CN103675722B - Rock T2-G experiment acquisition parameter automatic matching method - Google Patents

Abstract

The invention discloses a kind of rock T2-G experiment acquisition parameter automatic matching method, first the method constructs (T2, G) Equivalent Distributed model of rock to be measured, then automatically changes t according to manual adjustment rule₀, NE1 calculate corresponding echo string amplitude, determine in conjunction with the echo string amplitude constraint condition of optimization T2-G acquisition parameter the acquisition parameter t that is applicable to rock to be measured₀, NE1. The present invention designs a kind of t of substituting originally₀, NE1 manual adjustment T2-G experiment acquisition parameter automatic matching method, realized and ensured T2-G experiment measuring precision, reduced experimental implementation difficulty, improved the target of experiment detection efficiency.

Description

Rock T2-G experiment acquisition parameter automatic matching method

Technical field

The invention belongs to oil exploration rock physics experiment detection field, be specifically related to one and realize oil and gas reservoir rock T2-G experimentThe automatic matching method of acquisition parameter.

Background technology

Under the effect of rock interior magnetic field gradient, diffusion relaxation will speed up the transverse relaxation decay of pore-fluid, to nuclear magnetic resonance horizontal strokeMeasure and produce very important effect to the relaxation time, affect precision and the fluid identification effect of nuclear magnetic resonance log interpretation and evaluation.Obtaining the size in rock interior magnetic field and distributing is eliminate or reduce its prerequisite on Nuclear Magnetic Resonance Measurement impact, but internal magnetic fieldThe size of gradient not only has relation with difference, externally-applied magnetic field intensity, the pore radius of magnetic susceptibility, also with the granulated of rock matrixThe factors such as the microscopic geometry of Zhuan ﹑ rough degree and pore network are relevant, cause directly using formula to calculate.For quantitative study internal field gradient distributes, Chinese scholars has been carried out system research. Bendel(1990) by blowhole skyBetween inside gradient in each elementary volume, volume element is approximate regards constant as, obtain rock by all elementary volume, volume element integrations to interstitial spaceInternal field gradient, but this being similar to when longer in diffusion time cannot meet. Zhang etc. (1998), Shafer etc. (1999)Utilize the rock T2 T2 that long and short echo sounding is measured to calculate internal field gradient size, this method hypothesis is allThe corresponding identical internal field gradient size of hole, therefore the method can only obtain the mean value of rock interior magnetic field gradient, noCan study its distribution characteristics and scope. After two dimensional NMR concept proposes, Sun and Dunn(2002) design two windowsThe Improvement type cpmg sequence row of mouth, and (T2, G) two dimensional NMR inversion method is proposed, realize rock interior magnetic field gradient and dividedThe measurement of cloth. Based on conventional cpmg sequence row, Xie Ranhong and Xiao Lizhi (2009) utilize the echo string of different echo soundings to realizeThe calculating of (T2, G) Two dimensional Distribution. With respect to many echo soundings method, the unique design of Improvement type cpmg sequence row has realized insteadDrill the separation of two coupling functions in coefficient, the scale of single inverting coefficient matrix is reduced greatly, without compression and back wave train data,Effectively improve inversion speed, and along with this sequence popularizing on nuclear magnetic resonance petrographical analysis instrument, Improvement type cpmg sequence rowApplication in the research of rock interior magnetic field gradient is more and more extensive.

Practice is found, utilizes Improvement type cpmg sequence to be listed as while carrying out rock T2-G experiment measuring, t in acquisition parameter₀(firstThe duration of window) and first window of NE1(in the combination of echo number) select improperly will cause rock in inverting spectrum" hangover " phenomenon (from accompanying drawing 2(b) N-1 rock of internal field gradient is not optimized t₀、NE1（t₀=0.5ms) time correspondenceT2-G inverting spectrum can obviously find out), the true distribution that can not obtain rock interior magnetic field gradient; In order to ensure experiment measuring effectReally, need manual adjustment t when T2-G experiment measuring₀And NE1, but manual adjustment t₀, NE1 complex steps is time-consuming, especiallyThe interpolation combining random of NE1 is strong, and very high to the level requirement of experiment operator, it is real that these all do not meet Oil Field rockIn enormous quantities, the quick test request of testing.

