M-I Production ChemicalsM-I Production Chemicals(A Business Unit of M-I SWACO)
OBJECTIVE
To demonstrate how the M-I PC Scale Dissolver Range can assist in
restoring well productivity impaired by scale deposition
AgendaAgenda
• M-I Swaco Organisation
• Calcium Carbonate dissolvers
• Sulphate dissolvers
• Case history – well stimulation
M-I Swaco OrganisationM-I Swaco Organisation
• M-I Swaco 60:40 JV company of Smith & Schlumberger
• Global market leaders in Drilling, Completion Fluids & Waste Management
• World Class Technology, Support & Logistics delivering value to customer
Integrated Fluids
Engineering
Integrated Fluids
EngineeringDrilling FluidsDrilling Fluids
Completion Fluids
Completion Fluids
Drilling Waste Management
Drilling Waste Management
Federal Wholesale &
Industrial
Federal Wholesale &
Industrial
PRODUCTION CHEMICALS
PRODUCTION CHEMICALS
Production Chemicals provides ‘Cradle to Grave’ portfolio
Engineering & Technical Support Engineering & Technical Support LeadershipLeadership
• World Class experienced and trained engineers
• Proprietary software packages to optimise drilling, production and environmental performance
• Research centres, technical support operations strategically located worldwide
• Leader in developing drilling fluids, production chemicals and waste management technologies that deliver value-added performance with environmental acceptability
Technology FocusTechnology Focus
• Commitment to R&D- Significant reinvestment of
revenues in R&D programs
• Strong focus on joint customer research efforts- Develop practical, fit-for-market
technologies - Shorten development cycles
• Schlumberger offers M-I world’s most comprehensive reservoir expertise- Opportunity to generate
technologies that complement “fluid and production chemicals disciplines”
World Class Infrastructure, Distribution & World Class Infrastructure, Distribution & LogisticsLogistics
• Integrated procurement, manufacturing, inventory management and transportation system
• Blending and storage facilities in close proximity to customers
• Comprehensive network of centralised warehouses and dock facilities
• Exclusive deepwater port participation
Global Service OrganisationGlobal Service Organisation
M-I Production ChemicalsM-I Production Chemicals
Corporate Capabilities
Health Safety and EnvironmentHealth Safety and Environment
• Health and Safety is our first priority
• Operating to ISO 9001/2000 and ISO 14001 standards
• In-house ecotoxicology laboratory operating to GLP. Capable of performing all OSPARCOM approved tests
• R & D focus on more environmentally friendly chemistry
• Environmental management capability
• Corrosion Inhibitors
• Scale Inhibitors / Dissolvers
• Bactericides
• Demulsifiers
• Wax Inhibitors
• Water Treating Chemicals
• Antifoams
• Hydrate Inhibitors
• Hydrogen Sulphide Scavengers
• Drag Reducers/Flow Improvers
• Cleaning Compounds
• Commodities
Comprehensive Product OfferingComprehensive Product Offering
Research & TechnologyResearch & Technology
• 30% of technical professionals are lab-based
• Main laboratories in Bergen, Aberdeen, Dubai and Perth
• Long-term, client focused projects oriented toward novel chemistries
• Emphasis on more environmentally friendly chemistry- In-house ecotoxicology
laboratory
Scale DissolversScale Dissolvers
Mineral Scale Dissolution
Carbonate scale - CAL-Acid
Barium/Strontium Sulphate scale - BaSOL
Calcium Sulphate - Gypsol
Iron Sulphide - Pyrisol
Iron deposits/rust - R-Sol
MIPC Scale Dissolver Product LineMIPC Scale Dissolver Product Line
What is Scale?What is Scale?
• An adherent mineral deposit precipitated from solution
• Commonly found in conjunction with other fouling deposits- e.g. iron hydroxides and
sulphides, waxes, asphaltenes, etc..
• Once deposited, crystal growth can lead to the development of severe scaling problems
• Mineral scale deposition cuts oil production by plugging payzones and blocking tubing and topsides.
