission neutron logging instrument_T, according to formula (3) the clear water situation between the test tube outer wall of tested wellhole inwall and described fission neutron logging instrument is obtained Under water layer thickness d；

$d=\frac{1}{2}(D_k-D_T)---\left(3\right)$

2, obtain containing the equivalent water layer thickness d ' in the case of mud according to formula (4),

In formula, the equivalent water layer thickness that d ' is well liquid, mm；

ρ_SandGritty density, g/cm in mud³；

ρ_MudFor mud balance, g/cm³；

ρ_WaterFor density, g/cm³；

3, according to formula (5) obtain after fission neutron well logging alignment along borehole axis water correction factor μ_X1； According to formula (6) obtain fission neutron well logging alignment after by borehole wall water correction factor μ_X2；

μ_X1=0.7643e^0.0200d' (5)

μ_X2=0.8761e^0.0124d' (6)

Step 3, obtain tested WIH correction tailing edge borehole axis neutron count rate SS1 according to formula (9)； Borehole wall neutron count rate SS2 is depended on after obtaining tested WIH correction according to formula (10)；

SS1=DS1·μ_X1(9)

SS2=DS2·μ_X2(10)

Step 4, according to formula (11) obtain by well logging in the epithermal neutron life-span revise tailing edge borehole axis neutron Counting rate CS1；Obtain according to formula (12) after being revised by the epithermal neutron life-span in well logging by borehole wall neutron gauges Digit rate CS2；

$\mathrm{CS}1=\mathrm{SS}1\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(11\right)$

$\mathrm{CS}2=\mathrm{SS}2\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(12\right)$

In formula:

CS1 and CS2 unit is s^-1；

τ₀The epithermal neutron life-span recorded in fission neutron logging module standard set-up, μ s；

τ₁The epithermal neutron life-span recorded in tested wellhole, μ s.

Described formula (5) and formula (6) are prepared by the following:

In order to measure the water correction factor of different pore size, build the uranium content building blocks logging module of test, Its physical dimension is 3.5m × 1.5m × 1.7m, and aperture is 0.3m, base height 0.6m, top cover 0.4m, uranium Ore deposit section thickness is 0.7m；

Putting into the ferule of different-diameter and sealed bottom in building blocks model wellhole, ferule diameter exists In the range of 79mm～259mm, select the ferule of 6 diameter values, before and after injecting water in measuring ferule Along neutron count rate S3 and S3' of borehole axis, calculated by formula (7) and survey along borehole axis water correction factor μ_X1 ^'； Same, depend on neutron count rate S4 and S4' of the borehole wall before and after injecting water in measuring ferule, by formula (8) Calculate actual measurement by borehole wall water correction factor μ_X2 ^'；Concrete data are shown in Table 1；

${\mathrm{\μ}}_{{X1}^{\′}}=\frac{S3}{S{3}^{\′}}---\left(7\right)$

${\mathrm{\μ}}_{{X2}^{\′}}=\frac{S4}{S{4}^{\′}}---\left(8\right)$

Table 1 fission neutron logging instrument actual measurement water correction factor

According to the data in table 1, draw matched curve, and then obtain formula (5) and (6).

Beneficial effects of the present invention is as follows:

(1) change conventional uranium ore Gamma logging and can only indirectly calculate the logging mode of uranium by surveying radium, By applying the modification method of the present invention, fission neutron well logging can directly measure uranium content, with boring rock Heart sampling chemical analysis results compares, and deviation is less than 10%.The modification method of the present invention is for directly surveying uranium The application of fission neutron logging technique provides technical support；

(2) the fission neutron well logging result of the application present invention has the most objectively reacted uranium ore grade, especially It is the location being destroyed at U Ra equilibrium, in conjunction with conventional γ-ray logging, on-the-spot can determine the uranium radium of boring ore deposit section Coefficient of balance, decreases boring sample quantity, reduces uranium resource ex-ploration cost；

(3) the fission neutron well logging modification method of the application present invention can accurately measure uranium leaching in mining using leaching technology Go out rate, it is to avoid the environmental pollution caused during mining using leaching technology and cost waste because of the most excessive fluid injection, To improve soak adopt smelting efficiency, reduce cost, protection environment have important practical significance.

