produced water treating natco group

PRODUCED WATER TREATMENTCARACAS, VENEZUELANOVEMBER 6-7, 2001

By: Kevin JunielSenior Process Engineer

NATCO Group Houston, TX

Outline•INTRODUCTION•WHAT IS PRODUCED WATER?

•PROPERTIES OF PRODUCED WATER

•ENVIRONMENTAL ISSUES

•HOW IS PRODUCED WATER HANDLED?

•WHY TREAT PRODUCED WATER?

•WATER CHEMISTRY ISSUES

•HOW TO TREAT PRODUCED WATER

•SUSPENDED OIL REMOVAL

•SUSPENDED SOLIDS REMOVAL

•CHEMICAL TREATMENT

•BACKWASH WATER TREATMENT

•MATERIAL SELECTION ISSUES

•CONCLUSION

• Sources

• Formation Water

• Water-flood water

• Water from operations- i.e. kill fluids

• Chemicals from treatment

Produced Water Sources

Platform

Seawater Injection

SubseaSafetyValveSafety

Chemicals

Oil Injection Water

Ocean Surface

Bottom of Ocean

Produced Water Sources

Formation Water

Components in Produced Water

� Water� Organics� Salts� Solids� Biological Matter� Added Materials� NORM – Naturally

Occurring Radioactive Material

Typical Composition

Water,% 90 to 99.9

Organics,% 0.1 to 0.2

Salts,ppm 100 to 350000

Solids,ppm 10 to 50

Bacteria,colonies/ml 10,000

Example Produced Water

- 10,000 BWPD

- 1000 ppm oil of 34 º API

- 100 ppm solids of SG = 2.0

- 10 ppm dissolved organics

- 50,000 ppm TDS , SG = 1.03

- 100 °F @ 100 psig

Salinity

Gulf of Mexico

Seawater 27,000 to 44,000 mg/l

mostly sodium chloride

New Mexico field 75,000 mg/l

mostly magnesium sulphate

Environmental Regulations

�GOVERN EMISSIONS INTO WATER, AIR OR LAND (MUST HAVE UNDERSTANDING OF IMPACT ON ENVIRONMENT)

�DICTATE LEVEL OF TREATMENT FOR DISPOSAL INTO WATER BODIES (INTERNATIONAL, FEDERAL, STATE AND LOCAL)

�CHANGE IN REACTION TO DEVELOPING TECHNOLOGY (HOWEVER PRESSURE TO INSTILL TIGHTER LIMITS)

�NON-COMPLIANCE CAN BE DEVASTATING FOR OPERATORS

�INVESTMENTS IN ENVIRONMENTAL COMPLIANCE DO NOT SHOW UP ON THE BOTTOM LINE – OR DO THEY?

How Produced Water is Handled

• Disposal (Surface, Subsurface)

• Enhanced Recovery (Waterflood, Steamflood)

•Agriculture (Irrigation)

•Process/Plant Water

•It is estimated that the produced water volume will reach 3-6 times the oil volume over the life of an oilfield

Produced Water vs. Life of OilfieldQ

uant

ity

Time

Water

Oil

Gas

What is Water Treatment?

1. PREPARE WATER FOR INJECTION INTO WATERFLOOD OR DISPOSAL ZONE

2. PREPARE WATER FOR OVERBOARD/SURFACE DISPOSAL

3. UTILITY AT FACILITY

4. AGRICULTURAL USE

5. RECOVER OIL TO RE-ROUTE TO THE CASH REGISTER

Produced Water Treatment Objectives for Oilfield Use

� REDUCE SUSPENDED OIL CONCENTRATION TO COMPLIANCE LEVELS OR TO LEVELS SPECIFIED BY RESERVOIR DEPT.

� REDUCE SUSPENDED SOLIDS CONCENTRATION TO COMPLIANCE LEVELS OR TO LEVELS SPECIFIED BY RESERVOIR DEPT.

� ADDRESS ANY WATER CHEMISTRY ISSUES (CHEMICAL INJECTION SYSTEM)

� EXCLUDE OXYGEN FROM THE SYSTEM

� MINIMIZE CAPITAL AND OPERATING EXPENSE (DOWNTIME)

How Clean Does The Water Need To Be?

