2. 1. The Rotary System
A. Introduction
B. Kelly, Kelly Valves, and Kelly Saver Sub
C. Rotary Table and Components
2. Well Control System
3. Well Monitoring System
3. 1. Drillstring Tubulars
A. Drill Pipes
a.
properties of drill pipes
B. Drill Pipe Elevator
C. Drill Collars & Heavy Wall Drill Pipes
D. Special Tools
4.
5. Drillstring purpose & constitutes
The purpose of the drillstring is
to transmit mechanical power (torque and rotation),
hydraulic power (pressure and flow rate), and
weight to the bit.
The drillstring is composed mainly
of the following elements:
Drill pipes,
Heavy wall drill pipes,
Drill collars,
Several special elements and tools.
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Drilling Engineering 1 Course (1st Ed.)
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6. schematic of a typical rotary drillstring
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7.
8. Drill Pipe
Below the kelly assembly
(upper kelly valve + kelly +lower kelly valve + kelly saver
sub) is a length of drill pipes (DP).
Drill Pipe is a primary and important drillstring member.
Since the drill pipes are generally compose
the upper and longest portion of the drillstring,
they must be light and strong.
The drill pipe body is a seamless pipe
with outside diameter (OD) varying from 2 3/8in to 6 5/8in.
The outside diameter and the wall thickness t
determine the linear weight of the drill pipe.
The inside diameter (ID) is equal to OD minus 2t.
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9. Drill pipe material
Drill pipes are made of
high grade steel
(there are also drill pipes made of
aluminum, carbon fiber, etc).
API has standardized four steel grades:
E–75, X–95, G–105, and S–135.
The figures represent
the minimum yield strength Ys
(in ksi) of the the steel.
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10. Drill pipe specification and
following basic parameters
Drill pipes are specified with the following basic parameters:
1. Length range:
Range I: 18ft to 22ft,
Range II: 27ft to 30ft (most common),
Range III: 38ft to 45 ft,
2. Nominal linear weight:
in general 2 or 3 linear weight or wall thickness for each standard
OD
3. Wall upset:
EU (external upset), IU (internal upset),
and IEU (internal & external upset).
The wall upset is a length of extra thickness at both ends of the drill
pipe body to provide a smooth transition between the pipe body
and the tool joint, in order to reduce the stress concentration,
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11. Drill pipe specification and
following basic parameters (Cont.)
4. Tool joint OD, ID, and tong length,
5. Steel grade:
(D-55), E-75, X-95, G-105, S-135,
6. Connection size and type:
from 2 3/8in to 5 1/2in, type
IF (internal flush),
EF (external flush),
FH (full hole),
XH (extra hole),
SH (slim hole),
DS (double streamline), and NC (numbered connection),
The API RP-7G contains the specification of all API
standard drill pipes approved for oil and gas drilling use.
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12. The tool joints
The tool joints
are heavy coupling elements having coarse,
tapered threads and sealing shoulders designed
to sustain the weight and
to transmit torque along the drillstring.
The threads of the tool joints are specially designed
to offer strength (axial and torsional), easy handling,
fast connections (number of turns to make the
connection), and leak-proof sealing (metal to metal).
Tool joints might be
welded or screwed to the ends of the drill pipe body.
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13. Typical tool joint designs
(A)
Internal upset DP
with full–hole
shrink–grip TJ,
(B)
External upset DP
with internal–
flush shrink–grip
TJ,
(C) External upset
DP with flash–
weld unitized TJ,
(D) External–
internal upset DP
with Hydrill™–
pressure welded
TJ.
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14.
15. common properties of drill pipes
Two other common properties of drill pipes are
capacity and displacement.
Pipe Capacity:
The capacity Ap of a drill pipe is a measure of
its internal area, expressed as volume/length,
usually gal/ft or bbl/ft.
Sometimes the capacity is expressed as the reversal of the area,
usually in ft/bbl. The reader should be attended to the units.
If Di is the inside diameter (ID) of a drill pipe in inches,
then
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16. common properties of drill pipes
(Cont.)
