Compatibility Study of Treated Effluent from KNPC- MAB Refinery - - PowerPoint PPT Presentation

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Compatibility Study of Treated Effluent from KNPC- MAB Refinery with Brackish Water, PIC Water and GC’s Formation Water

Imad Al-Maheimid, Ahmad Kh. Al-Jasmi Research & Technology Group - KOC Surface Team

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Introduction

• Kuwait
• il

company extracts brackish groundwater from the Abdaliyah water field which is the single source of brackish water supplying West, SEK Oil Fields and Ahmadi residence areas.

m Demand of Source Water (based on last year data)

(Unit : BWPD)

Summer Winter Normal ge source Water required at STF/NTF = 135,000 85,000 105,000 ge source Water required at WK GCs = 35,000 25,000 30,000 ge source Water required at Camel Point + Irrigation = 25,000 10,000 15,000 al Demand of Source Water at KOC 195,000 120,000 150,000

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Introduction

• KOC is proposing to increase oil production,

accordingly, the use of ground water will increase,

• verexploitation of ground water will lower the

water table in Abdaliyah Brackish field this will allow the intrusion of the saline water and it my lead to brackish water deterioration.

• To avoid this phenomenon and to secure KOC low

salinity water future demand, suitability of KNPC, PIC effluent treated from MAB & MAA Refineries have been explored to be utilized in KOC for industrial applications.

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Introduction

• KNPC effluent treated water may will mixed with

Abdaliyah brackish water, this water mixture will be utilized for desalting wet crude at each of 14 Gathering Centers, GC's desalters which located downstream of separator. A scaling / precipitation may occur when the formation waters from each GC which containing high levels

• f

calcium, magnesium, strontium and barium are mixed with wash water with high level of sulphate ion.

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Introduction

• In order to establish the suitability of treated effluent from

both sources (KNPC + PIC) for KOC daily

• perational

activities, a comprehensive compatibility study

• f

the mentioned treated effluent with KOC brackish water and formation water from each GC was executed. Also full analysis

• f KNPC treated effluent water were conducted to explore the

suitability of this water for irrigation purposes, bacteria analysis were carried out in order to design the most suitable bacteria inhibitor (biocide) with its optimal dosing rate to control bacteria growth within the water distribution system.

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Objectives

• To analyze and characterize the mixing waters
• To perform computer scale compatibility study to

predict type and masses of scale that could be generated at recommended temperature and pressure conditions

• To predict scaling tendency and mass of individual

waters at defined temperature and pressure conditions

• To

check compatibility

• f

these waters using Laboratory Jar Tests

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Deliverables

• Executive summary
• Introduction and background
• Sampling and analysis techniques
• Results of the static and computer scale

prediction

• Interpretation and discussion
• Conclusions and recommendations

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BACKGROUND

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Common Oilfield Scales

Name Chemical formula Calcium carbonate (calcite) CaCO3 Calcium Sulphate Gypsum Hemi – Hydrate Anhydrite CaSO4.2H2O CaSO4.1/2 H2O CaSO4 Barium Sulphate BaSO4 Strontium Sulphate SrSO4 Iron Compounds Ferrous Carbonate Ferrous Sulfide Ferrous Hydroxide Ferric Hydroxide Ferrous Carbonate FeCO3 FeS Fe(OH)2 Fe(OH)3 Fe2CO3

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COMPATIBILITY STUDY EXPERIMENTS

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GC -A GC -A GC -B GC -B GC -C GC -C GC -D GC -D GC -E GC -E GC - F GC - F GC -G GC -G GC -H GC -H GC -I GC -I GC -J GC -J GC - K GC - K GC -L GC -L GC -M GC -M GC -N GC -N

SOUTH TANK FARM

ABDALLIYAH

PIC TREATED EFFLUENT WATER KNPC-MAB TREATED EFFLUENT WATER Brackish Water GC- GATHERING CENTER KNPC - Kuwait National Petroleum Company PIC - Petrochemical Industries Company

Schematic Diagram – Mixing of Water

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Mixing Water in De-salter

• At desalter we’ll have

 Wash Water  Formation Water  Crude in contact with the formation Water  Gas phase in equilibrium H2S and CO2

