CN102900372B - Method and device for predicting reasonable service life of PDC (Polycrystalline Diamond Compact) drill bit - Google Patents

Abstract

The embodiment of the invention provides a method and a device for predicting the reasonable service life of a PDC (Polycrystalline Diamond Compact) drill bit. The method comprises the following steps of: establishing a life calculation model of a PDC drill bit according to rock abrasivenesss, bit pressure and rotating speed; establishing a remaining newness degree predicting model of the PDC drill bit under the action of a moving load according to the linear cumulative damage law of a machine member and the life calculation model of the PDC drill bit; and predicting the reasonable service life of the PDC drill bit according to the remaining newness degree predicting model of the PDC drill bit. According to the method and the device disclosed by the invention, on the basis of a large amount of actual use data of the PDC drill bit, the influence of an internal friction angle of rock and drilling operation parameters on the life of the drill bit is researched by applying a statistical analysis theory system and the life calculation model of the PDC drill bit is established. In addition, the remaining newness degree predicting model of the PDC drill bit for comprehensively considering the stratum abrasivenesss change and the drilling operation parameter change is established according to the linear cumulative damage law of the machine member, and thus the reference for determining the reasonable drilling time of the drill bit is provided.

Description

A kind of PDC drill bit adequate service life Forecasting Methodology and device

Technical field

The present invention relates to PDC drill bit, relate to particularly a kind of PDC drill bit adequate service life Forecasting Methodology and device, particularly a kind of method and device that utilizes linear cumulative damage law to predict PDC drill bit adequate service life under dynamic load effect.

Background technology

The prediction of PDC drilling life of bit is a very complicated job, traditional analytical method is mainly by rule of thumb according to drill bit service time, size etc. judges while boring, due to drilling life of bit, be subject to the impact of the factors such as stratum, drill quality, drill-well operation parameter, utilize conventional method to determine that drill bit often causes drill bit not use just trip-out of optimum state service time, or blindly use and cause that downhole drill bit accident occurs, cause the significant wastage of human and material resources, time, affect normal drilling well and produce.

Particularly, if just pulled out of hole in advance before drill bit rust, drilling cost will be because making a trip, more bit change increases; If extend excessively drill bit service time, just will inevitably reduce bit speed, thereby drilling cost also can be increased because bit speed is slack-off; Under extreme case, also may occur because of drill bit badly damagedly, and cause down-hole accident (as rock bit is fallen pinch roller), thereby increase because processing accident makes drilling cost.

Therefore, in drilling process, rational prediction drilling life of bit, thus reasonably determine that the trip-out time has very important significance to reducing drilling failure, safety drilling and optimization drillng operation, for reducing drilling cost, increase economic efficiency also significant equally.But in prior art, also lack a kind of PDC drill bit adequate service life Forecasting Methodology.

Summary of the invention

The invention provides a kind of PDC drill bit adequate service life Forecasting Methodology and device, utilize linear cumulative damage law to predict PDC drill bit adequate service life under dynamic load effect, thereby for determining that the drill bit rationally trip-out time provides foundation.

For reaching above-mentioned purpose, on the one hand, the embodiment of the present invention provides a kind of PDC drill bit adequate service life Forecasting Methodology, and described method comprises:

According to rock abrasiveness, the pressure of the drill and rotating speed, set up PDC bit life computation model;

According to the linear cumulative damage law of parts and described PDC bit life computation model, set up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

According to the new degree of described PDC drill bit residue forecast model, the adequate service life of prediction PDC drill bit.

For reaching above-mentioned purpose, on the other hand, the embodiment of the present invention provides a kind of PDC drill bit adequate service life prediction unit, and described device comprises:

The first model is set up unit, for according to rock abrasiveness, the pressure of the drill and rotating speed, sets up PDC bit life computation model;

The second model is set up unit, for according to the linear cumulative damage law of parts and described PDC bit life computation model, sets up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

Life forecast unit, for according to the new degree of described PDC drill bit residue forecast model, predicts the adequate service life of PDC drill bit.

The embodiment of the present invention provides the useful technique effect of technique scheme to be:

The present invention is based on on-the-spot a large amount of actual use data of PDC drill bit, the system research of applied statistics analysis theories internal friction angle of rock, the impact of drill-well operation parameter on bit life, set up PDC bit life computation model.And according to the linear cumulative damage law of parts, set up and considered the new degree of the PDC drill bit residue forecast model that stratum abrasiveness changes and drill-well operation parameter changes, thereby for determining that the drill bit rationally trip-out time provides foundation.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, by the accompanying drawing of required use in embodiment or description of the Prior Art being done to one, introduce simply below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the overall flow figure of the PDC drill bit adequate service life Forecasting Methodology of the embodiment of the present invention;

Fig. 2 is bit life and the internal friction angle of rock graph of a relation of the embodiment of the present invention;

Fig. 3 is bit life and the pressure of the drill graph of a relation of the embodiment of the present invention;

Fig. 4 is bit life and the rotation speed relation figure of the embodiment of the present invention;

Fig. 5 is the parametric inversion flow chart of the embodiment of the present invention;

Fig. 6 is the new degree of the QP19L drill bit residue prediction while drilling result of the embodiment of the present invention;

Fig. 7 is the allomeric function block diagram of the PDC drill bit adequate service life prediction of the embodiment of the present invention;

Fig. 8 is the concrete function block diagram of the PDC drill bit adequate service life prediction of the embodiment of the present invention.

