drill fluids and offshore environmental · pdf filehow a well is drilled using drilling fluids...
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Drill Fluids and OffshoreEnvironmental ProtectionDrill Fluids and OffshoreEnvironmental Protection
John Candler, Art LeutermanJuly 2008
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Overview
• Overview of drilling mud andsolids control equipment.
• Waste minimization for offshoredrilling
• Global regulation of drilling fluiddischarges.
• Drilling fluid testing, productapproval
• Global field studies of waterbased mud discharges
• Local issues for dischargesoffshore
• Overview of drilling mud andsolids control equipment.
• Waste minimization for offshoredrilling
• Global regulation of drilling fluiddischarges.
• Drilling fluid testing, productapproval
• Global field studies of waterbased mud discharges
• Local issues for dischargesoffshore
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How a well is drilled usingdrilling fluids
• A drill bit designed for the expected type of formation to be drilled islowered into the well on the drill string.
• The drill string and bit are rotated by the rotary drive on the rig floor, atop drive in the derrick, or a mud motor directly above the bit which ispowered by the force of the mud flowing through it.
• The bit crushes or grinds the rock beneath it into pieces called cuttings
• Drilling Mud is circulated down the drill pipe and through openingscalled “jets” in the bit.
• The mud washes the formation cuttings from beneath the bit andcarries them to the surface.
• When the bit fails or wears out, all of the drill string must be pulledfrom the hole to replace it. This is called a trip.
• 25% - 50% of the time on location is used for non-drilling activitiessuch as running casing and tripping for new bits
• A drill bit designed for the expected type of formation to be drilled islowered into the well on the drill string.
• The drill string and bit are rotated by the rotary drive on the rig floor, atop drive in the derrick, or a mud motor directly above the bit which ispowered by the force of the mud flowing through it.
• The bit crushes or grinds the rock beneath it into pieces called cuttings
• Drilling Mud is circulated down the drill pipe and through openingscalled “jets” in the bit.
• The mud washes the formation cuttings from beneath the bit andcarries them to the surface.
• When the bit fails or wears out, all of the drill string must be pulledfrom the hole to replace it. This is called a trip.
• 25% - 50% of the time on location is used for non-drilling activitiessuch as running casing and tripping for new bits
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Types of Drilling Fluids• Water Based Muds
(WBMs)– Aqueous Based Fluids– Spud- muds
– PHPA muds
– KCl / Glycol systems
– Silca systems
• Oil Based Muds(OBMs)
- Non-AqueousBased Muds(NAF)
- Diesel Oil- Mineral Oil
• Synthetic BasedMuds (SBMs)
- Non-AqueousBased Muds (NAF)
- Esters- Olefins- Paraffins
• Water Based Muds(WBMs)
– Aqueous Based Fluids– Spud- muds
– PHPA muds
– KCl / Glycol systems
– Silca systems
• Oil Based Muds(OBMs)
- Non-AqueousBased Muds(NAF)
- Diesel Oil- Mineral Oil
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Water Based Muds
• Function / Sources of pollution– Controlling Sub surface pressures - Weight materials
– Removing Cuttings - Clays and polymers suspend solids
– Filtration Properties - Fluid loss reducers, polymers seal formations
– Lubricity - Lubricants - Glycols, friction reducers
– Other - corrosion, lost circulation, hydrate inhibitors
• Limitations/ Developments– Shale Inhibition
– Effective Lubricity
– Temperature Limitations
– Gas Hydrate Formation
– Drilling Efficiencies - days on location
• Function / Sources of pollution– Controlling Sub surface pressures - Weight materials
– Removing Cuttings - Clays and polymers suspend solids
– Filtration Properties - Fluid loss reducers, polymers seal formations
– Lubricity - Lubricants - Glycols, friction reducers
– Other - corrosion, lost circulation, hydrate inhibitors
• Limitations/ Developments– Shale Inhibition
– Effective Lubricity
– Temperature Limitations
– Gas Hydrate Formation
– Drilling Efficiencies - days on location
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Non-Aqueous Based Muds• Function/ Sources of Pollution
– Weight materials - barite
– Viscosity - provided by invert emulsion and clay
– Filtration Properties provided by Emulsion
– Lubricity provided by base fluid
• Limitations and developments– High Cost/cubic meter
