CN102735821A - Method and system for testing abrasiveness of rock - Google Patents

Abstract

The invention provides a method and a system for testing the abrasiveness of rock. The method for testing the abrasiveness of the rock comprises the following steps of: predetermining a relation between an inner friction angle of the rock and a granularity fractal dimension of the rock; preparing a filed rock sample and testing the granularity fractal dimension of the field rock sample; and determining the inner friction angle of the field rock sample according to the tested granularity fractal dimension of the field rock sample and the predetermined relation. Therefore, the abrasiveness of the rock can be determined.

Description

Measure the method and system of rock abrasivenesss

Technical field

The present invention relates to drilling technique, relate in particular to the method for evaluation of rock abrasive property.

Technical background

In the field of petroleum prospecting, exploitation etc., carry out drilling well widely.Drilling well is to utilize drill bit to creep into the process of rock stratum.In the process of drilling well, drill bit receives wearing and tearing and the rust of rock, thereby after using a period of time, needs replacing.The abrasive property of rock is a key factor that influences bit wear.Grasp the abrasive property of rock exactly, all have great significance for the bit type selection in the drilling engineering, parameter optimization and the formulation of each item technical measures etc.

The abrasive property of rock is the ability of rock wearing and tearing bit cutting edge material.The method of existing mensuration rock abrasivenesss comprises that mainly the mill method of boring, filing, micro drill creep into method and rubbing wear method.

This several method all belongs to the laboratory experiment method, exists many problems, such as: 1. the gained result is difficult to reflect that rock is at underground residing high temperature and high pressure environment; 2. be difficult to reflect the variation of heterogeneity formation rock character comprehensively; 3. receive the restriction of rock core information, the data that record in the big zone of lithological change possibly lack comparative; 4. be difficult to set up regional rock abrasivenesss serial section; 5. spend great amount of manpower and fund.

Summary of the invention

The present invention proposes in view of these problems of the prior art.

Inventor of the present invention starts with from the micromechanism of rock, and the relation according to the angle of internal friction of the abrasive property of rock and rock in conjunction with rock mechanics characterisitic parameter test result, is applied to Fractal Geometry Theory in the mensuration of rock abrasivenesss.

Inventor of the present invention finds that through a large amount of research there are close correlativity in internal friction angle of rock and rock particles granularity fractal dimension.

In one aspect of the invention, proposed a kind of method of measuring the abrasive property of rock, this method may further comprise the steps: step 1: confirm the relation between the granularity fractal dimension of angle of internal friction and rock of rock in advance; Step 2: obtain on-the-spot rock specimens, measure its granularity fractal dimension; Step 3:, confirm the angle of internal friction of said on-the-spot rock specimens according to the granularity fractal dimension and the said predetermined relation of the said on-the-spot rock specimens of being measured.

In another aspect of the present invention, proposed a kind of method of measuring the abrasive property of rock, this method may further comprise the steps: step 1: obtain on-the-spot rock specimens, measure its granularity fractal dimension; Step 2:, confirm the angle of internal friction of said on-the-spot rock specimens according to the relation between the granularity fractal dimension of the angle of internal friction of the granularity fractal dimension of the said on-the-spot rock specimens of being measured and predetermined rock and rock.

In another aspect of the present invention, proposed a kind of system that measures the abrasive property of rock, this system comprises: storage part, and it stores the relation between the granularity fractal dimension of angle of internal friction and rock of predetermined rock; Granularity fractal dimension determination part, it measures the granularity fractal dimension of on-the-spot rock specimens; Calculating part, it confirms the angle of internal friction of said on-the-spot rock specimens according to the said relation of storing in the granularity fractal dimension of the said on-the-spot rock specimens of being measured and the said storage part.

According to the present invention, can utilize landwaste (sand sample) to come in the scene with boring the evaluation of rock abrasive property.The present invention has important and practical meanings for the bit type selection in the drilling engineering, parameter optimization and the formulation of each item technical measures etc.

