1. FILE: EXTREACH2 -A Wellsite Perspective-
Improvements In Oil Base Mud Technology Enhances Drilling Efficiencies On Extended Reach Wells
-A Wellsite Perspective-

2. Developing The Mud Program Factors to Be Considered For ERD
FILE: EXTREACH2
Developing The Mud Program Factors to Be Considered For ERD
Hole Stability - What Mud Weight Is Required?
Pore Pressure
Fracture Gradient
Hole Inclination
Formation Characteristics
Lithology
Mechanical Strength
Chemical Reaction
smax
Wellbore
Collapse
smin P
Tensile
Fracturing

3. Developing The Mud Program Factors to Be Considered For ERD
FILE: EXTREACH2
Developing The Mud Program Factors to Be Considered For ERD
Formation
Mud Weight
Pipe Eccentricity
Pipe Rotation
Cuttings Size
Velocity Profile
Hole
Cleaning
Hole Angle
ROP
Section Length
Fluid Rheology
Flow Regime
Annular Velocity

4. Developing The Mud Program Factors to Be Considered For ERD
FILE: EXTREACH2
Developing The Mud Program Factors to Be Considered For ERD
Wellbore Path
Rate Of Build / Drop
Max. Angle
Azimuth Changes
Section Lengths
How Much Steering?
Lubricity
Torque & Drag
DP Make-up Torque Ratings
Computer Simulations
Top Drive Rating (Do You Have a Top Drive?)
COF Of The Mud
COF Of Formations

5. Avg. COF of Various Fluids
FILE: EXTREACH2
Avg. COF of Various Fluids
WBM
Synthetics
OBM
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
Coefficient Of Friction
Lubricant Enhanced

6. Developing The Mud Program Factors to Be Considered For ERD
FILE: EXTREACH2
Developing The Mud Program Factors to Be Considered For ERD
Hydraulics
Pressure Requirements/Limitations
Pumping Capability
Number of Pumps
Pressure Rating
ECD Concerns
Motors, Downhole Tools
Drillpipe Size (65/8, 5½, 5)
Mud Rheology (Minimization of PV’s)
Liner Instead of Casing?

7. Hydraulic Analysis 6-5/8” vs 5” DP
FILE: EXTREACH2
Hydraulic Analysis 6-5/8” vs 5” DP

8. Developing The Mud Program Factors to Be Considered For ERD
FILE: EXTREACH2
Developing The Mud Program Factors to Be Considered For ERD
Daily Operational Cost
Logistics
Rig Mud Mixing System
Displacements Procedures
Completion Technique
Environmental Issues
Marine Toxicity
HES
Discharge Restrictions

9. Selection of Mud System What To Use?
FILE: EXTREACH2
Selection of Mud System What To Use?
Marine Environment
Hole Stability
Hydraulics
Lubricity
Safety
Wellbore Trajectory
Logistics
Hole Cleaning
Formation Damage
WATER BASE
Inhibition
KCL, Salts
Glycols (DCP Product Line)
Lubricants
Rheologically Engineered
INVERT EMULSION
Arctic Diesel
#2 Diesel
Low Toxic Mineral Oil
Synthetic
Lubricants

10. Invert Systems Oil-Based Muds
FILE: EXTREACH2
Invert Systems Oil-Based Muds
Advantages
Shale Stability
Lubricity
Temperature Stability
Drill Solids Tolerant
Chemical Contamination Tolerant (CO2, H2S)
Re-usable
Reduce Sticking Potential
Near Gauge Hole
Corrosion Protection
Cost Effective (Drilling and Mud Cost)
Disadvantages
Lost Circulation
Promotes Fracture Propagation
Reduced Re-opening pressure
Slow Self Healing
Expensive (Especially Synthetics)
Potential Disposal Problems
HES Concerns
Environmental Discharge
Elastomer Compatibility
Kick Detection (Gas Solubility)
Cleanliness

