The document provides a review of casing drilling for the Asia Pacific business unit. It discusses candidate well selection, benefits like wellbore strengthening and reduced losses. It outlines Tesco's casing drilling systems from non-retrievable to directional drilling. The review shares global and regional casing drilling experience over the past few years and lessons learned. Key points are improved safety, efficiency, and cost savings compared to conventional drilling methods.

1. CASING DRILLING™ REVIEW
FOR
ASIA PACIFIC BUSINESS UNIT
By Andrew Harris – Manager, CASING DRILLING™
DRILLING™
Email: andrew_harris@tescocorp.com
WE SEE DRILLING

2. CASING DRILLING® Candidate Selection
Wells where tophole sections are controlled drilled for hole cleaning
Wells with Borehole Stability Problems
Wells with Borehole Stability Problems
Wells with significant Lost Circulation
Wells where CASING DRILLING® can eliminate a casing string
CASING DRILLING can provide significant time savings in areas where high rig
CASING DRILLING® can provide significant time savings in areas where high rig
rates apply
Utilising a small rig – Single mast, small pumps, Limited Horsepower

3. CASING DRILLING® Benefits: Wellbore Strengthening
Significant reduction in lost fluids
when Drilling with Casing due to
“Plastering Effect” (continuously
Plastering Effect (continuously
trowelling of the wellbore wall by
the couplings)
Filter Cake is plastered into the wall
Filter Cake is plastered into the wall
and is not scraped off by bit trips or
tool joint impacts
Cuttings are ground up finer and less
Cuttings are ground up finer and less
cuttings are returned to surface
Instead they are plastered into the
wall, strengthening the wellbore
wall, strengthening the wellbore
Reduced Losses and Improved
borehole stability

4. TESCO Casing Drilling® Systems
Casing String
MOTOR BHA ROTARY STEERABLE BHA
Drill Lock
D ill L k
Non Retrievable – Assembly
Drillable Casing Shoe
Level 2 system Casing Profile
+ No rig modification, very Nipple
easy to implement
+ Can drill out for Directional Retrievable BHA’s –
BHA s
Internal
subsequent casing strings Level 3 & 4
- Vertical holes only and 1 Stabilizers
+ Allows for multiple bit/bha changes
bit / hole section
+ Allows directional control, LWD
+ No Rig Modifications Required
Casing Shoe
- Requires up-front Eng. / planning.
PD Motor
Casing String
MWD Under‐ Reamer
Float Collar
Roller Reamer
Tesco XCD™ PDC
Non‐Mag
diamond enhanced Drill Collar
CASING DRILLING®
Bit
UG
UG MWD / LWD
MWD / LWD
Stabilizer
designed to drill soft to Float Sub
medium‐soft formations
at high rates of
Rotary Steerable
Rotary Steerable
penetration
12,000 psi UCS
D‐exp >1.0
Pilot Bit

5. CASING DRILLING™ Global Experience
OVER 3.2 MILLION FEET DRILLED WITH CASING
Subsea Casing Drilled with
4 Motor BHA
31 Casing drilled with
Rotary Steerable Tools
104 Directional Casing Drilling
7 ll d h l h
Drilled while Coring with Casing
629 Drilled with retrievable assembly
144 Drilled with drillable shoe
330 Drilled with disposable bit
Complexity
Updated 10/31/2010

6. CASING DRILLING™ APBU 2007 ‐ 2010
• Total 26 CD wells
• 23 x 13 3/8” / 3 x 9 5/8”
• 9 Level II
• 17 Level III s
17 Level III’s Level II (ft) Level III (ft)
l (f ) l (f ) Total Ftg.
l
• 25 Offshore / 1 Onshore 7,619 40,077 47,773
• All Level 3 using Motor Assy’s
ll l ’
• LWD – Gamma / Res / PWD
• 9 Wells were Dir. From Platforms
• Inclinations 20° to 76°
• 3 Wells, used Gyro Mwd for collision avoidance
• 4 Wells from Semi‐Submersible
4 Wells from Semi‐Submersible