The specific embodiment

For making object, technical scheme and the advantage of the embodiment of the present invention clearer, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

The present invention mainly studies PDC drill bit adequate service life Forecasting Methodology.The people such as J.R.Sparr study and show, rock abrasiveness and internal friction angle of rock have good correlation, with internal friction angle of rock, can measure well rock abrasiveness.Inventor finds in realizing the present invention, and rock abrasiveness, drill-well operation parameter are to bit life important.The embodiment of the present invention is based on the actual use data of a large amount of PDC drill bit in scene, the theoretical system of applied statistics analysis has been studied internal friction angle of rock, the affect rule of drill-well operation parameter on PDC bit life, sets up the computation model of PDC bit life under static load effect.Then on this basis, according to the linear cumulative damage law of parts, set up the new degree of the PDC drill bit residue forecast model considering under the dynamic load effect that stratum abrasiveness changes and drill-well operation parameter changes, be used for predicting PDC drill bit adequate service life, thereby for determining that the drill bit rationally trip-out time provides foundation.

Fig. 1 is the overall flow figure of the PDC drill bit adequate service life Forecasting Methodology of the embodiment of the present invention.As shown in Figure 1, the method comprises the steps

110,, according to rock abrasiveness, the pressure of the drill and rotating speed, set up PDC bit life computation model;

120,, according to the linear cumulative damage law of parts and described PDC bit life computation model, set up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

130, according to the new degree of described PDC drill bit residue forecast model, the adequate service life of prediction PDC drill bit.

During specific embodiment, step 110 can be collected the use record of well logging, log data and the drill bit of certain model drill bit institute drilling well section, and applied statistics analysis theories is set up the computation model of PDC bit life under static load effect:

T＝aΦ ^bW ^ce ^dN

In formula, T is bit life, and Φ is angle of internal friction, and W is the pressure of the drill, and N is rotating speed, and a is bit life coefficient, relevant with bit model; B, c, d are regression coefficient, relevant with bit model; T is bit life; Φ is internal friction angle of rock; W is the pressure of the drill; N is rotating speed.

Below the said method of the embodiment of the present invention is made a more detailed description:

1, PDC bit life computation model

When drill bit mates with drilled strata and drilling parameter is selected when reasonable, drill bit should form normal wear.The embodiment of the present invention is mainly studied PDC bit life computational methods and PDC drill bit adequate service life Forecasting Methodology under normal wear condition.Drilling practice shows, the factor that affects PDC bit life mainly contains formation lithology, bite type, drilling parameter, property of drilling fluid and hydraulic parameters etc.; Under normal wear condition, stratum abrasiveness and drilling operation parameter are the principal elements that affects PDC bit life.Therefore, the main study of rocks abrasiveness of the embodiment of the present invention, the impact of drill-well operation parameter on PDC bit life.

1.1, the statistical analysis of rock abrasiveness on the impact of PDC bit life

The impact of study of rocks abrasiveness on PDC bit life, need choose model drill bit of the same race (the pressure of the drill, rotating speed are identical, and hydraulic parameters is identical) under same operation parameter, and the data when different abrasive layers creep into are carried out statistical analysis.Fig. 2 be from Xinjiang, the oil field such as the Bohai Sea, long celebrating, Tarim Basin compile obtain 121/4 " bit life of QP19M drill bit and the graph of a relation between internal friction angle of rock.

Rock abrasiveness carrys out quantitative expression with internal friction angle of rock.The on-the-spot wear condition of describing PDC drill bit, has adopted multiple recording method, as new degree, and rank etc., during statistics, bit life convert formula is (during lower boring, drill bit is green bit):

$T=\frac{t}{H_f}=\frac{t}{1-N_f}---\left(1\right)$

In formula: T is bit life, h; T is drill bit drilling time, h; H _ffor bit wear degree; N _ffor the new degree of drill bit residue.To green bit N _f=100%; To scrapping drill bit N completely _f=0%.

As can be seen from Figure 2: along with internal friction angle of rock increases, the life-span of drill bit reduces.Data point is returned, and regression equation is:

T＝8×10 ⁶×Φ ^-3.071 (2)

In formula: Φ is angle of internal friction, unit is degree.Its index of correlation is 0.9228.Adopt F method of inspection to return significance test to formula (2),

given level of significance α=0.05, looks into F distribution table and obtains, F _0.95(1, n-2)=5.59.Because F=40.16 > is F _0.95(1, n-2), therefore regression effect is very remarkable.

1.2, the pressure of the drill, the statistical analysis of rotating speed on the impact of PDC bit life

Research the pressure of the drill, the impact of rotating speed on PDC bit life, need choose model drill bit of the same race under other same operation parameter (to the pressure of the drill: rotating speed is identical, and hydraulic parameters is identical; To rotating speed: the pressure of the drill is identical, and hydraulic parameters is identical), the data when identical abrasive layer creeps into are carried out statistical analysis.Fig. 3, Fig. 4 be respectively from Xinjiang, the oil field such as the Bohai Sea, long celebrating compile obtain 121/4 " bit life of QP19M drill bit and the graph of a relation between the graph of a relation between the pressure of the drill, bit life and rotating speed.When adding up, if the internal friction angle of rock of this model drill bit institute drilling well section is in certain deviation range, can be considered identical abrasive layer.