In sum, need one badly and can realize automatic search and the best t of coupling according to rock interior magnetic field gradient profile feature₀、The method of NE1 and technology reduce experimental implementation difficulty, improve experiment detection under the prerequisite that ensures T2-G experiment measuring precisionEfficiency. Up to now, also do not have correlation technique and the achievement of T2-G experiment acquisition parameter Auto-matching to be seen in report both at home and abroad.

Summary of the invention

For manual adjustment t in Improvement type cpmg sequence row T2-G experimentation₀, large, duration of NE1 operation easier is long etc.Drawback, the present invention designs a kind of t of substituting₀, NE1 manual adjustment T2-G experiment acquisition parameter automatic matching method, the methodUnder the prerequisite that ensures T2-G experiment measuring precision, reduce experimental implementation difficulty, improved experiment detection efficiency.

The technology used in the present invention solution is:

Rock T2-G experiment acquisition parameter automatic matching method, comprises the following steps:

(1) construct rock to be measured (T2, G) equivalent model

The T2 spectrum of being measured under long and short echo sounding cpmg sequence row by rock to be measured is calculated T2_gS、

T2_gSFor the T2 geometrical mean that rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit;

For the mean value of rock interior magnetic field gradient to be measured, the T/m of unit;Computing formula see formula (1);

$\stackrel{\‾}{G}=\sqrt{12\×\frac{(1/{T2}_{\mathrm{gL}}-1/{T2}_{\mathrm{gS}})}{{\mathrm{\γ}}^{2}D({{\mathrm{TE}}_L}^2-{{\mathrm{TE}}_S}^2)}}---\left(1\right)$

In formula (1):

The mean value of-rock interior magnetic field gradient to be measured, the T/m of unit;

T2_gLThe T2 geometrical mean that-rock to be measured is measured at long echo interval cpmg sequence row, the ms of unit;

T2_gSThe T2 geometrical mean that-rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s；

TE_LThe echo sounding size of-long echo interval cpmg sequence row, the ms of unit;

TE_SThe echo sounding size of-short echo sounding cpmg sequence row, the ms of unit;

With (T2_gS，) centered by construct two-dimentional normal distribution model f (T2_j,G_p), and make f (T2_j,G_p) meet normalizing condition:

$\underset{j=1}{\overset{64}{\mathrm{\Σ}}}\underset{p=1}{\overset{64}{\mathrm{\Σ}}}f({T2}_j,G_p)=1---\left(2\right)$

In formula (2):

T2_jT2 component corresponding to identical pore size in-rock to be measured, logarithm between [0.01ms, 10000ms]Equidistantly distribute, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock to be measured, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 is T2_j, internal field gradient component is the normalization porosity component that Gp is corresponding,J=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless;

(2) set up T2-G echo string computation model

The echo string amplitude computation model of second window collection is:

$b_{\mathrm{ik}}=\underset{j=1}{\overset{64}{\mathrm{\Σ}}}\underset{p=1}{\overset{64}{\mathrm{\Σ}}}f({T2}_j,G_p)\exp (-\frac{t_i+t_0}{{T2}_j})\exp \left(\frac{-{\mathrm{\γ}}^2{G_p}^2{{\mathrm{Dt}}_0}^3}{{12\mathrm{NE}1}_k^2}\right)---\left(3\right)$

In formula (3):

b_ikThe duration of-first window is t₀, echo number is NE1_kTime, the width of i echo in second windowDegree, dimensionless;

T2_jThe T2 component that in-rock, identical pore size is corresponding, between logarithm between [0.01ms, 10000ms] etc.Apart from distributing, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 is T2_j, internal field gradient is the normalization porosity component that Gp is corresponding, j=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless;

t_i—b_ikThe sampling time of corresponding second window, t_i=i×T_E, i=1,2,3 ... NE, the ms of unit; T_ERepresent secondThe echo sounding of window, the ms of unit; NE represents the echo number of second window;

t₀The duration of-first window, the ms of unit;

NE1_kThe echo number of-first window, k=1,2,3,4,5;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s；