11. Synthetic Fluid Options
FILE: EXTREACH2
Synthetic Fluid Options
BAROID PETROFREE - (Henkel Ester)
XP07 Linear Parafin Oil
M-I NOVADRIL - Polyalfaolefin (PAO)
ESTERDRIL - Ester (finagreen)
NOVALITE - Linear Olefin (LAO)
NOVAPLUS - Internal Olefin (IO)
ANCHOR AQUAMUL II - Acetal
Anchogreen - (Pronova Ester)
B.H.I. BIO-MUL - LAB (Phasing out In UK)
SYNTEQ - IO
DOWELL Finagreen - Ester
ULTIDRIL - LAO/IO
B.W. MUD ECODRIL - LAO/PAO
Regulatory Authorities > Commercial > Technical

12. Base Fluid Properties 0.85 5-7 179 -30 25 0.80 5-7 175 -65 107 0.78
FILE: EXTREACH2
Base Fluid Properties
FLUID
DENSITY
VISCOSITY
FLASH
POUR
ANALINE
(SG)
40°C
POINT °C
POINT °C
POINT °C
ESTER
0.85
5-7
179
-30 25
PAO
0.80
5-7
175
-65
107
LAO (16/18)
0.78
3.08
146 3
N/A
IO (16/18)
0.78
3.1
137
-24 81
LAO (14/16)
0.78
2.1
114
-12 69
ETHER
0.83 6
166
-10 40
LTOM
0.80
2-3
100
-18 76
DIESEL
0.85
3-4 66
-10 65

13. HES Issues - Oil Vapours
FILE: EXTREACH2
HES Issues - Oil Vapours
New Norwegian Guidelines
Oil Mist 1 mg/m³, Oil Vapour 50 mg/m³

14. Oil-Base Fluids Development Rheological Engineered Systems
FILE: EXTREACH2
Oil-Base Fluids Development Rheological Engineered Systems
Early - Mid 80’s, ERD Wells Drilled With OBM Experienced Severe Problems:
Using Existing Mechanical Technology
No Top Drive
No MWD
Etc.
Hole Cleaning
“Mud Engineer, Increase That Yield Point!”
Barite Sag
Static Problem
Gotta Raise That
YP and Gels!

15. Oil-Base Fluids Development Hole Cleaning Studies - MI’s ERL
FILE: EXTREACH2
Oil-Base Fluids Development Hole Cleaning Studies - MI’s ERL
Conclusions Of Study
Annular Velocity (No Substitute For The Pump)
Pipe Rotation Critical (Hard to Clean Without It!)
Elevated Low Shear Rate Reduces Cuttings Bed Thickness
High Viscosity Sweeps DO NO GOOD!
Turbulent Flow Sweeps Agitate Beds
Turbulent Flow Cleans Better IF....
If Turbulence Is Not Achievable, Go Laminar With Elevated LSRV.
Cuttings Move In Helical Flow Pattern
Viscoelastic Coupling Of Mud & Pipe Rotation
Rule Of Thumb: LSRV = 1.0 to 1.5 * Hole Dia.

16. Oil-Base Fluids Development Rheological Engineered Systems
FILE: EXTREACH2
Oil-Base Fluids Development Rheological Engineered Systems
LSRV Modifier Development

17. Oil-Base Fluids Development Barite Sag - MI’s ERL
FILE: EXTREACH2
Oil-Base Fluids Development Barite Sag - MI’s ERL

18. Oil-Base Fluids Development Barite Sag - MI’s ERL
FILE: EXTREACH2
Oil-Base Fluids Development Barite Sag - MI’s ERL
Conclusions Of Sag Study
Phenomena Independent of Mud Type
Occurs In OBM & WBM
Dynamic Settling A Major Contributing Factor
Previously Thought To Be A Static Problem
Sag Is NOT SOLELY A MUD RELATED PROBLEM
Slow Circulation Rates (Coring, Liner On Bottom)
Elevation Of LSRV & Gel Strengths Are Helpful In MINIMIZING The Problem
Development of Field Testing Procedures
Viscometer Sag Test (VST)
Sag Index (VST, MW, Angle, Hole Dia. & Length, Flow Rate)

19. FILE: EXTREACH2
Oil-Base Fluids Development Rheology Testing - Fann Model 70 HTHP Viscometer

20. ERD Experience With OBM Southern Norwegian Sector - North Sea
FILE: EXTREACH2
ERD Experience With OBM Southern Norwegian Sector - North Sea
Platform Set In 1981
Geology
Overpressured Shale
Weak “Gas Cloud” Section In the Shale (Low Frac)
Depleting Chalk/Limestone Reservoir
7.2 ppg In the Center
14.5 ppg In the Flanks
Subsidence In the Overburden (Stressed)
Early Drilling History
Started With Water-Based Fluids
Quickly Turned to OBM
Stuck Pipe
Unstable Hole Conditions

