1. casing drilling

February, 2000

A Revolutionary Approach to Reducing Well Costs

CASING DRILLING

What is Casing Drilling?

“Drilling and casing wells simultaneously where the casing is used to transmit mechanical and hydraulic energy to the bit.”

Elimination of drill pipe and drill collars. Elimination of tubular tripping. Reduction of unscheduled events. Increased drilling safety. Reduced rig costs. Reduced overall well costs.

Casing Drilling- A Complete Solution

Use Casing Drilling Process for Entire Well Conductor/Surface Intermediate Long String

Reduced Costs

Improved Performance

Improved Safety

Rotary Drilling vs. Casing Drilling

HOLE PROBLEMS WHICH RESULT IN EXCESSIVE ROTARY DRILLING COSTS - AND THE CASING DRILLING SOLUTIONS

1. SWELLING FORMATIONS 2. SLOUGHING FORMATIONS 3. WASHOUT

4. SWAB OIL & GAS 5. HOLE IN CASING OR KEYSEAT 6. RUNNING LOGS & CASING DIFFICULTIES

Industry “Flat Time” Lost(as percentage of total well time)

Non-scheduled Events 12-25%

Casing Installation 12-21%

Tripping 10-12%

Formation Evaluation 5-18%

Completions 5-10%

Range Total Flat Time 44-86%

(From DEA “Flat Time Reduction Opportunities” Houston, 21-Sept-99)

Casing Drilling Applications

Large Diameter Hole

No need for large drill collars or drilling tools

Significantly improved hydraulics & hole cleaning

Reduced risk of hole problems from tripping

Eliminate risk of getting stuck running casing

Improved safety and efficiency

Casing Drilling Applications- cont’d.

Offshore

Reduced deck loading through eliminating pipe and

collars- save space and weight

Flexibility for contingency strings

Improved well control

Time saved = significant economic advantage


Jungle/Helicopter Rigs

No drillpipe/collars to fly in and out

Casing goes one-way only

Rig is smaller and lighter for same depth rating

Reduced fuel consumption and transportation costs


Unstable or Sensitive Lithology

Casing is always on bottom

Excellent hydraulics for superior hole cleaning

No reaming/backreaming on trips- NO TRIPS

Time saved = significant economic advantage


Directional or Slant Wells

Fully steerable- use conventional directional assembly

Less torque and drag while drilling- increased reach?

Fewer hole cleaning problems


Shallow Gas

Drilling rate is competitive

Total drilling time improved over straight rotary

Better well control- reduced risk from shallow kicks,

especially while tripping

No tripping pipe and collars

Can use a smaller, lighter, faster moving rig

Reduced moving costs


High-mobility Rigs; Revamping

Reduced capital cost

Smaller footprint, lower lease prep costs

Reduced moving costs

Empower older rigs with new technology

Reduced fuel and maintenance costs

Casing Drilling Technical Challenges

Changing the Bit & Bottom Hole Assembly

Casing Connection

Bit Cutting Structure

Formation Evaluation

Cementing & Drilling Out the Shoe

Tesco’s Total Solution for Casing Drilling

Factors to be Considered in the Design of a Casing

Drilling Wellbore:

Casing Loadingfatigue limits, tension, compression, critical buckling

Connection Design (what level of service?)

Cutting Structure (bit program)

Well Control Issues

Directional Drilling (steering and/or correcting)

Logging, Testing, Coring, Cementing

Hole Integrity Issues

Tesco’s Total Solution for Casing Drilling

Tesco Provides the Only Total Solution:

Complete Drilling Engineering

Complete Technology Capabilities

Programming

Tools and Equipment

Fully Integrated Project Management Services

Complete Daywork, Lumpsum or Turnkey Capabilities

Casing Drilling Technical Challenges

Changing the Bit & Bottom Hole Assembly Run/retrieve tools and accessories without pulling casing

Casing Connection Handle drilling loads, minimize fatigue, competitive cost

Bit Cutting Structure Destroy rock with low torque, low RPM using PDC cutters- no

stick/slip Underreamer engineered for hard rock and continuous service- short

arm extension, robust

Formation Evaluation Log, test, core

Cementing & Drilling Out the Shoe Cement with pump-down float Drill out and drill ahead to next casing point with next casing string

Running & Retrieving

ToolTorque Anchor

(Locks into torque collar) Underreamer

BitStop Dogs

(Locate at No Go shoulder)

Add Mud Motor as required

Anchor & Seal Assembly(Incorporates by-pass)