Description of drawings

Fig. 1 shows an example of the capillary pressure curve of rock sample;

The residual error that Fig. 2 shows the linear regression of data shown in Figure 1 distributes;

Fig. 3 shows the linear regression result's of internal friction angle of rock and pore fractal dimension a example;

The residual error that Fig. 4 shows linear regression shown in Figure 3 distributes;

Fig. 5 shows linear regression result's the example of the sreen analysis data of rock sample;

The residual error that Fig. 6 shows linear regression shown in Figure 5 distributes;

Fig. 7 shows the linear regression result's of rock grain size fractal dimension and angle of internal friction a example;

The residual error that Fig. 8 shows linear regression shown in Figure 7 distributes;

Fig. 9 shows the process flow diagram of the rock abrasivenesss assay method of first embodiment of the invention;

Figure 10 shows the block diagram of the rock abrasivenesss mensuration system of third embodiment of the invention.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, be elaborated below in conjunction with the accompanying drawing specific embodiments of the invention.

The abrasive property of rock and the angle of internal friction of rock have good correlativity, and the angle of internal friction of rock is big more, and then the abrasive property of rock is big more.Therefore, generally adopt the angle of internal friction of rock to be used as weighing the index of rock abrasivenesss.

On the other hand, fractal theory is put forward in nineteen seventies by French mathematician Man Debu rood (B.B.Mandelbrot).At present; The fractal research of rock mechanics has begun to take shape three basic orientation; One is based on the basic assumption that the rock natural structure can be regarded fractal structure abstractively as; Inquire into the mathematics mechanical foundation of ROCK MECHANICS RESEARCH in the fractal space, construct its basic mathematics mechanical frame, comprise physical mechanics amount and the physical mechanics law re-recognizing and set up in the fractal space; The 2nd, fractal phenomenon, Fractal Properties and fractal mechanism in the further investigation rock mechanics, the fractal mechanism and the forming process of some the complicated physical mechanics behaviors in emphasis announcement and the quantitative description rock mechanics; The 3rd, the practical applications of the fractal research of rock mechanics is applied to solve engineering problem with achievement in research, promotes or realize quantification, precision and the predictability of complicated problems of rock mechanics.But in association area, also do not have to propose in the mensuration of rock abrasivenesss, to use fractal concept.

Inventor of the present invention studies the fractal characteristic of rock particles and the relation between the abrasive property (being the angle of internal friction of rock).

The fractal characteristic of rock particles can comprise pore fractal dimension and grain graininess fractal dimension.

At first, the inventor studies the correlativity between blowhole fractal dimension and the internal friction angle of rock.

According to the fractal geometry principle, if distributing, blowhole meets fractal structure, then rock mesoporosity radius has following power function relationship greater than the number of apertures N (r) of r with r:

$N\left(r\right)={\∫}_r^{r_{\max }}\mathrm{\ρ}\left(r\right)\mathrm{dr}={\mathrm{Ar}}^{-D_1}---\left(1\right)$

In formula (1): r _MaxBe maximum pore radius in the rock; ρ (r) is the density function of distribution of pores; A is a scale-up factor; D ₁Be the pore fractal dimension.Following formula to the r differentiate, can be obtained the expression formula of distribution of pores density function ρ (r),, can obtain rock mesoporosity radius and be less than the hole of r accumulative total volume V (r) again according to distribution of pores density function ρ (r):

$V\left(r\right)={\&Integral;}_{r_{\min }}^r\mathrm{\&rho;}\left(r\right)\&CenterDot;{\mathrm{<figure-callout\; id="3"\; label="Br"\; filenames="HDA00001860857300011.png,HDA00001860857300012.png"\; state="\{\{state\}\}">Br</figure-callout>}}^3\mathrm{dr}=\frac{{-\mathrm{ABD}}_1}{3-D_1}(r^{3-D_1}-r_{\min }^{3-D_1})---\left(2\right)$

In formula (2): r _MinBe minimum pore radius in the rock; (as if hole is cube to B, then B=1 for the constant relevant with pore texture; As if hole is spheroid, then B=4 π/3).In like manner, can obtain the total pore size volume V of rock _aFor:

$V_a={\&Integral;}_{r_{\min }}^{r_{\max }}\mathrm{\&rho;}\left(r\right)\&CenterDot;{\mathrm{<figure-callout\; id="3"\; label="Br"\; filenames="HDA00001860857300011.png,HDA00001860857300012.png"\; state="\{\{state\}\}">Br</figure-callout>}}^3\mathrm{dr}=\frac{{-\mathrm{ABD}}_1}{3-D_1}(r_{\max }^{3-D_1}-r_{\min }^{3-D_1})---\left(3\right)$