Accompanying drawing explanation

Fig. 1 is Drilling Water layer thickness schematic diagram in the present invention；

Fig. 2 is fission neutron well logging water correction matched curve in the present invention；

In figure, 1 is the test tube diameter of fission neutron logging instrument, and 2 is in tested wellhole inwall and described fission The water layer thickness in the case of clear water between the test tube outer wall of sub-logging instrument, 3 is the diameter of tested wellhole.

Detailed description of the invention

With embodiment, a kind of fission neutron logging instrument modification method of the present invention is situated between below in conjunction with the accompanying drawings Continue:

As it is shown in figure 1, a kind of fission neutron tool calibration modification method, specifically comprise the following steps that

Step one, obtain the correction counting rate of neutron monitor in tested wellhole

Gathered respectively in tested wellhole along borehole axis with by the neutron count rate S1 during borehole wall by fission neutron instrument And S2, and gather respectively in tested wellhole along borehole axis with by two neutrons supervision of fission neutron instrument during the borehole wall The difference △ M of the neutron count rate of device MON1 and MON2 record₁With △ M₂；At fission neutron logging module In standard set-up, gather respectively along borehole axis with by two neutron monitors of fission neutron instrument during the borehole wall The difference △ M of the neutron count rate of MON1 and MON2 record₀With △ M₀ ^'；

Fission neutron logging instrument is to calibrate on fission neutron logging module standard set-up, fission neutron Logging module standard set-up is with reference to International Atomic Energy Agency's skill that No. 309 technical reports were recommended in 1989 Art method and the construction of domestic and international similar standard facility.

Obtain neutron monitor in tested wellhole respectively according to formula (1) and (2) and along borehole axis and lean on the borehole wall Time neutron monitor correction neutron count rate DS1 and DS2；

$\mathrm{DS}1=S1\·\frac{{\mathrm{\ΔM}}_0}{{\mathrm{\ΔM}}_1}---\left(1\right)$

$\mathrm{DS}2=S2\·\frac{{\mathrm{\ΔM}}_{0^{\′}}}{\mathrm{\Δ}{M}_2}---\left(2\right)$

In formula:

S1、△M₁、△M₀、DS1、S2、△M₂、△M₀ ^', the unit of DS2 be s^-1；

Step 2, acquisition water correction factor

1, the diameter D of tested wellhole is gathered_K, the test tube diameter D of fission neutron logging instrument_T, according to formula (3) the clear water situation between the test tube outer wall of tested wellhole inwall and described fission neutron logging instrument is obtained Under water layer thickness d；As shown in Figure 1；

$d=\frac{1}{2}(D_k-D_T)---\left(3\right)$

In formula, D_K、D_T, the unit of d be mm；

2, the well liquid in the boring of field is frequently not clear water, but has the mud of certain weight proportion, in mud The impact of neutron well logging can be ignored by contained gravel, and the impact on fission neutron well logging is mainly derived from mud Water in slurry, obtains containing the equivalent water layer thickness d ' in the case of mud according to formula (4),

In formula, the equivalent water layer thickness that d ' is well liquid, mm；

ρ_SandGritty density, g/cm in mud³, its value is 2.65g/cm³(quartz sand density value)；

ρ_MudFor mud balance, g/cm³；

ρ_WaterFor density, g/cm³；

3, according to formula (5) obtain after fission neutron well logging alignment along borehole axis water correction factor μ_X1； According to formula (6) obtain fission neutron well logging alignment after by borehole wall water correction factor μ_X2；

μ_X1=0.7643e^0.0200d' (5)

μ_X2=0.8761e^0.0124d' (6)

It is calculated fission neutron well logging along borehole axis with by the water correction system of the borehole wall by formula (5) and (6) Number table, is shown in Table 2.

Table 2 fission neutron well logging water correction factor table

Described formula (5) and formula (6) are prepared by the following:

In order to measure the water correction factor of different pore size, build the uranium content building blocks logging module of test, Its physical dimension is 3.5m × 1.5m × 1.7m, and aperture is φ 0.3m, base height 0.6m, top cover 0.4m, uranium Ore deposit section thickness is 0.7m.