7. CASE HISTORIES
Malaysia

8. CASING DRILLING®
Implementation
Objectives for implementing retrievable CASING DRILLING™ :
1. Improve the safety and efficiency of casing running and handling with a stabber less
casing drive system (CDS™);
2. Prove the concept of batch CASING DRILLING™ commercially and technically;
3. To enable CASING DRILLING™ to become the base case for drilling top hole
3 To enable CASING DRILLING™ to become the base case for drilling top hole
sections;
4. Prove the directional capability of 13 3/8‐in. CASING DRILLING™ assemblies;
5. Minimize flat times associated with conditioning and cleaning the hole in soft
unconsolidated directional top hole sections in the field;
6. Improve the drilling performance in the top hole formations though superior hole
6 Improve the drilling performance in the top hole formations though superior hole
cleaning with 13 3/8‐in. casing versus 5 1/2‐in. drill pipe;
7. Log the section with gamma, resistivity and annular pressure while CASING
DRILLING™ ;
DRILLING™ ;
8. Casing drill from the conductor shoe to section TD in one run.

9. Success Offshore Brunei
Operator: Shell Brunei Petroleum (BSP)
Rig: BIMA (Jack‐Up)
Casing Size: 13 3/8 72lbs/ft, L80, VAM TOP
Casing Size: 13‐3/8 – 72lbs/ft, L80, VAM TOP
Operations:
Drilled to the MWD flowrate maximum of 800gpm
Drilled 580m, average penetration rate of 120m.hr
(390ft.hr)
No hole cleaning issues. Torque and Drags trended
Drilled with Seawater, pump Hi Vis pills every joint
Drilled with Seawater, pump Hi‐Vis pills every joint
Highlights:
No QHSE incidents occurred implementing a “New Technology”
No rig modification are required, just make up TESCO CDS™ to TDS
Faster on‐bottom ROP CASING DRILLING™ vs Conventional drilling
Successfully hung Casing in the wellhead and cemented
Once Drilled it’s Cased, the Motor assembly is tripped back thru
O D ill d it’ C d th M t bl i t i d b k th
the casing at TD
©2010 TESCO Corporation

10. Performance CASING DRILLING™ –
Batch Drilled Surface Intervals
1st WELL
BHA: Mud Motor w/1.5º bend / LWD (gamma/res./ pwd) &
Gyro‐MWD
Drilled to TD at 1005m ‐ 815m @ 82m/hr avg on Btm ROP
Built angle from 8.4º to 37.9º
Lost Circulation, switched to seawater to complete section
2nd WELL
BHA: Mud Motor w/1.5º bend / LWD (gamma / res./pwd)
Drilled to TD at 1201m ‐ 1001m @ 100m/hr avg.
on Btm ROP
Built angle from 11º to 58º
B ilt l f 11º t 58º
Good FIT prior to drilling 12‐1/4” section.
CASING DRILLING Saved 6.41days / 3 wells
©2010 TESCO Corporation OTC 20880

11. Subsea CASING DRILLING™ Implementation
Exploration Well - Offshore Sarawak
CHALLENGE
Subsea Exploration well from Semi‐Submersible
Water Depth of 340’
Regulations – Have to drill 8‐1/2” pilot hole for Shallow Gas
Require LWD Logs over section
Seismic shows no anomalies, low risk of Shallow Gas
Seismic shows no anomalies, low risk of Shallow Gas
SOLUTION
Implement TESCO CASING DRILLING® Technology
1st Well Drilled to TD – 2,191ft in 3.6 bit hrs @ 608ft/hr avg
2nd Well Drilled to TD – 2,281ft in 4.7 bit hrs @ 485ft/hr avg
3rd Well Drilled to TD – 2,330ft in 4.3 bit hrs @ 543ft/hr avg
Well Drilled to TD 2,330ft in 4.3 bit hrs @ 543ft/hr avg
Eliminate the 8‐1/2” pilot hole
Superior hole cleaning than Conventional drilling
Faster on‐bottom ROP than Conventional drilling
Faster on bottom ROP than Conventional drilling
CASING DRILLING Saved 1.25 days over Conventional
©2010 TESCO Corporation
Well