Formula (3) is write as matrix form:

B＝K_T·X·K_G(4)

In formula (4):

B-echo amplitude b_ikCorresponding matrix;

K_T-kernel functionCorresponding coefficient matrix;

K_G-kernel functionCorresponding coefficient matrix;

X-petrotectonic (T2, G) to be measured equivalent model f (T2_j,G_p)；

(3) rock T2-G experiment acquisition parameter (t to be measured₀, NE1) Auto-matching

The first step: automatic search coupling are applicable to the parametric t of rock T2-G experiment to be measured according to the following steps₀Size

a）t₀Initialize;

b）NE1_min=1、NE1_max=10t₀, substitution formula (4) calculates corresponding echo amplitude b_1min、b_1max；

If c) meet b_1min≤0.1b_1maxOr t₀≥T2_gS, t stops search₀，t₀Currency be exactly rock T2 to be measured ?G experimentOptimum value; Otherwise t₀Automatically add 0.1ms and return to step b) and continue search, until satisfy condition;

Second step: at definite t₀Size after, automatic search coupling are applicable to the ginseng of rock T2-G to be measured experiment according to the following stepsThe combination of number NE1

A) number of combinations of NE1 is 5, and NE1₁=1、NE1₅=10t₀, substitution formula (4) calculates corresponding echo amplitudeb₁₁、b₁₅，Δb=b₁₅-b₁₁, assignment NE1₂=NE1₁+1；

B) calculate NE1₂Corresponding echo amplitude b₁₂，Δb₁₂=b₁₂-b₁₁；

If c) meet Δ b/8≤Δ b₁₂≤ Δ b/3, NE1 stops search₂; Otherwise NE1₂=NE1₂+ 1, and return to step b)Continue search NE1₂, until satisfy condition;

D) at NE1₂After coupling finishes, assignment NE1₃=NE1₂+1；

E) calculate NE1₃Corresponding echo amplitude b₁₃，Δb₁₃=b₁₃-b₁₂；

If f) meet Δ b/8≤Δ b₁₃≤ Δ b/3, NE1 stops search₃; Otherwise NE1₃=NE1₃+ 1, and return to step e)Continue search NE1₃, until satisfy condition;

G) at NE1₃After coupling finishes, assignment NE1₄=NE1₃+1；

H) calculate NE1₄Corresponding echo amplitude b₁₄，Δb₁₄=b₁₄-b₁₃；

If i) meet Δ b/8≤Δ b₁₄≤ Δ b/3, NE1 stops search₄; Otherwise NE1₄=NE1₄+ 1, and return to step h)Continue search NE1₄, until satisfy condition;

j）NE1=1、NE1₂、NE1₃、NE1₄、10t₀It is exactly the acquisition parameter that is applicable to rock T2-G experiment to be measured;

Above-mentioned steps adopts programming software programming to realize.

In above-mentioned steps (1), the echo sounding size of long and short echo sounding cpmg sequence row is respectively TE_L=2.4ms，TE_S=0.1ms。

Useful technique effect of the present invention is:

The invention provides a kind of rock T2-G experiment acquisition parameter automatic matching method, the method is by inputting data: to be measuredT2 spectrum and echo sounding TE thereof that rock is measured under long and short echo sounding_L、TE_S, can go out T2-G experiment by Auto-matchingAcquisition parameter t₀, NE1. Empirical tests, the t of the present invention's design₀, NE1 automatic matching method meet rock T2-G experimental design wantAsk, realized and ensured experimental precision, reduce experimental implementation difficulty, improved the design object of testing detection efficiency.

