Speaking title: Hazardous waste drilling mud management – A case study on remediation technologies Oil Industry and the Environment Seminar (NOTES 2015), Delta Hotel, St. John's, Newfoundland and Labrador April 27, 2015

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HAZARDOUS WASTE DRILLING
MUD MANAGEMENT – A CASE
STUDY ON REMEDIATION
TECHNOLOGIES
Presented at:
Oil Industry and the Environment Seminar
(NOTES 2015)
April 27, 2015
Hesam Hassan Nejad
Ph.D. Candidate, Oil & Gas Engineering
Supervisors: Dr. Kelly Hawboldt and Dr. Lesley James

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Outline
 Drilling Mud Fundamentals
 Regulations on Waste Drilling Mud
 Remediation Technologies
• Chemical techniques
• Biological techniques
• Thermal techniques
• Physical techniques
 Technical Comparison of Individual Technologies

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Waste Drilling Mud Production
Purpose of Drilling Mud:
• Prevent blowouts
• Balance & control pressure
• Minimize corrosion
• Lubricate and cool
• Remove drill cuttings
[1]

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Drilling Mud Composition
Drilling mud:
• A solid-liquid slurry
• Very high viscosity
• High content of oil and heavy metals
• Bentonite, barite, and other polymers
The composition of the drilling mud depends on the:
• Type of drilling fluid in use
• Composition of the formation

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Non-Aqueous vs Water Based
Drilling Fluids
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Non-Aqueous Based Drilling Fluids
Diesel-based fluids
Aromatic content 25%, 2% ≤ PAH ≤ 4 %)
Low toxicity mineral oil-based fluids
0.001% ≤ PAH ≤ 0.35%
Synthetic-based fluids (SBFs)
PAH ≤ 0.001%
[2]
Water Based
Drilling Fluids

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Waste Drilling Mud Disposal
 Depending on the regulation, the treatment may vary
 Local authorities may have their own regulations
 Inject waste drilling mud into a formation with high porosity
and high permeability
 In the absence of overboard disposal, another option is to
bring it to shore for land disposal
EPA Regulations
 Environmental Protection Agency (EPA) and Oslo and Paris
Commission (OSPAR) regulations [3]:
• Oil on solid particles should not exceed 1% (wt./wt.)
 Hazardous metal concentrations should be less than specific
amounts
• Toxicity characteristics leaching procedure (TCLP)

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Waste Drilling Mud Disposal -
Newfoundland Regulations
Oil Based Drilling Fluids
• At no time can be discharged to sea
Synthetic Based Drilling Fluids
• Required to have a PAH concentration of < 10 mg/kg and be
able to biodegrade under aerobic conditions
• Oil on cuttings retention limit of 6.9% wet weight
Water Based Drilling Fluids
• Discharge of drill cuttings associated with water based
drilling muds is permitted
[4]

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Current Treatment Technologies
 Waste drilling mud treatment technologies are categorized
into four main groups:
• Chemical treatment
• Biological Treatment
• Thermal Treatment
• Physical Treatment

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Current Technologies
Chemical Treatment
 Destroys the contaminants or converts them to harmless
compounds.
 The most common chemical methods involve oxidants such as
hydrogen peroxide and ozone
 Disadvantages:
• High cost
• Ineffective at higher pH
[5]

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 Another chemical treatment option is to solidify/stabilize the
hazardous waste to convert them into less toxic materials.
 Many reports have been published regarding adding some
chemicals for drilling mud solidification such as lime, cement,
and aluminum sulphate
 Advantages:
• Relatively short processing time
• Effective
 Disadvantages:
• Increase in waste volume
• Difficult to implement
• Need for other chemical compounds increases cost
Current Technologies
Chemical Treatment

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 Biotechnologies involve the use of micro–organisms to
degrade or mineralize the organic components of drill waste
 Advantages:
• Cost effective
• Green process
Current Technologies
Biological Treatment
 Disadvantages:
• Slow reaction times
• Long processing times
• Temperature sensitivity
[6]

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 Removes or destroys hydrocarbon pollutants in the drilling
waste by desorption, incineration, gasification, volatilization,
and pyrolysis (or a combination thereof)
 Advantages:
• Very effective
• High volume reduction
Current Technologies
Thermal Treatment
 Disadvantages:
• Toxic gas production
• High energy requirement
• Very expensive
• No oil recovery
[7]

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 Surfactants (detergent) reduce the interfacial tension (IFT)
between the water and oil phases
 Surfactants liberate the oil from the solid surface
 Surfactants can be used in mixtures with/without additives [8]
[9]
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing

