International conference on Stabilisation/Solidification Treatment and Remediation, Cambridge 12-13 April 2005

Stabilisation/solidification of synthetic drill cuttings Stabilisation/solidification of synthetic drill cuttings representing Ras Shukier oil field in Egyptrepresenting Ras Shukier oil field in Egypt

UNIVERSITY OFCAMBRIDGE

M. S. AlM. S. Al--AnsaryAnsary & A& A.. AlAl--TabbaaTabbaa

OutlineOutline

I.I. Oil Drill CuttingsOil Drill Cuttings

II.II. Ras Shukier Case StudyRas Shukier Case Study

III.III. Experimental WorkExperimental Work

IV.IV. Ongoing programmeOngoing programme

V.V. ConclusionConclusion

ClaCla

Drill cuttings are heterogeneous wastes Drill cuttings are heterogeneous wastes that are generated from petroleum drilling industrythat are generated from petroleum drilling industry

Drill fluid Circulation SystemDrill fluid Circulation System

Recycle

d

Recycle

d fluid

fluid

Drill Cuttings + Drill Cuttings + fluidfluid

Drill Cuttings Drill Cuttings contaminated with contaminated with

chemicals from chemicals from fluidfluid & oil& oil

Treatment methods for drill cuttingsTreatment methods for drill cuttings

Leave in placeLeave in place-- disturbeddisturbedLeave in placeLeave in place-- undisturbedundisturbedEntombmentEntombmentCappingCappingGravel DumpingGravel DumpingBioremediation in situBioremediation in situBioBio--reactorreactorLand FarmingLand FarmingMechanical DredgingMechanical Dredging

Crawler retrievalCrawler retrievalReRe--injectioninjectionReRe--spreadingspreadingMechanical separationMechanical separationDistillationDistillationStabilisationStabilisationCombustionCombustionSupercritical extractionSupercritical extractionThermal Thermal DesorptionDesorption

II.II. Ras Shukier Drill CuttingsRas Shukier Drill Cuttings

Ras Shukier is an offshore oil production site located in the Gulf of Suez, Red Sea, Egypt. This site generates approximately 2,740 tonnes of cuttings per year. Ras Shukier consists of nine complex platforms.

TransportationService boat

Approved disposal byEnvironment

Offshore Onshore

Waste Disposal Area

Drill Cuttings

Manifest by Load Master

Manifest by ToolpusherCutting

Box

Drilling Rig

Physical and Chemical Characteristics Physical and Chemical Characteristics

• Brownish black, sticky with a clayey texture soil.

• Distinctive crude odour.

• Density ranges between 1.2 and 2.0 g/cm3.

(w/w)(w/w) Hydrocarbon%Hydrocarbon% Cr%Cr% Zn%Zn% BaBa%% PbPb%% ClCl%%

0.1 2.1

9.20.3

0.2

1.2

0.2

0.6

0.1

0.4

11.0

11.8

AverageAverage

MaxMax

III.III. Experimental WorkExperimental Work

Synthetic drill cuttings and their propertiesSynthetic drill cuttings and their properties

Soil composition %

Sand content 10Silt (rock flour) content 50Clay 1 (kaolin) 20

Clay 2 (bentonite) 20Property ValueWater content 20%pH 9Plastic Limit 25%

Liquid Limit 51%

Cutting composition %

Sodium Chloride 3.5

Paraffin oil (of dry soil) 11

Binder SystemBinder System

A. Conventional BindersA. Conventional Binders

Portland Cement (PC)Portland Cement (PC)

LimeLime

Pulverised Fuel Ash (PFA)Pulverised Fuel Ash (PFA)

BlastfurnaceBlastfurnace Slag (BFSSlag (BFS))

B. Novel BindersB. Novel Binders

MgOMgO cementcement

ZeoliteZeolite

MicrosilicaMicrosilica (silica fume)(silica fume)

Cement Kiln Dust (CKDCement Kiln Dust (CKD

CompostCompost

Sample PreparationSample Preparation

Water : Dry binder: Water : Dry binder: 0.6 : 10.6 : 1

Dry binder content by weight :Dry binder content by weight : 10%, 20% and 30%10%, 20% and 30%