Pipe Displacement:
The displacement As of the drill pipe is the measure of its
cross-section area, expressed as volume/length, normally
bbl/ft.
If Do is the outside diameter (OD) of a drill pipe in inches,
Annulus Capacity:
The annulus capacity Aa is not a property of the pipe because
it depends on the diameter of the hole opposite to the pipe.
DW is the diameter of the well, & the annulus capacity Aa in bbl/ft
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17. Drill pipe nominal weight
The capacity and displacement formulas above
do not take into account the tool joints,
and manufacturer tables must be consulted
when more accurate values are required.
In particular, the nominal weight that specify a
given drill pipe represents
neither the pipe body linear weight,
nor the average linear weight
(body plus tool joint divided by its length).
It is just a nominal value.
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18. adjusted linear weight of the drill
pipe
a typical 5in DP with 19.5 lb/ft has an internal
diameter of 4.276in.
The density of steel is 489.5 lb/ft3.
Therefore, one foot of pipe body weights
Considering a 30 ft long DP (Range II), the tool
joints (pin and box) comprise about 2 1/2 ft of its
length.
Outside and inside diameters of the tool joints are 6in
and 3 1/2 in respectively.
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19. adjusted linear weight of the drill
pipe (Cont.)
Therefore, the linear weight of the tool joint is
The weight of the drill pipe (body plus TJ) is
Consequently,
the adjusted linear weight of the drill pipe is
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20. DP Classification according to wearing
Drill pipes are subjected to wear during operation.
In particular,
reduction of tool joints OD and wall thickness
reduce tensile and torsion capacity of the element.
Used drill pipes are classified as
Premium or Class I
if the minimum wall thickness is at least 80%
of the wall thickness of a new pipe, and
A new pipe that for the first time is connected to a drillstring is
immediately re–classified to premium DP.
Class II when at least 70%.
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21. New Drill Pipe Dimensional Data
The table
presents
dimensional
data for new
drill pipes.
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22.
23.
24. drill pipe elevator
Drill pipes are handled during tripping using a drill
pipe elevator.
(The swivel and kelly are set aside in the rat hole.)
It is connected by two links to the hook body.
A hinge and latch allows opening and closing the
bi–parted collar around the drill pipe.
The elevator is operated
by the roughnecks at the rotary table level, and
by the derrick man at the monkey board.
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25. A DP elevator and the links to the
hook body
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26. Drill pipes
Drill pipes extend
across almost the whole length of the drillstring and,
although relatively light, they contribute with a significant
part of the drillstring weight (50% or more).
However, drill pipes are, in general,
used only under tension.
They should not be subjected to compression
due to its low resistance to buckling.
Therefore, they cannot be used to apply weight on the bit.
• In horizontal wells, drill pipes can be put under compression
if located in a suitably curved section of the hole; in addition,
compression service drill pipes
(CSDP, S-135 grade DP with 2 or 3 wear knots) are specially designed
to work under compression to drill short radius horizontal wells.
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27.
28. Drill collars role and specifications
Since drill pipes
cannot be used to apply weight on bit,
this role is played be the drill collars
(and also by heavy weight drill pipes as shown next).
Drill collars (DC)
are thick walled steel pipes
located normally right above the bit, and
purpose is to provide weight (axial force) to the bit.
are manufactured with carbon steel (AISI 4115), or
some non-magnetic alloy (stainless steel, monel metal).
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29. A spiraled and a slick drill collars
The outside of drill collars may
be slick (small diameters) or
spiral grooved (any size.).
The purpose of the groves is to
reduce or avoid the risk of
differential sticking opposite to
permeable formations.
The depth of the grooves is made
larger than the average thickness
of a flocculated mud.
Average length of drill collars is
34 ft, but re–threading normally
makes them shorter.
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30. Drill collars elevators
The elevators for drill collars are very similar to the
elevators for drill pipes.
They differ in the shape of the internal hole that clamps
on the pipe.