As can be seen from Figure 3: along with the pressure of the drill increases, bit life reduces.Data point is returned, and regression equation is:

T＝87691×W ^-1.5917 (3)

In formula: W is the pressure of the drill, unit is kN.Its index of correlation is 0.9492.Adopt F method of inspection to return significance test to formula (3),

given level of significance α=0.05, looks into F distribution table and obtains, F _0.95(1, n-2)=6.61.Because F=40.16 > is F _0.95(1, n-2), therefore regression effect is very remarkable.

As can be seen from Figure 4: along with rotating speed increases, bit life reduces.Data point is returned, and regression equation is:

T＝431.44×e ^-0.0145N (4)

In formula: N is rotating speed, unit is rpm.Its index of correlation is 0.954.Adopt F method of inspection to return significance test to formula (4),

given level of significance α=0.05, looks into F distribution table and obtains, F _0.95(1, n-2)=6.61.Because F=50.627 > is F _0.95(1, n-2), therefore regression effect is very remarkable.

1.3, PDC bit life computation model

According to aforesaid statistical analysis, can obtain following conclusion:

(1) relation of bit life and stratum abrasiveness: T ∝ Φ ^b;

(2) relation of bit life and the pressure of the drill: T ∝ W ^c;

(3) relation of bit life and rotating speed: T ∝ e ^dN;

Above-mentioned three formulas are carried out comprehensively, can obtain PDC bit life computation model and be:

T＝aΦ ^bW ^ce ^dN (5)

In formula: T is bit life, Φ is angle of internal friction, and W is the pressure of the drill, and N is rotating speed, and a is bit life coefficient, relevant with bit model; B, c, d are regression coefficient, relevant with bit model.

2, PDC drill bit adequate service life Forecasting Methodology under dynamic load effect

If use invariable drilling parameter to creep on the identical same stratum of abrasiveness, the adequate service life of available above-mentioned model prediction drill bit, determines reasonable trip-out time of drill bit.But, in actual well drilled process, the drilling well segment length of PDC drill bit institute, by hundreds of rice, even to several kms, pass many group Different Strata, and the measure of creeping into of taking also often changes in full well section, therefore, it is far from being enough only relying on above-mentioned PDC bit life computation model to carry out the prediction of PDC drill bit adequate service life, and this section is mainly inquired into (variation of stratum abrasiveness, drill-well operation parameter change) under dynamic load effect, PDC drill bit adequate service life Forecasting Methodology.

2.1, linear cumulative damage law

Value or purposes that damage ordinary solution is interpreted as damaged object have reduced.Injury tolerance is used for weighing the degree of parts fatigue damage under varying load effect, although it goes back the definite definition of neither one, but can understand like this: it refers to continuous expansion and the in-depth of microfissure under cyclic changeable stress effect, thereby the degree that the effective work area that makes parts reduces, the degree that makes in other words supporting capacity reduce.

Linear cumulative damage law is thought: the fatigue damage of parts under each Cyclic Stress effect is independently to carry out, total damage is the damage that causes of each load cycle cumulative forming linearly, when cumulative damage reaches a certain numerical value, just there is fatigue failure in parts.In linear cumulative damage law, representative and most widely used theory is Miner, Jack John Thomas (Miner) theory.Miner theory is thought: parts are subject to stress amplitude σ ₁effect, repeats N ₁inferior destruction, in whole process, each circulation is distributed in the suffered damage of material linearly, that is to say that the damage that circulation causes is each time

if the cycle-index of this stress amplitude effect is n ₁inferior, so, the damage that this stress amplitude causes

if the stress amplitude that parts bear also has σ ₂, σ ₃..., σ _m, as a same reason, the damage that each stress amplitude causes is respectively ${\mathrm{<figure-callout\; id="2"\; label="D\; n"\; filenames="HDA00002261490700031.png"\; state="\{\{state\}\}">D</figure-callout>}}_{n_{}}=\frac{n_2}{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="HDA00002261490700031.png"\; state="\{\{state\}\}">N</figure-callout>}}_2},{\mathrm{<figure-callout\; id="3"\; label="D\; n"\; filenames="HDA00002261490700031.png"\; state="\{\{state\}\}">D</figure-callout>}}_{n_{}}=\frac{n_3}{{\mathrm{<figure-callout\; id="3"\; label="N"\; filenames="HDA00002261490700031.png"\; state="\{\{state\}\}">N</figure-callout>}}_3},\&CenterDot;\&CenterDot;\&CenterDot;,D_{n_m}=\frac{n_m}{N_m}.$ According to linear superposition rule, total damage is:

$D=\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}{D}_i=\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\frac{n_i}{N_i}---\left(6\right)$

Obviously, when D=1, parts produce fatigue damage, are also that the criterion of fatigue failure is:

$D=\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\frac{n_i}{N_i}=1---\left(7\right)$

If replace cycle-index with the time, formula (7) becomes:

$D=\underset{i=1}{\overset{m}{\mathrm{\&Sigma;}}}\frac{t_i}{T_i}=1---\left(8\right)$

In formula: T _ifor parts expected life under i kind load; t _ifor parts bear time of i kind load.

