Offshore Drilling Waste Treatments & Risk Management

Plan

77thth Kwt. Waste Management Kwt. Waste Management ConferenceConference

Dr. Ahmad AgwaDr. Ahmad Agwa

IntroductionIntroduction

The environmental impact of oil and gas The environmental impact of oil and gas well drilling is a major issue facing todaywell drilling is a major issue facing today ’’s s petroleum industry.petroleum industry.

One of the most difficult environmental One of the most difficult environmental problems to resolve at the well site is the problems to resolve at the well site is the disposal of waste mud and cuttings that are disposal of waste mud and cuttings that are often physically unstable and unsuitable for often physically unstable and unsuitable for landfill.landfill.

Definitions of drilling fluidDefinitions of drilling fluid

Mud’s are essentially made of a fluid (water Mud’s are essentially made of a fluid (water and/or oil), ground rock and clays and have a and/or oil), ground rock and clays and have a consistency rather like smooth sauce or consistency rather like smooth sauce or custard.custard.

These fluids have evolved into complex These fluids have evolved into complex mixtures from over 200 minerals and chemicals mixtures from over 200 minerals and chemicals engineered to meet the requirements of engineered to meet the requirements of modern drilling.modern drilling.

Mud’s are expensive products and should be Mud’s are expensive products and should be reused as much as possible.reused as much as possible.

Drilling Mud SystemDrilling Mud System HISTORY OF USING DRILLING MUDsHISTORY OF USING DRILLING MUDs

Long ago, people were generally drilling for Long ago, people were generally drilling for water, not for oil. water, not for oil.

only in the 19th century that drilling became for only in the 19th century that drilling became for oil.oil.

In the 1960s, the first mud’s to be used were In the 1960s, the first mud’s to be used were water based. Later, in the 1970s and early water based. Later, in the 1970s and early 1980s, mud’s based on diesel, the only lubricant 1980s, mud’s based on diesel, the only lubricant available at the time, were introduced.available at the time, were introduced.

In 1984, diesel was replaced by low toxicity In 1984, diesel was replaced by low toxicity oil and from 1992 until 1996, in line with oil and from 1992 until 1996, in line with regulations; these oil-based muds were in regulations; these oil-based muds were in turn phased out to be replaced by turn phased out to be replaced by synthetic muds. synthetic muds.

Drilling fluid slurryDrilling fluid slurry

Factors Affecting Drilling Factors Affecting Drilling Fluid SelectionFluid Selection

(1)- Types of formations to be drilled(1)- Types of formations to be drilled

(2)- The range of temperature, strength, (2)- The range of temperature, strength, permeability, and pore fluid pressure permeability, and pore fluid pressure exhibited by the formationsexhibited by the formations

(3)- The formation evaluation procedure used(3)- The formation evaluation procedure used

(4)- The water quality available(4)- The water quality available

(5)- Ecological and environmental (5)- Ecological and environmental considerationconsideration

DRILLING MUD FUNCTIONS DRILLING MUD FUNCTIONS Cool the drill bit and lubricate its teeth. Cool the drill bit and lubricate its teeth. Cool and lubricate the drill string.Cool and lubricate the drill string. Providing a hydrostatic pressure just greater Providing a hydrostatic pressure just greater

than the formation pressure to prevent damage than the formation pressure to prevent damage to equipment and injury to drilling personnel. to equipment and injury to drilling personnel.

Mud carries these cuttings up the hole and to the Mud carries these cuttings up the hole and to the surface, to be separated from the mud.; The mud surface, to be separated from the mud.; The mud must also be capable of keeping the cuttings in must also be capable of keeping the cuttings in suspension when circulation is stopped, to suspension when circulation is stopped, to prevent them from accumulating on the bottom prevent them from accumulating on the bottom of the hole and causing pipe sticking.of the hole and causing pipe sticking.

Good Mud cake stabilize the wall of hall.Good Mud cake stabilize the wall of hall. Mud must possess such properties that it will aid Mud must possess such properties that it will aid

the production of good logs. the production of good logs.