By V (r) and V _aCan obtain pore radius less than the accumulative total volume of voids mark S of r is:

$S={\left(\frac{r}{r_{\max }}\right)}^{3-D_1}---\left(4\right)$

Venturi big or small arbitrarily in the rock is observed the capillary pressure equation to the resistance of oil-gas migration:

$p_c\left(r\right)=\frac{2\mathrm{\&sigma;}\cos \mathrm{\&theta;}}{r}---\left(5\right)$

In formula (5): p _cBe the pairing capillary pressure of pore radius r; σ is the surface tension of liquid, and σ gets 480N/m to mercury; θ is the moisten contact angle of liquid, and mercury θ is got 140 °.

By formula (4), (5) can obtain,

$S={\left(\frac{p_c}{p_{\min }}\right)}^{D_1-3}---\left(6\right)$

In formula (6): p _MinBe maximum pore radius r in the rock _MaxPairing capillary pressure, i.e. entrance capillary pressure.

Right logarithm is taken from formula (6) both sides is got,

lnS=(D ₁-3)lnp _c+(3-D ₁)lnp _min (7)

Formula (7) is explained, if blowhole has the character of fractal structure, and then wetting phase capillary pressure data lnS and lnp _cThe linear dependence relation should be arranged.The related coefficient that provides according to linear regression analysis can be explained the matching degree of pore fractal structure.If the slope of regression straight line is a, then convolution (7) can obtain pore fractal dimension D ₁For:

D ₁=3+a (8)

The inventor has gathered various types of rock core samples (following be also referred to as sometimes " rock specimens " or " rock sample ") from a plurality of oil fields, utilize three rock mechanics simulation test machines that the angle of internal friction of each rock core sample is measured.Table 1 shows the basic condition and the corresponding angle of internal friction of each rock core sample.

Table 1

The relation curve of the capillary pressure of rock and wetting phase (or nonwetting phase) saturation degree is called capillary pressure curve.The method of measuring capillary pressure curve is a lot, and the most frequently used method mainly contains three kinds at present: semi-permeable baffle method, mercury intrusion method and centrifuge method.The great advantage of mercury intrusion method is that measuring speed is fast, and is not strict to shape, the size requirements of rock sample, can measure the capillary pressure of irregular landwaste.Therefore as an example, adopt mercury intrusion method that the capillary pressure of each rock sample is measured in the present invention.

Fig. 1 shows the capillary pressure curve of rock sample 1.According to the computing method of above-mentioned blowhole fractal dimension, determination data shown in Figure 1 is carried out linear regression analysis, obtain regression equation and be: y=-0.68213x+1.24035, related coefficient is-0.99098.Again it is carried out residual analysis, as shown in Figure 2, residual error changes little.According to formula (8), can get the pore fractal dimension D1=3+ (0.68213)=2.31787 of rock sample 1.

All the other 19 rock samples are carried out linear regression and the residual analysis same with rock sample 1, can obtain the pore fractal dimension of all the other 19 rock samples, as shown in table 2.Can know that from table 2 pore texture of each rock sample has tangible fractal characteristic, its hole yardstick is distributed as the power-law distribution of self similarity.

Table 2

Internal friction angle of rock in the table 1 and the data based rock sample numbering of the pore fractal dimension in the table 2 are mapped one by one.Utilize least square method that it is carried out linear regression, its matched curve is as shown in Figure 3, and Fig. 4 shows its residual error and distributes.Its fit equation is y=2.49049x+29.76931, and related coefficient is 0.19733.

Residual analysis by related coefficient 0.19733 and Fig. 4 can know that the correlativity between rock pore structure fractal characteristic and the rock abrasivenesss is relatively poor.

Then the inventor to rock particles granularity fractal dimension and and internal friction angle of rock between correlativity study.

If the rock particles diameter is R, obtaining particle diameter through screen analysis is N (R) greater than the numbers of particles of R, if satisfy:

$N\left(R\right)={\&Integral;}_R^{\&infin;}\mathrm{\&rho;}\left(R\right)\mathrm{dR}={\mathrm{kR}}^{-D_2}---\left(9\right)$

D then ₂Be the grain graininess fractal dimension.Wherein, ρ (R) is the density function of distribution of particles.

