CN105317429A - Method for determining content of shale stratum kerogen - Google Patents

Abstract

The invention discloses a method for determining the content of shale stratum kerogen. The method includes the steps that a shale stratum volume model formed by framework mineral, kerogen and holes is established, wherein gas and water are included in the holes; a log response equation of a shale stratum under different volume content parameter conditions is established based on the volume model, and the error of the response equation and the measuring error are determined; an actual logging curve is collected, the mass content of shale stratum mineral is adopted as a constraint condition, and an objective function for well logging interpretation is established according to the logging response equation, the error of the response equation and the measuring error; the optimal volume content parameter enabling the objective function to achieve the minimum value is calculated, and a forward modeling result curve of logging responses corresponding to the optimal volume content parameter is drawn; whether the forward modeling result curve of the logging responses is matched with the actual logging curve or not is checked, and the kerogen volume content in the shale stratum optimal volume content parameter corresponding to the matched forward modeling result curve serves as a determination result.

Description

A kind of method determining shale formation kerogen content

Technical field

The present invention relates to shale oil gas exploration development technique field, particularly relate to a kind of method determining shale formation kerogen content.

Background technology

Shale oil gas is stored in oil in the heavier pulveryte of mud stone, shale or aleuritic texture or natural gas.Because shale has very large difference on mineral composition, physical property and seepage characteristic with sandstone, therefore, traditional well log interpretation Theories and methods is not suitable for shale oil gas-bearing formation.

Kerogen is the important component part in shale formation, and kerogen content directly affects adsorbed gas content, and kerogen content is more, and the adsorbed gas in shale formation is higher.Therefore, accurately identify that kerogenic content can evaluate raw hydrocarbon potentiality and the absorption tolerance of shale formation.

Have the kerogenic method for solving of two kinds of shale formations at present, one utilizes empirical formula to calculate kerogen content (Thaimar, 2011) by organic content; Another kind calculates (Herron, 2000) according to nuclear magnetic resonance log in conjunction with porosity logs.

In front a kind of method shale formation, kerogen and organic content relation are not completely the same, owing to being subject to the impact of the aspect such as maturity of organic matter, Kerogen, the transformational relation of different shale area between them is different, determines that conversion coefficient needs experimental technique and empirical method to determine.A kind of rear method utilizes NMR logging data to obtain effecive porosity size, utilize compensation sound wave, lithology and density logging, compensated neutron log opisometer calculates total porosity size, the difference of total porosity and effecive porosity is kerogen degree of porosity, and this method exists significant limitation.Such as, when not gathering NMR logging data, a kind of rear method can not be applied.

Therefore, a kind of method utilizing Using Conventional Logs determination shale formation kerogen content is needed badly.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, propose a kind of method determining shale formation kerogen content, comprise the following steps:

Set up the shale formation volume-based model be made up of matrix mineral, kerogen and hole, its mesopore comprises gas and water;

Based on the log response equation of described volume-based model structure shale formation under different volumes content parameter condition, determine response equation error and measure error;

Gather practical logging curve, with shale formation mineral quality content for constraints, according to described log response equation, response equation error and measure error set up the object function of well log interpretation;

Calculating makes described object function obtain the optimum volume content parameter of minimum value, and that draws log response corresponding to optimum volume content parameter just drills result curve;

Check described log response just drill result curve whether with practical logging Curve Matching, coupling just drilled kerogen volume content in the optimum volume content parameter of shale formation corresponding to result curve as determination result.

According to one embodiment of present invention, described shale formation volume-based model is:

The shale formation of unit volume comprises the multiple matrix mineral of local uniform, kerogen and hole, and its mesopore comprises gas and water, meets

$\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j+V_K+{\mathrm{\φ}}_g+{\mathrm{\φ}}_w=1;$

Wherein V _jfor jth kind matrix mineral volume content, V _kfor kerogen volume content, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water, N is matrix mineral quantity.