”Typical” Waterflood

• Solids < 5-10 mg/l

•Oil< 5-10 mg/l

• 95% removal of 5+ micron

Overboard in US GOMOil 42 mg/l daily max., 29 mg/l monthly avg.

Water Chemistry Issues

� HIGH DISSOLVED SOLIDS CONTENT

� HIGH SCALING TENDENCY

� MIXING PRODUCED WATERS

� MIXING PRODUCED WATER AND SURFACE WATER

� CORROSION POTENTIAL/CORROSION CONTROL

� CONTROL OF BACTERIA GROWTH (AEROBIC/ANAEROBIC)

Open System Versus Closed System Design

� ADVANTAGES OF CLOSED SYSTEM

1. EXCLUDE OXYGEN2. MINIMIZE CORROSION3. MINIMIZE SCALE

FORMATION4. MINIMIZE AEROBIC

BACTERIA5. PRESERVE PROCESS

HEAT6. EXCLUDE OUTSIDE

CONTAMINANTS7. MINIMIZE EMISSIONS

� ADVANTAGES OF OPEN SYSTEM

1. CHEAP TO BUILD

REVIEW

1. WHAT IS PRODUCED WATER?2. WHY MUST PRODUCED WATER BE TREATED?3. HOW IMPORTANT IS PRODUCED WATER TREATMENT TO

AN OPERATING FACILITY?4. WHY IS A CLOSED SYSTEM PREFERRED?5. WHAT MUST BE CONSIDERED WHEN MIXING

PRODUCED WATER WITH FRESH WATER?6. HOW DOES PRODUCED WATER TEEATMENT AFFECT

PROFITABILITY?7. WHAT ARE SOME USES OF PRODUCED WATER IN AN

OILFIELD OPERATION?8. HOW CLEAN MUST PRODUCED WATER BE?

Process Definition

�Bulk oil removal

�Free oil removal

�Dispersed oil removal

�Water polishing

�Proposal / injection

Processes That Treat Produced Waters

• Specific Gravity Differences

•Flotation

•Enhanced Gravity

• Physical trapping

•Chemical Treatment

SUSPENDED OIL/SOLIDS SETTLINGSUSPENDED OIL/SOLIDS SETTLINGSTOKES LAWSTOKES LAW

=V

F�sg(water-oil)(d2)V =�

where:

V = particle moving velocityF = force

� sg = densityd = droplet size� = viscosity

FACTORS AFFECTING PERFORMANCE BASED ON STOKE’S LAW

1. DROP SIZE2. TEMPERATURE (VISCOSITY,DENSITY)3. GRAVITATIONAL FORCE

HENCE, OUR GOAL IN PROCESS SYSTEM DESIGN IS TO MAXIMIZE OR ENHANCE THE FACTORS TO PROMOTE GOOD SEPARATION. EXAMPLES…..

Bulk Oil Removal (Gravity)

TECHNOLOGY PURPOSE

Skim Tanks

Horizontal Skimmers

Vertical Skimmers

API Separators

Mitigate flow surges

Evolve entrained gas

Reduce oil concentrations

Provide solids settling

Horizontal SeparatorOil droplets >150 micronsSettleable solids >50 micronRetention time <10 minutes

Onshore / Offshore Production Surge ProtectionPotential Pitch & Roll Concerns

Vertical Separator

Oil droplets >150 microns

Settleable solids >25 micron

Retention time <10 minutes

Offshore Production

Minimal Surge Protection

Less Sensitive to Pitch / Roll

API SeparatorOil droplets >150 micronsSettleable solids >50 micronRetention time 20 + minutes

Refinery Waste WaterIndustrial Waste Water

API Separator Options

� Inlet Distribution Headers for Flow Control

� Solids Hopper for Solids Collection

� Flight and Rake System for Solids/Oil Removal

� Adjustable Rotating Pipe Skimmer for Oil Removal

� Rotating Drum Skimmer for Enhanced Oil Removal

� Corrugated Plate Pack for 50 Micron Oil Droplet Removal Efficiency

Free Oil Removal

TECHNOLOGY PURPOSE

Corrugated Plate Interceptors(Upflow or Downflow )

Matrix PlateSeparatorsLiquid/Liquid HydrocyclonesSolid/Liquid Hydrocyclones

Primary separation of oil from

water

Primary separation of oil free

solids from water

Down Flow CPI

�Oil Removal (Gravity)