If M (R) is the particle accumulative total quality of diameter less than R, M _TBe the gross mass of all particles, size-grade distribution satisfies the Weibull distributed model:

$\frac{M\left(R\right)}{M_T}=1-\exp (-{\left(\frac{R}{\mathrm{\&sigma;}}\right)}^{\mathrm{\&alpha;}})---\left(10\right)$

In the formula: σ is the amount relevant with mean diameter, the maximum particle diameter of getting particle usually; α is a undetermined constant, is called the Weibull modulus.If

can be with following formula by series expansion and cast out second later all, then following formula can be reduced to power law relation commonly used:

$\frac{M\left(R\right)}{M_T}={\left(\frac{R}{\mathrm{\&sigma;}}\right)}^{\mathrm{\&alpha;}}---\left(11\right)$

Can get by formula (9) and (11)

$R^{-D_2-1}~R^{-3}{R}^{\mathrm{\&alpha;}-1}=R^{\mathrm{\&alpha;}-4}---\left(12\right)$

Thereby obtain rock particles granularity fractal dimension D ₂For:

D ₂=3-α (13)

Right logarithm is taken from formula (11) both sides is got,

$\ln \left(\frac{M\left(R\right)}{M_T}\right)=\mathrm{\&alpha;}\ln \left(\frac{R}{\mathrm{\&sigma;}}\right)---\left(14\right)$

Formula (14) is explained, if the rock particles size-grade distribution has fractal characteristic, then With

The linear dependence relation should be arranged, and the straight slope that linear regression analysis provides is Weibull modulus α, just can obtain granularity fractal dimension D by formula (13) again ₂

The inventor carries out sizing assay test after with the rock sample fragmentation shown in the table 1, and test findings is as shown in table 3.

Table 3 test rock sample sreen analysis data (R is a particle diameter, μ m)

The measured data based formula of sreen analysis (14) of each test rock sample is carried out linear regression analysis; Can respectively be tested rock sample size-grade distribution fractal curve; Again by each rock sample size-grade distribution fractal curve, convolution (13) can obtain the granularity fractal dimension and the related coefficient of each rock sample.

Be example still with rock sample 1.The relative granularity value that Fig. 5 records for rock sample 1 is carried out linear regression analysis.Obtaining regression equation is: y=0.80569x+0.78034.By related coefficient 0.96769, can know the regression equation highly significant.Again it is carried out residual analysis, as shown in Figure 6, residual error changes little.Convolution (13) can get the granularity fractal dimension of rock sample 1: D2=3-0.80569=2.19431.

All the other 19 rock samples are carried out linear regression and the residual analysis same with rock sample 1, can obtain the granularity fractal dimension of all the other 19 rock samples, as shown in table 4.Can know that from table 4 each rock particles size-grade distribution of testing rock sample has tangible fractal characteristic, its particle scale is distributed as the power-law distribution of self similarity.

Table 4

In order to study the relation of rock particles granularity fractal characteristic and rock abrasivenesss,, be mapped one by one according to the rock sample numbering with internal friction angle of rock in the table 1 and the granularity fractal dimension data in the table 4.Its matched curve is as shown in Figure 7, and its fit equation is y=14.86488x+1.1118, and related coefficient is 0.85721.Residual analysis is as shown in Figure 8.

Hence one can see that, has higher positive correlation between granularity fractal dimension and the internal friction angle of rock, that is: rock particles granularity fractal dimension is high more, and internal friction angle of rock is big more.In a word, along with rock particles granularity fractal dimension increases, it is big that rock abrasivenesss becomes.Therefore, can judge rock abrasivenesss according to the granularity fractal dimension.

[first embodiment]

According to inventor's above-mentioned research, a kind of method of measuring the abrasive property of rock has been proposed.This method can comprise the following steps: in advance to confirm the relational expression between the granularity fractal dimension of angle of internal friction and rock of rock substantially; The landwaste sample is obtained at the scene, measures its granularity fractal dimension; According to granularity fractal dimension of being measured and above-mentioned relation formula, confirm the angle of internal friction of this landwaste sample.

With reference to Fig. 9 this method is carried out detailed explanation below.In addition, will omit the explanation of repetition below for the part that repeats with foregoing.

At first, in step S11, confirm the relation between the granularity fractal dimension of angle of internal friction and rock of rock.