According to one embodiment of present invention, the log response equation of described structure shale formation under different volumes content parameter condition comprises:

Borehole compensated sonic log curve response equation $\mathrm{AC}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MAC}}_j+V_K{\mathrm{AC}}_K+{\mathrm{\φ}}_g{\mathrm{AC}}_g+{\mathrm{\φ}}_w{\mathrm{AC}}_w,$

Wherein MAC _jfor the sound wave skeleton value that jth kind matrix mineral is corresponding; AC _k, AC _g, AC _wthe sound wave skeleton value of kerogen, gas and water respectively;

Compensated neutron log curve response equation

$\mathrm{CNL}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MCNL}}_j+V_K{\mathrm{CNL}}_K+{\mathrm{\φ}}_g{\mathrm{CNL}}_g+{\mathrm{\φ}}_w{\mathrm{CNL}}_w,$

Wherein MCNL _jfor the neutron skeleton value that jth kind matrix mineral is corresponding; CNL _k, CNL _g, CNL _wthe neutron skeleton value of kerogen, gas and water respectively;

Compensated density log curve response equation

$\mathrm{DEN}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MDEN}}_j+V_K{\mathrm{DEN}}_K+{\mathrm{\φ}}_g{\mathrm{DEN}}_g+{\mathrm{\φ}}_w{\mathrm{DEN}}_w,$

Wherein MDEN _jfor the density skeleton value that jth kind Mineral pairs is answered; DEN _k, DEN _g, DEN _wthe density skeleton value of kerogen, gas and water respectively;

V in above formula _jfor jth kind matrix mineral volume content, V _kfor kerogen volume content, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water, N is matrix mineral quantity.

According to one embodiment of present invention, described response equation error comprises:

Acoustic logging response error in equation wherein, δ Δ t _mf, δ Δ t _ibe respectively the compensation sound wave error of F and mineral, V _jfor jth kind matrix mineral volume content, φ is degree of porosity;

Compensated neutron log response equation error wherein, δ CNL _mf, δ CNL _ibe respectively the compensated neutron error of F and mineral;

Compensated density log response equation error wherein, δ ρ _mf, δ ρ _ibe respectively the compensation density error of F and mineral;

V in above formula _ibe i-th kind of matrix mineral volume content, φ is degree of porosity, and N is matrix mineral quantity.

According to one embodiment of present invention, the object function of described well log interpretation is:

$F(x,a)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\frac{{[a_i-f_i(x,z)]}^2}{{\mathrm{\σ}}_i^2+{\mathrm{\τ}}_i^2}+\underset{j=1}{\overset{p}{\mathrm{\Σ}}}\frac{g_j^2\left(x\right)}{{\mathrm{\τ}}_j},$

Wherein, a _ibe i-th kind of log actual measured value, x=(V ₁... V _j, V _k, φ _g, φ _w) be shale formation volume content parameter, z is current depth-logger, σ _ibe the measure error of i-th kind of log, τ _ifor i-th kind of log response equation error of structure, f _i(x, z) i-th kind of log response for constructing when the z degree of depth, m is the kind of log;

G _jx jth kind constraints that () is x, τ _jfor jth kind constraint error, p is constraint number.

According to one embodiment of present invention, the constraints in the object function of described well log interpretation comprises:

wherein, V _jfor the volume content of jth kind shale formation matrix mineral, w _jfor the mineral quality content of shale formation, ρ _bfor density log value, ρ _mAfor mineral skeletal density.

According to one embodiment of present invention, calculate the optimum volume content parameter making described object function obtain minimum value to comprise:

The BFGS variable-metric method determination direction of search is utilized to be wherein for direction matrix, represent the gradient of object function, in the direction of search upper any point is expressed as (x, a) is converted to one-variable function φ (t) to objective function F;

DSPOW parabolic interpolation is utilized to ask for the minimum point t of one-variable function φ (t) ₀, according to t ₀determine the optimum volume content parameter x=of shale formation (V ₁... V _j, V _k, φ _g, φ _w).

According to one embodiment of present invention, just the drilling result curve and whether comprise with practical logging Curve Matching of the described log response of described inspection: draw the confidential interval just drilling curve according to practical logging curve, response equation error and measure error wherein a _ibe i-th kind of log actual measured value; σ _iand τ _icorrespond to measure error and log response equation error;

When described log response just drill result curve be in just drill curve confidential interval in time, the described log response of described inspection just drill result curve and practical logging Curve Matching.

According to one embodiment of present invention, the measure error of described i-th kind of log is 5% of actual measurement numerical value size.

