CN103266889B - The method of the rock drillability under the different drilling direction of prediction shale formation - Google Patents

Abstract

The present invention relates to a kind of method of the rock drillability predicted under the different drilling direction of shale formation, comprise the following steps: measure shale samples in the rock-drillability index value of different drilling direction and interval transit time; Set up the relational model of rock-drillability index value and interval transit time, dilling angle; Set up the relational model between the interval transit time of the different drilling direction of shale samples and direction, vertical stratification face interval transit time, dilling angle; Set up rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle of the different drilling direction of shale samples; Obtain well-log information, obtained the interval transit time in its direction, vertical stratification face by inverting; According to rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle of the different drilling direction of shale formation, determine the rock-drillability index value of the different drilling directions of on-the-spot shale samples.Rock drillability under the present invention can utilize Sonic Logging Data directly to predict the different drilling direction of shale formation.

Description

The method of the rock drillability under the different drilling direction of prediction shale formation

Technical field

The invention belongs to subterranean resource drilling field of engineering technology, particularly, relate to a kind of method of the rock drillability predicted under the different drilling direction of shale formation.

Background technology

Rock drillability, in the exploration and development process of oil gas field, as bit type selection and can instruct geological layer important evidence.From the middle of last century, scholars both domestic and external are just devoted to the research of the drillability of rock, determine that stratum rock drillability level value is extensively adopted by petroleum industry by laboratory core experimental method.Prediction rock drillability has very important meaning to raising deep well mechanical drilling speed, shortening drilling period, raising deep drilling level accurately.Along with the rise of shale gas, the experimental evaluation method for the drillability of rock of shale stratification does not also propose.

Summary of the invention

For overcoming the defect of prior art, the invention provides a kind of method of the rock drillability predicted under the different drilling direction of shale formation, the rock drillability under utilizing Sonic Logging Data directly to predict the different drilling direction of shale formation.

For achieving the above object, the present invention adopts following scheme:

Predict a method for the rock drillability under the different drilling direction of shale formation, comprise the following steps:

Step 1, measures the rock-drillability index value of shale samples at different drilling direction;

Step 2, measures the interval transit time of shale samples under corresponding drilling direction;

Step 3, sets up the relational model of the rock-drillability index value of the different drilling direction of shale samples and correspondence direction interval transit time, dilling angle;

Step 4, sets up the relational model between the interval transit time of the different drilling direction of shale samples and direction, vertical stratification face interval transit time, dilling angle;

Step 5, sets up rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle of the different drilling direction of shale samples;

Step 6, obtains the well-log information of on-the-spot shale, and Inversion Calculation obtains the interval transit time in direction, shale vertical stratification face;

Step 7, according to the interval transit time in the direction, shale vertical stratification face that rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle and the Inversion Calculation of the different drilling direction of determined shale formation obtain, determine the rock-drillability index value of the different drilling directions of described on-the-spot shale.

Advantageous Effects of the present invention is: the rock drillability under Sonic Logging Data can be utilized directly to predict the different drilling direction of shale formation.Compared with conventional method, this invention is simple and convenient, has saved down-hole and to have cored cost, decreases a large amount of repeated work such as measurement grade.

Accompanying drawing explanation

Fig. 1 is the method flow schematic diagram of the rock drillability under the different drilling direction of prediction shale formation.

Fig. 2 is the angled relationships schematic diagram between rock core axis and bed plane normal.

Fig. 3 is the flow chart utilizing Sonic Logging Data to ask for vertical shale bedding direction compressional wave time difference method.

Detailed description of the invention

As shown in Figure 1, the method for the rock drillability under the different drilling direction of prediction shale formation, comprises the following steps:

Step 1, measure the rock-drillability index value of shale samples at different drilling direction, concrete grammar is as follows:

1) machine of coring is utilized to take out from monoblock shale samples the rock core that diameter is 76.2mm, length is the different bedding direction of 50mm, use lathe that two of rock core end face cars are put down, the parallelism tolerance value of sample both ends of the surface is no more than 0.2mm, and rock core is put into baking box with 100 DEG C of temperature baking 24h;

2) the different bedding directions rock core after process is put into drillability of rock measuring system successively, measure the rock-drillability index value of different bedding directions rock core respectively;

Drilling direction, is the axis of shale samples, with the relationship consistency of angle shown in Fig. 2.