Particularly, gather a plurality of different rock specimens, for example gather various types of rock specimens from a plurality of oil fields from a plurality of different places.For the representative and popularity of relation between the granularity fractal dimension of the angle of internal friction that guarantees determined rock and rock, need gather rock sample as much as possible from different location as much as possible.

After gathering rock sample, utilize three rock mechanics simulation test machines that the angle of internal friction of each rock sample is measured, obtain the angle of internal friction of each rock sample.The process of utilizing three rock mechanics simulation test machines that the angle of internal friction of each rock sample is measured belongs to known content, and is bright specifically in this omission.

And, rock sample is carried out fragmentation, the rock sample after the fragmentation is carried out the sreen analysis experiment, obtain the sreen analysis data.These sreen analysis data comprise M (R): diameter is less than the particle accumulative total quality of R, M _T: the gross mass of all particles, σ: the amount relevant, the maximum particle diameter of getting particle in the first embodiment with mean diameter.For a plurality of different R, calculate and

respectively

Then; According to formula (14); That kind as shown in Figure 5 is carried out linear regression analysis to and , confirms the value of α.As stated, α is a undetermined constant, is called the Weibull modulus.

$\ln \left(\frac{M\left(R\right)}{M_T}\right)=\mathrm{\&alpha;}\ln \left(\frac{R}{\mathrm{\&sigma;}}\right)---\left(14\right)$

Thus, according to formula (13), calculate the granularity fractal dimension D of each rock sample ₂

D ₂=3-α (13)

After angle of internal friction that has obtained each rock sample and granularity fractal dimension, that kind as shown in Figure 7 is carried out linear fit to the angle of internal friction of each rock sample and the granularity fractal dimension of rock sample, obtains the relational expression of angle of internal friction and granularity fractal dimension.For example, the relational expression that in this embodiment, obtains is suc as formula shown in (15):

Φ＝14.86488D ₂+1.1118 (15)

In the formula, Φ is the angle of internal friction of rock; D ₂The granularity fractal dimension of rock.

Need to prove that the relational expression between angle of internal friction shown in the formula (15) and the granularity fractal dimension is not restrictive.According to the precision of the measuring accuracy of the collection situation of rock specimens, angle of internal friction, sreen analysis, computational accuracy etc., determined relational expression may have difference slightly, but this does not influence enforcement of the present invention.

In addition, the not restriction of sequencing between the step of the step of measurement rock sample angle of internal friction and mensuration granularity fractal dimension.Can measure the angle of internal friction of rock sample earlier, also can measure the granularity fractal dimension of rock sample earlier, also can carry out simultaneously.

After the relation of having confirmed as stated between angle of internal friction and the granularity fractal dimension, just can measure the abrasive property (being angle of internal friction) of rock easily.

In step S12, at the scene of needs mensuration rock abrasivenesss, obtain rock specimens, for example with the sample that bores landwaste, and measure its granularity fractal dimension.

With above-mentioned same, rock specimens is carried out fragmentation, the rock sample after the fragmentation is carried out the sreen analysis experiment, obtain the sreen analysis data.These sreen analysis data comprise M (R): diameter is less than the particle accumulative total quality of R, M _T: the gross mass of all particles, σ: the amount relevant, the maximum particle diameter of getting particle here with mean diameter.For a plurality of different R, calculate

and

respectively

Then; According to formula (14); That kind as shown in Figure 5 is carried out linear regression analysis to and

, confirms the value of α.

$\ln \left(\frac{M\left(R\right)}{M_T}\right)=\mathrm{\&alpha;}\ln \left(\frac{R}{\mathrm{\&sigma;}}\right)---\left(14\right)$

Thus, according to formula (13), calculate the granularity fractal dimension D of each rock sample ₂

D ₂=3-α (13)

Then, in step S13, the rock sample granularity fractal dimension D that the scene is recorded ₂The relational expression (15) that substitution is confirmed in step S11 in advance can be calculated the angle of internal friction of rock sample, i.e. the index of the abrasive property of evaluation of rock.

In the first embodiment; Confirm the relation between the granularity fractal dimension of angle of internal friction and rock of rock in advance; In the time of need measuring the abrasive property of rock so at the scene; Only need to measure the granularity fractal dimension of rock sample, can measure the angle of internal friction of rock easily, as the index of estimating abrasive property.According to first embodiment, simplified the mensuration process of rock abrasivenesss widely.