Axial Dogs(Lock into

Lock Collar)

Wireline BHA- “Drill Lock Assembly”

Casing Assembly- “Casing Landing Assembly”

CasingCentralizers

as req’dCasing Lock

CollarCasing Torque

Collar Casing Shoe

Casing Drilling Downhole Tools

Running & Setting BHA

Lower BHA (while circulating and

reciprocating) until stop dogs

locate at No Go shoulders

Stop pump and jar down to close

by-pass and lock axial dogs into

lock collar

Continue to jar down to release

running tool

Retrieve running tool while

circulating and reciprocating

Drilling Surface Casing

Bottom Hole Assembly

Bit (must pass through casing drill

string and drill pilot hole)

Underreamer (must pass through

casing drill string and

underream pilot hole out to

desired diameter)

Retrieving BHA

Latch running tool into BHA

Jar up to open bypass and

release axial dogs

Circulate through by-pass to

allow underreaming arms to

retract

Hoist tool out of casing while

circulating and reciprocating

Cement Surface Casing

Drilling Out Cement Plug

Options

-Bit/Underreamer

-Bit/ Drilling Casing

Shoe -Drilling Casing Shoe /

Flat Bottom Mill

Drilling Below A Cemented Casing String

Bottom Hole Assembly: -Bit (must pass through casing drill string and drill pilot hole)

-Underreamer (must pass through casing drill string and underream pilot hole out to the inside diameter of the last casing string set)

Note: Underreamer arms can be enlarged to underream the last casing string set if required

Drilling Directionally

Bottom Hole Assembly

-Bit

-

Underreamer -PDM

with bent housing -

MWD

-NMDC

-Anchor & Seal

Assembly (Locked

into casing)

Coring

Conventional coring 30-60

feet per run.

Core/underream as a

continuous operation.

Retrieve coring assembly

on wireline.

Logging

Retrieve BHA, pull casing from

section of interest, log

conventionally in open hole.

Log through steel casing

(cased hole logs)

Log while drilling:– Suspend BHA below casing shoe

and LWD as currently done and

demonstrated here.

Casing Drilling Tools Being Assembled on Catwalk

Making-up DLA

Lowering DLA Into First Joint of Casing

DLA Latched Into First Joint of Casing

Second Joint Picked Up, About to be Stabbed

Full Casing Drilling Ass’y - Drilling Ahead

BHA• Bit

• Underreamer

REED HYCALOG

DS74H98mm (3 7/8”)

25 X 8mmCutters

Tesco - RBI 3 Blade 98mm PDC Bit

Underreamer (3 nozzles), Pilot bit (5 nozzles) @ 0.45m3/min

PDC Cutters - 155.6mm (6-1/8”) hole with 114.3mm (4-1/2”) Casing

MODIFIED CUTTERS FORMER CUTTER DESIGN

PDC Cutters - 215.9mm (8-1/2”) hole with 177.8mm (7”) casing; two runs, 1200 ft, Wyoming

4.5” Hunting Interlock Coupling with Torque Ring

Grant Prideco Integral Upset Coupling with Torque Shoulder

SPIR-O-LIZERSZinc Alloy

Rotating Steel (Hard Banded) 7” Centralizers - Wyoming

Tesco Pump Down Float Plug

• Pump down while circulating prior to cement job. Lands in CLA. Burst out disc with pressure.

• Retains cement after standard wiper plug is bumped.

• Seven Loads

• Stiff Mast Range III Single

• 100 Ton Nominal Rating

• Rating With 139.7mm (51/2”) Casing

3000m (10,000ft) 25.3kg/m (17lb/ft)

• Rating With 114.3mm (4-1/2”) Casing

3960m (13,000ft)

20.08kg/m(13.5lb/ft)

Moving On and Rigging Up

Pipe Handling System in Operation

Innovative Casing Saver Drive System

• Elevator

• Circulating Head

• Non-threaded Drive

Fully Automated Controls

• Test Well Schematics

Conductor Casing– 9-5/8” 43.5 lb/ft P-110 WT- IPC– 12-1/4” Open Hole to 130 ft

Surface Casing– 7-5/8” 26.4 lb/ft N-80 WT-IPC– 10” Open Hole to 565 ft

Production Casing – 5-1/2” 17 lb/ft PZ- 50– WT-IPC / Buttress CNV-SC-BTC– 7” Open Hole to 3040 ft– Plugged back and directionally

drilled to 86deg. Plugged back and open hole side tracked to 60deg.