21. Early Experiences With OBM
FILE: EXTREACH2
Early Experiences With OBM
Diesel Þ Low Toxic Mineral Oil
No Major Problems When Drilling Low Angle Wells
Major Difficulties With Angles Over 50°
Hole Cleaning
Barite Sag
Rotating Mud Companies
Mud

22. Mud Weight Requirements
FILE: EXTREACH2
Mud Weight Requirements

23. Introduction Of New OBM Technology
FILE: EXTREACH2
Introduction Of New OBM Technology
Begin Hole Cleaning Studies
Identify Hole Cleaning Parameters
Elevated LSRV
Rotation
Rheological Modifiers
Improves Hole Cleaning
Reduce Sagging Tendencies
1989

24. Continuous Operation Last 5 Years
FILE: EXTREACH2
Continuous Operation Last 5 Years
All Wells Now Horizontal Through The Reservoir
Casing Deformation Due To Subsidence
Casing Pulling/Window Milling - Sidetracks
TVD vs. MD Typically 1:1.5 to 1:2.8
Max mTVD 7200 mMD
Integral Part Of Drilling Team With Other Contractors
Max. Input Into Drilling Programs
Incentive Drilling Program

25. Lessons Learned ERD With OBM
FILE: EXTREACH2
Lessons Learned ERD With OBM
Hole Cleaning
LSRV ” Hole ¼” Hole ½” >10
Maintain minimum pump rate of 850 GPM
Interrupt Drilling
Circulate & Rotate
Do Not Orient More Than 2 Joints Per Stand
Back Ream/Rotate ( rpm)....Continue To Drill
Circulate A Minimum Of 1.5 Times B/U Before POOH
May Circulate Up To 3-4 Times B/U
Max. usage of 6-5/8” DP
More Flow, More AV, Less Pressure
Pump Pills IF NECESSARY!
Lo-Vis/Hi-wt
<850 gpm DON`T DRILL

26. Lessons Learned ERD With OBM
FILE: EXTREACH2
Lessons Learned ERD With OBM
Drilling Practices
When POOH....
Begin By Just Pumping
If Tight Hole Encountered...Begin Backreaming
When Backreaming
Start With 3m/min.....increase gradually
Bring Up RPM`s Slowly to
Start Pumping In A Controlled Manner
No Arbitrary Wiper Trips
Only As Hole Conditions Dictate

27. Lessons Learned ERD With OBM
FILE: EXTREACH2
Lessons Learned ERD With OBM
Platform Practices
Monitoring Of Drilling Parameters
Plotting Torque, Drag Againts Predicted & Measured Values
Monitoring Of Cuttings Return Parameters
Done With Cuttings Injection System (Predicted vs. Measured)
Gunk Squeeze Pill Ready As Depleted Chalk Formation Is Approached
Pump Gunk Immediatedly When Losses Are Encountered “Do Not Try To Establish Circulated”
2-3 Gunk Squeezes Maybe Required (100% Success Rate)
Gilsonite Additions Aids When Sliding In 8-1/2” Hole Section
May Improve Wellbore Stability in 12-1/4” Hole Section?
Barite Sag Minimized If...
3 RPM > 10
10s Gel > 15

28. Hard Lesson Learned ERD With OBM
FILE: EXTREACH2
Hard Lesson Learned ERD With OBM
Experienced Personnel Is The Key
The Learning Curve Very Expensive!

29. Future Development OBM For ERD Wells
FILE: EXTREACH2
Future Development OBM For ERD Wells
Improved Hydraulic Calculation
Virtual Hydraulics (Temp. & Press. Accountability)
Base Oil Specific
Lubricant Development
OBM & Synthetic Fluids
Drag Reducers
Improve Hydraulics (Pressure Reduction, Hole Cleaning)
Hole Cleaning & Barite Sag
Non Rotation, Slow Annular Velocities
Ultra-Low Shear Rate Viscosity Analysis (Oil Base FLO-PRO)
Product Development (Elevated LSRV, Low PV)
Basic Emulsifier Package
Low shear Rate Modifiers