Miner theory is a linear Fatigue Summation Damage Theory, and it does not consider the impact of load order, and in fact loading sequence is very large on the impact of fatigue life, this has been had to a large amount of experimental studies.In situation for two-stage or seldom what loading, Critical Damage value D when testpieces destroys _cRdepart from 1 very large.For random load, Critical Damage value D when testpieces destroys _cRnear 1, this is also in current engineering, extensively to adopt the reason of Miner theory.

2.2, the new degree of PDC drill bit residue forecast model

Suppose that drill bit is from well depth H ₁get into well depth H ₂time, its residue is newly spent from F (H ₁) drop to F (H ₂).This well section is divided into l section along well depth, make the load that drill bit bears in each section (mainly refer to rock abrasiveness, act on the pressure of the drill and rotating speed on drill bit) substantially constant, be similar to and think that drill bit is subject to dead weight in each section, the corresponding well depth of each well section is designated as h successively ₀, h ₁..., h _l, obviously, h ₀=H ₁, h _l=H ₂.Certainly these branches are not necessarily equally spaced, every segment length Δ h _irepresent, that is:

Δh _i＝h _i-h _i-1 i＝1,2,…,l (9)

The rate of penetration of supposing i section is V _i, the drilling time of each well section is:

$\mathrm{\&Delta;}{t}_i=\frac{{\mathrm{\&Delta;h}}_i}{V_i},i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,l---\left(10\right)$

PDC bit wear and parts damage have good similitude.According to linear cumulative damage law and by residue, newly spend definition bit breakage, formula (8) can be changed into:

$F\left(H_1\right)-F\left(H_2\right)=F\left(h_0\right)-F\left(h_l\right)=\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{{\mathrm{\&Delta;t}}_i}{T_i}$ $\left(11\right)$

$=\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{\mathrm{\&Delta;}{h}_i}{V_i{T}_i}=\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W_i}^c{e}^{d{N}_i}}$

By formula (11), can obtain the PDC drill bit new degree of its residue forecast model under dynamic load effect is:

$F\left(H_2\right)=F\left(H_1\right)-\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W_i}^c{e}^{d{N}_i}}---\left(12\right)$

In formula: F (H ₂) be well depth H ₂the new degree of place's drill bit residue, dimensionless; F(H ₁) be well depth H ₁the new degree of place's drill bit residue, dimensionless; V _ibe the rate of penetration on i section stratum, m/h; h _ibe the corresponding well depth in i section stratum, m; Φ _ibe the angle of internal friction on i section stratum, degree; W _ibe the corresponding the pressure of the drill in i section stratum, kN, N _ibe the corresponding rotating speed in i section stratum, rpm; : a, b, c, d are model coefficient, relevant with bit model.

Suppose when drill bit starts to creep into be brand-new drill bit, the new degree of its residue is F (H ₁)=1, this bit drills is to well depth H ₂time, the new degree of residue is:

$F\left(H_2\right)=1-\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W_i}^c{e}^{d{N}_i}}---\left(13\right)$

In actual drilling process, we can judge according to the new degree of residue the adequate service life of drill bit, determine the termination well depth of drill bit, thus the reasonable trip-out time of definite drill bit.

2.3, the extracting method of relevant coefficient in the new degree of PDC drill bit residue forecast model

Well logging, log data and the drill bit of collecting a kind of model drill bit institute drilling well section are used record, by Optimization inversion method, extract relevant coefficient in the new degree of PDC drill bit residue forecast model, and the object function of its Optimization inversion is:

$E=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{(S_o\stackrel{\&RightArrow;}{\left(X\right)}-S_c\stackrel{\&RightArrow;}{\left(X\right)})}^2---\left(14\right)$

In formula: N is measuring point quantity; S _obe i measuring point observation; S _cfor basis is just being drilled i the measuring point calculated value that equation calculates; E is for take the object function that the difference of measuring point observation and measuring point calculated value is target;

it is one group of inverted parameters.

Given one group of initial value and the error requirements of wanting inverted parameters, adopts certain optimized algorithm, asks the minimum of object function, and when it meets given iteration error and requires, iteration stops, and the inverted parameters tried to achieve is its true value.As shown in Figure 5, Optimization inversion comprises following calculation procedure:

(1) for treating inverted parameters initialize, setting iteration precision ε;

(2) specification error object function E, as formula (14);

(3) ask for the value of object function E in formula (14);

(4) whether the value that judges object function E is less than given iteration precision ε; In this way, enter step (5), otherwise enter step (6);

(5) if E≤ε can determine the parameter for the treatment of inverting;

(6) if E > is ε, according to complex method optimized algorithm, carry out parameter adjustment, to adjust, treat inverted parameters value, then repeating step (3), (4).