According to one embodiment of present invention, described shale formation mineral quality content is captured interpretation of logging data by sample-pretreatment or ECS element and is determined.

Present invention offers following beneficial effect: according to mineral quality explanation results, shale formation mineral volume, kerogen volume and degree of porosity size is calculated in conjunction with the compensation sound wave in Using Conventional Logs, compensated neutron and density log Data Inversion, shale formation kerogen content can be identified fast, decrease the process of core experiment determination kerogen content, save expense and time.

Other features and advantages of the present invention will be set forth in the following description, and partly become apparent from manual, or understand by implementing the present invention.Object of the present invention and other advantages realize by structure specifically noted in manual, claims and accompanying drawing and obtain.

Accompanying drawing explanation

Fig. 1 is the technical thought schematic diagram of the embodiment of the present invention;

Fig. 2 is the flow chart of steps of the method for the determination shale formation kerogen content of the embodiment of the present invention one;

Fig. 3 is the shale formation volume-based model schematic diagram of the embodiment of the present invention one;

Fig. 4 is certain well shale formation kerogen content inversion result in the Practical Project of the embodiment of the present invention two.

Detailed description of the invention

Describe embodiments of the present invention in detail below with reference to accompanying drawing, to the present invention, how application technology means solve technical problem whereby, and the implementation procedure reaching technique effect can fully understand and implement according to this.It should be noted that, only otherwise form conflict, each feature in various embodiments of the present invention and each embodiment can be combined with each other, and the technical scheme formed is all within protection scope of the present invention.

In addition, can perform in the computer system of such as one group of computer executable instructions in the step shown in the flow chart of accompanying drawing, and, although show logical order in flow charts, but in some cases, can be different from the step shown or described by order execution herein.

As shown in Figure 1, the technical thought of the embodiment of the present invention is, the theoretical log value of tectonic response equation (compensation sound wave, compensated neutron, compensation density), according to mineral quality content results and Using Conventional Logs (compensation sound wave, compensated neutron, compensation density) complex optimum Inversion Calculation shale formation mineral volume, kerogen volume and degree of porosity size.

embodiment one

The present embodiment provides a kind of method determining shale formation kerogen content, elaborates to the method that the present embodiment provides below in conjunction with Fig. 2.

In step s 201, the shale formation volume-based model be made up of matrix mineral, kerogen and hole is set up.With reference to figure 3, the shale formation of unit volume comprises the multiple matrix mineral of local uniform, kerogen and hole, and its mesopore comprises gas and water, meets

$\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j+V_K+{\mathrm{\φ}}_g+{\mathrm{\φ}}_w=1;$

Wherein V _jfor jth kind matrix mineral volume content, V _kfor kerogen volume content, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water, N is matrix mineral quantity.V ₁... V _j, V _k, φ _g, φ _wrepresent the volume content at a certain depth of stratum place.

Concrete, different regions mineral composition is not identical, and common matrix mineral comprises: illite, chlorite, montmorillonite, quartz, feldspar, mica calcite, dolomite, anhydrite and pyrite etc.Under normal circumstances, siliceous in shale formation comprises quartz, feldspar and mica, calcareously comprises calcite and dolomite, and shale comprises montmorillonite, illite and chlorite.

In step S202, based on the log response equation of described volume-based model structure shale formation under different volumes content parameter condition, determine response equation error and measure error.

Log response equation under shale formation different matrix mineral, kerogen and hole condition is:

$f_i=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MA}}_{\mathrm{ij}}+V_K{\mathrm{MA}}_{\mathrm{iK}}+{\mathrm{\φ}}_g{\mathrm{MA}}_{\mathrm{ig}}+{\mathrm{\φ}}_w{\mathrm{MA}}_{\mathrm{iw}},$

Wherein f _iit is the response results of i-th kind of log; V _jfor jth kind shale formation mineral volume content; V _kfor kerogen volume content; φ _gfor volume concentration of gas phase, φ _wfor the volume content of water; MA _ijit is the skeleton value of i-th kind of log corresponding jth kind mineral; MA _iK, MA _ig, MA _iwbe respectively i-th kind of curve skeleton value that kerogen, gas and water are corresponding, N is matrix mineral quantity.

