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Part 1 - Glydril and Silicate (4NIDC Dec 05)
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1
Drilling Fluids Familiarisation
A Half-Day Seminar on M-I SWACO
Drilling Fluid Systems and Products
for the National Iranian Drilling Company
Thursday 8th December 2005
Presented by
Mark Sanders
UK Technical Services
2
Classification of Drilling Fluids Air / Mist /Foam Water-based fluids
– ‘Spud Muds’– Bentonite Fluids (including DRILPLEX)– Polymer Fluids– Glycol Fluids (GLYDRIL and ULTRADRIL)– Silicate fluids (SILDRIL)– High Temperature Fluids
Oil-based fluids– Invert Emulsion Fluids (VERSACLEAN)– ‘All Oil’ fluids (TRUDRIL)– High Temperature Fluids (VERSATHERM)
Synthetic-based fluids– Ester – IO (NOVAPLUS)– LAO (NOVAPRO, NOVATEC and RHELIANT)– Paraffin (PARADRIL, PARALAND)– High Temperature Fluids (PARATHERM)
Brines
• Reservoir Drilling Fluids FLOPRO NT DI-PRO FAZEPRO
3
Oil-Based Drilling Fluids Oil Phase
– Diesel – low-toxicity mineral oil - paraffin - ester - olefins Brine Phase
– CaCl2 or NaCl Emulsifiers / Wetting agents
– fatty acids - amidoamines– Imidazolines
Density – Barite - Calcium Carbonate– Hematite - Ilmenite
Viscosity – Organoclays– Rheological modifiers
Fluid Loss FL 170, Synthetic Polymers
Alkalinity – Lime
4
OBM Tests and Properties Density and Viscosity
– As per WBM but always measure viscosity at constant temp (usually 500C)
Oil / Water ratio– Ratio of volume of oil phase to water expressed as % e.g., 70/30– Data taken from the retort
Electrical stability (Es)– Voltage required to pass a current through the mud– Measured at 500C. Typical values 300-1000V.– Guide only. Trends are important. Value depends mainly on O/W ratio
Water phase salinity (WPS)– Grams chloride per litre water– % w/w is preferred
HPHT Fluid Loss Alkalinity
– Measurement of Lime content by titration on whole mud
5
Water Phase SalinityWater Activity ConceptAw is relative vapour pressure
Not enough saltCuttings soft and mushy
Possibly water-wet
Tight hole on trips
Too much saltCuttings hard, brittle and splintery.
Cavings
Coffee grounds-dry rounded cuttings reground in the annulus
Care - don’t jump to conclusions
0.95
0.90
0.85
0.80
0.75
0.70
1000 2000 3000 4000 5000 8000 10000
A f
DEPTH ( FT )
6
Water Activity
Small scale strain test with Pierre 1 shale
-0.1
-0.05
0
0.05
0.1
0.15
0 200 400 600 800 1000 1200
Time (mins)
% L
inea
r ex
pan
sio
n
0.95 Aw
0.85 Aw
7
OBM - HSE Considerations
1. All oils are potentially harmful and skin contact should be avoided
2. Emulsifiers are powerful surfactants that can defat the skin. Most are irritants. Handle with care.
3. Calcium chloride and lime are eye and skin irritants.
4. Contaminated overalls should always be changed.
5. Wear gloves or use barrier creams to protect the skin (but do not use barrier cream and gloves).
6. Ventilation is important to reduce oil mist/vapour. If possible chose a base fluid with a flash point well above the maximum anticipated flow line temperature.
7. No-smoking and hot work permit regulations must be observed.
8
OBM - Engineering
Emulsion and oil-wettingEs, water in filtrate
Drilling sand and shale
Drilling salt
Solids control equipment
Rig preparation
Need to minimise surface losses and transfer losses
Displacements
Barite sag
9
Water-based Fluids Water
– Freshwater - seawater - KCl - Saturated NaCl Density
– Barite - Calcium Carbonate -Iron Carbonate - Hematite - Ilmenite Viscosity
– Biopolymers - CMC - PAC - Guar - Bentonite (or other clays) - synthetic polymers Dispersants
– modified polyacrylates - lignosulphonates - Fluid Loss
– synthetic polymers - carboxymethyl celulluse - polyanionic cellulose - starch - bentonite - modified lignites (HT) -asphalt (HT) - resins (HT)
Inhibition– Glycols - silicate - KCl - Gypsum – Ultracap - Ultrahib - and other
pH Control– NaOH – MgO - Ca(OH)2 - Citric acid - NaHCO3
Other– Bactericides - lubricants - LCM - polymer temperature stabilisers - corrosion
control (oxygen scavengers, filming agents)
10
OBM vs WBM
Lubricity
Tolerance to Contaminants
Environmental Footprint
Drilling Performance
Corrosion Inhibition
Thermal Stability
Shale Inhibition
Formation Protection
Oil Based MudEster Based SOBMLAO SOBMKCl/PHPAWBM Glycol System
11
12
GLYDRILGLYDRIL
13
GLYDRILGLYDRIL
STANDARD MUD SYSTEMSTANDARD MUD SYSTEM
KCl/Glycol/Polymer systems used as standard WBM for bothexploration and production drilling.
High success rate with few wellbore problems. Low fluid costs associated with high mud re-use.