Binders: Binders: either PC only either PC only or or 1:1 PC:other binder1:1 PC:other binder

Sample size :Sample size : 50 x 100 mm50 x 100 mm

Testing ProgramTesting Program

Tests at 28 days of curingTests at 28 days of curing

1.1. Unconfined compressive strength (UCS)Unconfined compressive strength (UCS)

2.2. LeachabilityLeachability (Chloride and Oil)(Chloride and Oil)

3.3. LeachateLeachate pHpH

4.4. Microstructure analysisMicrostructure analysis

1.1. Unconfined Compressive Strength (UCS)Unconfined Compressive Strength (UCS)

Mic

rosi

lica-

PCPC

BFS

-PC

Zeo

lite-

PC

PFA

-PC

MgO

-Cem

ent 2

CK

D-P

C

Lim

e-PC

Com

post

-PC

MgO

-Cem

ent 1

3 0 %2 0 %

1 0 %

0

5 0 01 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

3 0 0 0

3 5 0 04 0 0 0

4 5 0 0

UC

S (k

Pa)

2.2. Chloride Chloride LeachabilityLeachability

10% 20% 30%

950

1250

1550

1850

PC

PFA

-PC

CK

D-P

C

Com

post

-PC

MgO

cem

ent1

MgO

cem

ent2

Mic

rosi

lica-

PC

BFS

-PC

Zeo

lite-

PC

Lim

e-PC

Chl

orid

e le

acha

teco

nc. (

mg/

L)

2.2. Oil Oil LeachabilityLeachability

10% 20% 30%

10

100

1000

10000

PC PFA

-PC

CK

D-P

C

Com

post

-PC

MgO

cem

ent1

MgO

cem

ent2

Mic

rosi

lica-

PC

BFS

-PC

Zeo

lite-

PC

Lim

e-PC

Para

ffin

oil

leac

hate

conc

. (m

g/L

)

3.3. LeachateLeachate pHpH

Binder contentBinder System

10% 20% 30%PC 12.0 12.4 12.6BFS - PC 12.0 12.2 12.4Microsilica - PC 10.5 10.4 10.6

Compost - PC 11.6 12.1 12.2PFA - PC 12.0 12.1 12.1

MgO cement2 10.9 12.0 12.0

12.1

9.9

11.6

Lime - PC

12.0

12.4

MgO cement1

12.5

11.0

11.9

11.0

12.3Zeolite - PC 11.7CKD- PC 12.4

4.4. Microstructural AnalysisMicrostructural AnalysisSEM at 28 days

Microsilica - PC

MgO cement 2

Lime - PC

Zeolite - PC Compost - PC

PC

IV. IV. Ongoing ProgrammeOngoing Programme

North Sea Case StudyNorth Sea Case StudyBest S/S systems selected for more detailed studyBest S/S systems selected for more detailed studyNext mixes to include heavy metalsNext mixes to include heavy metalsFor chloride, possibility of a low pH cementFor chloride, possibility of a low pH cementPelletisation of thermally treated drill cuttingsPelletisation of thermally treated drill cuttings

V. V. ConclusionConclusion

Drill cutting is a big problem that the petroleum industry is keen to find solutions

The utilisation of S/S techniques to treat drill cuttings by using conventional as well as novel binders indicated the following:

-- UCS of the drill cuttingsUCS of the drill cuttings--binder mixes at 28 days binder mixes at 28 days covered a wide range of feasible applications. covered a wide range of feasible applications.

V.V. Conclusion (contd.)Conclusion (contd.)

-- Chloride leachate concentrations showed a change from Chloride leachate concentrations showed a change from hazardous to nonhazardous to non--reactive hazardous waste. reactive hazardous waste.

-- Oil leaching concentrations decreased as the dry binder Oil leaching concentrations decreased as the dry binder content increased. content increased.

-- The The leachateleachate pH values indicated the use of lower pH binders.pH values indicated the use of lower pH binders.

-- The The microstructural analysis suggested an advanced level of microstructural analysis suggested an advanced level of hydration. hydration.

Future work will give more detailed information on the relative performance of different binders.

Thank YouThank YouMarwaMarwa at Ras Shukier oil field May 2003at Ras Shukier oil field May 2003