Putting into the ferule of different-diameter and sealed bottom in building blocks model wellhole, ferule diameter exists In the range of 79mm～259mm, select the ferule of 6 diameter values, before and after injecting water in measuring ferule Along neutron count rate S3 and S3' of borehole axis, calculated by formula (7) and survey along borehole axis water correction factor μ_X1 ^'； Same, depend on neutron count rate S4 and S4' of the borehole wall before and after injecting water in measuring ferule, by formula (8) Calculate actual measurement by borehole wall water correction factor μ_X2 ^'；Concrete data are shown in Table 1；

${\mathrm{\μ}}_{{X1}^{\′}}=\frac{S3}{S{3}^{\′}}---\left(7\right)$

${\mathrm{\μ}}_{{X2}^{\′}}=\frac{S4}{S{4}^{\′}}---\left(8\right)$

Table 1 fission neutron logging instrument actual measurement water correction factor

According to the data in table 1, matched curve can be drawn, as in figure 2 it is shown, with water layer thickness as horizontal stroke Coordinate, water correction factor is vertical coordinate, and then obtains fitting formula, i.e. formula (5) and (6).

Step 3, obtain tested WIH correction tailing edge borehole axis neutron count rate SS1 according to formula (9)； Borehole wall neutron count rate SS2 is depended on after obtaining tested WIH correction according to formula (10)；

SS1=DS1·μ_X1(9)

SS2=DS2·μ_X2(10)

In the epithermal neutron life-span that step 4, fission neutron logging instrument record and rock rich in uranium degree and The porosity of rock is relevant, for accurately calculating the uranium content in rock, and need to be to by neutron count rate in well logging Carry out the correction of epithermal neutron life-span；Obtain according to formula (11) after being revised by the epithermal neutron life-span in well logging Along borehole axis neutron count rate CS1；Obtain according to formula (12) and lean on after being revised by the epithermal neutron life-span in well logging Borehole wall neutron count rate CS2；

$\mathrm{CS}1=\mathrm{SS}1\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(11\right)$

$\mathrm{CS}2=\mathrm{SS}2\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(12\right)$

In formula:

CS1 and CS2 unit is s^-1；

τ₀The epithermal neutron life-span recorded in fission neutron logging module standard set-up, μ s；

τ₁The epithermal neutron life-span recorded in tested wellhole, μ s.

Neutron monitor counting rate correction, water correction factor correction and the epithermal neutron longevity in the application present invention Life modification method, has a positive effect:

(1) change conventional uranium ore Gamma logging and can only indirectly calculate the logging mode of uranium by surveying radium, By applying the modification method of the present invention, fission neutron well logging can directly measure uranium content, with boring rock Heart sampling chemical analysis results compares, and deviation is less than 10%.The modification method of the present invention is for directly surveying uranium Fission neutron logging technique provides technical support in China's uranium exploration application；

(2) the fission neutron well logging result of the application present invention has the most objectively reacted uranium ore grade, especially It is the location being destroyed at U Ra equilibrium, in conjunction with conventional γ-ray logging, on-the-spot can determine the uranium of boring ore deposit section Radium coefficient of balance, decreases boring sample quantity, reduces uranium resource ex-ploration cost；

(3) the fission neutron well logging modification method of the application present invention can accurately measure uranium in mining using leaching technology Leaching rate, it is to avoid the environmental pollution caused because of the most excessive fluid injection during mining using leaching technology and cost wave Take, to improve soak adopt smelting efficiency, reduce cost, protection environment have important practical significance.

Claims (2)

1. a fission neutron tool calibration modification method, it is characterised in that: comprise the following steps:

Step one, obtain the correction counting rate of neutron monitor in tested wellhole

Gathered respectively in tested wellhole along borehole axis with by the neutron count rate during borehole wall by fission neutron logging instrument S1 and S2, and gather respectively in tested wellhole along borehole axis with by two neutrons of fission neutron logging instrument during the borehole wall The difference Δ M of the neutron count rate of monitors M ON1 and MON2 record₁With Δ M₂；At fission neutron well logging mould In type standard set-up, gather respectively along borehole axis with by two neutron monitors of fission neutron logging instrument during the borehole wall The difference Δ M of the neutron count rate of MON1 and MON2 record₀With Δ M_0'；