Brief description of the drawings

Below in conjunction with accompanying drawing and detailed description of the invention, the invention will be further described:

Fig. 1 is that two window Improvement type cpmg sequences that T2-G experiment adopts list intention;

Fig. 2 is that N-1 rock is not optimized t₀, corresponding T2-G measures curve and inverting spectrum thereof, t when NE1₀=0.5ms；

Fig. 3 is N-1 rock manual adjustment t₀, NE1 during to optimum value corresponding T2-G measure curve and inverting spectrum thereof,t₀=6.7ms；

Fig. 4 is the T2 spectrum of the long and short echo sounding of N-1 rock and (T2, G) equivalent model of structure;

Fig. 5 is T2-G experiment acquisition parameter (t₀, NE1) Auto-matching flow chart;

Fig. 6 is N-1 rock Auto-matching t₀, corresponding T2-G measures curve and inverting spectrum thereof, t when NE1₀=6.4ms。

Detailed description of the invention

For manual adjustment t in Improvement type cpmg sequence row T2-G experimentation₀, large, duration of NE1 operation easier is long etc.Drawback, the present invention designs a kind of t of substituting originally₀, NE1 manual adjustment T2-G experiment acquisition parameter automatic matching method,Realize and ensured T2-G experiment measuring precision, reduced experimental implementation difficulty, improved the target of testing detection efficiency.

The general principle of the rock T2-G experiment acquisition parameter automatic matching method of the present invention's design is: first construct rock to be measured(T2, G) Equivalent Distributed model, then changes t automatically according to manual adjustment rule₀, NE1 calculate corresponding echo string amplitude,Echo string amplitude constraint condition in conjunction with optimization T2-G acquisition parameter is determined the acquisition parameter t that is applicable to rock to be measured₀、NE1。

By reference to the accompanying drawings, rock T2-G experiment acquisition parameter automatic matching method, comprises the following steps:

(1) construct rock to be measured (T2, G) equivalent model

From the inverting spectrum of N-1 rock in Fig. 3, all there is obvious main peak on distributing in T2 spectrum, the G spectrum of rock, because ofThis can construct (T2, G) two-dimentional normal distribution model (T2, G) equivalent model as rock to be measured. For ensure tectonic model andThe degree of approximation that rock to be measured true (T2, G) distributes, is measured under long and short echo sounding cpmg sequence row by rock to be measuredT2 spectrum is calculated the parameter T2 of rock to be measured_gS、

T2_gSFor the T2 geometrical mean that rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit.

For the mean value of rock interior magnetic field gradient to be measured, the T/m of unit;Computing formula see formula (1);

$\stackrel{\‾}{G}=\sqrt{12\×\frac{(1/{T2}_{\mathrm{gL}}-1/{T2}_{\mathrm{gS}})}{{\mathrm{\γ}}^{2}D({{\mathrm{TE}}_L}^2-{{\mathrm{TE}}_S}^2)}}---\left(1\right)$

In formula (1):

The mean value of-rock interior magnetic field gradient to be measured, the T/m of unit;

T2_gLThe T2 geometrical mean that-rock to be measured is measured at long echo interval cpmg sequence row, the ms of unit;

T2_gSThe T2 geometrical mean that-rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s；

TE_LThe echo sounding size of-long echo interval cpmg sequence row, the ms of unit;

TE_SThe echo sounding size of-short echo sounding cpmg sequence row, the ms of unit.

With (T2_gS，) centered by construct two-dimentional normal distribution equivalent model f (T2_j,G_p), as shown in Figure 4, and make f (T2_j,G_p) fullFoot normalizing condition:

$\underset{j=1}{\overset{64}{\mathrm{\Σ}}}\underset{p=1}{\overset{64}{\mathrm{\Σ}}}f({T2}_j,G_p)=1---\left(2\right)$

In formula (2):

T2_jT2 component corresponding to identical pore size in-rock to be measured, logarithm between [0.01ms, 10000ms]Equidistantly distribute, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock to be measured, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 is T2_j, internal field gradient component is the normalization porosity component that Gp is corresponding,J=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless.

(2) set up T2-G echo string computation model

When manual adjustment T2-G experiment acquisition parameter, be according to the poor preferred t of the echo amplitude of second window₀, NE1. Set upT2-G echo string computation model is to realize t₀, NE1 automatic matching method necessary condition. Managed by porous media NMR relaxationOpinion, in conjunction with the feature of Improvement type cpmg sequence row, the echo string amplitude computation model of second window collection is:

$b_{\mathrm{ik}}=\underset{j=1}{\overset{64}{\mathrm{\Σ}}}\underset{p=1}{\overset{64}{\mathrm{\Σ}}}f({T2}_j,G_p)\exp (-\frac{t_i+t_0}{{T2}_j})\exp \left(\frac{-{\mathrm{\γ}}^2{G_p}^2{{\mathrm{Dt}}_0}^3}{{12\mathrm{NE}1}_k^2}\right)---\left(3\right)$

