Upload
saeedjad
View
229
Download
1
Embed Size (px)
Citation preview
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 1/66
© 2001 PetroSkills LLC, All Rights Reserved
TORQUE AND DRAG
Drag is the increase in string
weight when pulling out of the
hole or the reduction in string
weight while tripping in the hole
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 2/66
© 2001 PetroSkills LLC, All Rights Reserved2
Torque and Drag
Torque is the force required toturn the drill string
In a perfectly vertical well, thetorque and drag in a well arenegligible
In directional wells, torque anddrag can be significant
In horizontal or extended reachwells, torque and drag arecrucial
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 3/66
© 2001 PetroSkills LLC, All Rights Reserved3
Torque and Drag
The magnitude of the torque anddrag is determined by the force
with which the pipe contacts the
hole wall and the frictioncoefficient between the wall and
pipe
The contact force is called the
normal force
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 4/66
© 2001 PetroSkills LLC, All Rights Reserved4
Torque and Drag
First, consider simple friction
F
W
The force F
required to movethe block of weight
W (normal force) is
F = μW Where μ is the
friction coefficient
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 5/66
© 2001 PetroSkills LLC, All Rights Reserved5
Torque and Drag
If the plane isinclined, the
normal force is a
function of thecosine of θ
T=-W sin θ +
μ W cos θ θ
T
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 6/66
© 2001 PetroSkills LLC, All Rights Reserved6
Torque and Drag
At 0 degrees, thenormal force
equals the
weight of theblock
At 90 degrees,
the normal forceis zero
θ
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 7/66© 2001 PetroSkills LLC, All Rights Reserved7
Torque and Drag
The same is true for a drill stringin the hole
However, inclination is measured
from the vertical rather than thehorizontal
If the inclination is zero, the normal
force is zero
If the inclination is 90o, the normal
force equals the weight of the pipe
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 8/66© 2001 PetroSkills LLC, All Rights Reserved8
Torque and Drag
Class problem:Given the two blocks below
F1
W = 100 lbs
F2
W = 100 lbs
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 9/66© 2001 PetroSkills LLC, All Rights Reserved9
Torque and Drag
Multiple choice – which is true
A. F1 = F2
B. F1 < F2
C. F1 > F2
D. None of the above
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 10/66© 2001 PetroSkills LLC, All Rights Reserved10
Torque and Drag
Pipe weight is not the onlysource of drag
When hole curvature is
considered, an additional force
is added to the normal force
That force is a function of pipetension and dogleg severity
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 11/66© 2001 PetroSkills LLC, All Rights Reserved11
Torque and Drag
Most of the torque and drag in adirectional well comes from pipe
tension (or compression) in a
dogleg
Horizontal and other high angle
wells do have a significant drag
component from the pipe weight
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 12/66© 2001 PetroSkills LLC, All Rights Reserved12
Torque and Drag
The normalforce is a
function of
tension anddogleg severity
Consider a pipe
segment bentaround a corner
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 13/66© 2001 PetroSkills LLC, All Rights Reserved13
Torque and Drag
Summing forces in the x and ydirection yields
avg x I W I T F sinsin
avg y I AT F sinsin
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 14/66© 2001 PetroSkills LLC, All Rights Reserved14
Torque and Drag
The normal force is the vectorialsum of the x and y forces
Once the normal force is
calculated, the drag for the pipesegment can be calculated
22
sinsinsinsin avg avg N I AT I W I T F
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 15/66© 2001 PetroSkills LLC, All Rights Reserved15