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 Advantages:
• Cost-effective
• Easy to implement
 Disadvantages:
• Usually ineffective in hydrocarbon removal
• May increase waste volume
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing

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 Cationic Surfactants:
• Hazardous nature to humans and nature
• Very high soil sorption
 Anionic Surfactants:
• Lower toxicity than cationic surfactants
• CMC values greater than cationic and non-ionic surfactants
• Least adsorption to soil (significant advantage)
 Non-ionic Surfactants:
• Intermediate sorption
• Low biotoxicity
• CMC values much less than anionic and cationic
surfactants
Current Technologies
Physical Treatment:
Surfactant Enhanced Washing

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 Supercritical Fluids posses:
• Temperature above the critical temperature
• Pressure above the critical pressure
• Liquid-like densities
• Gas-like viscosities
• Zero surface tension
 Carbon dioxide is the most widely used supercritical fluid:
• Non-flammability
• Chemically inert
• Low toxicity
• Low environmental impacts
• Low critical temperature and pressure (31oC and 74 bar)
Current Technologies
Physical Treatment:
Supercritical Fluid Extraction

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 Advantages:
• Efficient
• No/less solvent required
• Short extraction times
• Easy to separate pollutants from the solvent
 Disadvantages:
• High cost
• More safety issues
Current Technologies
Physical Treatment:
Supercritical Fluid Extraction

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Technical Comparison
Factor
Weighting
Treatment Method
Chemical Thermal Physical Biological
Removal Efficiency 30 20 28 18 20
Environmental Pollution
Volume of produced waste 10 6 6 9 9
Hazardous pollution caused 10 8 1 9 9
Cost
Capital cost 10 8 4 8 6
Operational cost 10 8 6 10 6
Energy requirements 10 7 4 9 6
Processing time 10 7 9 5 1
Particle size
(ability to treat very fine particles)
10 9 9 8 8
Total 100 73 67 76 65

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Recommendations
 According to the literature, no current technology, except the
thermal treatment processes, is capable of achieving the NL
or EPA’s regulations of 6.9% or 1% oil on cuttings,
respectively
 There is a need for a combined process with appropriate pre
and post treatment processes to treat the waste drilling mud
 As recommended, physical treatments are suitable
candidates for designing and developing a combined method
to treat the waste drilling mud to meet the strict regulations

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Future Work
 There is no sole technology, except thermal treatment,
capable of reaching disposal regulations, there is a need to
find alternative solutions including combination physical
technologies to treat the drilling mud for land disposal.
 Research is currently being conducted at Memorial
University to test the optimal removal efficiency using
• surfactant enhanced washing and
• supercritical fluid extraction processes.

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References
[1]. Growcock, F. and T. Harvey (2005). Drilling fluids. Drilling Fluids Processing Handbook.
ASME Shale Shaker Committee. Burlington, MA, Gulf Professional Publishing.
[2]. A. M. Shaikh, Environmental Management of Drilling Mud, Master’s thesis, Delft
University of Technology, January 2010
[3]. OSPAR convention for the protection of the marine environment of the north east
Atlantic, OSPAR Commission summary record OIC 2002, ANNEX 12, 2002
[4]. J. Whitford, Stantec Limited, Cuttings Treatment Technology, Evaluation Environmental
Studies Research Funds Report No. 166. St. John’s, NL, July 2009, ISBN 0-921652-85-2
[5]. Ozone secondary disinfection system, Public swimming venues under MAHC compiliance,
January 1st, 2013
[6]. Available at: https://www.sintef.no/projectweb/nomremove/water-treatment-
processes/biological-treatment/
[7]. Available at: http://www.eisenmann.com/en/products-and-services/environmental-
technology/waste-disposal/rotary-kiln.html
[8] P. Yan et al., Remediation of oil-based drill cuttings through a biosurfactant-based
washing followed by a biodegradation treatment, Bioresource Technology 102 (2011)
10252–10259
[9]. Thomkatt, Understanding Basic Chemicals, Available at:
http://www.janitorkatt.com/understanding-basic-chemicals

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Acknowledgements
 Dr. Lesley James and Dr. Kelly Hawboldt for developing this
project and their kindest help and support throughout the
whole project
 Leslie Harris Centre of Regional and Policy Development
for partially funding this project through their 2014-15
MMSB Waste Management Applied Research Fund
Supportedby

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Thank You for Your Attention