3.5 design and selection of energy efficient drill string for drilling of project well

7/28/2019 3.5 Design and Selection of Energy Efficient Drill String for Drilling of Project Well

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6. Design and selection of energy efficient drill string for project well

drilling

6.1. Overview of the program for design and selection of energy

efficient drill string

For the drill string designing that will be used for project well drilling the DrillStr

program the algorithm of which was described in Section 4 should be used.

After loading the program one can see starting working window in the fields of

which the data needed for further calculations is put upon loading.

Figure 6.1 - Starting window of DrillStr program

In the field of regime parameters the meanings of the following ones can be

introduced:

- weight on the bit;- turning number;- pump output.

In the field of data concerning well construction we can change the data on:

- the diameter of the bit;- index of cavernous;- lenght of well;- casing shoe;


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- inside diameter of casing string;- inclination angle.

The next section on the start screen is information about drilling mud in which one

can change:

- drilling mud weight;- jet velocity.

In case of necessity of manual input of rheological parameters of drilling mud it's

necessary to activate appropriate option in this section. Otherwise rheological parameters

will be calculated according to appropriate empirical formulas.

In the field of data on drill string arrangement you must enter the following data:

- type and diameter of drill collar that are included in BHA;- length of the BHA;- length of joint;- quantity, length and weight of stabilizers;- type and diameter of drill collar;- type and diameter of the drill pipe;- length of the middle part of drill string;- type of tool joint.

Figure 6.2 - View of starting windows after entering the required information


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Having data on 1 meter of drill pipe value one can carry out economic calculation of

drill string by activating the appropriate option and pressing a button to open the appropriate

program window.

Figure 6.3 - The window for entering price of pipes

After entering all necessary meanings click the button Calculate. Thus designingof three drill strings constructions that can be used at project well drilling takes place. Data

about construction of drill strings, their weight, loss of capacity for mud circulation and

rotation, coefficients of endurance in the corresponding sections and pressure losses are

displayed in the appropriate fields.

By pressing the button Advanced results opens a window at the work field of

which one can see 3 (4 in the case of available prices of pipes) graphics.

The following parameters are presented in graphic form:

At the 1st graphthe weight of the drill string;

At the 2nd graph - the maximum and minimum values endurance coefficient;

On the 3rd graphthe loss of pressure in the circulation system, depending on

pump output;

At the 4th graph - the cost of the drill string.


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Figure 6.4 - View of starting window after drill strings designing

Figure 6.5 - View of window Extended results

To select the optimal drill string using the data on designed drill strings constructions

press the button Selection of Optimal DS placed in the starting window.


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By clicking this button you will open the window in which, depending on the number

of criteria which will evaluate energy efficiency of each drill strings, there'll be located 4 or

5 fields with values of weight coefficients of each of the corresponding criteria.

For correct selection of the optimal of the drill string construction one should keep

to the following conditions:

= 1.

After entering all necessary values click the button Select. The sequence of

calculation that occurs when pressing the button is shown in Figure 3.6. After finishing the

calculation a message with the number of optimal drill string construction will appear on

display.

Figure 6.6 - The window for entring weight coefficients

In the top right corner of the starting window there are switches for language

selection of the program. It's possible to select the following languages:

- English;

- Ukrainian.

To quit the program click Close.


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Figure 6.7 - Message with result of choice of the optimal drill string construction

6.2. Design and selection of energy efficient drill stringfor project

well drilling

We perform the design and selection of energy efficient drill string for the hole

drilling 909 at Pasichnyanska area for exploitation of gas reservoirs.

The input data for the calculation will be as follows:

Regime parameters:

- weight of the bit, WOB, kN = 210;- turning number, n, RPM = 60;- pump output, Q, l/s = 18,4.

Information about well construction:

- the diameter of the bit, Db, m = 0.2159;- index of cavernous, k = 1.2;- lenght of well, L, m = 3982;- casing shoe, HCS, m = 3632;- inside diameter of casing string, dCS, m = 0.2245;- inclination angle, , = 8.

Information about drilling muds:

- drilling mud weight, , kg/m3= 1120;


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- jet velocity,Vj, m/s = 100.Information about drill string ssembly:

BHA:

- type of drill collarOBTZ2;- outer diameter of drill collar, DBHA, m = 0.178;- length of the BHA, LBHA, m = 42;- quantity of stabilizers,nS = 4;- length of stabilizers,LS, m = 1;- weight of stabilizers, GS, m = 170.

Drill collar:

-

type of drill collarOBTZ2;- outer diameter of drill collar, DBHA, m = 0.178;

Middle part of drill string:

- type of drill pipeTBPK;- outer diameter of drill pipe, DDP, m = 0.14;- type of the toolZSH-178.- length of joint, LJ, m = 36.