Torque and Drag
The drill string isbroken intosegments starting atthe bit where the
tension is knownThe normal force iscalculated and thetension at the top of
the segment iscalculated based ondrag and pipe weight
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 16/66© 2001 PetroSkills LLC, All Rights Reserved16
Torque and Drag
The tension at the top of the
segment becomes the tension at
the bottom of the next segment
The drag and pipe weight for that
segment are used to calculatethe tension at the top
N avg
F I W T T cos12
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 17/66© 2001 PetroSkills LLC, All Rights Reserved17
Torque and Drag
The process is repeated until thecalculations reach the surface ,
which is the hook load
Tripping in the hole, the drag
acts in the opposite direction
N avg F I W T T cos12
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 18/66© 2001 PetroSkills LLC, All Rights Reserved18
Torque and Drag
While tripping in the hole, thereis an additional normal force that
can be imposed on the pipe
If there is sufficient
compression, the pipe can be
buckle
In a vertical well, the pipe
buckles almost immediately
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 19/66© 2001 PetroSkills LLC, All Rights Reserved19
Torque and Drag
In a directional well, it takes afinite amount of compression to
cause buckling
A very simple buckling equation
is as follows:
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 20/66© 2001 PetroSkills LLC, All Rights Reserved20
Torque and Drag
The critical buckling load is a
function of the sine of theinclination, the radial clearance
and the moment of inertia
At zero degrees, the pipebuckles immediately
F E Ag I
r crit 2
I sin
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 21/66© 2001 PetroSkills LLC, All Rights Reserved21
Torque and Drag
As the pipe gets stiffer (larger OD and smaller ID), it takes more
force to cause buckling
As the hole gets bigger, the pipe
buckles easier
In oil field terms, the equation isas follows
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 22/66© 2001 PetroSkills LLC, All Rights Reserved22
Torque and Drag
If the pipe is buckled, an
additional normal force isapplied according to the
following equation:
)(sin)/)((1082.9
445
OD D I B ft Wt IDOD F
h
crit
W rF
E N
f
2
4 I
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 23/66© 2001 PetroSkills LLC, All Rights Reserved23
Torque and Drag
Note that the normal forcechanges with the square of the
force that exceeds the buckling
load
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 24/66
© 2001 PetroSkills LLC, All Rights Reserved24
Torque and Drag
Calculate the critical buckling load of 4 ½” OD (3.826” ID), 16.6#/ft (nominal)
drill pipe at 90o in an 8 ½” hole. The
mud weight is 10 ppg. The actual wt/ftof the drill pipe is 18.3#/ft with tool
joints.
85.0)10)(015.0(1))(015.0(1
B MW B
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 25/66
© 2001 PetroSkills LLC, All Rights Reserved25
Torque and Drag
It takes 27,343 lbs to buckle 4 ½” drill
pipe in an 8 ½” horizontal well
lbs F
F
crit
crit
343,27
)5.45.8(
90sin)85.0)(3.18)(826.35.4(1082.9445
)(
sin)/)((1082.9 445
OD D
I B ft Wt IDOD F
h
crit
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 26/66
© 2001 PetroSkills LLC, All Rights Reserved26
Torque and Drag
Class ProblemCalculate the critical buckling load for 1.5”
coiled tubing in an 8 ½” hole
1.5” OD by 1.31” ID 1.42 lbs per foot
Fluid is water at 8.34 ppg
Inclination is 90
o
Answer 607 lbs
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 27/66
© 2001 PetroSkills LLC, All Rights Reserved27
Torque and Drag
In 4 ½” casing it takes 1012 lbs
In 2 7/8” tubing it takes 1652 lbs
lbs F
F
crit
crit
607)5.15.8(
90sin)87.0)(42.1)(31.15.1(1082.9 445
87.0)34.8)(015.0(1))(015.0(1
B MW B
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 28/66
© 2001 PetroSkills LLC, All Rights Reserved28