12. Subsea CASING DRILLING™ Implementation
Exploration Well – West Malaysia
CHALLENGE
Subsea Exploration well from Semi‐Submersible
in 55m water with subsea BOP stack
Require LWD Logs over section
Fault predicted at 950m, potential losses or
p
pressure connectivityy
SOLUTION
Use retrievable CD‐BHA ‐ MWD/ LWD / Motor
assembly to drill 13‐3/8” Casing from 20” shoe to
TD at 1100m
Drilled to TD at 1100m – 650m in 13hrs @ 50m/hr
avg. on Btm ROP
Bt
Reduce risk of hole problems associated with losses
Reduce risk of hole problems associated with
borehole instability
borehole instabilit
©2010 TESCO Corporation OTC 20880

13. OBSERVATIONS AND
OBSERVATIONS AND
LESSONS LEARNT APBU
Tophole CASING DRILLING™
p

14. DEPTH VS ANNULAR VELOCITY CASING DRILLING™ vs 5 ½” DP
”
0
13-3/8" Casing in
26" Conductor
Velocity @ 700gpm
Comparison of Annular
Velocity @ 1100gpm
Velocities
200
5 ½” DP x 17 ½” hole
” ”h l
5.5" DP in 26"
vs
13 3/8” Casing x 17 ½” hole
400
Conventional DP
Limit ROP to ~60m/hr
5-1/2"
600 Drillpipe in 13-3/8" Casing
17-1/2" CASING DRILLING™
epth,
in 17-1/2"
mtrs
Openhole Openhole
• Superior Hole Cleaning
m
De
800 • Faster Penetration Rates
1000
1200 BUSINESS CASE FOR
CASING DRILLING™
MALAYSIA
8" BHA in
1400
0 10 20 30 40 50 60 70 80 90 100
Annular Velocity m/min

15. Lessons Learnt – APBU CASING DRILLING™
Lessons Learnt – APBU CASING DRILLING™
Well Planning
Single point of contact from concept through to implementation
Project Management – TESCO LEADS!‐ We understand the SYSTEM and interfaces
Detailed Risk Assessments
Detailed CASING DRILLING™ programs
(Eng./ Equip. / Procedures / Contingencies / Well Control)
Alignment with DD company as to directional / logging objectives and drilling
performance

16. Lessons Learnt APBU
13 3/8”Directional CASING DRILLING™
Motor with a 1.5° bend and Milltooth bit capable of >6°/30m DLS (100% slide)
Motor with a 1.5º bend and PDC bit capable of 3.5º/30m DLS (100% Slide)
Mitigate against high dogleg severities – recommend a 1.15° bend on motor
CASING DRILLING™ w/ motor assy –dropping tendencies in soft formations
Steady toolfaces while sliding, no hanging up in either well from 36° to 58° with 13 3/8”
Casing
First implementation of Gyro‐MWD in CASING DRILLING™ system for surveys / collision
avoidance – no issues.
No issues running LWD – Real‐time Gamma / Resistivity / Pressure While Drilling
g / y/ g
Trending Torques &Drags while CASING DRILLING™ is essential for success.
CASING DRILLING with mud No issues with detection from MWD
CASING DRILLING™ with mud – No issues with detection from MWD
CASING DRILLING™ with seawater – Detection issues surveys / real‐time data

17. Directional Performance 13 3/8” CASING DRILLING™
100% slide : 2.0 – 5.8°/30m at the start of section
Wellplan • 80 slide /20 Rot : 4.5 – 5°/30m
• Planned DLS is 2.5°/30m • In Rotary – Assy dropping ‐0.9°/30m
/ y /
• Total ratio for Slide / Rotary : 49% / 51%
• B ild I f
Build Inc. from 8.43° t 60°
8 43° to 60°
• Avg ROP rotating : 120 – 180 m/hr
• Turn Azi from 125° to 115° then left to 126° • Avg Rop Sliding : 80 – 100m/hr

18. Cuttings‐ CASING DRILLING™ Seawater Tophole
West Malaysia
Seawater / Hi‐Vis sweeps
CASING DRILLING Tophole with Motor CD‐
CASING DRILLING™ Tophole with Motor CD
BHA c/w 1.5º bend
Seawater c/w 20bbl Hi‐Vis sweeps every
j
joint, Claystone formation
, y
Directional CASING DRILLING™ at +400m/hr
(Inst)

19. Tophole 13 3/8” CASING DRILLING™
East Malaysia ‐ Seawater
Block
height
FAST !!
CASING DRILLING™ Tophole with Motor CD‐
BHA c/w 1.5º bend
Seawater c/w 20bbl Hi‐Vis sweeps every
S t / 20bbl Hi Vi
joint, sandstone formation
Directional CASING DRILLING™ at
+1400ft.hr
+1400ft hr