Drilling Mud Cycle at well siteDrilling Mud Cycle at well site

Types of Mud’sTypes of Mud’s

WATER BASED MUDWATER BASED MUD Oil BASED MUDOil BASED MUD Synthetic BASED MUDSynthetic BASED MUD

(1)- Liquid water (1)- Liquid water

(2)- Reactive fractions to provide further viscosity (2)- Reactive fractions to provide further viscosity and yield point;and yield point;

(3)- Inert fractions to provide the required mud (3)- Inert fractions to provide the required mud weight; andweight; and

(4)- Chemical additives to control mud properties. (4)- Chemical additives to control mud properties.

Drilling waste discharge Drilling waste discharge regulationsregulations

Definition of Drill CuttingsDefinition of Drill Cuttings

Drill cuttings are created when a well is Drill cuttings are created when a well is drilled in rock to reach oil and gas trapped drilled in rock to reach oil and gas trapped below. These cuttings can vary in size and below. These cuttings can vary in size and texture, from fine silt to gravel. The cuttings texture, from fine silt to gravel. The cuttings are carried back to the surface by the drilling are carried back to the surface by the drilling mud. mud.

International Regulation of International Regulation of offshore Drilling Waste Dischargesoffshore Drilling Waste Discharges

- Oslo (72-74) and Paris convention (74-1978)- Oslo (72-74) and Paris convention (74-1978)

- The OSPAR convention (92-1998)- The OSPAR convention (92-1998)

At present there are four main OSPAR At present there are four main OSPAR measures regulating the majority of discharges measures regulating the majority of discharges and emissions from offshore installations:and emissions from offshore installations:

- - Decision 92/2 Decision 92/2 on the Use of Oil-based Muds on the Use of Oil-based Muds - this was the start of the ban on OBM - this was the start of the ban on OBM discharges; discharges;

- - Recommendation 92/6 Recommendation 92/6 on Best Available on Best Available Technology for Produced Water Management Technology for Produced Water Management on Offshore Gas and Oil Installations - this set on Offshore Gas and Oil Installations - this set the 40ppm oil: water content for produced the 40ppm oil: water content for produced water discharges;water discharges;

- - Decision 96/3 Decision 96/3 on a Harmonized on a Harmonized Mandatory Control System for the Use and Mandatory Control System for the Use and Reduction of the Discharge of Offshore Reduction of the Discharge of Offshore Chemicals - this coordinated the different Chemicals - this coordinated the different countries' regulations;countries' regulations;

- - Decision 97/1 Decision 97/1 on on Substances/Preparations Used and Substances/Preparations Used and Discharged Offshore - this attempted, Discharged Offshore - this attempted, unsuccessfully, to make a list of banned unsuccessfully, to make a list of banned substances. substances.

The Egyptian Drilling Wastes The Egyptian Drilling Wastes Discharge Regulations (National Discharge Regulations (National Laws)Laws)

Article 52 Article 52 Article 54 Article 54 Article 57 Article 57 Article 58Article 58

NEW TECHNIQUES NEW TECHNIQUES (TREATMENTS) FOR MUD & (TREATMENTS) FOR MUD &

CUTTINGS DISPOSALCUTTINGS DISPOSAL

Drilling Waste Management (Treatments& Drilling Waste Management (Treatments& Disposal) Methods:Disposal) Methods:

Source reduction methodsSource reduction methods ReuseReuse Recycling/RecoveryRecycling/Recovery

Onshore (Treatments) FacilitiesOnshore (Treatments) Facilities Onshore reception and temporary storageOnshore reception and temporary storage Pre-treatmentPre-treatment

Figure (4.7) Cuttings pile material onshore Figure (4.7) Cuttings pile material onshore

disposal routedisposal route

Processing facility (Different treatments)Processing facility (Different treatments)

After source reduction, reuse, recycling and After source reduction, reuse, recycling and recovery opportunities have been examined, recovery opportunities have been examined, different treatments involved minimizing waste different treatments involved minimizing waste volumes or toxicity should be considered.volumes or toxicity should be considered.