In the present embodiment, the borehole compensated sonic log under different volumes content parameter condition, compensated neutron log and compensated density log response equation is constructed:

Borehole compensated sonic log curve response equation $\mathrm{AC}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MAC}}_j+V_K{\mathrm{AC}}_K+{\mathrm{\φ}}_g{\mathrm{AC}}_g+{\mathrm{\φ}}_w{\mathrm{AC}}_w,$

Wherein MAC _jfor the sound wave skeleton value that jth kind matrix mineral is corresponding; AC _k, AC _g, AC _wthe sound wave skeleton value of kerogen, gas and water respectively;

Compensated neutron log curve response equation

$\mathrm{CNL}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MCNL}}_j+V_K{\mathrm{CNL}}_K+{\mathrm{\φ}}_g{\mathrm{CNL}}_g+{\mathrm{\φ}}_w{\mathrm{CNL}}_w,$

Wherein MCNL _jfor the neutron skeleton value that jth kind matrix mineral is corresponding; CNL _k, CNL _g, CNL _wthe neutron skeleton value of kerogen, gas and water respectively;

Compensated density log curve response equation

$\mathrm{DEN}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MDEN}}_j+V_K{\mathrm{DEN}}_K+{\mathrm{\φ}}_g{\mathrm{DEN}}_g+{\mathrm{\φ}}_w{\mathrm{DEN}}_w,$

Wherein MDEN _jfor the density skeleton value that jth kind Mineral pairs is answered; DEN _k, DEN _g, DEN _wthe density skeleton value of kerogen, gas and water respectively.

Because logger and data collecting system all exist certain measure error, the measure error σ of certain log response in the present embodiment _iget 5% of its actual measurement numerical values recited.

Any well logging equation is all the theoretical formula drawn according to log interpretation model actual formation being done to set up after a series of mathematical physics simplifies, and there is certain response equation error τ in response equation _i.

In step S202, response equation error comprises:

Acoustic logging response error in equation wherein, δ Δ t _mf, δ Δ t _ibe respectively the compensation sound wave error of F and matrix mineral, V _jfor jth kind matrix mineral volume content, φ is degree of porosity, φ=φ _g+ φ _w, as described above, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water;

Compensated neutron log response equation error ${\mathrm{\τ}}_{\mathrm{CNL}}={\left(\mathrm{\φ\δ}{\mathrm{CNL}}_{\mathrm{mf}}\right)}^2+\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(V_i\mathrm{\δ}{\mathrm{CNL}}_i\right)}^2,$

Wherein, δ CNL _mf, δ CNL _ibe respectively the compensated neutron error of F and matrix mineral;

Compensated density log response equation error

Wherein, δ ρ _mf, δ ρ _ibe respectively the density error of F and matrix mineral.

In step S203, gather practical logging curve, with shale formation mineral quality content for constraints, according to described log response equation, response equation error and measure error set up the object function of well log interpretation:

$F(x,a)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\frac{{[a_i-f_i(x,z)]}^2}{{\mathrm{\σ}}_i^2+{\mathrm{\τ}}_i^2}+\underset{j=1}{\overset{p}{\mathrm{\Σ}}}\frac{g_j^2\left(x\right)}{{\mathrm{\τ}}_j},$

Wherein,

A _ibe i-th kind of log actual measured value, %;

X=(V ₁... V _j, V _k, φ _g, φ _w) be shale formation volume content parameter, %;

Z is current depth-logger, m;

σ _iit is the measure error of i-th kind of log;

τ _ifor i-th kind of log response equation error of structure;

F _i(x, z) i-th kind of log response for constructing when the z degree of depth;

M is the kind of log;

G _jx jth kind constraints that () is x;

τ _jfor jth kind constraint error;

P is constraint number.

In the present embodiment, f _i(x, z) is respectively borehole compensated sonic log curve response AC, compensated neutron log curve response CNL, compensated density log curve response DEN.

Preferably, in the present embodiment using the mineral quality content of shale formation as constraints:

Constraints g _jx () is expressed as wherein,

V _jfor the volume content of jth kind shale formation matrix mineral, w _jfor the mineral quality content of shale formation, ρ _bfor density log value, ρ _mAfor mineral skeletal density.Shale formation mineral quality content w _jcapture well-log information by sample-pretreatment or ECS element to determine.