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Mixing Scenarios

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METHODOLOGY

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Methodology

Computer Scale Predictability

• Balancing the ionic composition of water

analysis

• Predicting

the self scaling potential

• f

individual water

• Compatibility of two waters at various temp

and pressure

• Study the worst case mixing scenario

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Methodology

Static Jar Test

• Mixing water samples at various ratios
• Incubation at 65 °C for 72 hours
• Mixture – cool down to room temperature
• Filtration through 0.45 micron membrane

filter

• Weighing filtrate in mg per liter
• SEM / EDS analysis of the membrane

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Full Ionic Composition of Water

 Anions

(CO3

• 2, HCO3
• 1 SO4
• 2 ,Cl-1 ,S-2 )

 Cations

(Ca+2,Mg+2,Sr+2,Ba+2,Na+1,K+1, Fe+2, Fe+3)

 Dissolved gases (O2 and H2S)  Specific Gravity  Total Dissolved Solids

Methodology

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Analytical Parameters

Physical Parameters of PIC, KNPC and Brackish water. Parameters Unit Brackish KNPC PIC

Conductivity mS/cm 4.64 2.00 0.02 pH 7.63 7.83 5.97 Density gm/cm3 1.0000 0.9980 0.9970

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Analytical Parameters

Compositional Analysis of PIC, KNPC and Brackish water.

Elements Unit Brackish KNPC PIC

Sodium mg/l 534 551 5 Calcium mg/l 387 30 2 Magnesium mg/l 146 19 0.38 Potassium mg/l 41 32 1.41 Strontium mg/l 14 6 2 Barium mg/l

0.02 0.17 0.19

Iron mg/l 0.11 0.05 0.06 Lithium mg/l 0.06 0.01 0.002 Silicon mg/l 8.92 0.75 0.08 Boron mg/l 1.20 0.04 0.24 Aluminum mg/l 0.10 0.00 0.00 Chloride mg/l 872 664 8 Bicarbonate mg/l 140.79 214 6 Sulfate mg/l

1288 177 1.3

Phosphate mg/l 0.05 1.18 0.01 Ammonia Nitrogen mg/l 0.01 3.1 0.8 Nitrite mg/l 0.02 0.7 0.08 Nitrate mg/l 1.1 4.3 0.02 Total Dissolved Solid gm/l

3.43 1.69 0.03

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Analytical Parameters

ELEMENTS Unit GC- A GC -B GC -C GC -D

Sodium mg/l 51293 56670 45875 43094 Calcium mg/l 10726 11892 9416 9372 Magnesium mg/l 2462 2684 2238 2147 Potassium mg/l 3261 2780 2654 2504 Strontium mg/l 295 327 228 283 Barium mg/l

3.46 3.12 2.04 2.50

Iron mg/l 5.67

16.46

0.68 1.40 Lithium mg/l 4.17 4.25 3.97 4.60 Silicon mg/l 7.20 4.44 3.65 3.30 Boron mg/l 32.85 44.10 29.32 38.40 Aluminum mg/l 0.04 4.04 0.85 0.10 Chloride mg/l 103971 114796 92381 86398 Bicarbonate mg/l 231.07 247.42 189.59 141 Sulfate mg/l

589.1 579.6 411.1 524

Phosphate mg/l 1.417 1.727 6.803 2.4 Conductivity mS/cm 144.8 143 170.7 129 pH 6.46 6.36 6.38 6.66 Density gm/cm3 1.1080 1.1060 1.1020 1.0970 Dissolved H2S ppm <0.1 <0.1 1 <0.1 Total Dissolved Solid mg/l

172882 190053

153433 144513

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Analytical Parameters

ELEMENTS Unit GC -E GC-F GC -G GC -H

Sodium mg/l 49169 45470 47079 49505 Calcium mg/l 10343 9457 9725 10450 Magnesium mg/l 2480 2420 2347 2278 Potassium mg/l 2950 1917 2645 2416 Strontium mg/l 190 300 293 273 Barium mg/l

1.70 2.30 2.10 3.22

Iron mg/l 0.80 4.20 2.30 1.66 Lithium mg/l 4.31 7.53 7.01 3.66 Silicon mg/l 4.60 5.00 7.20 5.41 Boron mg/l 25.80 35.20 35.30 40.09 Aluminum mg/l 0.00 0.10 0.10 0.10 Chloride mg/l 98455 99111 94383 100044 Bicarbonate mg/l 247 249 259 305.24 Sulfate mg/l

537 211 523 769.1

Phosphate mg/l 0.35 1.06 2.15 0.008 Conductivity mS/cm 103 133 143 178.7 pH 6.40 6 6 6.35 Density gm/cm3 1.1060 1.1010 1.1080 1.1100 Dissolved H2S ppm 1.5 1 <0.1 <0.1 Total Dissolved Solid mg/l 164408 159189 157308 166094

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FINAL CONCLUSION & RECOMMENDATION

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Conclusion

• All waters were found to be self scaling except

PIC water.

