Petroleum Engineering 406 Lesson 21 Wellbore Trajectory Control.
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Transcript of Petroleum Engineering 406 Lesson 21 Wellbore Trajectory Control.
Petroleum Engineering 406
Lesson 21
Wellbore Trajectory Control
Lesson 18 - Wellbore Trajectory Control
Bent Motor and Bent Sub
Examples
Directional Drilling Measurements
Single Shot and Multishot
Magnetic and Gyro
Steering Tools
MWD tools
Homework
READ: “Applied Drilling Engineering”,
Ch. 8 (to page 390)
Fig. 8.39: Bent sub unconstrained and constrained in a wellbore.
Nonmagnetic
Drill Collar
HoleOrienting Sub
Bent Sub
Mud Motor
Bent Sub Angle
Bit
is not necessarily equal to the bent sub angle, but it may be close in (a) above
Problem 1
Determine the effective bent sub response for a 1 1/2o bent sub in a motor run where at 6,357’, = 1o and is S85E and at 6,382, = 1o and is S20E; the tool face is 160o right of high side.
95 160N65
ft25L
1601 1N
Solution to Problem 1
Calculate from Eq. 8.53:
Dogleg severity:
coscossinsincoscos NN1
1cos1cos1sin1sin65coscos 1
07.1999824.0cos 1
ft10028.425
10007.1
L
i o
Solution to Problem 1 - cont’d
If the mud motor length is 25 ft from the bit face to the bent sub, the maximum angle change that could be reached if there are no restrictions is:
The lower rate of build implies that the formation resisted the maximum rate of build by a factor of:
ft1000.625
1005.1 o
72.00.6
3.4
An efficiency factor?
= Bent Sub Angle?
Since the value of for any given run may differ from the bent sub angle, it should not surprise us if
predicted = measured
Let us look at some examples.
77th
62ac 30ac
14th 16ac
33th
Fig. 8.40: Example of three jetting stops while trying to kick off and set the wellbore lead.
Jetted 7’ 1745-52’
Surv 1722’: S32W 2.25o
Orient S90E
Final 1799’:
S30E 2.75o
= -122o
Nozzle Orientation
77th 62ac
Jetted 12’ 1850-62’
Surv 1814’ S20E 3.0o
Orient N80E
Final 1877’ S36E 3.25o
= -80o
14th 16ac
Jetted 6’ 1925-31’
Surv 1877’ S36E 3.25o
Orient N70E
Final 1940’ S66E 4.75o
= -74o
30ac 33th
Directional Drilling Measurements
The trajectory of a wellbore is determined
by the measurement of:
inclination I
direction A
measured depth MD, L, L
Directional Drilling Measurements - cont’d
A tool-face measurement is required to
orient:
a whipstock
the large nozzle on a jetting bit
a bent sub or bent housing
Directional Drilling Measurements - cont’d
Tools available
single-shot magnetic or gyroscopic multi-shot magnetic or gyroscopic magnetometers, accelerometers,
MWD tools
Magnetic Single-Shot Instrument
Records
– inclination
– direction
– tool face position
on sensitized paper or photographic film Inclination may be determined by
– a float on a liquid
– a pendulum
Magnetic Single-Shot Instrument
Unit may be triggered by:
– clock timer.
– inertial timer (after stop).
Unit may be dropped (pumped down) and later retrieved by wireline or the drillpipe.
Magnetic Single-Shot Instrument
Single-shot instruments are used:
– to monitor progress of directional-control well.
– to monitor progress of deviation-control well.
– to help orient tool face for trajectory change.
Magnetic Single-Shot Instrument - cont’d
Procedure:
– load film into instrument
– activate timer (activate stopwatch)
– make up the tool
– drop the tool
– retrieve tool (wireline or drillpipe)
Fig. 8.41: Schematic diagrams of magnetic single-shot angle-compass unit (courtesy Kuster Co.).
LightHousingCenter PostFloat
FluidReference Mark
Main Frame
Photographic Disc
A. 0-20o
Angle-Compass UnitB. 0-70o
Angle-Compass Unit
Fig. 8.43: Pendulum suspended
inclinometer and
compass unit for a 0 to
17oo singe-shot unit.
1. Pendulum
2. Circular Glass
3. Compass
4. Pressure equalization
5. Cover glass
Indicated inclination 5o. Direction of inclination N 45 degrees 0’ or azimuth 45 degrees.
Fig. 8.42: Single-shot film disks
(courtesy of Kuster Co.).