Most drill collars are recessed so as to be handled with
the elevator.
If the drill collar is not recessed (sometimes even if it is!),
a special sub called lift sub is used.
Lift subs have the shape of the upper end of a drill pipe, and
connects to the top of sections of drill collars during trips.
• Then the drill pipe elevator can be used to lift or lower the
drillstring.
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31. heavy wall drill pipes (HWDP)
In addition to drill pipes and drill collars, there are
special pipes called heavy wall drill pipes (HWDP).
They are intermediary pipes between drill pipes and drill
collars,
being strong enough to be put under compression
(they contribute to the available weight
to apply to the bit), and
they are flexible enough to be used in directional drilling (less
torque and drag than drill collars.)
The use of HWDP also
allow a gradual transition
between the flexible drill pipes and the stiff drill collars
(less stress concentration, and
therefore, less mechanical fatigue on the threads.)
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32. Heavy wall drill pipes
HWDPs look very similar to regular drill pipes,
being of the same length of Range II DP (27 to 30 ft),
but with longer tool joints (to permit re–threading).
HWDPs have a central external upset.
it provides an additional third point of contact,
increasing the overall stiffness and protecting the pipe
sections from excessive wearing in high inclination wells
(normally the tool joints and central upset have a band
of hard material to prevent/reduce wear).
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33.
34. Drillstring equipment
Several drilling equipment are used in the
drillstring.
The most important are:
stabilizers,
provide localized additional support points
(localized larger diameter)
in one or more positions along the drillstring.
reamers,
hole–openers.
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35. Advantages of drillstring
For vertical wells, the stabilizer prevents low
frequency vibration in the drillstring during
rotation.
The advantages are:
reduce wear (of both drillstring and casing),
reduce mechanical fatigue,
reduce mechanical instability of formation (caving),
reduce tortuous hole.
Stabilizers are essential equipment for directional
drilling.
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36. Stabilizer special characteristics and
types
angle drop–off,
Suitable choice of
angle hold.
number and position of
stabilizers in the
Stabilizer may be of the
drillstring lend to the
following types:
bottom hole assembly
integral blade,
(BHA, the lower part of
the drillstring composed
of drill collars, stabilizers
and HWDP)
special characteristics in
terms of inclination
control:
interchangeable blade,
non–rotating blades,
replaceable blades,
clamp–on
near-bit,
angle build–up,
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37. The diameter of stabilizers
The diameter of stabilizers can be in gauge or under
gauge.
More recently, remote adjustable blade stabilizers
were introduced.
Changing suitably the diameter of the stabilizers provide
a level of control in the directional behavior of BHAs.
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39. Reamers
The purpose of the reamer is to keep
the diameter of the open hole in
gauge, that is, with the expected
original diameter of the bit.
Two reasons may cause
a decrease in the original diameter:
formation swelling (hydrated shales,
moving salt),
bit diameter reduction (hard and
abrasive formations).
The reamer also functions as a
stabilizer since the rollers touch the
borehole wall.
Different types of rollers can be
selected to suit the formations being
reamed.
A roller reamer
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40. The hole–opener
The hole–opener is a tool designed to
enlarge the diameter of a previously (or
simultaneously drilled smaller borehole.
Three situations (at least) are possible:
to drill the borehole section with a smaller bit,
and later to enlarge to the final diameter (a
special tool called bull nose is connected in the
place of the bit, to guide the hole opener along
the pre-drilled hole),
to drill the borehole section with a smaller bit
and simultaneously enlarge to the final
diameter,
to enlarge a section below a casing with a
diameter larger than the internal diameter of
the casing.
In this case, a special hole opener (also caller
underreamer) with hinged arms actuated
hydraulically is used (the drilling fluid pressure
actuates in rams that open the arms forcing the
cutters against the borehole wall).
A fixed hole–opener
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41. 1. Jorge H.B. Sampaio Jr. “Drilling Engineering
Fundamentals.” Master of Petroleum
Engineering. Curtin University of Technology,
2007. Chapter 3