Step 2, measure the interval transit time of shale samples under corresponding drilling direction, concrete grammar is as follows:

1) machine of coring is utilized to take out from above-mentioned shale core the rock core that diameter is 25mm, length is 50mm, the bedding direction of each rock core is corresponding with the bedding direction of rock core each in step 1, use lathe that two of rock core section cars are put down, then rock core is put into baking box with 100 DEG C of temperature baking 24h;

2) the different bedding directions rock core after process is put into sound wave measuring system successively, measure the interval transit time of different bedding directions rock core respectively;

Above-mentioned steps 1, the rock drillability under the 2 different drilling directions measured, interval transit time experimental result are as shown in table 1 below:

Table 1

As shown in Figure 2, vertical stratification direction is 0 degree to drilling direction, and parallel bedding direction is 90 degree.

Step 3, sets up the relational model of the rock-drillability index value of the different drilling direction of shale samples and correspondence direction interval transit time, dilling angle; Concrete grammar is as follows:

Nonlinear regression analysis is carried out to the interval transit time of the rock-drillability index value of the different drilling direction of shale samples and corresponding drilling direction, dilling angle, sets up following Mathematical Modeling:

(formula 1)

In formula: rock drillability under different drilling direction; interval transit time under different drilling direction, unit (us/m); the angle of rock core axis and bedding normal direction, unit (°).

It should be noted that, each coefficient depends on the data performing multiple regression, and not exclusive value.

Step 4, sets up the relational model between the interval transit time of the different drilling direction of shale samples and direction, vertical stratification face interval transit time, dilling angle; Concrete grammar is as follows:

Nonlinear regression analysis is carried out to the interval transit time in the interval transit time in the different bedding direction of shale samples and vertical stratification direction, dilling angle, sets up following Mathematical Modeling:

(formula 2)

In formula: interval transit time under different drilling direction, unit (us/m); the angle of rock core axis and bedding normal direction, unit (°); for the interval transit time in vertical stratification direction, unit (us/m).

Step 5, set up rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle of the different drilling direction of shale samples, concrete grammar is as follows:

Formula 2 is brought in formula 1, obtains Mathematical Modeling as follows:

(formula 3)

In formula; rock drillability under different drilling direction; the angle of rock core axis and bedding normal direction, unit (°); for the interval transit time in vertical stratification direction, unit (us/m).

Step 6, obtains the well-log information of on-the-spot shale, and Inversion Calculation obtains the interval transit time in direction, shale vertical stratification face, and concrete grammar is as follows:

As shown in Figure 3, well-log information is utilized to ask for vertical stratification direction interval transit time method as follows,

After the rock anisotropy parameter ε determining a certain well section and δ, wherein $\mathrm{\δ}=\frac{1}{{2C}_{33}^2}[2{(C_{13}+C_{44})}^2-(C_{33}-C_{44})(C_{11}+C_{33}-2C_{44})].$ In formula, C _ijimplication in accordance with Hooke's law, be not described further at this.

First crowd angle φ is calculated according to attitude of stratum data and hole trajectory data _g.

Secondly a given initial perpendicular bed plane direction velocity of longitudinal wave v _{p, 0},

$v_{\mathrm{SV},0}=\frac{v_{P,0}-1.36}{1.16}$ (formula 4)

V _{p, 0}for direction, vertical stratification face velocity of longitudinal wave, unit (km/s); v _{sV, 0}for direction, vertical stratification face shear wave velocity, unit (km/s).

Calculate shear wave velocity, determine ripple ratio in length and breadth.