– Physical properties
– Reduced Logging Quality
– Lost Circulation
– Environmental Concerns
• Function/ Sources of Pollution– Weight materials - barite
– Viscosity - provided by invert emulsion and clay
– Filtration Properties provided by Emulsion
– Lubricity provided by base fluid
• Limitations and developments– High Cost/cubic meter
– Physical properties
– Reduced Logging Quality
– Lost Circulation
– Environmental Concerns
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Solids Control Equipment
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Selection of Drilling Fluids• SAFETY/ENVIRONMENTAL
– APPROVED CHEMICALS
– LOW ENVIRONMENTAL IMPACT
• TECHNICAL– FORMATION PRESSURE CONTROL
– HYDRATE PREVENTION
– ABILITY TO REACH WELL OBJECTIVES
– PRODUCTION QUALITY
– LOGGING QUALITY
– PREVENTION OF DRILLING PROBLEMS
– TEMPERATURE STABILITY
• .ECONOMIC– COST OF MUD SYSTEM TO ACHIEVE $/m, m/DAY GOALS
– EFFICIENCY OF DRILLING OPERATION- MINIMISE DAYS
• SAFETY/ENVIRONMENTAL– APPROVED CHEMICALS
– LOW ENVIRONMENTAL IMPACT
• TECHNICAL– FORMATION PRESSURE CONTROL
– HYDRATE PREVENTION
– ABILITY TO REACH WELL OBJECTIVES
– PRODUCTION QUALITY
– LOGGING QUALITY
– PREVENTION OF DRILLING PROBLEMS
– TEMPERATURE STABILITY
• .ECONOMIC– COST OF MUD SYSTEM TO ACHIEVE $/m, m/DAY GOALS
– EFFICIENCY OF DRILLING OPERATION- MINIMISE DAYS
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Waste Minimization for DrillingFluids and Cuttings
Waste Minimization for DrillingFluids and Cuttings
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Sources of Pollution from Offshore Drilling
Discharges to Air
Discharges to Land
Discharges to Water
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Waste Management and Minimization Approaches
• Improve performance of drilling fluids and solids controlequipment:– Gauge Hole reduces waste volume
– Less shale hydration means less dilution required
– Improved Solids Control efficiency means less dilutionrequired.
• Reduced drilling problems reduces days on location andassociated discharges.
• Improved drilling efficiency reduces days on location andassociated discharges
• Drilling efficiency and waste minimization go hand in hand.
• Improve performance of drilling fluids and solids controlequipment:– Gauge Hole reduces waste volume
– Less shale hydration means less dilution required
– Improved Solids Control efficiency means less dilutionrequired.
• Reduced drilling problems reduces days on location andassociated discharges.
• Improved drilling efficiency reduces days on location andassociated discharges
• Drilling efficiency and waste minimization go hand in hand.
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Waste Management Options
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General Considerations for Waste Management Options
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Marine Transport and Onshore Disposal Considerations
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Injection Considerations
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Offshore Discharge Considerations
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Global WBM regulationsGlobal WBM regulations
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OSPAR• Oslo and Paris Commissions (OSPARCOM) OSPAR
• Harmonized mandatory control scheme (HMCS)
• CHARM (Chemical and Risk Management) model.
• HCMS results in management decisions based on assessment of theprocess with the following outcomes:– Permission
– Substitution
– Temporary Permission
– Refusal of Permission
Test function Applicability of test
• Oslo and Paris Commissions (OSPARCOM) OSPAR
• Harmonized mandatory control scheme (HMCS)
• CHARM (Chemical and Risk Management) model.
• HCMS results in management decisions based on assessment of theprocess with the following outcomes:– Permission
– Substitution
– Temporary Permission
– Refusal of Permission
Log Pow (Mandatory)
Aerobic biodegradability (Mandatory for all organicsubstances)
Algae test (Mandatory)
Crustacean test (Mandatory)
Fish test (Mandatory)
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US EPA - Offshore
• Effluent Limitation Guidelines
• General Permits by EPA RegionsIV,VI, IX, X
• Stock Limitations for Barite andBase Fluids
• End of Pipe Limits for:– Free Oil
– Sediment Toxicity
– Water column Toxicity
– Formation Oil Contamination
Requirement Categories Permit Discharge Limit
Free Oil No free oil (i. e. no static sheen)
Mercury/Cadmium Content of Stock
Barite
1.0 mg/kg mercury max.; 3.0 mg/kgcadmium max.