Causes of ScaleCauses of Scale
• The causes of scale and fouling deposits are many, varied and complex
• Oilfield waters contain a large number of potential scaling species
• These include soluble ions such as calcium, magnesium, barium, etc which precipitate when they encounter changes in water conditions- e.g. temperature, pH, concentration effects and
incompatibilities
• In addition, corrosion by-products, process contaminants and incompatible chemical treatments lead to fouling and scaling
Types of ScaleTypes of Scale
Scaling speciesScaling species
CaCO3CaCO3
FeO/OHFeO/OHFeCO3FeCO3
FeSFeS
BaSO4BaSO4SrSO4SrSO4
CaSO4CaSO4
Acid soluble scales
Acid insoluble scales
Scale RemovalScale Removal
CaCO3 + 2HCl CaCl2 + CO2 + H2O
BaSO4 + AEDTA BaEDTA + ASO4
(A - alkali metal)
Acid soluble scales
• Scale removed through reaction to generate new chemical species
Acid insoluble scales
• Much harder scale type to remove. Requires chelation chemistry
Calcium Carbonate DissolutionCalcium Carbonate Dissolution
Carbonate Scale DissolvingCarbonate Scale Dissolving
Ca2+ + CO3 CaCO3
Ca2+ + 2(HCO3) CaCO3 + CO2 + H2O
• Most common scale type found in oilfield production systems..
Calcium Carbonate• Formed by the combination of the calcium ion with either
carbonate or bicarbonate in water
Carbonate Scale – Deposition FactorsCarbonate Scale – Deposition Factors
pH
Increasing alkalinity leads to carbonate scale deposition
Pressure
Pressure drops lead to CaCO3 deposition, hence deposits at valve locations
Temperature
CaCO3 solubility decreases with increasing temperature
Carbonate Scale RemovalCarbonate Scale Removal
• Traditionally performed with Hydrochloric acid- Very reactive – quick dissolution time- Cheap- Readily available
• BUT……- Very corrosive- Hazardous- ‘Secondary’ scaling can occur- Possibility of formation damage
MIPC CAL-AcidMIPC CAL-Acid
• Developed as a viable alternative to HCl
• Low corrosivity
• ‘Sequesters’ scaling ions
• Loading capacity comparable to HCl
• Slower to react, but…- Allows better reaction control in contacting critical scale- Penetrates deeper into affected reservoir areas
MIPC CAL-AcidMIPC CAL-Acid
• Affords rapid, yet controlled reaction
• Loading capacity – 260 g/ltr (neat product)
• Typically applied as 50% solution- Maximises performance vs. concentration effects
• Inherent sequestering capacity ensures prevention of ‘secondary scaling’
Carbonate Dissolvers ComparedCarbonate Dissolvers Compared
0
10
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60
70
80
90
100
% S
cale
dis
solv
ed
0 1 2 3 4 5 6Time (Hours)
Dissolution of Calcium Carbonateat 60 deg C, static, 260g/ltr CaCO3
EDTA
CAL-acid
15% HCl
Secondary ScalingSecondary Scaling
• Mineral acids liberate calcium and iron which can re-precipitate during the treatment
This can lead to formation damage
• MIPC CAL-Acid has an inherent sequestering capacity
• Scaling ions released by acid treatment are sequestered and held in solution
• No expensive additives are necessary!!