Again calculate phase angle:

$\tan \mathrm{\θ}=\frac{\left\{2\right[M_3\left(\mathrm{\θ}\right)-M_2\left(\mathrm{\θ}\right){]\sin }^2\mathrm{\θ}-M_4\left(\mathrm{\θ}\right)\}\tan {\mathrm{\φ}}_g}{2[M_3\left(\mathrm{\θ}\right)-M_2\left(\mathrm{\θ}\right)-2M_1]{\sin }^2\mathrm{\θ}-M_4\left(\mathrm{\θ}\right)-2M_3\left(\mathrm{\θ}\right)}$ (formula 5)

Wherein, M ₁=ε ²-2t δ+2t ε; M ₂(θ)=4t δ+ε R (θ)-2t ε; M ₃(θ)=2t δ+ε R (θ)-t ε; M ₄(θ)=t ²-tR (θ)+2R (θ); $R\left(\mathrm{\θ}\right)={(4({\mathrm{\ϵ}}^2+2\mathrm{t\ϵ}-2\mathrm{t\δ}){\sin }^4\mathrm{\θ}+4t(2\mathrm{\δ}-\mathrm{\ϵ}){\sin }^2\mathrm{\θ}+t^2)}^{\frac{1}{2}}=2D\left(\mathrm{\θ}\right)+t$ $t=1-{\mathrm{\β}}_0^2/{\mathrm{\α}}_0^2.$ φ _gfor group angle, unit (°); v _afor phase velocity, unit (°); θ is phase angle, unit (°); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s); β ₀for the shear wave velocity in direction, vertical stratification face, unit (km/s).

Then phase velocity is calculated,

$\frac{v_{\mathrm{Pa}}^2\left(\mathrm{\θ}\right)}{{\mathrm{\α}}_0^2}=1+\mathrm{\ϵ}{\sin }^2\mathrm{\θ}+D\left(\mathrm{\θ}\right)$ (formula 6)

Wherein $D\left(\mathrm{\θ}\right)=\frac{1}{2}\sqrt{4({\mathrm{\ϵ}}^2+2\mathrm{t\ϵ}-2\mathrm{t\δ}){\sin }^4\mathrm{\θ}+4t(2\mathrm{\δ}-\mathrm{\ϵ}){\sin }^2\mathrm{\θ}+t^2}-\frac{1}{2}t,$ V _pafor compressional wave phase velocity, unit (km/s); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s); θ is phase angle, unit (°).

Calculate group velocity:

$v_{\mathrm{Pg}}\left({\mathrm{\φ}}_g\left(\mathrm{\θ}\right)\right)=\frac{1}{v_{\mathrm{Pa}\left(\mathrm{\θ}\right)R\left(\mathrm{\θ}\right)}}{\{v_{\mathrm{Pa}}^4\left(\mathrm{\θ}\right)R^2\left(\mathrm{\θ}\right)+{\mathrm{\α}}_0^4{\sin }^2\mathrm{\θ}{\cos }^2\mathrm{\θ}{[2M_1{\sin }^2\mathrm{\θ}+M_3\left(\mathrm{\θ}\right)]}^2\}}^{\frac{1}{2}}$ (formula 7)

V _pgfor compressional wave group velocity, unit (km/s); v _pafor compressional wave phase velocity, unit (km/s); θ is phase angle, unit (°); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s).

Finally the velocity of wave of the group velocity calculated and well-log information is compared, if both coincide, then this v _{p, 0}required by being.If both differences are comparatively large, then change v _{p, 0}repeat above step until both match.

After obtaining the velocity of wave in direction, vertical stratification face, the interval transit time in this direction can be obtained

(formula 8)

for direction, vertical stratification face interval transit time, unit (us/m); v _{p, 0}for direction, vertical stratification face velocity of longitudinal wave, unit (km/s).