Relevant coefficient in the new degree of PDC drill bit residue forecast model is carried out to inverting, first well logging, log data and the drill bit that should collect certain model drill bit institute drilling well section are used record, the objectives function of determining Optimization inversion is formula (15), treat that inverted parameters is a, b, c, d, embodiment of the present invention application complex method optimized algorithm carries out inverting.

$E=\underset{j=1}{\overset{p}{\mathrm{\&Sigma;}}}{[F_j\left(H_2\right)-F_j\left(H_1\right)+\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_{\mathrm{ij}}-h_{\mathrm{ij}-1}}{V_{\mathrm{ij}}a{{\mathrm{\&Phi;}}_{\mathrm{ij}}}^b{W_{\mathrm{ij}}}^c{e}^{d{N}_{\mathrm{ij}}}}]}^2---\left(15\right)$

In formula: subscript j represents the data of j drill bit; P is the number of samples of this model drill bit of collection; F _j(H ₂) be that j drill bit is at well depth H ₂the residue at place is newly spent, dimensionless; F _j(H ₁) be that j drill bit is at well depth H ₁the residue at place is newly spent, dimensionless; V _ijbe j drill bit at the rate of penetration on i section stratum, unit is m/h; h _ijbe j drill bit at the corresponding well depth in i section stratum, unit is m; Φ _ijbe j drill bit in the angle of internal friction on i section stratum, unit for degree; W _ijbe j drill bit at the corresponding the pressure of the drill in i section stratum, unit is kN, N _ijbe j drill bit at the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are model coefficient, relevant with bit model.

2.4, application example

Apply above-mentioned principle and inversion method QP19L drill bit data information has been carried out to Inversion Calculation, the coefficient that obtains its life-span equation is as follows: a=9.2937 * 10 ⁹, b=-3.04063, c=-1.24374, d=-0.01867.The new degree of the PDC drill bit residue forecast model of setting up according to the embodiment of the present invention, we use the well section of this model drill bit to carry out bit wear prediction to Bohai Bay Oil well, (in drilling process, by offset well data process the regression formula Φ=0.0024 * H+27.669 that obtain calculate as shown in Figure 6 by angle of internal friction for result of the test.Note: H is well depth, m).

As can be seen from Figure 6, this drill bit institute drilling well section is grown (drilling depth reaches 1080m), and the measure of creeping into of taking in full well section has larger variation, and the abrasiveness of drilled strata also has larger variation.The new degree of the PDC drill bit residue forecast model that application is set up herein predicts that this drill bit is when 3160m, and the new degree of residue is 54%, and this drill bit of result is when 3160m is removed, and its actual wear level is 4, and this coincide better with predicting the outcome.This application example shows: the new degree of the PDC drill bit residue forecast model that the embodiment of the present invention is set up is rational.

The advantage of said method embodiment of the present invention is: based on the actual use data of a large amount of PDC drill bit in scene, applied statistics analysis theories of the present invention system research internal friction angle of rock, the impact of drill-well operation parameter on bit life, set up PDC bit life computation model.According to the linear cumulative damage law of parts, set up and considered the new degree of the PDC drill bit residue forecast model that stratum abrasiveness changes and drill-well operation parameter changes, thereby for determining that the drill bit rationally trip-out time provides foundation.

Corresponding to said method embodiment, the embodiment of the present invention also provides a kind of PDC drill bit adequate service life prediction unit.Fig. 7 is the allomeric function block diagram of the PDC drill bit adequate service life prediction of the embodiment of the present invention.As shown in Figure 7, this device 200 comprises:

The first model is set up unit 210, for according to rock abrasiveness, the pressure of the drill and rotating speed, sets up PDC bit life computation model;

The second model is set up unit 220, for according to the linear cumulative damage law of parts and described PDC bit life computation model, sets up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

Life forecast unit 230, for according to the new degree of described PDC drill bit residue forecast model, predicts the adequate service life of PDC drill bit.

Fig. 8 is the concrete function block diagram of the PDC drill bit adequate service life prediction of the embodiment of the present invention.As shown in Figure 8, in a preferred embodiment, this first model is set up unit 210 and specifically can be comprised:

The first relational expression is set up module 212, for setting up the first relational expression of PDC bit life and rock abrasiveness: T ∝ Φ ^b;

The second relational expression is set up module 214, for setting up second relational expression of PDC bit life and the pressure of the drill: T ∝ W ^c;

The 3rd relational expression is set up module 216, for setting up the 3rd relational expression of PDC bit life and rotating speed: T ∝ e ^dN;

PDC bit life computation model acquisition module 218, for according to described the first relational expression, described the second relational expression and described the 3rd relational expression, obtains PDC bit life computation model: T=a Φ ^bw ^ce ^dN; Wherein, a is PDC bit life coefficient, relevant with PDC bit model, and b, c, d are regression coefficient, relevant with PDC bit model.