• Test Well # 1 • Test Well # 2

Surface Casing– 9-5/8” 36 lb/ft

Buttress-CNV K-55– 12-1/4” Open Hole to 689 ft

Intermediate Casing– 7” 23 lb/ft

Buttress CNV-SC-K-55– 8 1/2” Hole to horizontal @ 2900 ft– Plug back, drill S profile and

cement @ 2200 ft (vertical)

Production Casing (Long String)

– 4-1/2” 11.6 lb/ft Buttress CNV-SC PS-80

– 6 1/4” Open Hole to 3000 ft

Note: All Casing is ERW

First Shallow Wells in CanadaH

ou

rs fr

om

sp

ud

to r

ig r

ele

ase

• 520m vertical wells (Cessford)• 177.8mm conductor pre-set• Drilled in and cemented 114.1mm casing

59.5

3125

19.25

0

10

20

30

40

50

60

1st Well 2nd Well 3rd Well 4th Well

Operational Improvements-Countess Project

• 800m+ vertical wells (Countess)• 177.8mm conductor pre-set• Utilized Integral Buttress 114.1mm casing

UNDEREAMER - New Cutter Design with Nozzles

TOP DRIVE ALIGNMENT - Better Counterbalance, New Torgue Bushing

CASING CONNECTION - Integral Upset Shouldered Buttress

CASING SHOE - 152mm OD, strengthened perimeter, reaming pads

CEMENTING - Pumpdown Float Plug, Plug Loading Head

DRILLING DATA - Full Electronic Pason recorder and displays

Wyoming Depths for Casing Drilling

Surface Casing– 9-5/8” 36 lb/ft – Buttress-CNV L80 @ 803 ft

Production Casing – 7” 23 lb/ft– Buttress - CNV L80 @ 6,480

ft

Marathon Oil CompanyTribal E #32

Fremont Co., Wyoming

0

1000

2000

3000

4000

5000

6000

7000

0 4 9 14 19 24 29 34 39

Days on Location

MD

De

pth

(F

ee

t)

0

5

10

15

20

25

30

35


Rotating hours to surface casing depth

803

ft

846

ft

814

ft

786

ft

(RC)

(RC) (RC)

(PDC)

Ho

urs

38

62

4538

29.5

0

10

20

30

40

50

60

70

Hrs From Spud to Plug Down

BestOffset


• 250m+/-, 12 1/4” Surface Hole• 9 5/8” x 36ppf K-55 Surface Casing • Wells one and two with Hunting Interlock Convertible Buttress• Wells three and four used API Buttress Couplings

Surface Hole Learning Curve in Wyoming

Conclusions

Commercially available casing and connections can handle

the required torsional and compressive loads while drilling

with casing if drilling parameters are controlled and annular

clearance is minimal

Equivalent penetration rates were observed as compared to

conventional rotary drilling (through alternating siltstone,

shales, coal, sandstone)

Significant time can be saved for tripping with wireline

compared to conventional tripping with pipe

Tesco Casing Drilling Advantages

Rig Efficiencies

Reduced capital and logistics costs due to lighter

substructures and single derricks

Reduced personnel and increased safety by eliminating

extensive pipe handling

Separate strings of drill collars and drill pipe need not be

acquired, transported and maintained

Lower horsepower from reduced circulating pressure and

elimination of drawworks tripping


Operational Efficiencies

Elimination of backreaming and reaming to bottom

following trips

Lower prime mover fuel consumption

Increased bit hydraulics

Lower mud and cementing costs

Elimination of casing handling and drill string running time


Unscheduled events eliminated

Taking a kick while tripping the drill string

Unintentional sidetracks while reaming back into the hole

Hole problems caused by swab and surge pressures

Key seats and wearing holes in previously set casing

Built-in washover capabilities if BHA becomes stuck

INNOVATIVE TECHNOLOGY WITH AN INTERNATIONAL FOCUS

Tesco Corporation is a global provider of innovative, technology

based solutions to the upstream energy industry. Tesco designs,

manufactures and services equipment that reduces the cost of

drilling for and producing oil and gas and, is a supplier of value-

added products and services to heavy industry.

Tesco is growth oriented and committed to an ongoing, in-house

research and development program that leads to the practical

application of new technologies.

February, 2000

A Revolutionary Approach to Reducing Well Costs

CASING DRILLING

1. casing drilling

Documents

bottom hole

14 open hole

8mm conductor

tescos total

drill pilot

casing string

underream

casing drill