Step 7, according to the interval transit time in the direction, shale vertical stratification face that rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle and the Inversion Calculation of the different drilling direction of determined shale formation obtain, determine the rock-drillability index value of the different drilling directions of described on-the-spot shale.Concrete grammar is as follows:

Bring the interval transit time in the direction, on-the-spot shale vertical stratification face obtained in step 6 into rock-drillability index value that formula 3 can obtain each drilling direction of shale formation.

Claims (8)

1. predict a method for the rock drillability under the different drilling direction of shale formation, it is characterized in that, comprise the following steps:

Step 1, measures the rock-drillability index value of shale samples at different drilling direction;

Step 2, measures the interval transit time of shale samples under corresponding drilling direction;

Step 3, sets up the relational model of the rock-drillability index value of the different drilling direction of shale samples and correspondence direction interval transit time, dilling angle;

Step 4, sets up the relational model between the interval transit time of the different drilling direction of shale samples and direction, vertical stratification face interval transit time, dilling angle;

Step 5, sets up rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle of the different drilling direction of shale samples;

Step 6, obtains the well-log information of on-the-spot shale, and Inversion Calculation obtains the interval transit time in direction, shale vertical stratification face;

Step 7, according to the interval transit time in the direction, shale vertical stratification face that rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle and the Inversion Calculation of the different drilling direction of determined shale formation obtain, determine the rock-drillability index value of the different drilling directions of described on-the-spot shale.

2. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 1, it is characterized in that, the concrete grammar of step 1 is as follows:

1) machine of coring is utilized to take out from monoblock shale samples the rock core that diameter is 76.2mm, length is the different bedding direction of 50mm, use lathe that two of rock core end face cars are put down, the parallelism tolerance value of sample both ends of the surface is no more than 0.2mm, and rock core is put into baking box with 100 DEG C of temperature baking 24h;

2) the different bedding directions rock core after process is put into drillability of rock measuring system successively, measure the rock-drillability index value of different bedding directions rock core respectively.

3. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 2, it is characterized in that, the concrete grammar of step 2 is as follows:

1) machine of coring, is utilized to take out from above-mentioned shale core the rock core that diameter is 25mm, length is 50mm, the bedding direction of each rock core is corresponding with the bedding direction of rock core each in step 1, use lathe that two of rock core section cars are put down, then rock core is put into baking box with 100 DEG C of temperature baking 24h;

2), by the different bedding directions rock core after process put into sound wave measuring system successively, measure the interval transit time of different bedding directions rock core respectively.

4. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 3, it is characterized in that, the concrete grammar of step 3 is as follows: carry out nonlinear regression analysis, founding mathematical models to the interval transit time of the rock-drillability index value of the different drilling direction of shale samples and corresponding drilling direction, dilling angle.

5. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 4, it is characterized in that, the concrete grammar of step 4 is as follows: carry out nonlinear regression analysis, founding mathematical models to the interval transit time in the interval transit time in the different bedding direction of shale samples and vertical stratification direction, dilling angle.

6. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 5, it is characterized in that, the concrete grammar of step 5 is as follows: step 4 gained Mathematical Modeling is brought in step 3 gained Mathematical Modeling into the rock-drillability index value and the interval transit time in direction, vertical stratification face, the relational model of dilling angle that obtain the different drilling direction of shale samples.

7. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 6, is characterized in that, utilize well-log information to ask for direction, vertical stratification face interval transit time method as follows,

After the rock anisotropy parameter ε determining a certain well section and δ, wherein $\mathrm{\δ}=\frac{1}{2C_{33}^2}\[2{(C_{13}+C_{44})}^2-(C_{33}-C_{44})(C_{11}+C_{33}-2C_{44})\],$ In formula, C _ijimplication in accordance with Hooke's law;

First crowd angle φ is calculated according to attitude of stratum data and hole trajectory data _g;

Secondly a given initial perpendicular bed plane direction compressional wave group velocity v _{p, 0},

$v_{SV,0}=\frac{v_{P,0}-1.36}{1.16}$

V _{p, 0}for direction, vertical stratification face compressional wave group velocity, unit (km/s); v _{sV, 0}for direction, vertical stratification face shear wave group velocity, unit (km/s);