Adaptable fluid formulations to meet drilling and environmental demands
14
Glycol - Shale Inhibition MechanismGlycol - Shale Inhibition Mechanism
Mechanism for shale inhibition not well understood
Glycols are strongly adsorbed by clay
Pore plugging from clouding effect
15
• >400 Wells Drilled>400 Wells Drilled• Highest Temperature - 412°FHighest Temperature - 412°F• Longest Horizontal - 6567 ftLongest Horizontal - 6567 ft• Longest step out - 7827ft 17 1/2” hole at 50Longest step out - 7827ft 17 1/2” hole at 50oo
• Fastest ROP - 4785 ft 12 1/4” hole in 24 hrsFastest ROP - 4785 ft 12 1/4” hole in 24 hrs• Highest Overbalance - 4500 psiHighest Overbalance - 4500 psi• Drilled - Reactive Clays, Shale, Sandstone, Drilled - Reactive Clays, Shale, Sandstone,
Field Use of Glycol Fluids
Siltstone,Limestone, Carbonates, Salt, Anhydrite, Siltstone,Limestone, Carbonates, Salt, Anhydrite,
Zechstein, CoalsZechstein, Coals• Must be matched by good solids-controlMust be matched by good solids-control
16
NaCl or KCl Brine DUOVIS PAC R and/or UL Starch HIBTROL Glycol @ 3 – 5 % v/v pH Control Weighting Agent
GLYDRIL System Composition
17
Benefits Environmentally acceptable Safe Handling for Rig Crews Good Shale inhibition Good wellbore stability Good Lubricity Lower Cost per Ft
GLYDRIL
18
SILDRILSILDRIL
SILDRIL –Inhibitive WBMSILDRIL –Inhibitive WBM
Silicate-based Fluids– essentially a polymer-
based system– utilizes silicate
chemistry for inhibition– Used primarily for
drilling troublesome shale sections
SILDRIL - Inhibitive WBMSILDRIL - Inhibitive WBM
BEFORE
AFTER
Strongly minimises shale hydration and improves formation integrity
In some applications, these systems can be used as
an economic and environmental replacement for oil-base muds
21
Soluble Silicates Soluble Silicates are the
metal salts of Silica Acid that exist in multiple polymeric forms in solution. Amorphous solids and powders are also manufactured.
All silicates contain three basic components:– Silica -- SiO2 (Sand)– Alkali -- Na2O or K2O (Soda
Ash or Pot Carb)– Water -- H2O
OSi
OSi
OSi
O
O
O
O
O
O
O
22
pH/Alkalinity
Silicates are alkaline materials (ie. pH range from 11.0 to 13.5)
Silicate species need a pH >10.7 to remain soluble in solution
pH of silicate solutions is maintained until almost complete neutralization
23
Mechanisms for Shale Stabilization
Polymerization in the shale pores
Precipitation– Soluble Silicates can react with all multivalent cationic metal ions to
form the corresponding insoluble metal silicate, depending on reaction conditions
Direct bonding of shale substrate
There are many theories as to the actual mechanisms at work
24
Mechanisms for Shale Stabilization
The glassy nature of silicates imparts strong and rigid physical coating to surfaces
25
0
10
20
30
40
50
60
70
80
90
100
% R
EC
OV
ER
Y
FW /
PO
LYP
LUS
KC
l / P
OLY
PLU
S
CA
LDR
IL
GLY
DR
IL
GLY
DR
IL P
LUS
SIL
DR
IL
SIL
DR
IL /
GLY
DR
IL
SIL
DR
IL /
SIL
-LU
BE
INV
ER
T E
MU
LSIO
NFL
UID
REACTIVE SHALES (High Smectite Content)
HIGHLY DISPERSIVE SHALES
SILDRIL Inhibition
26
Silicate-base fluids were used decades ago. Now, proper formulation and engineering design allow their successful use.
SILDRIL Composition
• Silicate - primary shale inhibitor (provides water barrier)• Potassium - secondary shale inhibitor (reduces swelling)• Biopolymer - rheology control• PAC / Starch - provides fluid loss control• Compatible with conventional anionic and non-ionic fluid
additives• Used with mono-valent salts (KCl & NaCl)
27
Rheology Xanthan for 6/3 RPM readings
Fluid Loss ±3.0 ppb PAC U/L & Reg (9 – 6 cc)
Silicate 5 - 8% by vol.
KCl 25 - 35 ppb
MBT Generally low (highly inhibitive)
pH 11 - 12 (natural level)
Hardness Zero (positive Silicate)
Corrosion Inhibitors not necessary
SILDRIL™ Engineering Guidelines
28
SILDRIL Experience
0 20 40 60 80 100 120 140 160
AlgeriaAustralia
AustriaCanada
DenmarkEgypt
GermanyIndia
IndonesiaIreland
IsraelMalaysia
New ZealandNigeria
NorwayOman
PakistanQatar
RussiaSyriaUAE
UKUS
Viet Nam
29
SILDRIL - Experience
Minimum down-time attributed to formation chemical instability Minimal “bit balling” problems In-gauge wellbore for optimum cement jobs Excellent cuttings integrity for geology interpretation and for
effective removal by the solids control equipment High solids removal efficiency, comparable to invert emulsion
fluids Minimal environmental impact: uses all “environmentally friendly”
products Minimal environmental impact: reduced discharges. Low dilution rates, which are also beneficial with regard to waste
control and management. Ease of formation identification.