�Plates at 45º Angle

�Plate spacing 18mm

�Plate pack material is

316SS or FRP

Coalescing Plate

Up Flow CPI

�Solids Removal (Gravity)

�Plates at 60º Angle

�Plate spacing 25mm

�Plate pack material is

316SS or FRP

Matrix Plate Separators (Gravity)Oil droplets d90 @ 50 micronSettleable solids d50 @ 25 micronVelocity 1–3 ft/min

Onshore / Offshore ProductionMinimal Surge ProtectionInsensitive to Pitch / Roll

REVIEW

1. DESCRIBE STOKE’S LAW?2. WHAT ARE COMMON WATER TREATING PROCESSES THAT ARE

BASED ON STOKE’S LAW?3. HOW DOES THE SIZE OF THE OIL DROPLET AFFECT THE

PERFORMANCE OF OIL REMOVAL EQUIPMENT?4. WHICH OIL WILL PERFORM BETTER – 16 API OR 34 API?

WHY?5. HOW DO PLATE SEPARATORS WORK?6. WHICH ORIENTATION IS BETTER FOR SEPARATION –

HORIZONTAL OR VERTICAL?7. WHICH ORIENTATION IS LESS SENSITIVE TO MOTION –

HORIZONTAL OR VERTICAL?8. WHAT IS THE ADVANTAGE OF ADDING MATRIX PACKING TO A

SKIMMER OR SEPARATOR VESSEL? WHAT ARE POTENTIAL DISADVANTAGES OF THIS TYPE OF INTERNALS?

Liquid/Liquid Hydrocyclones

Enhanced GravityConvert Pressure Energy to Centrifugal EnergyInsensitive to Motion or SurgesNo Chemicals or Power (if high enough pressure)Small Oily Reject Stream (2% of Inlet Flow)

Liquid/Liquid Hydrocyclones

Operating Principles� Internal geometry creates a vortex (inlet,taper)� Centrifugal force accelerates separation� Oil droplets separate and coalesce in the center� Oil is funnelled into the overflow for removal

PRINCIPLE OF OPERATION

L/L Hydrocyclones

� Developed, proven technology

� High efficiency� Flexible, Easy to Expand� Compact Design� Lightweight

L/L Hydrocyclone VesselLiner Bundle

� Easy to Install for Future Expansion � Individually Accessible

Liner Design

Oilspin AVh

Oilspin AV

Oilspin AVi

� Corrosion resistant liner

material

� Erosion resistant liner

material

� Ease of operation

� No moving parts

� Low maintenance

“Typical” PerformanceCorrected Efficiency

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0Droplet daimeter, micron

Prob

abili

ty o

f rem

oval

LQAV"dev 2"

Produced Water Treatment

LPSep

PV

Degasser LC

Liquid/LiquidHydrocyclone

Fuel Gas Supply

PVCFrom HPSeparator

PV

From LPSeparator PC

LC

From TestSeparator

PV

To HazardousDrain

FlowmeterDischarge

LVC

Reject to LPSeparator

L/L Hydrocyclone Construction

�Efficiency equal to or better than all competinghydrocyclones�Internal geometry and Stelliteinlet reduce erosion�Cones : duplex SS Tails: Sanicro 28�Easily installed and removed -no special tools required

Installation

BP GEISUM PLATFORM

NORTH SEA

PRODUCED WATER

23,000 BWPD

OILSPIN AVi INSTALLATION DESIGN

•MINIMIZE SPACE

•MINIMIZE INSTRUMENTS

•INCREASE OPERATING FLEXIBILITY

•OVERALL REDUCTION IN COST

•MAINTAINING HIGHEST EFFICIENCY

OILSPIN AVi - UNLIMITED TURNDOWN!!!

Oilspin AVi Interactive Hydrocyclone

Method of operation - on line

Oilspin AViInteractive Hydrocyclone

Method of operation - off line

Oilspin AVi Interactive Hydrocyclone

Method of operation - on line


�Hydrocyclones switched

individually or in groups

�2 years operating

experience on Tyra East

�Ideal for test separators,

frequently changing systems

or difficult separations

H. P.SOURCE

L. P.DRAIN


�Eliminates need for multiple or compartmented vessels�Fully automatic hydraulic operation�New manual activation system under development.