For the validity of the method for verifying this embodiment, the inventor with drill through the chip sample of certain oil field well well section, carry out the sreen analysis experiment after the fragmentation, can get following data:

Table 5

According to the method described above; Data in the his-and-hers watches 5 are carried out linear regression analysis; The value of its Weibull modulus α is 0.80569, and the granularity fractal dimension that substitution formula (13) can get rock sample is 2.19431, and then can to get the angle of internal friction of rock sample be 33.73 degree to substitution formula (15).The angle of internal friction of the corresponding well section rock core sample that records through laboratory experiment on the other hand, is 32.81 degree.Can know that error is 2.8%, within allowed band.Therefore, the rock abrasivenesss assay method of first embodiment of the invention can satisfy the actual needs of drilling well.

[second embodiment]

The present invention can also be embodied as the method for the abrasive property of following mensuration rock.This method can comprise the following steps: that the scene obtains the landwaste sample, measures its granularity fractal dimension; According to the relation between the granularity fractal dimension of the angle of internal friction of granularity fractal dimension of being measured and predetermined rock and rock, confirm the angle of internal friction of this landwaste sample.

In the method, the relation between the granularity fractal dimension of the angle of internal friction of predetermined rock and rock can be that processing through above-mentioned steps S11 obtains.

The others of this method are identical with above-mentioned first embodiment, therefore repeat no more here.

According to second embodiment, can realize the advantage same with first embodiment.In addition, in second embodiment, can obtain the relation between the granularity fractal dimension of angle of internal friction and rock of predetermined rock from other people, thus the angle of internal friction of on-site measurement rock more easily, as the index of estimating abrasive property.

[the 3rd embodiment]

The present invention can also be embodied as rock abrasivenesss and measure system.Carry out detailed explanation below.

Shown in figure 10, the rock abrasivenesss of this embodiment is measured system and can be comprised: storage part 21, granularity fractal dimension determination part 22 and calculating part 23.In addition, can also comprise input part 24 and efferent 25.

Store the relation between the granularity fractal dimension of angle of internal friction and rock of predetermined rock in the storage part 21.This relation can be the form of formula, also can be form of mapping table etc., and is unqualified at this.Relation between the granularity fractal dimension of the angle of internal friction of this predetermined rock and rock can be that the processing through the step S11 in above-mentioned first embodiment obtains, and is not giving unnecessary details at this.

Storage part 21 can integrate with granularity fractal dimension determination part 22 and calculating part 23 grades, also can be physically separating, and be connected through networks such as internet, LAN and granularity fractal dimension determination part 22 and calculating part 23 etc.

Granularity fractal dimension determination part 22 is used to measure the granularity fractal dimension of rock specimens.Granularity fractal dimension determination part 22 can comprise rock failure device, sreen analysis device and arithmetic unit.

The rock failure device carries out fragmentation to rock specimens, and the rock sample of sreen analysis device after to fragmentation carries out sreen analysis, obtains the sreen analysis data, and arithmetic unit is based on the granularity fractal dimension of this sreen analysis data computation rock sample.The processing that granularity fractal dimension determination part 22 is measured the granularity fractal dimension of rock sample can be with reference to the explanation of the step S12 in above-mentioned first embodiment.

Calculating part 23 is connected with granularity fractal dimension determination part 22 with storage part 21; Obtain the relation between the granularity fractal dimension of angle of internal friction and rock of predetermined rock from storage part 21; Obtain the granularity fractal dimension of on-the-spot rock sample from granularity fractal dimension determination part 22, and calculate the angle of internal friction of rock sample based on the two.Calculating part 23 can be made up of the equipment that computing machine, PLC etc. has an arithmetic capability.

Input part 24 is used for to calculating part 23 input operations instruction, and calculating part 23 can begin the calculating of angle of internal friction etc. according to the instruction from input part 24 inputs.Input part 24 can be made up of keyboard, mouse, touch-screen etc.

Efferent 25 is used to export the angle of internal friction that calculating part 23 is calculated, the rock abrasivenesss of perhaps estimating based on this angle of internal friction.Efferent 25 can be made up of display device, printing equipment or memory storage etc.

According to the 3rd embodiment, can obtain the advantage same with first and second embodiments.