SPP Aquatic Toxicity Testwith Mysidopsis bahia
96-hour LC50 ≥ 30,000 ppm
• Effluent Limitation Guidelines
• General Permits by EPA RegionsIV,VI, IX, X
• Stock Limitations for Barite andBase Fluids
• End of Pipe Limits for:– Free Oil
– Sediment Toxicity
– Water column Toxicity
– Formation Oil Contamination
SPP Aquatic Toxicity Testwith Mysidopsis bahia
96-hour LC50 ≥ 30,000 ppm
Sediment Toxicity Test withLeptocheirusplumulosus SBMONLY
Ratio of 96- hour LC50 ≤1.00
Formation Oil SBM Only No Discharge
No Discharge
Base Fluids Retained onCuttings (ROC) SBMOnly
≤ 6.9% IO≤ 9.4% ester or default value: 25%
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Other WBM Discharge Regions
• USA– Gulf of Mexico
– California
– Alaska
• Brazil
• Trinidad
• North Sea– Norway
– UK
• Canada East Coast
• USA– Gulf of Mexico
– California
– Alaska
• Brazil
• Trinidad
• North Sea– Norway
– UK
• Canada East Coast
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Timeline of Technology DevelopmentTimeline of Technology Development1970 1980 1990 2000
High Density BrinesHigh Density Brines
LTOBMLTOBMInvert dieselInvert diesel
KCl/PHPAKCl/PHPA
Gyp/polyGyp/polyAl/polyAl/poly
Cr free HTWBMCr free HTWBM
SBMSBM
DrillDrill--in WBMin WBM
UHT WBMUHT WBM
CationicsCationics
HT ResinsHT ResinsGLYCOLSGLYCOLS
POBMPOBMLOHOBM
XX--fazefaze
OSIOSI
Virtual HydraulicsVirtual Hydraulics
Low pH disp.Low pH disp. HT WBMHT WBM
Deeper DrillingDeeper Drilling Offshore ExpansionOffshore ExpansionUltraUltra--Deep DrillingDeep DrillingEnhanced RecoveryEnhanced Recovery
High Angle DrillingHigh Angle DrillingHorizontal DrillingHorizontal DrillingLarge Diameter DrillingLarge Diameter DrillingDeepwater DrillingDeepwater DrillingEnvironmentalEnvironmentalAwarenessAwareness
Extended Reach DrillingExtended Reach DrillingUltraUltra--Deepwater DrillingDeepwater DrillingNonNon--Damaging DrillingDamaging DrillingDepleted Zone DrillingDepleted Zone DrillingOpen Hole CompletionsOpen Hole CompletionsEnvironmental ResponsibilityEnvironmental ResponsibilitySubSub--Salt DrillingSalt Drilling
Gyp/polyGyp/polyAl/polyAl/poly
Gas Hydrate TechnologyGas Hydrate Technology
DrillDrill--in WBMin WBM
SilicatesSilicates
Technology MilestonesTechnology Milestones
Advancements in Drilling TechnologyAdvancements in Drilling Technology
HT ResinsHT Resins
WBM LubricantsWBM Lubricants
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Selection of Drilling Fluids• SAFETY/ENVIRONMENTAL
– APPROVED CHEMICALS
– LOW ENVIRONMENTAL IMPACT
• TECHNICAL– FORMATION PRESSURE CONTROL
– ABILITY TO REACH WELL OBJECTIVES
– PREVENTION OF DRILLING PROBLEMS
• .ECONOMIC– COST OF MUD SYSTEM TO ACHIEVE $/m, m/DAY GOALS
– EFFICIENCY OF DRILLING OPERATION- MINIMISE DAYS
• SAFETY/ENVIRONMENTAL– APPROVED CHEMICALS
– LOW ENVIRONMENTAL IMPACT
• TECHNICAL– FORMATION PRESSURE CONTROL
– ABILITY TO REACH WELL OBJECTIVES
– PREVENTION OF DRILLING PROBLEMS
• .ECONOMIC– COST OF MUD SYSTEM TO ACHIEVE $/m, m/DAY GOALS
– EFFICIENCY OF DRILLING OPERATION- MINIMISE DAYS
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FIELD STUDIES
• NEED TO BE ECOLOGICALLY RELEVANT
• VERIFICATIONS OF LAB PREDICTIONS
• VARIABILITY ISSUES
• SPECIES IDENTIFICATION
• SIGNIFICANCE OF ENVIRONMENTAL FACTORS– MAJOR DIFFERENCES BETWEEN AREAS
• NEED TO BE ECOLOGICALLY RELEVANT
• VERIFICATIONS OF LAB PREDICTIONS
• VARIABILITY ISSUES
• SPECIES IDENTIFICATION
• SIGNIFICANCE OF ENVIRONMENTAL FACTORS– MAJOR DIFFERENCES BETWEEN AREAS
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Geographic RegionsGrandBanks
ScotianShelf
North Sea GOM Australia
Energy HIGH HIGH HIGH - MED LOW/MED HIGH
Depth (m) 70-90 14-110 50-600
(125 m)
30 - 200
300-4000
50-80
Shllw/deep
Sediment Sand Sand Sand/fine Fine SandSediment Sand Sand Sand/fine Fine Sand