Corrosivity of MIPC CAL-AcidCorrosivity of MIPC CAL-Acid
• Mineral acids very corrosive – potential for tubular damage
• Central to low corrosivity of CAL-Acid is corrosion inhibitor package- Stable to 100oC
• Corrosivity against L80 & 13Cr steel presented
Corrosivity of MIPC CAL-AcidCorrosivity of MIPC CAL-Acid
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
Cor
rosi
on r
ate
(mpy
)
4 8 24
Time (Hours)
Corrosion of L80 Steel100 deg C, static
CAL-acid 100% CAL-acid (uninhib) 15% HCl
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
Cor
rosi
on r
ate
(mpy
)
4 8 24
Time (Hours)
Corrosion of 13Chrome Steel100 deg C, static
CAL-acid 100% CAL-acid (uninhib) 15% HCl
MIPC CAL-AcidMIPC CAL-Acid
Advantages
• Low corrosivity
• ‘Sequesters’ scaling ions
• Load capacity similar to HCl
• Better reaction control in contacting critical scale
• Penetrates deeper into affected reservoir areas
Disadvantages
• Longer contact time
Barium Sulphate DissolutionBarium Sulphate Dissolution
Sulphate Scale DissolutionSulphate Scale Dissolution
• Sulphate scales of barium, strontium and calcium present a complex dissolution problem
• Characteristics- Insoluble in acid- Very low solubility in
water- Forms hard,
consolidated scales- Usually found as ‘mixed’
scale deposit
Barium SulphateBarium Sulphate
• Least soluble scale found in oilfield systems- 2.3 mg/l at 25oC
• Many formation waters contain high barium concentrations
• Not usually a problem until seawater breakthrough- High SO4 levels
Barite - naturally occurring BaSO4
Barium Sulphate Scale RemovalBarium Sulphate Scale Removal
• Low solubility yields a difficult dissolution problem
• Acid insoluble, thus we must employ a different chemical approach…....CHELATION
• Chelating agents complex with metal ions to return water soluble species - increasing solubility - e.g. EDTA - Ethylene Diamine Tetra-acetic Acid
Chelation ProcessChelation Process
• Divalent metal ions can form stable complexes with chelating agents
• Even with low solubility, barium ions solvate in water
BaSO4 Ba+ + SO42-
• Addition of a chelating agent (L) gives
Ba2+ + L BaL
• Effectively “removing” barium ions from solution
BaSO4 + L BaL + SO42-
• Driving solvation of more barium ions and thus scale
Dissolver FormulationDissolver Formulation
• Sulphate scale still has a low solubility even in the presence of some chelating agents
• To deliver effective dissolver chemistry we need to consider...
Chelation Conversion Catalysis
Sulphate scale dissolver
Dissolver FormulationDissolver Formulation
• Chelation- Must have high metal affinity – log K1
- Operate at optimum pH
• Conversion- Conversion agents assist in metal ion chelation eg
• Catalysis- Enables dissolution process to proceed more efficiently
Fe (II) Fe (III)
Favours chelation of ferric rather than ferrous ions
BaSOL and BaSOL 2000BaSOL and BaSOL 2000
Latest advance in the field of barium sulphate dissolution
Delivers optimum pH conditions for scale dissolution
Non-corrosive
Non-hazardous for handling
Affords rapid dissolution rates
High loading capacity - 120g/ltr possible
Relative Dissolution RateRelative Dissolution Rate
00.5
1.52.5
612
0
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100S
cale
rem
aini
ng (
%)
Time (hours)
Relative dissolution rate of BaSOL and EDTA Barium sulphate, 85 deg C, 4% w/v
BaSOL
EDTA
Temperature EffectsTemperature Effects
0 0.5 1 1.5 2 2.5 3 4 6 10 12
120C
100C
80C
60C40C
20C
0
10
20
30
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50
60
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90
100S
cale
rem
aini
ng (
%)
Time (hours)
Dissolution of oilfield scale as a function of tem peratureBaSOL 5%w/v
WettabilityWettability
0 1 2 3 4 5 6 7 8 9 10
0
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% S
cale
rem
aini
ng
Time (hours)
Dissolution of barium sulphate scale as a function of wettability80 deg C, static conditions
Water w et
Crude w et
Asphaltene w et
Progress in Barium Sulphate DissolutionProgress in Barium Sulphate Dissolution
Sequestering capacity in g/ltr @ 6 hrs @ 90oC
Analar BaSO4 Field scale Comments
High low Multi-stage
20 12 Very slow
30 30 Slow
40 80 Fast
120 120 Best so far
Converter + acid
EDTA
DTPA
BaSOL
BaSOL 2000