When obtaining in tested wellhole neutron monitor respectively along borehole axis with by the borehole wall according to formula (1) and (2) Neutron monitor correction neutron count rate DS1 and DS2；

$DS1=S1\·\frac{{\mathrm{\ΔM}}_0}{{\mathrm{\ΔM}}_1}---\left(1\right)$

$DS2=S2\·\frac{{\mathrm{\ΔM}}_{0^{\′}}}{{\mathrm{\ΔM}}_2}---\left(2\right)$

Step 2, acquisition water correction factor

1) the diameter D of tested wellhole, is gathered_K, the test tube diameter D of fission neutron logging instrument_T, according to formula (3) Obtain the water in the case of the clear water between the test tube outer wall of tested wellhole inwall and described fission neutron logging instrument Layer thickness d；

$d=\frac{1}{2}(D_k-D_T)---\left(3\right)$

2), obtain containing the equivalent water layer thickness d ' in the case of mud according to formula (4),

In formula, the equivalent water layer thickness that d ' is well liquid, mm；

ρ_SandGritty density, g/cm in mud³；

ρ_MudFor mud balance, g/cm³；

ρ_WaterFor density, g/cm³；

3), according to formula (5) obtain after fission neutron well logging alignment along borehole axis water correction factor μ_X1； According to formula (6) obtain fission neutron well logging alignment after by borehole wall water correction factor μ_X2；

μ_X1=0.7643e⁰ _. ^0200d′' (5)

μ_X2=0.8761e^0.0124d′ (6)

Step 3, obtain tested WIH correction tailing edge borehole axis neutron count rate SS1 according to formula (9)；Root Borehole wall neutron count rate SS2 is depended on after obtaining tested WIH correction according to formula (10)；

SS1=DS1 μ_X1 (9)

SS2=DS2 μ_X2 (10)

Step 4, according to formula (11) obtain by well logging in the epithermal neutron life-span revise tailing edge borehole axis neutron gauges Digit rate CS1；Obtain according to formula (12) after being revised by the epithermal neutron life-span in well logging by borehole wall neutron count rate CS2；

$CS1=SS1\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(11\right)$

$CS2=SS2\·\frac{{\mathrm{\τ}}_0}{{\mathrm{\τ}}_1}\·\frac{e^{(-192/{\mathrm{\τ}}_0)}}{e^{(-192/{\mathrm{\τ}}_1)}}---\left(12\right)$

In formula:

CS1 and CS2 unit is s^-1；

τ₀The epithermal neutron life-span recorded in fission neutron logging module standard set-up, μ s；

τ₁The epithermal neutron life-span recorded in tested wellhole, μ s.

2. according to the fission neutron tool calibration modification method described in claim 1, it is characterised in that: institute State formula (5) and formula (6) be prepared by the following:

In order to measure the water correction factor of different pore size, build the uranium content building blocks logging module of test, Its physical dimension is 3.5m × 1.5m × 1.7m, and aperture is 0.3m, base height 0.6m, top cover 0.4m, uranium ore Duan Houdu is 0.7m；

Putting into the ferule of different-diameter and sealed bottom in building blocks model wellhole, ferule diameter exists In the range of 79mm～259mm, select the ferule of 6 diameter values, in measuring ferule, inject edge before and after water Neutron count rate S3 and S3' of borehole axis, is calculated by formula (7) and surveys along borehole axis water correction factor μ_X1'；With Sample, depend on neutron count rate S4 and S4' of the borehole wall before and after injecting water in measuring ferule, by formula (8) Calculate actual measurement by borehole wall water correction factor μ_X2'；Concrete data are shown in Table 1；

${\mathrm{\μ}}_{X{1}^{\′}}=\frac{S3}{S{3}^{\′}}---\left(7\right)$

${\mathrm{\μ}}_{X{2}^{\′}}=\frac{S4}{S{4}^{\′}}---\left(8\right)$

Table 1 fission neutron logging instrument actual measurement water correction factor

According to the data in table 1, draw matched curve, and then obtain formula (5) and (6).