Thermal treatment methodsThermal treatment methods

Incineration Incineration Thermal desorptionThermal desorption Distillation Distillation SRD TechnologySRD Technology TCC technologyTCC technology Open BurningOpen Burning

Biological treatmentsBiological treatments

Biological treatments operate on the principle of Biological treatments operate on the principle of microbial breakdown of the waste microbial breakdown of the waste with with specific techniques for particular waste streams. specific techniques for particular waste streams.

There are bacterial products available on the There are bacterial products available on the market capable of treating a wide range of market capable of treating a wide range of organic wastes, including organic wastes, including chlorinated chlorinated materialsmaterials. These products are bred from . These products are bred from naturally occurring materials evolved to naturally occurring materials evolved to tolerate tolerate heavy metals and degrade toxic organic heavy metals and degrade toxic organic compounds. compounds.

Most important factors controlling biological Most important factors controlling biological degradation of hydrocarbons are:degradation of hydrocarbons are:

An adequate supply of hydrocarbon degrading bacteriaAn adequate supply of hydrocarbon degrading bacteria

Availability of sufficient oxygen (and mixing) for cell Availability of sufficient oxygen (and mixing) for cell metabolismmetabolism

Availability and balance of nutrients and micro-Availability and balance of nutrients and micro-nutrients necessary for optimum bacterial metabolismnutrients necessary for optimum bacterial metabolism

Moisture controlMoisture control

Temperature and PH valuesTemperature and PH values

Salinity Salinity

Biotreatment methodsBiotreatment methods

Land-farming Land-farming LandspreadingLandspreading compostingcomposting Biological treatment in tanks Biological treatment in tanks Biological treatment (package units)Biological treatment (package units)

Chemical treatmentsChemical treatments

Solidification/Stabilization and Encapsulation Solidification/Stabilization and Encapsulation Solvent extractionSolvent extraction Flocculation of waste fluidsFlocculation of waste fluids Slag-Mix CementSlag-Mix Cement Soil washing with surfactants Soil washing with surfactants

Minimizing Offshore drilling Waste Minimizing Offshore drilling Waste DischargesDischarges

Using less toxic alternatives (SBM) Using less toxic alternatives (SBM)

Cleaning onboard prior to discharge [Solid Cleaning onboard prior to discharge [Solid Control Equipment (Mechanical Treatment)]Control Equipment (Mechanical Treatment)]

Cuttings Re-injection (CRI)Cuttings Re-injection (CRI)

Mechanical solids-removal Mechanical solids-removal equipment: equipment:

Screen devices, Centrifugal separation Screen devices, Centrifugal separation devicesdevices

Cross-section of a decanting centrifuge. Cross-section of a decanting centrifuge.

Hydrocyclones solids-removal processHydrocyclones solids-removal process

Shipment of wastes ashoreShipment of wastes ashore

- SKIP (Boxes) & SHIP- SKIP (Boxes) & SHIP

- BULK SHIPMENT - BULK SHIPMENT

Fig.,(4.24) Bulk containment operationsFig.,(4.24) Bulk containment operations

Drilling Waste SlurriesDrilling Waste Slurries Interaction of factors affecting slurry viscosityInteraction of factors affecting slurry viscosity By using treatment chemicals it should be By using treatment chemicals it should be

possible to engineer the slurry viscosity to possible to engineer the slurry viscosity to achieve three objectivesachieve three objectives::

1)1) Optimize the solids loading of the slurry (i.e. Optimize the solids loading of the slurry (i.e. minimize dilution).minimize dilution).

2)2) Optimize the slurry viscosity to enable pumping Optimize the slurry viscosity to enable pumping and slurry transfer.and slurry transfer.

3)3) Optimize the slurry stability to minimize settling Optimize the slurry stability to minimize settling during transit.during transit.

Re-injection Offshore (CRI)Re-injection Offshore (CRI)

Cuttings re-injection (CRI) is a waste disposal Cuttings re-injection (CRI) is a waste disposal technique where drill cuttings and other oilfield technique where drill cuttings and other oilfield wastes are mixed into slurry with water and wastes are mixed into slurry with water and pumped at high pressure down an injection well.pumped at high pressure down an injection well.