20. Cuttings‐ CASING DRILLING™ KCL‐PHPA MUD
Tophole West Malaysia
p y
KCL‐PHPA Mud
• Mud System – Inhibits reaction with clays
• Cuttings are removed – even sliding
• At higher ROP’s difficult to remove solids
• Mud Wt increases while drilling – ECD’s
• Observe higher break over torque at conns
Observe higher break‐over torque at conns.
• Spend time Circulating hole clean

21. MWD Detection Top hole CASING DRILLING™
Experience in APBU using Seawater
Top hole CASING DRILLING™ with a Mud System – No issues with Survey / real‐time LWD detection
MWD Systems are primarily setup for drilling with mud system
13 3/8 Casing Drilling with Seawater less viscous fluid
13 3/8” Casing Drilling with Seawater – less viscous fluid
Issues with detection ‐ Cavitation / turbulent flow / Noise / Attenuation of signal/ Smaller Signal)
Company A
Solution ‐ R d d
S l i Reduced modulator gap to 0.12mm – S
d l 0 12 Stronger Pulse
P l
Set Frequency of 16Hz at 3BPS – Decodable signal while drilling / surveying
Company B
Signal attenuates going from BHA ID to larger Casing ID (therefore better for smaller casing sizes)
Changed MWD pulser ‐ slower bigger pulse
q y p ( y y)
Frequency 0.5Hz at 3bps worked for detection with seawater (D&I surveys only)
However the above is not Compatible with Gwd
Implemented EM Tools (Electro‐Magnetic pulse MWD) in‐combination with mud‐pulse tools successful.

22. Lessons Learnt APBU
Cementing Issues
Presently not using Centralization on the Casing
p y j
Decision taken to perform ‘Poor‐boy’ cement job
Under‐displace cement, drop the top plug only
Typically hold pressure for 5.5hrs – ok
Pumped 50% excess‐ No returns to surface due to over‐gauge hole
Increase to 75% excess
CBL – yielded good cement
Surface Wellhead Issues
Surface Wellhead Issues PDDP
Q1, 2011
Keep the Wellhead hanger assembly loose
Faster method of installation with the CDS™
After release BHA with PDRT, pick up hanger and Land – no wiper trip

23. Lessons Learnt APBU – Shallow SS Wells
Lessons Learnt APBU –
Semi‐Submersible Rigs
Alignment – ballast control needs to keep “double bubble”
Can be an issue, best practice keep a slope indicator in Doghouse
b b k l h
Water Depth – Currently only using in Shallow Water depths – 350ft
At TD, require to POH with Casing, to space out to run CHRT or Wellhead hanger
At TD require to POH with Casing to space out to run CHRT or Wellhead hanger
Can Casing Drill Riser‐less or with SSBOP stack installed in shallow water
13 3/8” x 16” thru potential Shallow gas, higher ECD’s than 8 ½” hole pilot hole

24. Conclusion ‐ Highlights in APBU
Footage ft
30,000
No accidents or injuries from CASING DRILLING™ after 47,773ft Level II (ft)
25,000 Level III (ft)
TESCO DOWNHOLE TOOL RELIABILITY – 100%!!!! 20,000 Total Ftg
15,000
Track Record in APBU with Global relevance
10,000
5,000
Some 1st in CASING DRILLING™ operations 0
2007 2008 2009 2010
Directionally Drilling 13 3/8” Casing to inclinations of 58º ‐ 76º
Di ti ll D illi 13 3/8” C i t i li ti f 58º
Drilling with Retrievable CASING DRILLING™ system from a Semi‐Submersibles (Subsea)
Successfully deployed Gyro Mwd in BHA for tophole Anti‐collision
Successfully deployed Gyro Mwd in BHA for tophole Anti collision
Gamma Logged thru 9 5/8” Casing in PNG – No attenuation of the Signal
Proved up Performance CASING DRILLING tophole formations with Seawater
Proved up Performance CASING DRILLING™ tophole formations with Seawater
Inst. ROP’s of +1600ft.hr (+500m/hr), Average ROP’s of 390ft.hr (120m/hr)