Torque and Drag
Torque can be calculated in avery similar manner
However, the drag is generally
ignored while calculating the
tension in a simplified torque
and drag model
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 29/66
© 2001 PetroSkills LLC, All Rights Reserved29
Torque and Drag
Weight Indicator
Hook Load Down
Hook Load UpRotating Weight
Martin Decker
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 30/66
© 2001 PetroSkills LLC, All Rights Reserved30
Torque and Drag
Drag influence is alleviated whenthe pipe is rotated so the tension
is simply
The normal force is calculated
based on the pipe weight and thetorque can be calculated from
the normal force
avg I W T T cos12
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 31/66
© 2001 PetroSkills LLC, All Rights Reserved31
Torque and Drag
Torque is in foot-poundsThe normal force supplies the pounds
The radius of the pipe supplies the
moment arm or foot
The bit torque is entered and thetorque is summed up the holethe same as the drag
M M F R N 2 1
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 32/66
© 2001 PetroSkills LLC, All Rights Reserved32
Torque and Drag
Compare the drag from twodifferent wells
The average inclination is the same
in both wells
Case A has an average dogleg
severity of 4o/100’
Case B has an average doglegseverity of 2o/100’
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 33/66
© 2001 PetroSkills LLC, All Rights Reserved33
Torque and Drag
Also assume that each case has
50,000 lbs or 200,000 lbs tensionThe tension would change depending
upon how much hole was drilled
below the dogleg
MD I A DLS
2000
2100
2200
2300
40
44
48
52
135
135
135
135
4o/100
4o/100
4o/100
4o/100
MD I A DLS
2000
2100
2200
2300
43
45
47
49
135
135
135
135
2o/100
2o/100
2o/100
2o/100
Case A Case B
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 34/66
© 2001 PetroSkills LLC, All Rights Reserved34
Torque and Drag
The air weight of the 4 1/2 inchdrill pipe is 18.1 lbs/ft including
tool joints (can be found in API
RP7G)
Calculate the buoyant weight per
100 feet
W Length wt ft Bouyancy Factor /
W 100 18 1 1 0 015 10. .
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 35/66
© 2001 PetroSkills LLC, All Rights Reserved35
Torque and Drag
The drag is equal to the normal
force times the friction
coefficient
W lbs 1538 50 100. / '
T F N
22 sinsinsinsin avg avg I AT I W I T T
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 36/66
© 2001 PetroSkills LLC, All Rights Reserved36
Torque and Drag
Make the calculations at 100 footintervals
Case A: 50,000 pound tension
502/4852 avg I
I 52 48 4
A 135 135 0
2250sin0sin5000050sin50.15384sin5000040.0 T
T lbs drag 92371.
T d D
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 37/66
© 2001 PetroSkills LLC, All Rights Reserved37
Torque and Drag
In order to calculate the drag inthe next interval, the tension at
2,200 feet must be calculated.
From Equation 6:
N avg F I W T T cos12
T
250000 1538 50 50 923 71 . cos .
T lbs2 51912 64 .
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 38/66
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 39/66
© 2001 PetroSkills LLC, All Rights Reserved39
Torque and Drag
Now calculate the drag from2,000 feet to 2,100 feet
2246sin0sin64.5191246sin50.15384sin64.5191240.0 T
T lbs drag 100582.
N avg F I W T T cos12
82.100546cos50.153864.519122 T
T lbs2 53987 19 .
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 40/66
© 2001 PetroSkills LLC, All Rights Reserved40
Torque and Drag
I avg 44 40 2 42/
I 44 40 4
A 135 135 0
T F N
2s0sin19.5398742sin50.15384sin19.5398740.0 T
T lbs drag 1094 60.
N avg F I W T T cos12
60.109442cos50.153819.539872 T
T lbs2 5622512 .
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 41/66
© 2001 PetroSkills LLC, All Rights Reserved41
Torque and Drag
Total drag for the 300 footinterval in Case A with 50,000
pound tension is:
Drag 923 71 1005 82 1094 60. . .
Drag lbs 3024 13.