In a preferred embodiment, alternatively, this second model is set up unit 220 and specifically can be comprised:

Linear cumulative damage law corresponding relation formula acquisition module 222, for obtaining the relational expression corresponding to linear cumulative damage law of parts:

wherein, T _ifor parts expected life under i kind load, t _ifor parts bear time of i kind load;

The new degree of residue forecast model is set up module 224, for supposing that drill bit is from well depth H ₁get into well depth H ₂time, its residue is newly spent from F (H ₁) drop to F (H ₂); Bored well section is divided into l sub-well section along well depth, and described drill bit is subject to dead weight in each sub-well section, and the corresponding well depth of each sub-well section is designated as h successively ₀, h ₁..., h _l, and h ₀=H ₁, h _l=H ₂, the length Δ h of each sub-well section _icorresponding relational expression is: Δ h _i=h _i-h _i-1i=1,2 ..., l; The rate of penetration of supposing i section is V _i, the drilling time Δ t of each sub-well section _icorresponding relational expression is:

i=1,2 ..., l; According to the length Δ h of relational expression corresponding to the linear cumulative damage law of described parts, each sub-well section _icorresponding relational expression, the drilling time Δ t of each sub-well section _icorresponding relational expression and described PDC bit life computation model, obtain the residue of PDC drill bit under dynamic load effect and newly spend forecast model:

$F\left(H_2\right)=F\left(H_1\right)-\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W_i}^c{e}^{d{N}_i}}$

Wherein: F (H ₂) be well depth H ₂the new degree of place's drill bit residue, dimensionless; F(H ₁) be well depth H ₁the new degree of place's drill bit residue, dimensionless; V _ibe the rate of penetration on i section stratum, unit is m/h; h _ibe the corresponding well depth in i section stratum, unit is m; Φ _ibe the angle of internal friction on i section stratum, unit is degree; W _ibe the corresponding the pressure of the drill in i section stratum, unit is kN, N _ibe the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are model coefficient, relevant with bit model.

Further, in a preferred embodiment, this device 200 can also comprise: coefficient inverting unit 240, and for the inverting of carrying out to the relevant coefficient of described PDC drill bit residue new degree forecast model.

Alternatively, this coefficient inverting unit 240 specifically can comprise:

Collection module 242, is used record for collecting well logging, log data and the drill bit of a kind of model drill bit institute drilling well section;

Object function determination module, 244 are used to and treat inverted parameters initialize and set iteration precision ε; And the objectives function of definite Optimization inversion, treat that inverted parameters is a, b, c, d; The objectives function of described Optimization inversion is: $E=\underset{j=1}{\overset{p}{\mathrm{\&Sigma;}}}{[F_j\left(H_2\right)-F_j\left(H_1\right)+\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_{\mathrm{ij}}-h_{\mathrm{ij}-1}}{V_{\mathrm{ij}}a{{\mathrm{\&Phi;}}_{\mathrm{ij}}}^b{W_{\mathrm{ij}}}^c{e}^{d{N}_{\mathrm{ij}}}}]}^2;$ In formula: subscript j represents the data of j drill bit; P is the number of this model drill bit of collection; F _j(H ₂) be that j drill bit is at well depth H ₂the residue at place is newly spent, dimensionless; F _j(H ₁) be that j drill bit is at well depth H ₁the residue at place is newly spent, dimensionless; V _ijbe j drill bit at the rate of penetration on i section stratum, unit is m/h; h _ijbe j drill bit at the corresponding well depth in i section stratum, unit is m; Φ _ijbe j drill bit in the angle of internal friction on i section stratum, unit for degree; W _ijbe j drill bit at the corresponding the pressure of the drill in i section stratum, unit is kN, N _ijbe j drill bit at the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are for treating inverted parameters;

Inverting module 246, for asking for the value of described objectives function E; If the value of the described objectives function E asking for is greater than given iteration precision ε, applies complex method optimized algorithm each undetermined coefficient in the new degree of the PDC drill bit residue forecast model of this kind of model is carried out to inverting.

The course of work of this device or principle refer to aforesaid embodiment of the method, do not repeat them here.

The advantage of said apparatus embodiment of the present invention is:

Based on the actual use data of a large amount of PDC drill bit in scene, applied statistics analysis theories of the present invention system research internal friction angle of rock, the impact of drill-well operation parameter on bit life, set up PDC bit life computation model.According to the linear cumulative damage law of parts, set up and considered the new degree of the PDC drill bit residue forecast model that stratum abrasiveness changes and drill-well operation parameter changes, thereby for determining that the drill bit rationally trip-out time provides foundation.

Through the above description of the embodiments, those skilled in the art can be well understood to the mode that the present invention can add essential general hardware platform by software and realize, and can certainly pass through hardware, or the combination of the two is implemented.Understanding based on such, the part that technical scheme of the present invention contributes to prior art in essence in other words can embody with the form of software product, this software module or computer software product can be stored in a storage medium, comprise that some instructions are with so that a computer equipment (can be personal computer, server, or the network equipment etc.) carry out the method described in each embodiment of the present invention.Storage medium can be the storage medium of interior known any other form of random access memory (RAM), internal memory, read-only storage (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.

Above embodiment only, in order to the technical scheme of the embodiment of the present invention to be described, is not intended to limit; Although the embodiment of the present invention is had been described in detail with reference to previous embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or part technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the spirit and scope of each embodiment technical scheme of the embodiment of the present invention.

