05 lifting capacity

8/10/2019 05 Lifting Capacity

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Lifting Capacity


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2005 PetroSkills LLC, All Rights Reserved56

Lifting Capacity

0

200

400

600

800

1000

1200

1400

1600

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2000

0 5 10 15 20 25 30 35 40

Yield Point, lb/100 sq ft

K

V i s c o s i

t y ,

e q u

i v a

l e n

t c p

5 cp10 cp

15 cp

20 cp

25 cp30 cp

35 cp

40 cp

P V

Lifting Capacity


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Lifting Capacity

Example 5-3 in the book with the14 ppg mud (1680 kg/m 3), andannular velocity of 98 fpm (29.9

m/min)PV = 100 60 = 40YP = 60 40 = 20 (10)n = 0.7365

Calculate the K value

Lifting Capacity


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Lifting Capacity

Calculate the K value)(511 )1( YP PV K n

cp K 310)2040(511 )7365.01(

Lifting Capacity


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0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 5 10 15 20 25 30 35 40


K

V i s c o s i

t y ,

e q u

i v a

l e n

t c p

5 cp10 cp

15 cp

20 cp

25 cp30 cp

35 cp

40 cp

P V

Lifting Capacity

310

Lifting Capacity


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Lifting Capacity

Calculate the CCI

000,400

v K CCI f

1.1000,400

9831014CCI

Lifting Capacity


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Lifting Capacity

Class problemHole size = 8 (222mm) Dp = 4 (114mm)

MW = 9.8 ppg (1180 kg/m 3)Q = 275 gpm (1.04 m 3/min)Plastic Viscosity = 14

Yield Point = 12 (6)Calculate the Carrying CapacityIndex or CCI

Lifting Capacity


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Lifting Capacity

Calculate the annular velocity

225.24

ph DD

Qv

m/min36.5or fpm6.1195.475.8

2755.2422

v

Lifting Capacity


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Lifting Capacity

DetermineK

from the graph

Lifting Capacity


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0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 5 10 15 20 25 30 35 40


K V

i s c o s i

t y ,

e q u

i v a

l e n

t c p

5 cp10 cp

15 cp

20 cp

25 cp30 cp

35 cp

40 cp

P V

Lifting Capacity

12

14

276

Lifting Capacity


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Lifting Capacity

Or you can calculate the K value

)(511)1(

YP PV K n

cpK 276)1214(511 )6211.01(

YP PV YP PV

n2

log32.3

6211.01214

12142log32.3

n

Lifting Capacity


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Lifting Capacity

Calculate the CCI

May need more viscosity orannular velocity

000,400

v K CCI f

81.0000,400

6.1192768.9CCI

Directional Wells


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Directional Wells

Hole cleaning in avertical well is afunction of

Annular velocityParticle diameterMud viscosity, andMud density

71.0

4.06.0

6.1

6.346f e

f P ps

d V

Directional Wells


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Directional Wells

If the annular velocity of the drillingfluid exceeds the settling velocity ofthe particle, the particle will be

carried out of the holeIf not, the particle must be groundsmaller until the settling velocity islower than the annular velocity

V p = V f V s

Directional Wells


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Directional Wells

In a directional well,the particle velocityis still a function ofthe velocity of thefluid and settlingvelocity but they areno longer directly

opposingThe particle willseek the low side of

the hole

Directional Wells


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Directional Wells

A cuttings bedwill form on thelow side of the

hole unless theannularvelocity is highenough toerode thecuttings bed

ShakerWellbore

Cuttings

Mud

Cuttings Bed

Directional Wells


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D ect o a We s

After a cuttings bed is formed, thefluid in the annulus will have toerode the cuttings bed in order to

carry the cuttings up the holeThe bed will continue to grownarrowing the annular space and

causing an increase in the annularvelocity until the rate of erosionequals the rate of deposition

Directional Wells


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Experiments were conducted inthe laboratory to determine howmud viscosity, flow regime and

annular velocity affects holecleaning in a directional wellThree drilling fluids were used.

The first was water, which has avery low viscosity and is alwaysin turbulent flow

Directional Wells


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The second fluid was a lightlygelled mud with a low viscosity.The viscosity was low enough so

that the fluid was in turbulent floweven at lower annular velocitiesThe third fluid was a higher

viscosity mud. Even at high flowrates, the flow was still laminar

Directional Wells


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Water PV = 1 YP = 0, always turbulentMud PV = 3 YP = 2 (1), alwaysturbulentMud PV = 19 YP = 17 (8), alwayslaminar

Results

0 and 10Wells with inclinations between 0 and10 behave the same as vertical wells

Directional Wells


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Increasing annular velocity andviscosity will improve hole cleaning

71.0

4.06.0

6.1

6.346f e

f P ps

d V

Directional Wells


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0

10

20

30

40

0 20 40 60 80Inclination, degrees

C u

t t i n g s

C o n c e n

t r a t i o n

Turb. Water 115'/min Turb. Mud 115'/min Lam. Mud 115'/min

Lam. Mud 172'/min Turb. Mud 229'/min Lam. Mud 229'/min

Laminar Mud PV= 19 YP= 17

Turbulent Mud PV= 3 YP= 2Turbulent Water PV= 1 YP= 0

Directional Wells


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10 to 30 At velocitiesless than 120fpm (37

m/min), thecuttings willsettle to thelow side ofthe hole andslide downthe wellbore