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 42/66
© 2001 PetroSkills LLC, All Rights Reserved42
Torque and Drag
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
50,000.00
51,912.64
53,987.19
56,225.12
TOTAL
923.71
1005.82
1094.60
3024.13
4o/100’ with 50,000 lbs
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds) 2300
2200
2100
2000
200,000.00
206,098.02
212,474.74
219,134.88
TOTAL
5109.09
5307.99
5516.81
15,933.89
4o/100’ with 200,000 lbs
At 4o/100’
The
tension istimes 4
The drag is
times 5.3
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 43/66
© 2001 PetroSkills LLC, All Rights Reserved43
Torque and Drag
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
50,000.00
51,270.12
52,611.89
54,025.55
TOTAL
240.66
273.04
306.96
820.66
2o/100’ with 50,000 lbs
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
200,000.00
203,364.09
206,829.06
210,395.56
TOTAL
2334.63
2396.24
2459.80
7190.67
2o/100’ with 200,000 lbs
At 2o/100’
The
tension istimes 4
The drag is
times 8.8
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 44/66
© 2001 PetroSkills LLC, All Rights Reserved44
Torque and Drag
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
50,000.00
51,912.64
53,987.19
56,225.12
TOTAL
923.71
1005.82
1094.60
3024.13
4o/100’ with 50,000 lbs
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
50,000.00
51,270.12
52,611.89
54,025.55
TOTAL
240.66
273.04
306.96
820.66
2o/100’ with 50,000 lbs
At 50,000
lbs tension
The doglegseverity is
times 2
The drag is
times 3.7
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 45/66
© 2001 PetroSkills LLC, All Rights Reserved45
Torque and Drag
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
200,000.00
206,098.02
212,474.74
219,134.88
TOTAL
5109.09
5307.99
5516.81
15,933.89
4o/100’ with 200,000 lbs
DEPTH
(feet)
TENSION
(pounds)
INTERVAL
DRAG
(pounds)
2300
2200
2100
2000
200,000.00
203,364.09
206,829.06
210,395.56
TOTAL
2334.63
2396.24
2459.80
7190.67
2o/100’ with 200,000 lbs
At 200,000
lbs tension
The doglegseverity is
times 2
The drag is
times 2.2
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 46/66
© 2001 PetroSkills LLC, All Rights Reserved46
Torque and Drag
Increasing both tension anddogleg severity will increase the
torque and drag
However, for a 2o /100’ dogleg, ittakes twice as much hole to
achieve the same inclination as a
4o /100’ dogleg
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 47/66
© 2001 PetroSkills LLC, All Rights Reserved47
Torque and Drag
Class Problem
The buoyant weight of a pipe segment is-2000 lbs (100 foot long) and there is100,000 lbs tension at the bottom of thesegment
The average inclination for the pipesegment is 200 and the friction coefficient is0.30
Two cases:
Case 1 Case 2
ΔI = 00 ΔI = 00
Δ A = 00 Δ A = 180
What is the tension at the top of the pipesegment
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 48/66
© 2001 PetroSkills LLC, All Rights Reserved48
Torque and Drag
Drilling torque increasing withdepth
45
40
35
30
25
20
1510,000 10,500 11,000 11,500 12,000 12,500 13,000 13,500 14,000 14,500 15,000
PDC Torque
Trend
Roller Cone Torque Trend
Increased Torque Caused by Cuttings
Buildup
Depth, ft
Erratic Torques Caused by Torsional Dynamics
T
o r q u e ,
1 0 0 0 l b f - f t
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 49/66
© 2001 PetroSkills LLC, All Rights Reserved49
Torque and Drag
Three ways to change the drag ina well
Change the friction coefficient
Change the directional profile
Change the string weight or tension
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 50/66
© 2001 PetroSkills LLC, All Rights Reserved50
Torque and Drag
Reducing the friction coefficientcan have the most dramaticaffect on torque and drag
The friction coefficient can beaffected by mud type, bentonitecontent, solids content and variousadditives
Generally, oil base muds will havethe lowest friction coefficient but notalways
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 51/66
© 2001 PetroSkills LLC, All Rights Reserved51
Torque and Drag
Friction coefficients will depend uponthe torque and drag model used
Below are some ranges for friction
coefficients from Sperry SunDrilling Fluid μ in Casing μ in Formation
Oil based 0.16 to 0.20 0.17 to 0.25
Water based 0.25 to 0.35 0.25 to 0.40
Brine 0.30 to 0.40 0.30 to 0.40
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 52/66
© 2001 PetroSkills LLC, All Rights Reserved52
Torque and Drag
With a top drive, pipe can be runin the hole even if it will not fall
by its own weight because
rotation reduces the drag
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 53/66
© 2001 PetroSkills LLC, All Rights Reserved
Direction of
Friction Drag
V A
= Axial Velocity
Component
V C
= Circumferential
Velocity Component
V R
= Resultant Velocity Component
Axial Drag
RotationV C
DownwardTravel
V R
V A
F N = Normal Force
q g
Resultant Drag = μFN = Constant
Circumferential Drag
Axial
Drag
Axial drag is reduced when rotational speed is increased.