In formula (3):

b_ikThe duration of-first window is t₀, echo number is NE1_kTime, the width of i echo in second windowDegree, dimensionless;

T2_jThe T2 component that in-rock, identical pore size is corresponding, between logarithm between [0.01ms, 10000ms] etc.Apart from distributing, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 is T2_j, internal field gradient is the normalization porosity component that Gp is corresponding, j=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless;

t_i—b_ikThe corresponding sampling time (second window), t_i=i×T_E, i=1,2,3 ... NE, the ms of unit; T_ERepresentThe echo sounding of two windows, the ms of unit; NE represents the echo number of second window;

t₀The duration of-first window, the ms of unit;

NE1_kThe echo number of-first window, k=1,2,3,4,5;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s。

Formula (3) is write as matrix form:

B＝K_T·X·K_G(4)

In formula (4):

B-echo amplitude b_ikCorresponding matrix;

K_T-kernel functionCorresponding coefficient matrix;

K_G-kernel functionCorresponding coefficient matrix;

X-petrotectonic (T2, G) to be measured equivalent model f (T2_j,G_p)。

(3) rock T2-G experiment acquisition parameter (t to be measured₀, NE1) Auto-matching

As shown in Figure 5, manual adjustment parametric t while experiment according to T2-G₀, NE1 rule, syncaryon magnetic resonance core analyzerThe performance parameter of device, and on the basis of above-mentioned steps (1), (2), the T2-G experiment acquisition parameter (t of rock to be measured is proposed₀、NE1) Auto-matching flow process is as follows:

The first step: (T2, the G) equivalent model f (T2 that constructs rock to be measured_j,G_p)

A) T2 spectrum (TE when rock to be measured is measured long and short echo sounding cpmg sequence row_L=2.4ms，TE_S=0.1ms）；

B) calculate the parameter T2 of rock to be measured_gL、T2_gS、

C) with (T2_gS，) centered by construct two-dimentional normal distribution model f (T2_j,G_p)。

Second step: automatic search coupling are applicable to the parametric t of rock T2-G experiment to be measured according to the following steps₀Size

a）t₀Initialize 0.5ms;

b）NE1_min=1、NE1_max=10t₀, substitution formula (4) calculates corresponding echo amplitude b_1min、b_1max；

If c) meet b_1min≤0.1b_1maxOr t₀≥T2_gS, t stops search₀，t₀Currency be exactly rock T2 to be measured ?G experimentOptimum value; Otherwise t₀Automatically add 0.1ms and return to step b) and continue search, until satisfy condition.

The 3rd step: at definite t₀Size after, automatic search coupling are applicable to the ginseng of rock T2-G to be measured experiment according to the following stepsThe combination of number NE1

A) number of combinations of NE1 is 5, and NE1₁=1、NE1₅=10t₀, substitution formula (4) calculates corresponding echo amplitudeb₁₁、b₁₅，Δb=b₁₅-b₁₁, assignment NE1₂=NE1₁+1；

B) calculate NE1₂Corresponding echo amplitude b₁₂，Δb₁₂=b₁₂-b₁₁；

If c) meet Δ b/8≤Δ b₁₂≤ Δ b/3, NE1 stops search₂; Otherwise NE1₂=NE1₂+ 1, and return to step b)Continue search NE1₂, until satisfy condition;

D) at NE1₂After coupling finishes, assignment NE1₃=NE1₂+1；

E) calculate NE1₃Corresponding echo amplitude b₁₃，Δb₁₃=b₁₃-b₁₂；

If f) meet Δ b/8≤Δ b₁₃≤ Δ b/3, NE1 stops search₃; Otherwise NE1₃=NE1₃+ 1, and return to step e)Continue search NE1₃, until satisfy condition;

G) at NE1₃After coupling finishes, assignment NE1₄=NE1₃+1；

H) calculate NE1₄Corresponding echo amplitude b₁₄，Δb₁₄=b₁₄-b₁₃；

If i) meet Δ b/8≤Δ b₁₄≤ Δ b/3, NE1 stops search₄; Otherwise NE1₄=NE1₄+ 1, and return to step h)Continue search NE1₄, until satisfy condition;

j）NE1=1、NE1₂、NE1₃、NE1₄、10t₀It is exactly the acquisition parameter that is applicable to rock T2-G experiment to be measured.