Calcium Sulphate DissolutionCalcium Sulphate Dissolution
Calcium SulphateCalcium Sulphate
• Formed in a similar way to Barium and Strontium Sulphates
• Often found as a co-deposit with Barium & Strontium
• Removal assured with chelation chemistry
Gypsum - naturally occurring CaSO4
MIPC GypsolMIPC Gypsol
• Gypsol dissolves calcium sulphate at ~2.8 times the speed of BaSOL
• Designed specifically for Calcium sulphate scale
• Outperforms EDTA - traditional calcium sulphate dissolver
• Non- corrosive
• Supplied as a pH 7-8 solution, thus low handling hazard
Comparative DissolutionComparative Dissolution
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100%
Cal
cium
Sul
phat
e re
mai
ning
0 0.5 1 1.5 2
Time (Hours)
Calcium sulphate dissolution[100 deg c, static conditions]
EDTA Gypsol
Temperature EffectsTemperature Effects
0 1 2 3 4 5 6 7
0
20
40
60
80
100%
Sca
le R
emai
ning
Time (hours)
Dissolution of Anhydrite scale
147 deg
95 deg
60 deg
Sulphate Scale Dissolvers - SummarySulphate Scale Dissolvers - Summary
BaSOL 2000
•Rapid dissolution rates
•High load capacity
•Non corrosive
•Safe to handle
Best Barium/Strontium sulphate de-scaling
solution
Gypsol
•Outperforms EDTA
•Non corrosive
Designed specifically for the removal of calcium
sulphate
BaSOL Scale DissolverBaSOL Scale Dissolver
CASE HISTORYCASE HISTORY
Case History – BaSOL Sulphate DissolverCase History – BaSOL Sulphate Dissolver
• North Sea well with severe decline in production- Sulphate scale across
perfs
• Tail pipe scale preventing access to perforating guns
• Scale analysis- 72% BaSO4
- 25% SrSO4
- 3% CaCO3
BaSOL Case History – Treatment BaSOL Case History – Treatment SummarySummary
• Bullhead application used
• Spearhead with KCl brine with demulsifiers
• Spot dissolver & allow to reach formation temperature
• Series of displacement & soak sequences- Maximise dissolution
• Total of 5 dissolver sequences carried out- First two across perforations- Last three in tailpipe- PI noted after each flowback
BaSOL Case History - ResultsBaSOL Case History - Results
• Production increased from 350 m3/day to 1975 m3/day- 464% increase over 5 treatments
• Total mass of 500 kg sulphate scale removed- 233.2 kg BaSO4
- 266.4 kg SrSO4
• 53 kg sulphate scale removed from perforations/near well bore- Represents greatest detrimental affect on production
• Success meant that well did not need re-perforation
- Represents added value benefit
BaSOL Case History - ResultsBaSOL Case History - Results
Dissolver sequence
Kg BaSO4 removed
Kg SrSO4 removed
Production rate
(m3/day)
Dissolver target zone
0 - - 350 -
1 20 19.5 1390 Perfs
2 4.5 9.1 1560 Perfs
3 100.9 110.9 1755 Tail Pipe
4 93.2 82.9 1800 Tail Pipe
5 14.6 44.0 1975 Well Bore
BaSOL Case History – Production ProfileBaSOL Case History – Production Profile
Production increase - Post Treatments
350
13901560
1755 18001975
0
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1500
2000
2500
0 1 2 3 4 5
Dissolver sequence
Pro
duct
ion r
ate
(m
3/d
ay)
Production Rate (M3/ day)
BaSOL Case History – Scale Removal BaSOL Case History – Scale Removal ProfileProfile
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120
0 1 2 3 4 5
Dissolver sequence
BaSO4 removed (kg)
0
20
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120
0 1 2 3 4 5
Dissolver sequence
SrSO4 removed (kg)
SummarySummary
SummarySummary
• The MIPC range of Scale Dissolvers represent leading edge technology in the market place- CAL-Acid for carbonate scales- BaSOL 2000 for barium & strontium sulphates- Gypsol for calcium sulphate
• Field experience in removal of barium & strontium sulphate scales from tubulars and formations- Significant increase in productivity
• Personnel in China with experience in scale dissolver and scale inhibitor squeeze treatments
M-I Production Chemicals has the chemical resourcesto remove any commonly encountered field scale
MIPC Expertise Innovative range
COMPREHENSIVE SCALE CONTROL PACKAGECOMPREHENSIVE SCALE CONTROL PACKAGE
MIPC Scale Dissolver Product LineMIPC Scale Dissolver Product Line
Mineral Scale Dissolution
Carbonate scale - CAL-Acid
Barium/Strontium Sulphate scale - BaSOL
Calcium Sulphate - Gypsol
Iron Sulphide - Pyrisol
Iron deposits/rust - R-Sol
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