According to rock abrasivenesss assay method of the present invention and system, do not receive the restriction of landwaste size, therefore be particularly suitable for the thinner well section of the broken landwaste of PDC drill bit.In addition, utilize on-the-spot landwaste (sand sample) to come with boring the evaluation of rock abrasive property, complete have that the source is sufficient, cost is low and advantage such as well piecewise analysis.

Above-described embodiment is to be used for helping to understand the object of the invention, technical scheme and beneficial effect; Be understood that; The above is merely embodiment of the present invention, and is not used in qualification protection scope of the present invention, and is all within spirit of the present invention and principle; Any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (8)

1. method of measuring the abrasive property of rock, this method may further comprise the steps:

Step 1: confirm the relation between the granularity fractal dimension of angle of internal friction and rock of rock in advance;

Step 2: obtain on-the-spot rock specimens, measure its granularity fractal dimension;

Step 3:, confirm the angle of internal friction of said on-the-spot rock specimens according to the granularity fractal dimension and the said predetermined relation of the said on-the-spot rock specimens of being measured.

2. the method for the abrasive property of mensuration rock according to claim 1, wherein, said step 1 comprises:

Step 11 is gathered a plurality of rock specimens, measures the angle of internal friction of each rock specimens;

Step 12 with carrying out sreen analysis after each rock specimens fragmentation, obtains the granularity fractal dimension of each rock specimens;

Step 13 according to the angle of internal friction of each rock specimens and the granularity fractal dimension of each rock specimens, is carried out linear fit, obtains the relation of angle of internal friction and granularity fractal dimension.

3. the method for the abrasive property of mensuration rock according to claim 2, wherein, in said step 12, according to formula

Carry out linear regression analysis, confirm the value of alpha, then by formula D ₂=3-α obtains the granularity fractal dimension D of each rock specimens ₂,

Wherein, M (R) is the particle accumulative total quality of diameter less than R, M _TBe the gross mass of all particles, σ is the amount relevant with mean diameter, and α is the Weibull modulus.

4. the method for the abrasive property of mensuration rock according to claim 1, wherein,

In said step 2, with carrying out sreen analysis after the said on-the-spot rock specimens fragmentation, according to formula

Carry out linear regression analysis, confirm the value of alpha, then by formula D ₂=3-α obtains the granularity fractal dimension D of said on-the-spot rock specimens ₂,

Wherein, M (R) is the particle accumulative total quality of diameter less than R, M _TBe the gross mass of all particles, σ is the amount relevant with mean diameter, and α is the Weibull modulus.

5. method of measuring the abrasive property of rock, this method may further comprise the steps:

Step 1: obtain on-the-spot rock specimens, measure its granularity fractal dimension;

Step 2:, confirm the angle of internal friction of said on-the-spot rock specimens according to the relation between the granularity fractal dimension of the angle of internal friction of the granularity fractal dimension of the said on-the-spot rock specimens of being measured and predetermined rock and rock.

6. the method for the abrasive property of mensuration rock according to claim 5, wherein,

In said step 1, with carrying out sreen analysis after the said on-the-spot rock specimens fragmentation, according to formula

Carry out linear regression analysis, confirm the value of alpha, then by formula D ₂=3-α obtains the granularity fractal dimension D of said on-the-spot rock specimens ₂,

Wherein, M (R) is the particle accumulative total quality of diameter less than R, M _TBe the gross mass of all particles, σ is the amount relevant with mean diameter, and α is the Weibull modulus.

7. system that measures the abrasive property of rock, this system comprises:

Storage part, it stores the relation between the granularity fractal dimension of angle of internal friction and rock of predetermined rock;

Granularity fractal dimension determination part, it measures the granularity fractal dimension of on-the-spot rock specimens;

Calculating part, it confirms the angle of internal friction of said on-the-spot rock specimens according to the said relation of storing in the granularity fractal dimension of the said on-the-spot rock specimens of being measured and the said storage part.

8. the system of the abrasive property of mensuration rock according to claim 7, wherein,

Said granularity fractal dimension determination part carries out sreen analysis after with said on-the-spot rock specimens fragmentation, according to formula

Carry out linear regression analysis, confirm the value of alpha, then by formula D ₂=3-α obtains the granularity fractal dimension D of said on-the-spot rock specimens ₂,

Wherein, M (R) is the particle accumulative total quality of diameter less than R, M _TBe the gross mass of all particles, σ is the amount relevant with mean diameter, and α is the Weibull modulus.

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