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 54/66
© 2001 PetroSkills LLC, All Rights Reserved54
Torque and Drag
Changing the directional profilecan affect the torque and drag
Consider a well with a target TVD
of 15,500 feet and departure of 8,800 feet
There are any number of directional profiles that can be
used to hit the target
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 55/66
© 2001 PetroSkills LLC, All Rights Reserved55
Torque and Drag
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 56/66
© 2001 PetroSkills LLC, All Rights Reserved56
Torque and Drag
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 57/66
© 2001 PetroSkills LLC, All Rights Reserved57
Torque and Drag
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 58/66
© 2001 PetroSkills LLC, All Rights Reserved58
Torque and Drag
The directional profile does notmake a significant difference
Getting from point A to point B
takes a certain amount of drag
Generally, lower dogleg
severities will yield slightly lower
drag values
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 59/66
© 2001 PetroSkills LLC, All Rights Reserved59
Torque and Drag
When drilling a directional well,the actual dogleg severity will begreater than the planned dogleg
severity; therefore, the actualdrag values will be greater thanthe calculated values
To compensate, you can use aslightly higher friction coefficientwhen planning
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 60/66
© 2001 PetroSkills LLC, All Rights Reserved60
Torque and Drag
Reducing the pipe weight will
reduce the tension and therefore
drag values
Replace drill collars with HWDPand drill pipe
Drill pipe can be run in
compression in a directional wellif required but should not exceed
the critical buckling load
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 61/66
© 2001 PetroSkills LLC, All Rights Reserved61
Torque and Drag
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 62/66
© 2001 PetroSkills LLC, All Rights Reserved62
Torque and Drag
In horizontal wells, the drill pipewill not fall in the hole under its
own weight
The pipe must be pushed intothe hole using the weight of the
pipe above the critical inclination
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 63/66
© 2001 PetroSkills LLC, All Rights Reserved63
Torque and Drag
The critical inclination is werethe drag equals the weight
component along the axis of the
holeThe critical inclination can be
calculated based on the friction
coefficient
1tan 1 I
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 64/66
© 2001 PetroSkills LLC, All Rights Reserved64
Torque and Drag
Anything above the criticalinclination must be pushed
Keep the pipe in the horizontal
section as light as possibleDrill collars require more weight
to push them along the wellbore
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 65/66
© 2001 PetroSkills LLC, All Rights Reserved65
Torque and Drag
The pipe in the horizontalsection should be as light as
practical so limit the BHA
HWDP is used in and above thecurve
Drill collars may or may not be
required in the vertical portionabove the HWDP
Torque and Drag
7/28/2019 Torque and Drag
http://slidepdf.com/reader/full/torque-and-drag 66/66
Torque and Drag
Typical drill string design for
horizontal well
Higher Weight
or StandardDrillpipe
Steerable Motor
Bit
MWD/LWD
Non-magCompressive
Service Pipe
Premium Drillpipe
0
2000
4000
6000
8000
10,000
12,000
14,000
16,0000 1000 2000 3000 4000 5000
HWDP
D e p t h ,
f t