H. P.SOURCE

L. P.DRAIN

SUSPENDED SOLIDS REMOVAL

SOLID/LIQUID HYDROCYCLONES

TYPICAL APPLICATIONS

PRODUCED WATER DESANDING

WELLHEAD DESANDING

FILTER PRE-TREATMENT

SAND WASHING

Hydrocyclone Design

•MULTI LINER VESSEL

•D95 >15 MICRONS

•VARIOUS DUMP OPTIONS

•CERAMIC LINERS AVAILABLE

Large Diameter Range

15”

12”

9”

Small Diameter Range

1” Canned

2”Canned

2”Vessel

1” Vessel

1” Cut-away

12 mm Desanders

� d90 5 to 7 microns� Flowrate typically below

0.1 m3/h so huge numbers required

� Very prone to blockage� Upstream strainers or

desanders required for protection

Ceramic Desanders

� Default 3” ceramicdesander

� Flowrate/efficiency modified by vortex finder selection

� Capacity 10 to 30 m3/h each

� Potted underflow or continuous (>2%)

� d90 15 to 50 microns � 2” and 1” also

available taking d90

down to 11 microns

Performance Range

Solid/Liquid HydrocycloneInstallation

�Gamra, Libya Well-head Desanders

�3,700,000 bpd

�90 off 15 PHQ

�95% removal > 100 microns

�Aquifer water


�Al Furat Petroleum�Omar Phase II Field, Syria�110,000 bpd�13 off 10 PHQ�95% removal > 40 microns�River water

Mounting arrangements


� Anadarko/SonatrachAlgeria

� HBNS Development

� 10 Micron Separation

� 150,000 bwpd� Aquifer Water

� 306 off 2CLQ


� Maersk Petroleum Qatar� Al-Shaheen Field� Development

� 98% > 10 micron � rating

� 75,000 BWPD� Produced water

� 146 off 2PHQ

� Used in conjunction with � Oilspin AV LLC’s

High Pressure Wellhead Desander

Halliburton for PDOWelltesting Operations

� Designed to separate solids from multi-phase fluids

� Welltesting and clean up � First fully coded ASME

VIII Division 2hydrocyclone vessel supplied globally

� 3” x 7 way, 10,000 psiunit

Wellhead DesanderShell/PDO Marmul Field

� Compact with high throughput

� Ultra high erosion resistance

� No backflushing� Reduced weight & size

compared with conventional filters

� Continuous or batch operation

Wellhead Desander

� Wide operational envelope� Maintains separation during

slugging, varying flow rates, very high GLR and varying phase composition

� Gas/liquid ratios between 5 and 100 possible

� Higher pressure, higher GLR � Pressure drop 1-15 bar

depending on application� High erosion resistance due

to inlet geometry and materials

Sandwash System

� Designed to separate and remove oil contaminated solids to produce oil free sand (<10g/kg oil on sand by weight)

RECIRCULATION

PROCESSWATER

MOZLEY HYDROCYCLONES

OILYWATER

Sand Cleaning System

� Designed to separate and remove oil contaminated solids to produce oil free sand (<10g/kg oil on sand by weight)

� No chemical addition required� Cleans sand by physical

attrition� Compact system� Maintains cleaning efficiency

with varying solid concentrations Chevron Cabinda Kungulo Field

Desanding Skid for Water Injection Platform

Pressure Let Down Hydrocyclone

� Ceramic cyclonic device for reducing slurry pressure

� Used on desander underflows� Very high erosion resistance� Sized to suit each duty

Sand Fluidizer

� Device under development

� Uses a small amount of water to fluidise and

transport settled sand

� Competitor to Merpro Tore

Centrifuge

REVIEW

1. BY WHAT MECHANISM DO LIQUID/LIQUID HYDROCYCLONES WORK?2. IS HYDROCYCLONE PERFORMANCE AFFECTED BY THE SIZE OF THE OIL

DROPLET?3. WHAT HAPPENS TO HYDROCYCLONE PERFORMANCE AS FLOW RATE

DECREASES? IF A VESSEL HAS 20 LINERS INSTALLED AND THE FLOW RATE DECREASES BY 40%, WHAT ADJUSTMENT MUST BE MADE?