Corresponding qualitative restrain error τ _jvalue is 1.

Be not limited thereto, also comprise following constraints:

V _j>=0, j is mineral species; φ _g>=0, φ _w>=0.

In step S204, calculate and make described object function obtain the optimum volume content parameter of minimum value, that draws log response corresponding to optimum volume content parameter just drills result curve.

By target component F (x, a) can build the Mathematical Modeling of optimum logging interpretation:

$\min F(x,a)=\min \underset{i=1}{\overset{m}{\mathrm{\Σ}}}\frac{{[a_i-f_i(x,z)]}^2}{{\mathrm{\σ}}_i^2+{\mathrm{\τ}}_i^2}+\underset{j=1}{\overset{p}{\mathrm{\Σ}}}\frac{g_j^2\left(x\right)}{{\mathrm{\τ}}_j},$

Calculating makes described objective function F, and (x a) obtains the optimum volume content parameter x=(V of minimum value ₁... V _j, V _k, φ _g, φ _w), the immediate volume content parameter with actual volume content can be determined.

Preferably, the BFGS variable-metric method determination direction of search is utilized to be in the present embodiment in the direction of search on can find the minimum of object function.

Wherein positive definite symmetric matrices for Scale Matrixes, (x, a) in the gradient at kth time iteration point place, in the kth time direction of search to represent objective function F upper any point is expressed as (x a) is converted to one-variable function φ (t) to objective function F.

DSPOW parabolic interpolation is utilized to ask for the minimum point t of one-variable function φ (t) ₀, according to t ₀determine the optimum volume content parameter x=of shale formation (V ₁... V _j, V _k, φ _g, φ _w).

Above BFGS variable-metric method and DSPOW parabolic interpolation well known to a person skilled in the art well log interpretation optimal method, can with reference to " Teaching Materials at College level: log data processing and integrated interpretation " (harmony generation and work, on August 1st, 2007 publishes).

In step S205, check described log response just drill result curve whether with practical logging Curve Matching, coupling just drilled kerogen volume content in volume content parameter corresponding to result curve as determination result.

Concrete, according to practical logging curve, response equation error and measure error draw just drilling curve confidential interval wherein a _ibe i-th kind of log actual measured value; σ _iand τ _icorrespond to measure error and log response equation error;

When described log response just drill result curve be in just drill curve confidential interval in time, the described log response of described inspection just drill result curve and practical logging Curve Matching, namely the optimum volume content parameter x=(V that obtains of inverting is described ₁... V _j, V _k, φ _g, φ _w) fully react actual volume content in shale formation.

In addition, can according to the size of object function optimal value inspection log response just drill result curve whether with practical logging Curve Matching.The optimum volume content parameter x calculated for utilizing optimal method ^*, object function optimal value F ^*(x ^*, a) ≈ 0.F ^*(x ^*, be a) weigh just to drill the total mark whether log approaches practical logging curve.F ^*(x ^*, a) value is less, illustrate log response just drill result curve and practical logging Curve Matching degree is better.

In sum, the method that the embodiment of the present invention provides can according to shale formation mineral quality explanation results, shale formation mineral volume, kerogen volume and degree of porosity size is calculated in conjunction with the compensation sound wave in Using Conventional Logs, compensated neutron and density log Data Inversion, shale formation kerogen content can be identified fast, decrease the process of core experiment determination kerogen content, save expense and time.

embodiment two

Fig. 4 is certain well shale formation kerogen content inversion result in the Practical Project of the embodiment of the present invention two.Southwest China block well ECS geochemical well logging data is utilized to carry out inverting.This block high-quality shale lithology is mainly based on yellow-gray shale, silty shale folder thin layer lenticular limestone, shale formation mineral kerogen content is determined to utilize geochemical well logging material computation mineral quality result as input curve, carry out inverting in conjunction with the compensation sound wave in conventional logging, compensation density and compensated neutron data, inversion result as shown in Figure 4.

In Fig. 4, first is utilize the mineral quality content of ECS geochemical well logging material computation to combine, second to the 4th road is compensation sound wave, the forward response value of compensation density, compensation density and just drilling the confidential interval of curve, 6th road is object function optimal value, 7th road is the mineral volume content of inverting, kerogen and degree of porosity size, and its porosity size comprises the volume content of gas and water.