Claims (2)

1. a PDC drill bit adequate service life Forecasting Methodology, is characterized in that, described method comprises:

According to rock abrasiveness, the pressure of the drill and rotating speed, set up PDC bit life computation model;

Described according to rock abrasiveness, the pressure of the drill and rotating speed, set up PDC bit life computation model and comprise:

Set up the first relational expression of PDC bit life and rock abrasiveness: T ∝ Φ ^b;

Set up second relational expression of PDC bit life and the pressure of the drill: T ∝ W ^c;

Set up the 3rd relational expression of PDC bit life and rotating speed: T ∝ e ^dN;

According to described the first relational expression, described the second relational expression and described the 3rd relational expression, obtain PDC bit life computation model: T=a Φ ^bw ^ce ^dN; Wherein, T is bit life, and Φ is angle of internal friction, and W is the pressure of the drill, and N is rotating speed, and a is PDC bit life coefficient, relevant with PDC bit model, and b, c, d are regression coefficient, relevant with PDC bit model;

According to the linear cumulative damage law of parts and described PDC bit life computation model, set up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

Described according to the linear cumulative damage law of parts and described PDC bit life computation model, the new degree of the PDC drill bit residue forecast model of setting up under dynamic load effect comprises:

Obtain the relational expression corresponding to linear cumulative damage law of parts:

wherein, T _ifor parts expected life under i kind load, t _ifor parts bear time of i kind load;

Suppose that drill bit is from well depth H ₁get into well depth H ₂time, its residue is newly spent from F (H ₁) drop to F (H ₂); Bored well section is divided into l sub-well section along well depth, and described drill bit is subject to dead weight in each sub-well section, and the corresponding well depth of each sub-well section is designated as h successively ₀, h ₁..., h _l, and h ₀=H ₁, h _l=H ₂, the length Δ h of each sub-well section _icorresponding relational expression is: Δ h _i=h _i-h _i-1i=1,2 ..., l; The rate of penetration of supposing i section is V _i, the drilling time Δ t of each sub-well section _icorresponding relational expression is:

i=1,2 ..., l;

According to the length Δ h of relational expression corresponding to the linear cumulative damage law of described parts, each sub-well section _icorresponding relational expression, the drilling time Δ t of each sub-well section _icorresponding relational expression and described PDC bit life computation model, obtain the residue of PDC drill bit under dynamic load effect and newly spend forecast model:

$F\left(H_2\right)=F\left(H_1\right)-\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W}_i^c{e}^{d{N}_i}}$

Wherein: F (H ₂) be well depth H ₂the new degree of place's drill bit residue, dimensionless; F(H ₁) be well depth H ₁the new degree of place's drill bit residue, dimensionless; V _ibe the rate of penetration on i section stratum, unit is m/h; h _ibe the corresponding well depth in i section stratum, unit is m; Φ _ibe the angle of internal friction on i section stratum, unit is degree; W _ibe the corresponding the pressure of the drill in i section stratum, unit is kN, N _ibe the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are model coefficient, relevant with bit model;

The inverting of carrying out to relevant coefficient in the new degree of described PDC drill bit residue forecast model;

Comprise:

Well logging, log data and the drill bit of collecting a kind of model drill bit institute drilling well section are used record;

For treating inverted parameters initialize, and set iteration precision ε;

Determine the objectives function of Optimization inversion, treat that inverted parameters is a, b, c, d; The objectives function of described Optimization inversion is: $E=\underset{j=1}{\overset{p}{\mathrm{\&Sigma;}}}[F_j\left(H_2\right)-F_j\left(H_1\right)+\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_{\mathrm{ij}}-h_{\mathrm{ij}-1}}{V_{\mathrm{ij}}a{{\mathrm{\&Phi;}}_{\mathrm{ij}}}^b{W}_{\mathrm{ij}}^c{e}^{d{N}_{\mathrm{ij}}}}{]}^2;$

In formula: subscript j represents the data of j drill bit; P is the number of this model drill bit of collection; F _j(H ₂) be that j drill bit is at well depth H ₂the residue at place is newly spent, dimensionless; F _j(H ₁) be that j drill bit is at well depth H ₁the residue at place is newly spent, dimensionless; V _ijbe j drill bit at the rate of penetration on i section stratum, unit is m/h; h _ijbe j drill bit at the corresponding well depth in i section stratum, unit is m; Φ _ijbe j drill bit in the angle of internal friction on i section stratum, unit for degree; W _ijbe j drill bit at the corresponding the pressure of the drill in i section stratum, unit is kN, Ni _jbe j drill bit at the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are for treating inverted parameters;

Ask for the value of described objectives function E, if the value of the described objectives function E asking for is greater than given iteration precision ε, applies complex method optimized algorithm each undetermined coefficient in the new degree of the PDC drill bit residue forecast model of this kind of model is carried out to inverting;

According to the new degree of described PDC drill bit residue forecast model, the adequate service life of prediction PDC drill bit.