Wtr Temp Sfc -1 to 14 2 – 20 7.5 – 13 13 – 26 10 – 30
Wtr TempBottom
0 to – 0.5 < 5 3 – 8 ~ 4 NA
Currents –SFC
45 – 80 30 – 40 13 – 36 5 - > 110 10 – 70
Currents –Bottom
Usually < 4 1 – 7 NA 0 - ~ 110 NA
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RECEIVING ENVIRONMENT FACTORS
• WATER TEMP
• BOTTOM TYPE
• THERMOCLINE
• CURRENT
• WATER QUALITY
• WAVE TYPE
• STORM EVENTS
• BIOTA
• WATER DEPTH
• RIVER INPUTS
• OTHER ACTIVITIES
• WATER TEMP
• BOTTOM TYPE
• THERMOCLINE
• CURRENT
• WATER QUALITY
• WAVE TYPE
• STORM EVENTS
• BIOTA
• WATER DEPTH
• RIVER INPUTS
• OTHER ACTIVITIES
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WBM FIELD STUDIESWBM FIELD STUDIES
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WBM FIELD STUDIES• MID-ATLANTIC (1978)
– 120 M; PHYSICAL ALT TO 150 M– ONLY BA ELEVATED– > CRABS & FISH NEARFIELD; NO CORRELATION W/ BARIUM– GENERAL LACK OF SIGNIFICANT EFFECTS
• NORTH SEA– 45 M; 2 MONTHS & 1 YEAR– CUTTINGS TO 25 M; NO TRACE IN 10 MONTHS– NO BENTHIC EFFECTS OBSERVED– HIGH ENERGY ENVIRONMENT (SIMILAR TO SABLE ISLAND)
• CALIFORNIA (JENKINS, 1989)– METAL UPTAKE STUDY– CLAM; DEPOSIT & FILTER FEEDING POLYCHAETES– NO BENTHIC EFFECTS– BA IN SEDIMENT TO 1,500 M– > BA IN CLAM & FILTER FEEDER
• > 97% GRANULAR BA SULPHATE IN CELLS
• GOOMEX– 3 PLATFORMS; MUD/CUTTINGS/PW– SHUNTING AT ONE– NO BIOACCUMULATION– IMPACTS < 200 M– PHC < 500 M; METALS TO 5 KM
• GEORGES BANK• COOK INLET• TANNER BANK• CALIFORNIA – CAMP• BEAUFORT SEA
• MID-ATLANTIC (1978)– 120 M; PHYSICAL ALT TO 150 M– ONLY BA ELEVATED– > CRABS & FISH NEARFIELD; NO CORRELATION W/ BARIUM– GENERAL LACK OF SIGNIFICANT EFFECTS
• NORTH SEA– 45 M; 2 MONTHS & 1 YEAR– CUTTINGS TO 25 M; NO TRACE IN 10 MONTHS– NO BENTHIC EFFECTS OBSERVED– HIGH ENERGY ENVIRONMENT (SIMILAR TO SABLE ISLAND)
• CALIFORNIA (JENKINS, 1989)– METAL UPTAKE STUDY– CLAM; DEPOSIT & FILTER FEEDING POLYCHAETES– NO BENTHIC EFFECTS– BA IN SEDIMENT TO 1,500 M– > BA IN CLAM & FILTER FEEDER
• > 97% GRANULAR BA SULPHATE IN CELLS
• GOOMEX– 3 PLATFORMS; MUD/CUTTINGS/PW– SHUNTING AT ONE– NO BIOACCUMULATION– IMPACTS < 200 M– PHC < 500 M; METALS TO 5 KM
• GEORGES BANK• COOK INLET• TANNER BANK• CALIFORNIA – CAMP• BEAUFORT SEA
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WBM FIELD STUDY SUMMARY
• NO SIGNIFICANT BIOACCUMULATION
• LOW TOXICITY
• LIMITED BENTHIC IMPACT– < 150 M; IMPACTS PHYSICAL
• LIMITED CUTTINGS ACCUMULATION
• NO SIGNIFICANT WATER COLUMN IMPACTS
• NO SIGNIFICANT BIOACCUMULATION
• LOW TOXICITY
• LIMITED BENTHIC IMPACT– < 150 M; IMPACTS PHYSICAL
• LIMITED CUTTINGS ACCUMULATION
• NO SIGNIFICANT WATER COLUMN IMPACTS
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Local Receiving EnvironmentConsiderations
• Depth of Water
• Currents
• Local species and bottom conditions
• Depth of Water
• Currents
• Local species and bottom conditions
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Conclusions• Drilling Fluids, waste management
strategies can be designed to meeta of technical, economic andenvironmental requirements.
• Significant investments have beenmade to study and understandpotential impacts from disposal ofdrilling fluids and drill cuttings.
• Many areas around the world haveachieved drilling goals combinedwith protection of the environmentwith the support of good scienceand good technology.
• Drilling Fluids, waste managementstrategies can be designed to meeta of technical, economic andenvironmental requirements.
• Significant investments have beenmade to study and understandpotential impacts from disposal ofdrilling fluids and drill cuttings.
• Many areas around the world haveachieved drilling goals combinedwith protection of the environmentwith the support of good scienceand good technology.