In Fig. 4, first is combine according to the mineral quality content of geochemical well logging material computation, indicates following mass content respectively: pyrite WPYR, illite WILL, chlorite WCHL, montmorillonite WMON, quartzy WQRZ, feldspar WFLD, calcite WCLC, anhydrite WANH, mica WMIC and dolomite WDOL.

Second to the 4th road is compensation sound wave, the forward response value of compensation density, lithology and density logging and just drilling the confidential interval of curve, and the 5th road is depth track, and the 6th road is object function optimal value.

In second, curve A CL and ACH represents that compensation sound wave is just drilling the confidential interval of curve; Curve A C represents actual borehole compensated sonic log curve; Curve A CT represents the borehole compensated sonic log response optimal value just drilled.Similar, curve C NLL and CNLH represents that compensated neutron is just drilling the confidential interval of curve; Curve C NL represents actual compensated neutron log curve; Curve C NLT represents the compensated neutron log response optimal value just drilled.Similar, curve D ENL and DENH represents that compensation density is just drilling the confidential interval of curve; Curve D EN represents actual compensated density log curve; Curve D ENT represents the compensated density log response optimal value just drilled.

7th road is the volume content of the mineral volume content of inverting, kerogen, gas and water.Indicate following volume content respectively: pyrite VPYR, illite VILL, chlorite VCHL, montmorillonite VMON, quartzy VQRZ, feldspar VFLD, calcite VCLC, anhydrite VANH, mica VMIC and dolomite VDOL, and kerogen VKER, gas VPRG, water VPGW and other volume content VSM.Thus can accurately obtain at the kerogenic volume content VKER of Different Strata depth.

Although embodiment disclosed in this invention is as above, the embodiment that described content just adopts for the ease of understanding the present invention, and be not used to limit the present invention.Technician in any the technical field of the invention; under the prerequisite not departing from spirit and scope disclosed in this invention; any amendment and change can be done what implement in form and in details; but scope of patent protection of the present invention, the scope that still must define with appending claims is as the criterion.

Claims (10)

1. determine a method for shale formation kerogen content, it is characterized in that, comprise the following steps:

Set up the shale formation volume-based model be made up of matrix mineral, kerogen and hole, its mesopore comprises gas and water;

Based on the log response equation of described volume-based model structure shale formation under different volumes content parameter condition, determine response equation error and measure error;

Gather practical logging curve, with shale formation mineral quality content for constraints, according to described log response equation, response equation error and measure error set up the object function of well log interpretation;

Calculating makes described object function obtain the optimum volume content parameter of minimum value, and that draws log response corresponding to optimum volume content parameter just drills result curve;

Check described log response just drill result curve whether with practical logging Curve Matching, coupling just drilled kerogen volume content in the optimum volume content parameter of shale formation corresponding to result curve as determination result.

2. method according to claim 1, is characterized in that, described shale formation volume-based model is:

The shale formation of unit volume comprises the multiple matrix mineral of local uniform, kerogen and hole, and its mesopore comprises gas and water, meets

$\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j+V_K+{\mathrm{\φ}}_g+{\mathrm{\φ}}_w=1;$

Wherein V _jfor jth kind matrix mineral volume content, V _kfor kerogen volume content, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water, N is matrix mineral quantity.

3. method according to claim 2, is characterized in that, the log response equation of described structure shale formation under different volumes content parameter condition comprises:

Borehole compensated sonic log curve response equation $\mathrm{AC}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MAC}}_j+V_K{\mathrm{AC}}_K+{\mathrm{\φ}}_g{\mathrm{AC}}_g+{\mathrm{\φ}}_w{\mathrm{AC}}_w,$

Wherein MAC _jfor the sound wave skeleton value that jth kind matrix mineral is corresponding; AC _k, AC _g, AC _wthe sound wave skeleton value of kerogen, gas and water respectively;

Compensated neutron log curve response equation

$\mathrm{CNL}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MCNL}}_j+V_K{\mathrm{CNL}}_K+{\mathrm{\φ}}_g{\mathrm{CNL}}_g+{\mathrm{\φ}}_w{\mathrm{CNL}}_w,$

Wherein MCNL _jfor the neutron skeleton value that jth kind matrix mineral is corresponding; CNL _k, CNL _g, CNL _wthe neutron skeleton value of kerogen, gas and water respectively;