ShakerWellbore

Cuttings

Mud

Directional Wells


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Within a shortdistance, theywill again endup in the highervelocity portionsof the annulusand be carriedup the hole

ShakerWellbore

Cuttings

Mud

Directional Wells


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The hole cleaning capacity of themud at this inclination is not asefficient as vertical wells

At annular velocities above 120 fpm(37 m/min), the cuttings are not ableto form a bed on the low side of thehole, but rather are carried up thewellbore along the low side in slugs ordunes

Directional Wells

40


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0

10

20

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0 20 40 60 80

Inclination, degrees

C u

t t i n g s

C o n c e n

t r a

t i o n

Turb. Water 115'/min Turb. Mud 115'/min Lam . Mud 115'/min


Laminar Mud PV= 19 YP= 17

Turbulent Mud PV= 3 YP= 2

Turbulent Water PV= 1 YP= 0

At flow rates in excess of 180 fpm (55m/min), the cuttings are carried smoothlyalong the low side of the hole

Directional Wells


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30 to 60Hole cleaning is the most critical atinclinations between 30 and 60 withthe inclinations between 40 and 50being the most difficult A cuttings bed forms at 40 with anannular velocity less than 150 fpm (46m/min) At 50, a bed would form at annularvelocities of 180 fpm (55 m/min)

Directional Wells


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Not only can acuttings bedform rapidly attheseinclinations, butthe cuttings slidedown thewellbore on thelow side of the

hole when thepump is turnedoff

ShakerWellbore

Cuttings

Mud

Cuttings Bed

Slumped Cuttings Bed

Directional Wells


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In directional wells with inclinationsless than 40, the cuttings will fall tothe bottom of the hole

Poor hole cleaning will be evidencedby fill on bottom

Directional Wells


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In high inclination or horizontal wells,the cuttings will fall to a maximuminclination

Poor hole cleaning will be evidencedby excessive drag while pulling thebottomhole assembly through thesection where the cuttings quit fallingWhile tripping in the hole, bridges willbe encountered in this section

Directional Wells


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60 o to 90 o Above an inclination of 60, cuttings beddevelopment does not get any worse A cuttings bed will build up reducing the

annular area which increases the annularvelocity As the annular velocity increases, thedrilling fluid will erode the bed faster At some point, an equilibrium will bereached between the deposition anderosion of the cuttings bed

Directional Wells


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Annular velocity Annular velocity is the variable thatwill affect hole cleaning the most

Increasing the viscosity may actuallyreduce hole cleaning at lower flowrates

At higher flow rates, viscosity makesless of a difference

0

10

20

30

40

0 20 40 60 80Inclination, degrees

C u

t t i n g s

C o n c e n

t r a t

i o n

Turb. Water 115'/min Turb. Mud 115'/min Lam. Mud 115'/min


Laminar Mud PV= 19 YP= 17Turbulent Mud PV= 3 YP= 2Turbulent Water PV= 1 YP= 0

Directional Wells


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Fluids in turbulent flow have relatively flatvelocity profiles; whereas, the laminarvelocity profile is much more pointedIn laminar flow, there can be a significant

difference between the velocity of the fluidin the center of the annular space ascompared to the velocity near the pipe andhole walls

Laminar Turbulent

Directional Wells


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Pipe movementDrill pipe movement is an important holecleaning consideration in directional wells

Both rotation and reciprocation willincrease the hole cleaning capacity in adirectional wellWhen reciprocating the drill pipe, theannular velocity around the tool jointincreases aiding hole cleaning

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As an example, if the annular velocity ina 4 1/2 (114mm) by 8 1/2 inch (216mm)annulus is 120 fpm (36.6 m/min), then theannular velocity around 6 1/4 inch(159mm) tool joints would be 208 fpm(63.4 m/min) or a 73 percent increase

Directional Wells


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Rotation will also aid hole cleaningWhile drilling with a steerable systemin the oriented mode (slide mode), thedrag in a horizontal well increased After the connection was made,rotation was resumed and the drag inthe well decreasedIn this case, the increased drag wasdue to a cuttings buildup in the well

Directional Wells


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As in vertical wells, washoutswill impair hole cleaningThe annular velocity in awashout will be reduced makinghole cleaning more difficult

Directional Wells


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If the washout is at an inclination of

35 to 55, the cuttings accumulationcan slide down the hole when thepump is turned offHole cleaning in formations that aresensitive to hole erosion can bedifficultThe high annular velocities requiredto clean a directional well canenlarge the hole causing a reductionin annular velocity

Directional Wells


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However, it should beremembered that the formationof a cuttings bed will reduce holesize causing an increase inannular velocity anyway, whichcan still lead to erosion

05 lifting capacity

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