4. HOW DOES THE DIAMETER OF THE SOLID/LIQUID HYDROCYCLONE AFFECT FLOW RATE AND PARTICLE SIZE REMOVED?

5. DESCRIBE HOW THE INTERACTIVE LIQUID/LIQUID HYDROCYCLONE SYSTEM WORKS?

6. WHEN WOULD IT BE APPROPRIATE TO USE POLYURETHANE LINERS IN A SOLID/LIQUID HYDROCYCLONE?

7. WHY IS THE LEVEL CONTROL VALVE PLACED DOWNSTREAM OF THE LIQUID/LIQUID HYDROCYCLONE VESSEL?

8. WHY IS A DEGASSER VESSEL PLACED DOWNSTREAM OF A LIQUID/LIQUID HYDROCYCLONE VESSEL?

Dispersed Oil Removal (Flotation)TECHNOLOGY PURPOSE

Hydraulic Induced Gas Flotation Units

Horizontal Hydraulic IGFHorizontal Sparged IGFSingle Cell Hydraulic IGFHydraulic Column IGFMPE Sparged Column IGF

Mechanical Induced Gas Flotation Units

Separation of emulsified oil from water

Separation of oil coated solids from water

Horizontal Hydraulic IGF�Inlet oil concentration 200-300ppm�Outlet oil concentration 20-30ppm�90-98% Removal Efficiency

Onshore / Offshore

Production

Handles Upsets

Advantages of Horizontal Hydraulic IGF

� No Internal Moving Parts

� Over and Under Internal Baffles to Prevent Short Circuiting

� 25-50 % Water Recycle Rate for Increased Gas Contact Time

� Dual Internal Eductors for Increased Gas Bubble Dispersement

� Mechanical Wipers or Spillover Weirs for Oil Removal

� PVC or 316 SS Internals

� ASME Code Design

� Cylindrical Vessel Design for Improved Solids Collection

Mechanical Induced Gas Flotation(Pressurised)

Cycloturbine� 2 or 4 per vessel� Rotor creates negative pressure

in draft tube, pulling down gas from above the liquid surface

� Gas bubbles are thrown out by the rotor and impinge on the stator

� Turbine design enhances flow pattern and gas/oil contact

CYCLOTURBINES

• 65 SCFM/BBL GAS:WATER RATIOS

• BUBBLE SIZE = <50 MICRONS

• EFFECTIVE DISTRIBUTION

• GEAR REDUCTION DRIVE

AUTOSTABLE SKIMMER

• SITS AT OIL / WATER INTERFACE

• MINIMIZES OIL SKIMS <2%

• HANDLES UPSETS

• OPERATES UNDER MOTION

• NO MOVING PARTS

Floating skimmers

� Oil draw off regulated by oil outlet valve

� Oil box and floating skimmer designed to provide gas seal between water and separated oil

� External buoyancy chambers keep skimmer close to surface

Floating skimmers

� Internal buoyancy chambers regulate skimmer depth and therefore amount skimmed

� Insensitive to motion or throughput

Produced Water TreatmentMechanical Induced Gas Flotation�Maximum operating pressure 4 barg�Maximum inlet oil concentration 1000ppm�Typical efficiency 90-98% oil removal with chemicals�Typical efficiency 80 - 90% without chemicals

Produced Water TreatmentMechanical Induced Gas Flotation

�Typical outlet concentration 15-20 ppm �Typical solids removal 20-50%�Patented by Ceca(Elf) and supplied under licence

Single Cell Hydraulic IGF

Inlet oil concentration 200-300ppm

Outlet oil concentration 30-50ppm

75-90% Removal Efficiency

Onshore / Offshore Production

Handles Upsets


Single Cell Sparged IGF





Handles Upsets


Vertical Downflow Column IGF

Counter Current Contacting


Handles Upsets

Insensitive to Pitch / Roll




REVIEW

1. DESCRIBE HOW FLOTATION WORKS.2. WHAT IS THE DIFFERENCE BETWEEN HYDRAULIC

FLOTATION AND MECHANICAL FLOTATION?3. HOW IS OIL REMOVED IN THE HYDRAULIC IGF?4. HOW IS OIL REMOVED IN THE MECHANICAL IGF?5. WHAT CAN AFFECT THE PERFORMANCE OF THE IGF?6. WHAT IS THE MAXIMUM INLET OIL CONTENT THAT THE

IGF CAN HANDLE?

