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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 NejadPh.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 BasedDrilling Fluids

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Non-Aqueous Based Drilling FluidsDiesel-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 BasedDrilling 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 RegulationsOil 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 MethodChemical Thermal Physical Biological

Removal Efficiency 30 20 28 18 20

Environmental PollutionVolume of produced waste 10 6 6 9 9Hazardous pollution caused 10 8 1 9 9

CostCapital cost 10 8 4 8 6Operational cost 10 8 6 10 6

Energy requirements 10 7 4 9 6Processing time 10 7 9 5 1Particle 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

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Thank You for Your Attention