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Drilling Fluid Viscosity Program: VISCOSDF Purpose : To determine shear rate
نویسنده : رضا سپهوند - ساعت ۱:٥۱ ‎ب.ظ روز ۱۳٩٤/٢/۳۱
 

Drilling Fluid Viscosity

 

 

Program: VISCOSDF

Purpose : To determine shear rate from data gathered from theFann rotational viscometer test.                                          

Input       :   Shear rate model to be used : A

                     First rotor speed : N1 (rpm)

                     First dial reading : D1

                     Second rotor speed : N2

                     Second dial reading : D2

                     Radius of interest : R (centimeters)

                     If A = 2( Power low model ):

                             Inner radius of rotor : R2 (centimeters)

                            Outer radius of bob : (centimeters)

Output     :  If A= 1 ( Bingham plastic model ) :

                            Plastic vicosity : PV ( centipoises )

                            Yield point : YP ( pounds/100 sq.feet )

                             Shear rate : SR ( 1/second )

                     If A = 2 ( Power low model )

                              Flow behavior index : n

                              Consistancy Index : K

                              Shear rate : SR ( 1/second )

Equation   :   (1) If =1 ( Bingham plastic model ) :

                             (a) For plastic viscostiy:

 

                           

                                                    

                           

                            (b) For yield point:

                            

 

 

 

                              (C) For shear rate :

 

 

 

 

                             (2) If A=2(power law model) :

                                    (a) For behavior index :

 

 

 

                               (b) For consistency index:

                              

 

 

                                (C) For shear rate :

 

 

 

Variables:              A   : Program flag for model type

                                N1 : First rotor speed

                                D1 : First dial reading

                                N2 : Second rotor speed

                                ND: Desired speed (rpm)

                                 R  : Radius of interest ( centimeters )

                                PV : Plastic viscosity ( centipoise ) 

                                YP : Yield point ( pound / 100 sq.ft )

                                SR : Shear rate ( 1/second )

                                R1 : Outer radius of bob ( centimeters )

                                R2 : Inner radius of bob ( centimeters )

                                n    : Flow behavior index

                                K   : Consistency index

 

 

 


 

Example :

 

Viscosity of Drilling Fluid             

  

                                SHEAR RATES CAN BE CALCULATED BY :

                                                <1> BINGHAM PLASTIC MODEL                                                        <2> POWER LAW MODEL

                                ENTER <1> OR <2> FOR DESIRED METHOD

                                ? 1

                              WHAT IS FIRST ROTOR SPEED (RPM) ?

                               ? 250

                              WHAT IS CORRESPONDING DIAL READING ?

                               ? 24

                              WHAT IS SECOND ROTOR SPEED (RPM) ?                                       ? 480

                              WHAT IS CORRESPONDING DIAL READING ?

                               ? 40

                               WHAT IS DESIRE RPM?

                               ? 250

                               WHAT IS RADIUS OF INTEREST(CM) ? 

                               ?1.7245

                                

                              FIRST ROTOR SPEED IS : 250

                              FIRST DAIL READING IS : 24

                              FIRST SECOND SPEED : 480 RPM

                              FIRST DAIL READING IS : 40

                              DESIRED RPM IS : 250

                              RADIUS OF INTEREST IS : 1.7245 CM

                              BINGHAM PLASTIC MODEL

                              PLASTIC VISCOSITY IS:20.8696 CENTIPOISES

                              YIELD POINT : 6.6087 LB-100-FT2

                              SHEAR RATE IS : 436.078 1/SEC

 

 

200 CLS:PRINT

210 PRINT "VISCOSITY OF DRILLING FLUID"

220 PRINT

230 PRINT "SHEAR RATE CAN BE CALCULATED BY"

240 PRINT "<1> BINGHAM PLASTIC MODEL"

250 PRINT "<2> POWER LAW MODEL"

260 PRINT "ENTER<1> OR <2> FOR DESIRED METHOD"

270 INPUT A

280 IF A<1 OR A>2 THEN GO TO 230

290 PRINT "WHAT IS FIRST ROTOR SPEED (RPM)? "

300 INPUT N1

310 PRINT "WHAT IS CORRESPOUNDING DIAL READING ?"

320 INPUT D1

330 PRINT "WHAT IS SECOND ROTOR SPEED (RPM) ?"

340 INPUT D2

370 PRINT "WHAT IS DESIEDRPM ?"

380 INPUT ND

390 PRINT "WHAT IS RADIUS OF INTEREST (CM) ?"

400 INPUT R

410 ON A GO TO 420,460

420 PV= ( 300/(N2-N1))×(D2-D1)

430 YP = D1-(PV×(N1/300))

440 G = ((5.066/R(2)×ND)+((479×YP/PV)× ((3.17/r[2)-1))

450 GO TO 450

460 PRINT "WHAT IS INNER RADIUS OF ROTOR (CM)?"

470 INPUT R2

480 PRINT "WHAT IS OUTER RADUIS OF BOB(CM) ?"

490 INPUT R1

500 n = LOG(D1/D2)/LOG(N1/N2)

510 K = (520×D1)/((1.703×N1)[n)

520 G=(0.2094×ND×((R{2))[((1/n)))/(n×(((1/R1[2))[(1/n))-((1/R2[2))[1/n))))

540 CLS: PRINT

550 PRINT "FIRST ROTOR SPEED IS:";N1;"RPM"

560 PRINT "FIRST DIAL READING IS: ";D1

570 PRINT "SECOND ROTOR SPEED IS:";N2;"RPM"

580 PRINT "SECOND DIAL READING IS: ";D2

590 PRINT "DESIRE RPM IS: ";ND

600 PRINT "RADIUS OF INTEREST IS: ";D2

610 PRINT

620 ON GO TO 630,680

630 PRINT "BINGHAM PLASTIC MODEL"

640 PRINT "PLASTIC VISCOSITY IS: ";PV;" CENTIPOISE"

650 PRINT "YIELD POINT IS: "; YP;" LB-100-FT2"

660 PRINT "SHEAR RATE IS: ";SR;"1/SEC"

670 GO TO 740

680 PRINT "POWER LAW MODEL"

690 PRINT " INNER RADIUS OF ROTOR IS: ";R2;"CM"

700 PRINT " OUTER RADIUS OF BOB IS: ";R1;"CM"

710 PRINT " FLOW BEHAVIOR INDEX IS: ";n

720 PRINT " CONSISTENCY INDEX IS: ";K

730 PRINT " SHEAR RATE IS: ";SR;"1/SEC"