Calculate shear wave phase velocity, determine phase velocity of wave ratio in length and breadth;

Again calculate phase angle:

$tan\mathrm{\θ}=\frac{\{2\[M_3\left(\mathrm{\θ}\right)-M_2\left(\mathrm{\θ}\right)\]{\sin }^2\mathrm{\θ}-M_4\left(\mathrm{\θ}\right)\}{\mathrm{tan\φ}}_g}{2\[M_3\left(\mathrm{\θ}\right)-M_2\left(\mathrm{\θ}\right)-2M_1\]{\sin }^2\mathrm{\θ}-M_4\left(\mathrm{\θ}\right)-2M_3\left(\mathrm{\θ}\right)}$

Wherein, M ₁=ε ²-2t δ+2t ε; M ₂(θ)=4t δ+ε R (θ)-2t ε; M ₃(θ)=2t δ+ε R (θ)-t ε; M ₄(θ)=t ²-tR (θ)+2R (θ); $R\left(\mathrm{\θ}\right)={\left(4\right({\mathrm{\ϵ}}^2+2t\mathrm{\ϵ}-2t\mathrm{\δ}){\sin }^4\mathrm{\θ}+4t(2\mathrm{\δ}-\mathrm{\ϵ}){\sin }^2\mathrm{\θ}+t^2)}^{\frac{1}{2}}=2D\left(\mathrm{\θ}\right)+t$ φ _gfor group angle, unit (°); θ is phase angle, unit (°); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s); β ₀for the shear wave phase velocity in direction, vertical stratification face, unit (km/s);

Then phase velocity is calculated,

$\frac{v_{Pa}^2\left(\mathrm{\θ}\right)}{{\mathrm{\α}}_0^2}=1+{\mathrm{\ϵsin}}^2\mathrm{\θ}+D\left(\mathrm{\θ}\right)$

Wherein $D\left(\mathrm{\θ}\right)=\frac{1}{2}\sqrt{4({\mathrm{\ϵ}}^2+2t\mathrm{\ϵ}-2t\mathrm{\δ}){\sin }^4\mathrm{\θ}+4t\left(2\mathrm{\δ}-\mathrm{\ϵ}\right){\sin }^2\mathrm{\θ}+t^2}-\frac{1}{2}t,$ V _pafor compressional wave phase velocity, unit (km/s); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s); θ is phase angle, unit (°);

Calculate group velocity:

$v_{Pg}\left({\mathrm{\φ}}_g\right(\mathrm{\θ}\left)\right)=\frac{1}{v_{Pa}\left(\mathrm{\θ}\right)R\left(\mathrm{\θ}\right)}{\{v_{Pa}^4\left(\mathrm{\θ}\right)R^2\left(\mathrm{\θ}\right)+{\mathrm{\α}}_0^4{\sin }^2{\mathrm{\θcos}}^2\mathrm{\θ}{\[2M_1{\sin }^2\mathrm{\θ}+M_3\left(\mathrm{\θ}\right)\]}^2\}}^{\frac{1}{2}}$

V _pgfor compressional wave group velocity, unit (km/s); v _pafor compressional wave phase velocity, unit (km/s); θ is phase angle, unit (°); α ₀for the velocity of longitudinal wave in direction, vertical stratification face, unit (km/s);

Finally the velocity of wave of the group velocity calculated and well-log information is compared, if both coincide, then this v _{p, 0}required by being; If both differences are comparatively large, then change v _{p, 0}repeat above step until both match;

After obtaining the compressional wave group velocity in direction, vertical stratification face, the interval transit time in this direction can be obtained

8. the method for the rock drillability under the different drilling direction of prediction shale formation according to claim 7, it is characterized in that, the concrete grammar of step 7 is as follows: the Mathematical Modeling of the interval transit time in the direction, vertical stratification face obtained in step 6 being brought into step 4 gained can obtain the rock-drillability index value of each drilling direction of shale formation.