Water Polishing (Physical Trapping)

TECHNOLOGY PURPOSE

Separation of emulsified oil from water

Separation of oil coated fines from water

Media FiltrationNutshell Filter

Cartridge Filter

Produced (Oily) Water Multi-Media Filter

� Proven technology�Dual/multimedia� Anthracite/sand/garnet combinations�Max inlet oil 30-50 ppm�Outlet oil < 5 ppm�Max inlet TSS 30 - 50 mg/l� Efficiency typically 95% removal of particles

> 5 microns

Water Injection SystemsMedia Filters

� Best technology for removing solid particulates from produced water

� Flux rates 15 - 35 m3/m2/h on produced water

� Polyelectrolyte required� Surfactant usually

required for backwash� Gas scour used during

backwashing� Hundreds of operating

references

Media Filter - Installation

MEDIA FILTER INTERNALS

COLLECTION LATERALSINLET DISTRIBUTOR

Backwash Sequence

Nutshell Filter

�Max inlet oil 50-100 ppm�Outlet oil < 5 ppm�Max inlet TSS 30 - 50 mg/l�Efficiency typically 95% removal of

particles > 10 microns (or 90% > 5 microns)

Nutshell Filter

� Effective oil removal filter� Handles waxy oils

without fouling� Solids removal worse

than suppliers claim� Flux rates 30 - 35

m3/m2/h � Polyelectrolyte not

required� Surfactant not required � Sensitive to biocides� Can be retrofitted to

existing filters

Retrofitted

Nutshell Filter

Nutshell Filter

� Normal flow dowward through the crushed nutshell media

� Nutshells are recirculated through the Powerhead to strip off the oil

� Dirty water passes through a screen to drain

� Clean nutshell media returns to the filter vessel

Cartridge Filters

� Polishing filters for produced water where treatment specification is very tight

� Vertical or horizontal vessels

� Cartridges made by Pall and supplied to special NATCO design

� Sized on basis of hydraulic and solids loadings

� Absolute cartridges (cannot be compared with cheap nominal cartridge elements)

� Quick opening and counterbalanced lid designs available

Coalescer Technology for Complex Gas Condensate Application

� Inlet oil up to 10%� Outlet oil below 10 ppm� Used for low flow

applications with small oil droplets

� Ideal solution for gas condensate fields where LLC’s and IGF’s do not work well

Pall Phasesep�

� Does not disarm unlike glass fiber media

� Low Maintenance/ High Reliability

� Effectively handles process upsets� Efficiently separates difficult low IFT liquids� Competitive coalescers lose efficiency as IFT gets below

20 dyne/cm� Surfactants (in sulfur compounds, corrosion inhibitors

and found naturally in hydrocarbons) lower IFT

IFT = interfacial tension

BACKWASH WATER TREATMENT ISSUES

�What are the contaminants?

�Options for removal

�Equipment required

�Concerns

�Experience of the class

DISPOSAL

Discharge / Injection

TECHNOLOGY PURPOSE

Disposal CaissonSkim Pile

Submerged Column Flotation Unit

(SCFU)

No slick no sheen

No disposal well plugging

Skim Pile

• Free Oil Removal from Open Drains

• Internal Baffles with Oil Risers for Improved Separation

• No Solids Build up in Vessel

• No Moving Parts

• Internal or External Oil Removal Pump

• No Deck Space Required

• Minimal Platform Weight

Submerged ColumnFlotation Unit (SCFU)

•Combination of Flotation and Disposal In Single Vessel

• No Deck Space Required

• Minimal Platform Weight (Partially Submerged in Water)

• No Internal Moving Parts

• Low Maintenance

• Insensitive to Motion

• Reduced Installed Cost

This Submerged Column Flotation Unit (SCFU) is installed offshore Brazil on a FPSO. Directly mounted to the hull, this unit is designed to treat 115,000 bpd of Produced Water. The system was installed to eliminate deck space and weight requirements and minimize the impact of pitch and roll on flotation performance – a major concern for conventional vessels.