By above-mentioned T2-G experiment acquisition parameter (t₀, NE1) Auto-matching C, C++, Fortran, Matlab etc. for flow processProgramming software is weaved into calculation procedure. The input data of program: the T2 that rock to be measured is measured under long and short echo sounding composes and returnsWave spacing TE_L、TE_S; The output data of program: T2-G optimum experimental acquisition parameter t₀、NE1。

Application example:

N-1 rock utilizes t₀, NE1 automatch result of calculation: t₀=6.4ms，NE1=1、3、8、17、64，Use this group parameter to carry out N-1 rock T2-G experiment measuring, experimental result is shown in Fig. 6. Comparison diagram 6(b) and Fig. 3 (b),Can find out t₀, the inverting spectrum of NE1 Auto-matching parameter and the inverting of manual adjustment parameter spectrum distributional pattern and scope consistent, explanationThe t of the present invention's design₀, NE1 automatic matching method meets rock T2-G experimental design requirement, realized guarantee experimental precision, fallenLow experimental implementation difficulty, the design object of testing detection efficiency that improves.

Claims (2)

1. rock T2-G experiment acquisition parameter automatic matching method, is characterized in that comprising the following steps:

(1) construct rock T2-G equivalent model to be measured

The T2 spectrum of being measured under long and short echo sounding cpmg sequence row by rock to be measured is calculated T2_gS、

T2_gSFor the T2 geometrical mean that rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit;

For the mean value of rock interior magnetic field gradient to be measured, the T/m of unit;Computing formula see formula (1);

$\stackrel{\‾}{G}=\sqrt{12\×\frac{(1/T{2}_{gL}-1/T{2}_{gS})}{{\mathrm{\γ}}^{2}D({{\mathrm{TE}}_L}^2-{{\mathrm{TE}}_S}^2)}}---\left(1\right)$

In formula (1):

The mean value of-rock interior magnetic field gradient to be measured, the T/m of unit;

T2_gLThe T2 geometrical mean that-rock to be measured is measured at long echo interval cpmg sequence row, the ms of unit;

T2_gSThe T2 geometrical mean that-rock to be measured is measured at short echo sounding cpmg sequence row, the ms of unit;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s；

TE_LThe echo sounding size of-long echo interval cpmg sequence row, the ms of unit;

TE_SThe echo sounding size of-short echo sounding cpmg sequence row, the ms of unit;

WithCentered by construct two-dimentional normal distribution model f (T2_j,G_p), and make f (T2_j,G_p) meet normalizing condition:

$\underset{j=1}{\overset{64}{\Σ}}\underset{p=1}{\overset{64}{\Σ}}f(T{2}_j,G_p)=1---\left(2\right)$

In formula (2):

T2_jT2 component corresponding to identical pore size in-rock to be measured, logarithm between [0.01ms, 10000ms]Equidistantly distribute, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock to be measured, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 component is T2_j, internal field gradient component is that the normalization porosity that Gp is corresponding dividesAmount, j=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless;

(2) set up T2-G echo string computation model

The echo string amplitude computation model of second window collection is:

$b_{ik}=\underset{j=1}{\overset{64}{\Σ}}\underset{p=1}{\overset{64}{\Σ}}f(T{2}_j,G_p)\exp (-\frac{t_i+t_0}{T{2}_j})\exp \left(\frac{-{\mathrm{\γ}}^2{G_p}^2{{\mathrm{Dt}}_0}^3}{12NE{1}_k^2}\right)---\left(3\right)$

In formula (3):

b_ikThe duration of-first window is t₀, echo number is NE1_kTime, the width of i echo in second windowDegree, dimensionless;

T2_jT2 component corresponding to identical pore size in-rock to be measured, logarithm between [0.01ms, 10000ms]Equidistantly distribute, j=1,2,3 ... 64, the ms of unit;