2. a PDC drill bit adequate service life prediction unit, is characterized in that, described device comprises:

The first model is set up unit, for according to rock abrasiveness, the pressure of the drill and rotating speed, sets up PDC bit life computation model;

Described the first model is set up unit and is comprised:

The first relational expression is set up module, for setting up the first relational expression of PDC bit life and rock abrasiveness: T ∝ Φ ^b;

The second relational expression is set up module, for setting up second relational expression of PDC bit life and the pressure of the drill: T ∝ W ^c;

The 3rd relational expression is set up module, for setting up the 3rd relational expression of PDC bit life and rotating speed: T ∝ e ^dN;

PDC bit life computation model acquisition module, for according to described the first relational expression, described the second relational expression and described the 3rd relational expression, obtains PDC bit life computation model: T=a Φ ^bw ^ce ^dN; Wherein, T is bit life, and Φ is angle of internal friction, and W is the pressure of the drill, and N is rotating speed, and a is PDC bit life coefficient, relevant with PDC bit model, and b, c, d are regression coefficient, relevant with PDC bit model;

The second model is set up unit, for according to the linear cumulative damage law of parts and described PDC bit life computation model, sets up the new degree of the PDC drill bit residue forecast model under dynamic load effect;

Described the second model is set up unit and is comprised:

Linear cumulative damage law corresponding relation formula acquisition module, for obtaining the relational expression corresponding to linear cumulative damage law of parts:

wherein, T _ifor parts expected life under i kind load, t _ifor parts bear time of i kind load;

The new degree of residue forecast model is set up module, for supposing that drill bit is from well depth H ₁get into well depth H ₂time, its residue is newly spent from F (H ₁) drop to F (H ₂); Bored well section is divided into l sub-well section along well depth, and described drill bit is subject to dead weight in each sub-well section, and the corresponding well depth of each sub-well section is designated as h successively ₀, h ₁..., h _l, and h ₀=H ₁, h _l=H ₂, the length Δ h of each sub-well section _icorresponding relational expression is: Δ h _i=h _i-h _i-1i=1,2 ..., l; The rate of penetration of supposing i section is V _i, the drilling time Δ t of each sub-well section _icorresponding relational expression is:

i=1,2 ..., l; According to the length Δ h of relational expression corresponding to the linear cumulative damage law of described parts, each sub-well section _icorresponding relational expression, the drilling time Δ t of each sub-well section _icorresponding relational expression and described PDC bit life computation model, obtain the residue of PDC drill bit under dynamic load effect and newly spend forecast model:

$F\left(H_2\right)=F\left(H_1\right)-\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_i-h_{i-1}}{V_{i}a{{\mathrm{\&Phi;}}_i}^b{W_i}^c{e}^{d{N}_i}}$

Wherein: F (H ₂) be well depth H ₂the new degree of place's drill bit residue, dimensionless; F(H ₁) be well depth H ₁the new degree of place's drill bit residue, dimensionless; V _ibe the rate of penetration on i section stratum, unit is m/h; h _ibe the corresponding well depth in i section stratum, unit is m; Φ _ibe the angle of internal friction on i section stratum, unit is degree; W _ibe the corresponding the pressure of the drill in i section stratum, unit is kN, N _ibe the corresponding rotating speed in i section stratum, unit is rpm; C _t, a, b, c be model coefficient, relevant with bit model;

Described device also comprises coefficient inverting unit, for the inverting of carrying out to the relevant coefficient of described PDC drill bit residue new degree forecast model;

Described coefficient inverting unit comprises:

Collection module, is used record for collecting well logging, log data and the drill bit of a kind of model drill bit institute drilling well section;

Object function determination module, is used to and treats inverted parameters initialize and set iteration precision ε; And the objectives function of definite Optimization inversion, treat that inverted parameters is a, b, c, d; The objectives function of described Optimization inversion is:

$E=\underset{j=1}{\overset{p}{\mathrm{\&Sigma;}}}[F_j\left(H_2\right)-F_j\left(H_1\right)+\underset{i=1}{\overset{l}{\mathrm{\&Sigma;}}}\frac{h_{\mathrm{ij}}-h_{\mathrm{ij}-1}}{V_{\mathrm{ij}}a{{\mathrm{\&Phi;}}_{\mathrm{ij}}}^b{W_{\mathrm{ij}}}^c{e}^{{\mathrm{dN}}_{\mathrm{ij}}}}{]}^2;$ In formula: subscript j represents the data of j drill bit; P is the number of this model drill bit of collection; F _j(H ₂) be that j drill bit is at well depth H ₂the residue at place is newly spent, dimensionless; F _j(H ₁) be that j drill bit is at well depth H ₁the residue at place is newly spent, dimensionless; V _ijbe j drill bit at the rate of penetration on i section stratum, unit is m/h; h _ijbe j drill bit at the corresponding well depth in i section stratum, unit is m; Φ _ijbe j drill bit in the angle of internal friction on i section stratum, unit for degree; W _ijbe j drill bit at the corresponding the pressure of the drill in i section stratum, unit is kN, N _ijbe j drill bit at the corresponding rotating speed in i section stratum, unit is rpm; A, b, c, d are for treating inverted parameters;

Inverting module, for asking for the value of described objectives function E; If the value of the described objectives function E asking for is greater than given iteration precision ε, applies complex method optimized algorithm each undetermined coefficient in the new degree of the PDC drill bit residue forecast model of this kind of model is carried out to inverting;

Life forecast unit, for according to the new degree of described PDC drill bit residue forecast model, predicts the adequate service life of PDC drill bit.

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