DISPOSAL METHODSSubmerged Column Flotation Unit (SCFU)

SCFU Installed On Deepwater Floating Production Platform� No Space Available on Topsides for Conventional Flotation

� Serve as Degassing Vessel for Upstream Hydrocyclones

� Final Disposal After Flotation

� Met Outlet Water Specification of 20 ppm

Compact Offshore Produced Water Treatment System

� Minimal Deck Space Required

� Reduced Weight

� No Moving Parts

� Insensitive to Pitch and Roll

REVIEW1. WHAT ARE THE MECHANISMS EMPLOYED TO MAKE THE

MULTI-MEDIA FILTER WORK PROPERLY?2. WHAT ARE THE MECHANISMS USED TO MAKE THE

NUTSHELL FILTER WORK PROPERLY?3. IF A MULTI-MEDIA FILTER IS USED IN OILY WATER

SERVICE, WHAT STEP IS ADDED TO THE BACKWASH PROCEDURE?

4. WHEN ARE CARTRIDGE FILTERS REQUIRED IN PRODUCED WATER?

5. WHAT ADVANTAGE IS OFFERED BY THE SKIM PILE?

Common Produced Water Treating Chemicals

Upstream of Flotation Unit

10-25 ppmBreak Emulsions

Reverse Demulsifier

Downstream of Booster Pumps

10-20 ppmCorrosion Control

Corrosion Inhibitor

Downstream of Booster Pumps

10-20 ppmScale ControlScale Inhibitor

Various400 ppm for 4 hours (intermittent)

Biological Control

Biocide

In Bottom of Filter

2-4 gal. per backwash

Cleanse Oil Off Media Bed

Surfactant

Upstream of Media Filter

0.5-1 ppmFilter AidCoagulant

Upstream of Media Filter

1-2 ppmFilter AidPolyelectrolyte

Normal Dose Point

Dose RatePurposeChemical

Water Analysis as a Diagnostic Tool

Review Information from Manual

Range of droplet sizes removed by various types of de-oiling equipment

MEMBRANE FILTER

CENTRIFUGE

MEDIA FILTER

COALESCER

HYDROCYCLONE

WITH CHEMICAL FLOTATION

PLATE SEPARATOR

API GRAVITY

0.1 1 10 100 1000

Oily Water TreatmentRequired Minimum Design Parameters

Flow Rate Oil/Water

Pressure Available pressure upstream.Required pressure downstream.

Temperature Operating temperature.

Contaminant Loading Oil / Solids/Oxygen/Bacteria.Inlet/Outlet

Chemical Analysis of Water Anions-Cations-pH

Density Oil - Water - Solids.

Particle Size Analysis Oil-Solids

Oily Water TreatmentRequired Minimum Design Parameters

Existing Process Type of equipment and performance.Upstream/Downstream

Motion Characteristics Pitch/Roll/etc.

Design Conditions Temperature/Pressure

Ambient Conditions Environmental Data/etc.

Outlet Requirements Oil/Solids/Bacteria/Oxygen/Pressure/Temperature

Process Design and Control

Review PFD and P&ID’s from PWTS Proposal

SIZING CRITERIA1. Gravity Settling Devices Stoke’S Law for Drop Rise

2. CPI Flux Rate, Drop Size

3. Hydrocyclone Devices Droplet Removal Efficiency,Capacity per Liner

4. Filtration Equipment Flux Rate, Particle Size Removal

5. Flotation Equipment Retention Time per Cell

Performance Testing

1. Suspended Solids

2. Oil Content

3. Biological Content

4. Sampling Techniques

MATERIAL SELECTION ISSUES

CLASS DISCUSSION OF RELEVANT EXPERIENCE IN VENEZUELA

Engineered Systems Approach To Produced/Oily Water Treatment

REVIEW

1. FOR WHAT PURPOSE IS POLYELECTROLYTE USED?2. FOR WHAT PURPOSE IS SURFACTANT USED?3. WHAT TYPE OF TESTING IS RECOMMENDED TO DESIGN

A PRODUCED WATER TREATING SYSTEM?4. HOW CAN WE USE CHEMICAL TESTING TO

TROUBLESHOOT PROBLEMS?5. WHY IS CARBON STEEL SO COMMON IN PRODUCED

WATER SYSTEMS?6. WHAT BASIC INFORMATION IS REQUIRED TO PROVIDE

TO THE EQUIPMENT SUPPLIER?7. WHAT CRITERIA ARE USED TO SIZE MEDIA FILTRATION

EQUIPMENT?

produced water treating natco group

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