Sometimes it is necessary to grind up the particles Sometimes it is necessary to grind up the particles

in the slurry to make them finer. The hydraulic in the slurry to make them finer. The hydraulic pressure can also be used to break open layers in pressure can also be used to break open layers in the rock to make subsequent injection easier and to the rock to make subsequent injection easier and to

contain the wastes in a defined area.contain the wastes in a defined area.

.Finally and very recently, we can install on-.Finally and very recently, we can install on-site (more) advanced plants (units) or site (more) advanced plants (units) or processes which are more advanced than processes which are more advanced than HI-G Dryer and give us with no doubt HI-G Dryer and give us with no doubt

((((Zero DischargeZero Discharge)))) treatment such treatment such asas: :

The Thermal Oil The Thermal Oil Recovery system [ THOR Recovery system [ THOR 8'] plant. 8'] plant.

THORTHOR™™ Flow Diagram Flow Diagram

Feed Hopper

Dryer Unit

Rehydration Pug M ill

Condensor

AdaibaticQ uench

O il/W aterSeparator

W aterTank

O il Tank

CoolingTow er

W ater toCondensor

CleanOil toClient

M ain Blow er

Recovered O ilCleanM aterial

CoolingSprays

Clean Exhaust

Oxidizer

Clean ExhaustHigh Tem pBaghouse

DIESEL = 20 %

WATER = 25 %

SOLIDS = 55 %

45 %moisture

Typical Feed Cuttings Typical Feed Cuttings THOR THOR

Post Treatment (clean) Soil UsesPost Treatment (clean) Soil Uses Fill material Fill material

oilfield pit closures oilfield pit closures landfillslandfills

Filler that is used in concrete and Filler that is used in concrete and cementcement

Blended with stabilization material, then Blended with stabilization material, then used as a road base used as a road base

Made into bricks for construction Made into bricks for construction projectsprojects

Value added product / possible saleValue added product / possible sale Fertilized and seededFertilized and seeded

Summary of Typical Disposal Summary of Typical Disposal TechnologiesTechnologies

CONCLUSION & CONCLUSION & RECOMMENDATIONSRECOMMENDATIONS

It is legal, in most jurisdictions, to dump It is legal, in most jurisdictions, to dump water-based drilling mud’s (WBM) and WBM-water-based drilling mud’s (WBM) and WBM-contaminated drill cuttings into the sea, if the contaminated drill cuttings into the sea, if the dumper has a dumper has a licenselicense and meets certain and meets certain conditions, such as reducing the oil content conditions, such as reducing the oil content to a stated minimum, (Where Drill cuttings to a stated minimum, (Where Drill cuttings when using water base mud does not need when using water base mud does not need special; treatment since it doesnspecial; treatment since it doesn’’t contain oil t contain oil contents or small percentage not more than contents or small percentage not more than 0.5%0.5%). ).

RecommendationsRecommendations

We can install on-site more advanced plants (on-We can install on-site more advanced plants (on-shore Thermal treatment plants) for all oilfield shore Thermal treatment plants) for all oilfield companies here in Egypt which are capable of companies here in Egypt which are capable of treating drilled cuttings contaminated with oil treating drilled cuttings contaminated with oil based mud (OBM) and reach zero discharge based mud (OBM) and reach zero discharge regimes (zero oil% percentage in cuttings) such regimes (zero oil% percentage in cuttings) such as:as:

(The Thermal Oil Recovery (The Thermal Oil Recovery system [THOR 8' ft (or system [THOR 8' ft (or Buckets)] Onshore plant)Buckets)] Onshore plant)

As a future work,As a future work,

II‘‘d like to recommend also that all d like to recommend also that all researchers and engineers which are researchers and engineers which are interested ininterested in

{Drilling waste management subject }, could {Drilling waste management subject }, could focus on cuttings re-injection method focus on cuttings re-injection method (CRI)(CRI) as Economical &friendly environmentally as Economical &friendly environmentally method,method,

And try to implement this method in the And try to implement this method in the Egyptian drilling companies in Egypt. Egyptian drilling companies in Egypt.

THANK YOUTHANK YOU

Dr. Ahmad AgwaDr. Ahmad Agwa

99thth April 2015 April 2015