Compensated density log curve response equation

$\mathrm{DEN}=\underset{j=1}{\overset{N}{\mathrm{\Σ}}}{V}_j{\mathrm{MDEN}}_j+V_K{\mathrm{DEN}}_K+{\mathrm{\φ}}_g{\mathrm{DEN}}_g+{\mathrm{\φ}}_w{\mathrm{DEN}}_w,$

Wherein MDEN _jfor the density skeleton value that jth kind Mineral pairs is answered; DEN _k, DEN _g, DEN _wthe density skeleton value of kerogen, gas and water respectively;

V in above formula _jfor jth kind matrix mineral volume content, V _kfor kerogen volume content, φ _gfor volume concentration of gas phase, φ _wfor the volume content of water, N is matrix mineral quantity.

4. method according to claim 3, is characterized in that, described response equation error comprises:

Acoustic logging response error in equation wherein, δ Δ t _mf, δ Δ t _ibe respectively the compensation sound wave error of F and mineral;

Compensated neutron log response equation error ${\mathrm{\τ}}_{\mathrm{CNL}}={\left(\mathrm{\φ\δ}{\mathrm{CNL}}_{\mathrm{mf}}\right)}^2+\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{\left(V_i\mathrm{\δ}{\mathrm{CNL}}_i\right)}^2,$ Wherein, δ CNL _mf, δ CNL _ibe respectively the compensated neutron error of F and mineral;

Compensated density log response equation error wherein, δ ρ _mf, δ ρ _ibe respectively the compensation density error of F and mineral;

In above formula, V _ibe i-th kind of matrix mineral volume content, φ is degree of porosity, and N is matrix mineral quantity.

5. method according to claim 4, is characterized in that, the object function of described well log interpretation is:

$F(x,a)=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}\frac{{[a_i-f_i(x,z)]}^2}{{\mathrm{\σ}}_i^2+{\mathrm{\τ}}_i^2}+\underset{j=1}{\overset{p}{\mathrm{\Σ}}}\frac{g_j^2\left(x\right)}{{\mathrm{\τ}}_j},$

Wherein, a _ibe i-th kind of log actual measured value, x=(V ₁... V _j, V _k, φ _g, φ _w) be shale formation volume content parameter, z is current depth-logger, σ _ibe the measure error of i-th kind of log, τ _ifor i-th kind of log response equation error of structure, f _i(x, z) i-th kind of log response for constructing when the z degree of depth, m is the kind of log;

G _jx jth kind constraints that () is x, τ _jfor jth kind constraint error, p is constraint number.

6. method according to claim 5, is characterized in that, the constraints in the object function of described well log interpretation comprises:

wherein, V _jfor the volume content of jth kind shale formation matrix mineral, w _jfor the mineral quality content of shale formation, ρ _bfor density log value, ρ _mAfor mineral skeletal density.

7. method according to claim 6, is characterized in that, calculates the optimum volume content parameter making described object function obtain minimum value and comprises:

The BFGS variable-metric method determination direction of search is utilized to be wherein for direction matrix, represent the gradient of object function, in the direction of search upper any point is expressed as (x, a) is converted to one-variable function φ (t) to objective function F;

DSPOW parabolic interpolation is utilized to ask for the minimum point t of one-variable function φ (t) ₀, according to t ₀determine the optimum volume content parameter x=of shale formation (V ₁... V _j, V _k, φ _g, φ _w).

8. method according to claim 6, is characterized in that, just the drilling result curve and whether comprise with practical logging Curve Matching of the described log response of described inspection:

The confidential interval just drilling curve is drawn according to practical logging curve, response equation error and measure error wherein a _ibe i-th kind of log actual measured value; σ _iand τ _icorrespond to measure error and log response equation error;

When described log response just drill result curve be in just drill curve confidential interval in time, the described log response of described inspection just drill result curve and practical logging Curve Matching.

9. the method according to claim 7 or 8, is characterized in that, the measure error of described i-th kind of log is 5% of actual measurement numerical value size.

10. the method according to claim 7 or 8, is characterized in that, described shale formation mineral quality content is captured interpretation of logging data by sample-pretreatment or ECS element and determined.