G_pInternal field gradient component in-rock to be measured, between [0.001T/m, 1000T/m], logarithm equidistantly distributes, p=1,2,3 ... 64, the T/m of unit;

f(T2_j,G_p)-T2 component is T2_j, internal field gradient component is the normalization porosity component that Gp is corresponding,J=1,2,3 ... 64, p=1,2,3 ... 64, dimensionless;

t_i—b_ikThe sampling time of corresponding second window, t_i＝i×T_E, i=1,2,3 ... NE, the ms of unit; T_ERepresent secondThe echo sounding of window, the ms of unit; NE represents the echo number of second window;

t₀The duration of-first window, the ms of unit;

NE1_kThe echo number of-first window, k=1,2,3,4,5;

The gyromagnetic ratio of γ-proton, constant, 2.675 × 10⁸rad·s^-1·T^-1；

The diffusion coefficient of D-rock to be measured mesopore fluid, 25 DEG C time, equals 2.5 × 10^-9m²/s；

Formula (3) is write as matrix form:

B＝K_T·X·K_G(4)

In formula (4):

B-echo amplitude b_ikCorresponding matrix;

K_T-kernel functionCorresponding coefficient matrix;

K_G-kernel functionCorresponding coefficient matrix;

X-petrotectonic T2-G equivalent model f (T2 to be measured_j,G_p)；

(3) rock T2-G experiment to be measured gathers t₀, NE1 Auto-matching

The first step: automatic search coupling are applicable to the t of rock T2-G experiment to be measured according to the following steps₀Size

a)t₀Initialize;

b)NE1_min＝1、NE1_max＝10t₀, substitution formula (4) calculates corresponding echo amplitude b_1min、b_1max；

If c) meet b_1min≤0.1b_1maxOr t₀≥T2_gS, t stops search₀，t₀Currency be exactly rock T2 to be measured ?G experimentOptimum value; Otherwise t₀Automatically add 0.1ms and return to step and b) continue search, until satisfy condition;

Second step: at definite t₀Size after, automatic search coupling are applicable to the ginseng of rock T2-G to be measured experiment according to the following stepsThe combination of number NE1

A) number of combinations of NE1 is 5, and NE1₁＝1、NE1₅＝10t₀, substitution formula (4) calculates corresponding echo amplitudeb₁₁、b₁₅，Δb＝b₁₅-b₁₁, assignment NE1₂＝NE1₁+1；

B) calculate NE1₂Corresponding echo amplitude b₁₂，Δb₁₂＝b₁₂-b₁₁；

If c) meet Δ b/8≤Δ b₁₂≤ Δ b/3, NE1 stops search₂; Otherwise NE1₂＝NE1₂+ 1, and return to step b)Continue search NE1₂, until satisfy condition;

D) at NE1₂After coupling finishes, assignment NE1₃＝NE1₂+1；

E) calculate NE1₃Corresponding echo amplitude b₁₃，Δb₁₃＝b₁₃-b₁₂；

If f) meet Δ b/8≤Δ b₁₃≤ Δ b/3, NE1 stops search₃; Otherwise NE1₃＝NE1₃+ 1, and return to step and e) continueContinuous search NE1₃, until satisfy condition;

G) at NE1₃After coupling finishes, assignment NE1₄＝NE1₃+1；

H) calculate NE1₄Corresponding echo amplitude b₁₄，Δb₁₄＝b₁₄-b₁₃；

If i) meet Δ b/8≤Δ b₁₄≤ Δ b/3, NE1 stops search₄; Otherwise NE1₄＝NE1₄+ 1, and return to step h)Continue search NE1₄, until satisfy condition;

j)NE1＝1、NE1₂、NE1₃、NE1₄、10t₀It is exactly the acquisition parameter that is applicable to rock T2-G experiment to be measured;

Above-mentioned steps adopts programming software programming to realize.

2. rock T2-G experiment acquisition parameter automatic matching method according to claim 1, is characterized in that: step (1)In, the echo sounding size of long and short echo sounding cpmg sequence row is respectively TE_L＝2.4ms，TE_S＝0.1ms。