After entering all the necessary data we will conduct design of drill string that can be

used for the given well building.

As a result of the calculations we've got three drill strings constructions.

Drill string #1

This drill string consists of drill pipes of the same outside diameter, different inside

diameters which change in turn, and the group of strength that increases by turns too. The

lgorithm for calculating this drill string is shown in Figure 4.2.

As a result of designing we get such drill string arrangement:

Length of drill collar, LDC = 180 m;

Lenght of middle part of drill string, LMPS = 288 m;

Section #1:

Outer diameter, D = 0.1397 m;

Inner diameter, d = 0.1213 m;


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Weight 1 m of pipe, q = 348.5493 N/m;

Group of strength -D (373 MPa);

Length of section, LS = 1764 m.

Section #2:Outer diameter, D = 0.1397 m;



Group of strength - D (373 MPa);


Section #3:




Group of strength - (539 MPa);


Section #4:




Group of strength - (539 MPa);


Section #5:




Group of strength - L (637 MPa);


Calculation of drill string endurance:

Section 1-1: n = 2.56.

Section 2-2: n = 2.62.

Section 3-3: n = 6.88.

Section 4-4: n = 3.78.


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Section 5-5: n = 4.39.

Section 6-6: n = 2.15.

Section 7-7: n = 2.25.

Section 8-8: n = 1.85.

Section 9-9: n = 1.81.

Section 10-10: n = 1.73.

Pressure loss for this construction:

General loss of pressure, MPa = 9.78.

Pressure loss without bit, MPa = 3.53.

Loss of capacity for this construction:

General loss of capacity, kW = 258.94.

Loss of capacity for drill string rotation, kW = 79.73.

Loss of capacity for mud circulation, kW = 179.21.

Weight of the drill string, kN = 1468.54.


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Figure 6.8 - Scheme of drill string #1

V V

64.4m

1764m

288

m

9 D

D

DS 1

MP

0.178 m

V

VI VI180mDS 2

V

10 D

DS 5

DS 4

VI

11 L

VI

VI

14m

540m

10

DS 3

936m

VI9 E

115.6m

DC

BHA

6m

IIII40m

I I

0 0


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Drill string #2

This drill string consists of drill pipe of the same outside and inside diameter and the

same group of strength at all lenght of drill string. The algorithm for calculating this drill

string is shown in Figure. 4.3.

As a result we get the next construction of drill string:



Section #1:


Inner diameter, d = 0.1213 m;Weight 1 m of pipe, q = 354.141 N/m;

Group of strength -L (637 MPa);


Calculation drill string of endurance:

Section 1-1: n = 2.56.

Section 2-2: n = 2.62.Section 3-3: n = 6.88.

Section 4-4: n = 3.78.

Section 5-5: n = 4.39.

Section 6-6: n = 1.73.










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V V

64.4m

288

m

9 L

D

DS 1

MP

0.178 m

V

VI VI

V

3470m

115.6m

DC

BHA

6m

IIII40m

I I

0 0


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Drill string #3

This drill string consists of drill pipe of the same outside and inside diameter at all

lenght of the drill string just with the group of strength taking turns. The algorithm for

calculating this drill string is shown in Figure. 4.4.

As a result we get the next construction of drill string:



Section #1:


Inner diameter, d = 0.1213 m;Weight 1 m of pipe, q = 348.5493 N/m;

Group of strength -D (373 MPa);


Section #2:



Weight 1 m of pipe, q = 348.5493 N/m;Group of strength -E (539 MPa);


Calculation drill string of endurance:

Section 1-1: n = 2.56.

Section 2-2: n = 2.62.

Section 3-3: n = 6.88.

Section 4-4: n = 3.78.Section 5-5: n = 4.39.

Section 6-6: n = 2.81.

Section 7-7: n = 2.25.


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V V

64.4m

288

m

9 D

D

DS 1

MP

0.178 m

V

VI VI

V

1512m

115.6m

DC

BHA

6m

IIII40m

I I

0 0

DS 2

9

1958m

VI VI


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The next step is to choose energy efficient drill string. To do this press the

appropriate button and in the window "enter the weight coefficients of criteria" will appear.

Having used the expert evaluation, the following weight coefficients are obtained in this

case:

- weight of drilling string, 1 = 0.3;- loss of capacity for mud circulation, 2 = 0.3;- loss of capacity for drilling string rotation, 3 = 0.2;- coefficient of endurance, 4 = 0.2.

After entering the data the choice of the optimal drill string is carried out. Without

considering the value of the columns the most energy efficient is drill string #2.

3.5 design and selection of energy efficient drill string for drilling of project well

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