lec 7 oct iii tripping and trajectory.pdf
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Tripping and Trajectory Control
Lecture 7
PET 356
Q 1 2015-2016
Abu Dhabi Polytechnic
Normal Drilling Operations Practices
Tripping
Tripping is the act of pulling pipe out of or running pipe into a well
- To change bits
- At the end of a hole section
- Mechanical problems
- Change bottom hole assembly (BHA)
Normal Drilling Operations Practices
Tripping
- The kelly is removed from the drill string before tripping
- The kelly and swivel are stored in the rathole
Normal Drilling Operations Practices
Tripping
The pipe is pulled or run using the elevators attached to the hook
Normal Drilling Operations Practices
Tripping practices
-Determine initial overpull limit prior to tripping out of hole (0.5 of BHA Wt.).
•If the tight spot at the same depth (WB G-Back ream).•If the tight spot moved up (Hole cleaning problem)
-Determine initial set down limit (0.25 of the drill string overpull limit).* 0.25 of (ST tension limit – ST Wt. – Up drag).
Normal Drilling Operations Practices
Normal Drilling Operations Practices
Recording off BTM torque & Rotating weight
1- Position the bit off BTM about 20 ft.2- Stop the pump.3- Slowly increase the RPM to a preselected standard RPM.4- Record rotating weight & off BTM torque after stabilization.
Normal Drilling Operations Practices
Recording Up weight
1- Stop rotation.2- Stop the pump.3- Raise the string with a preselected standard Speed.4- Record up weight after stabilization.
Normal Drilling Operations Practices
Recording Down weight
1- Stop rotation.2- Stop the pump.3- Lower the string with a preselected standard Speed.4- Record down weight after stabilization.
Normal Drilling Operations Practices
Effect of circulating pressure
Recording string weights without circulation provides actual string drag information.
Stop circulation when recording string weight data
Normal Drilling Operations Practices
Basic Rotary Assembly Types
Dropping Assembly (Pendulum)
Building Assembly (Fulcrum)
Holding Assembly (Packed Hole)
Normal Drilling Operations PracticesAngle Dropping Assembly
wellbore contact
tangency length
negative side force
To increase drop rate :
•Increase stiffness
•Increase bit/DC size ratio
•Increase DC weight
•Decrease WOB
•Increase rotary speed
Normal Drilling Operations Practices
The Pendulum Principle
Pendulum assemblies drop angle as a pendulum
creates negative side force
Fs = Wc x BF x TL x sin IN
Fs Side force on bit (lbs)
Wc Weight below tangency point (lbs/ft)
TL Length of pendulum (ft)
IN Inclination at tangency point (deg)
BF Buoyancy factor (-)
Fs
tangency point
Normal Drilling Operations Practices
Generic Angle Dropping (Pendulum) Assembly
Bit
Drill collar, 30-90ft
String stabilizer, full gauge
Drill collar, 30ft
String stabilizer, full gauge
Drill collar,90ft
HWDP, 90ft min.
Drill pipe
Normal Drilling Operations Practices
The Fulcrum PrincipleThe fulcrum uses a near-bit stabilizer
WOB (if sufficient) will cause the bottom DC to bend
In holes with inclination > 5°, DC will bend towards the low
side of the hole
This bend will cause bit to exert a side force against the
high side of the hole, resulting in a build-up of angle as
drilling progresses
WOB
Normal Drilling Operations Practices
Generic Angle Building (Fulcrum) Assembly
Bit
Near-bit Stabilizer, full gauge
Drill collar, 30-90ft
String stabilizer, full gauge
Drill collar, 30-60ft
String stabilizer, full gauge
Drill collar,90ft
HWDP, 90ft min.
Drill pipe, as required
a b
Normal Drilling Operations Practices
Packed Hole Assembly
The packed hole assembly is used to maintain
angle
or build/drop at mild rates
3 or more stabilizers are placed at specified
points to
control the deflection of the drill collar string
The increased straightness of the drill collars
reduces
or eliminates the bit tilt
Normal Drilling Operations Practices
Generic Packed Hole Assembly
Bit
Near-bit Stabilizer, full
gauge
Short Drill collar, 6-20ft
String stabilizer, full gauge
Drill collar, 30ft
String stabilizer, full gauge
Drill collar,90ft
HWDP, 90ft min.
Drill pipe, as required
Normal Drilling Operations Practices
Typical Configurations - Summary
30 – 90 ft
9 – 27 m
30 ft
9 m
dropping pendulum
30 – 90 ft
9 – 27 m
30 ft
9 m
as close as
possible
building fulcrum
30 - 60 ft
9 - 18 m
30 ft
9 m
5-20 ft
1.5 – 6 m
holding packed hole
Operations Management• Basic Organization