A/C Units Plumb-Bob Units Incl. Only Units
• Inclination • Direction• Tool Face Angle
Fig. 8.12:
Pendulum assembly:
a) plumb-bob angle unit
b) drift arc inclinometer
Pendulum
Glass ring
Piston
(a) (b)
Fig. 8.13: Schematic drawing of magnetic single and multi-shot
instruments.
Hole direction with reference to Magnetic North
N35oW I = 5.5o
Fig. 8.44: Cardan suspended
compass and inclinometer for a
single-shot
5o to 90o unit.
CompassInclination Scale
Fig. 8.45: Typical
magnetic single-shot
tool with landing sub.
Rope Socket
SwivelStabilizerStabilizer Fingers
Wire Line Socket
Overshot
Bottom Landing Assembly
Protective Case
Mule Shoe Mandrel
Bottom Hole Orienting Sub
Orienting Anchor & Plug
Takes time. Rig time is costly. Temperature limitation. May have to pump down.
Fig. 8.46: Typical single-shot operation.
Free Falling to Bottom
Tool seated
Ready to be Dropped
Retrieve single shot
Fig. 8.46: Typical
single-shot operation.
Compass Unit3 min.
Single Shot Free Falling in Mud to Bottom
Non Magnetic Drill Collar
Orienting Sub Sleeve
*Single Shot Instruments are run on slickline if there is a mule shoe sub in the hole
Single Shot Ready to be Dropped
Timer On
Fig. 8.46: Typical single-shot operation.
3 min.
Overshot Used to Fish Single Shot
Tool seated in orienting sleeve or at stop taking picture
Wireline unit to retrieve single shot
10 min.
Fig. 8.47: Arrangement of the
mule shoe for orienting a mud
motor.
Fishing Neck
Non Magnetic CollarSingle Shot
Mud Motor
Top View
Existing CenterlineNew Centerline
Bent SubMule Shoe Key Position
Mule Shoe Orienting Sub
Orienting Sleeve Lined up with Bent Sub
Direction of Tool Face Via Bent Sub
Magnetic Multishot Instruments
Are capable of taking numerous survey records in one run.
May be dropped down the drillpipe or run on wireline in open hole.
The unit contains a watch that is spring wound and uses the power of the spring to operate a timer cam.
Fig. 8.48: Typical
arrangement for landing a
multi-shot instrument.
Non-Magnetic Drill Collar(s)
Compass Position
Multi-shot Instrument
Landing Plate
Fig. 8.49: Drop
multi-shot survey
instrument
Angle Unit
Rope Socket
Bottom Landing
Battery CaseBattery Connector
Bottom Shock Absorber Assembly
Stabilizer with Rubber Pins
Connector Shock Absorber
Barrel Lower Ball Plug
Aluminum Spacer Bar
Protective Instrument Barrel
Watch Assembly
Fig. 8.50: Views of the watch and camera unit of a typical multi-shot tool.
Watch Section Motor
Light Switch Lever
Geneva Gear
Winding Stem
Time Cycle Cam
Watch Switch
Supply Film Spool
Takeup Film Spool
Film Sprocket
Motor Lever Switch
Geneva Drive Wheel Assembly
Knife Switch Terminal
Magnetic Multishot - cont’d
The multishot tool is usually dropped down
the drillpipe and landed in the nonmagnetic
drill collar.
During the trip out, a survey is taken every
90 ft, i.e. every stand.
Magnetic Multishot - cont’d
More closely spaced stations could be
obtained by stopping the pipe more often,
and waiting for a picture.
A stopwatch at the surface is synchronized
with the instrument watch.
Synchronize with instrument watch by starting at the instant camera lights go on.
Fig. 8.51: Use of the
surface watch while running a magnetic multi-shot operation.
A. 10 seconds -
Lights are on, exposing film
B. 15 seconds - Delay before moving.
This is an allowance for instrument
watch lag during survey.
Time Intervals:
C. 20 seconds - Instrument is idle allowing movement of drill string
without affecting picture. Most moves require sufficient time for taking one or more shots while moving
D. 15 seconds - Minimum time for plumb bob and compass to settle for
good picture, plus allowance for
instrument gain during survey.
Time Intervals - cont’d
Fig. 8.52b: Projection of one survey frame for
determining inclination and
direction.
Steering Tools
Used with mud motors and bent sub
Can either pull every stand or use a side entry sub for continuous drilling
Mud Motor
Bent SubMule Shoe
Monel DC
Probe
Standard Measuring Cable
MWD Tools
MWD Tools
Gyroscopic Tools
Non-magnetic drill collars used to prevent magnetic interference from drillstring
Gyros used if magnetic interference is from non drillstring source