• PIC acts as a diluent for all mixing calculations.
• GC waters showed comparatively higher scaling

tendency than wash waters.

• In most of the mixing cases, total scale mass

increases with increasing GCs formation water.

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Conclusion

• Scale predicted are:

calcite, barite, anhydrite, celestine.

• Barite (BaSO4)
• Celestine (SrSO4)
• Calcite (CaCO3)

Worst Case Combination: 20% KNPC and 80% GC formation water

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Recommendation

• Scale Inhibitor

Application of suitable scale inhibitor will be possibly best scale controlling method. Chemical should be compatible with other chemicals used and with the waters. Laboratory trial is necessary for selection of most suitable chemical.

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Recommendation

• PIC water can be used as diluent for minimizing

scaling mass.

• Worst case combinations should be avoided.
• Dissolved gases like H2S and O2 should be

removed completely.

• Scaling occurring at STF (if any) should not

carry over to the desalter.

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Recommendation

• Scaling at STF should be removed either by using

filtration unit or by giving enough retention time to the solids in the settling tank.

• pH and temperature control will be another
• perational approach to control scaling tendency.
• It is also advisable to monitor scale deposits

regularly at the expected locations.

• Exact composition of solid deposit should be

identified by SEM /EDS / XRD methods.

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Scale Inhibitor Screening & Assessment.

The conclusions drawn from the study are as follows:

• Jar test did not show sufficient content of scale formation, even

for uninhibited brine. Hence it was not possible to evaluate the performance of chemicals and optimize their dosage level

• Initial tube blocking test was conducted at 105 F and 15 psi

pressure which did not show any scale precipitation. Hence additional tests were conducted at elevated temp of 160 F to increase the quantity of scale formation which would plug the test coil.

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Scale Inhibitor Screening & Assessment.

• Uninhibited brine at elevated temp of 160 F showed significant

scale precipitation, plugging the test coil within 6 hours. Also differential pressure increased to about 600 psi while all the four chemicals did not show plugging of test coil over a 20 hour continuous flowing period and differential pressure did not exceed 0.5 psi under the same temp and pressure conditions which clearly indicates need for suitable scale inhibitor.

• All the scale inhibitors with a concentration as low as 2 ppm

were successful in the prevention of scale formation during the tests.

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Scale Inhibitor Screening & Assessment.

Recommendation

• Since all the inhibitors, are successful in preventing scale

deposit, it is recommended that the final selection of scale inhibitor should be based on cost and availability of chemicals.

• Scale inhibitor should be dosed at 5 ppm in the initial stage.

Later, it can be reduced to 2 ppm on plant stabilization if the results are favorable in the prevention of scale formation.

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Suitability of KNPC Treated Effluent Water for Irrigation Purposes

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Suitability of KNPC Treated Effluent Water for Irrigation Purposes, Cont.

KNPC Effluent Treated Water Specifications are within KEPA Appendix – 15 but it is recommended not to use this water for crops irrigations.

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KNPC Treated Effluent Water Microbiology Analysis

Parameter Samples Results Units Method used Heterotrophic Plate Counts (HPC) 2000 Mpn/1ml MPN Total Coliform Bacteria (TC) 3500 Mpn/100ml MPN E.Coli Bacteria <1 Mpn/100ml MPN Fecal Coliform Bacteria (FC) 14 Cfu/100ml MF Enterococci Bacteria 13.4 Mpn/100ml MPN Salmonella Bacteria 6 Cfu/100ml MF Streptococci Bacteria 4 Cfu/100ml MF Sulphate Reducing Bacteria (SRB) P P/A Injection Nitrate Reducing Bacteria (SRB) P P/A Injection

MPN; Most Probable Number, MF; Membrane Filtration, Cfu; Colony Forming Unit, P/A; Presence/Absence The existing bacteria can be controlled and inhibited by chlorine dioxide or any available biocide, biocide screening is needed to select the most suitable one with its optimal dosing rate.

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Acknowledge

• KISR PRC.
• KISR WRC.
• KNPC.

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THANKS