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1 - Crude Oil Treatment - Separation

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SURFACE PROCESSING

A CRUDE OIL TREATMENTI- SEPARATION 2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

SEPARATION Contents1- Well effluents Generalities 2- Gas/liquid separation -equilibrium calculations -influence of the process recovery rate 3- Separator sizing principles -diphasic vertical separator -diphasic horizontal separator 2007 ENSPM Formation Industrie - IFP Training

4- Gas/Liquid Separator different types 5- Foaming (difficult gas/liquid separation) Next course: Oil/Water separationPRO01198 CRUDE OIL TREATMENT - Separation

1- Well head effluents 2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

WELL HEAD EFFLUENTS

GAS WELLHEAD EFFLUENTS OIL WATERFORMATION SAND AND SILT COLLOID STATE CLAY CORROSION PRODUCT WAXES ASPHALTENES MINERAL CRYSTALS NaCl CaCO3 BaSO4 SrSO4

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

SEPARATION CHAIN

FOAMSWELLHEAD EFFLUENTS

LIQUID DROPLETS IN GAS

GAS

GAS TREATMENT DEHYDRATION CONDENSATE RECUPERATION

CONDENSATE WATER

GAS-LIQUID SEPARATION

EMULSION INTERMINGLED WATER/OIL

export crudeOIL-WATER SEPARATIONOPERATIONS SOMETIMES CARRIED OUT in 1 PROCESS EQUIPMENTPRO01198 CRUDE OIL TREATMENT - Separation

2007 ENSPM Formation Industrie - IFP Training

EMULSION TREATMENT

EMULSION FREE WATER WATER

SOURCE OF WATER

WATER AND OIL ZONES IN RESERVOIR

OIL OIL 2007 ENSPM Formation Industrie - IFP Training

* Active Water Reservoir * Water Injection : Injection of 1-2 volumes of water Production of 1-5 volumes of water per oil volume * Faulty Cementing JobPRO01198 CRUDE OIL TREATMENT - Separation

SOURCE OF SALTRESERVOIR WATER SALT INJECTED WATER (SEA WATER)

*HASSI MESSAOUD : CAMBRIEN WATER 370g/l Low Water Cut 0,1% HIGH SALT CONTENT SALT CONTENT 370 mg/l

*If Salt Content>10mg/l , Reservoir Water INGRESS *Sometimes HIGH SALT CONTENT without Water EAST BAGDAD As much as 265ppm of salt *** * Same for Hassi Messaoud - Fateh - ABK -Zadco This Phenomenon is limited in Time Produced Water Not Detected; only salt content is measured 2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

OIL , BSW and GOR EVOLUTION WITH TIMEProduction3 106 m3 / an

difficulty to design separation equipment

OIL

2

BSW%

GOR 300

30

1

20

200 2007 ENSPM Formation Industrie - IFP Training

10

100

GOR1 2 3 4 5 6 7

BSW8 9 10 11 12

YEARS

PRO01198 CRUDE OIL TREATMENT - Separation

CONTRACTUAL WATER AND SALT CONTENTS

CRUDE OIL MARKETING PRODUCERS TRANSPORTERS REFINERS

$

Business is business!!

$

AGREEMENT

TRANSPORTERS : LIMITATION FOR WATER CONTENT *PIPELINE - PIPE OVER LOADING - CORROSION ( WATER + SALT ) BSW P2

P2 V2 T2 G2 L2 P2 T2

P1 > P2 T1 > T2

2007 ENSPM Formation Industrie - IFP Training

2. Differential processP1 > P2 G1 L1 P1 T1 total composition varies : there is draw off GS Gi Li G2 L2 P2 T2

If T = constant = differential liberation 2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

3. Composite process : combination of the twoReservoir PG TG LDifferential Liberation (T cst)

Separators PF TG G LFlash

Storage P2 T2 G2 L2 Pa Ta GS LSFlash

P1 T1 G1 L1Flash

PPG PF

P1 P2 Pa Ta T2 T1 TG

2007 ENSPM Formation Industrie - IFP Training

T

PRO01198 CRUDE OIL TREATMENT - Separation

OPTIMAL SEPARATION PRESSURE IN HYDROCARBON PRODUCTION FIELDS IS AN APPLICATION OF PHASE EQUILIBRIUM IN THERMODYNAMICS

AMOUNT OF LIQUID RECOVERED IS DEPENDENT OF THE COMPOSITE PROCESS SEPARATION EFFICIENCY YIELD (R) = final stock tank oil mass / mass of hydrocarbons entering the processing unit

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

Influence of the Process Recovery rateP Pb 1 Liberation 1 3 15 RsFROM PVT LAB EXPERIMENTS

Separation 2 TG T

Flash Differential Rs = V gas produced V oil at Pb Pb

2007 ENSPM Formation Industrie - IFP Training

P

PRO01198 CRUDE OIL TREATMENT - Separation

Influence of the Process Recovery rate

QUANTITIES OF FREE GAS ARE MORE IMPORTANT IN FLASH LIBERATION THAN IN DIFFERENTIAL LIBERATION SIMILARLY, VOLUME OF LIQUID IS GREATER IN A DIFFERENTIAL PROCESS THAN IN A FLASH PROCESS THE RELATIVE DIFFERENCE BETWEEN THE TWO CURVES DEPENDS ON THE NATURE OF THE OIL : SLIGHT FOR HEAVY OILS AND GREATER FOR VOLATILE OILS the higher the number of separation stages, the greater the liquid recovery but P at 1st stage is governed by well head P (i.e. reservoir P) number of stages is a compromise between costs of installation and liquid recovery

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

Influence of the process Recovery rateApplication / Field One stage G L Pi T1 Several stages G L P1 T1 G L P2 T1 Separators G L P3 T1 G L Ps T1 Storage G L Ps T1 Flash liberation max gas & min liquid

2007 ENSPM Formation Industrie - IFP Training

in each separator : flash liberation but the whole chain of separators represents a differential separation max of liquid recovery for an infinite number of separation stages

PRO01198 CRUDE OIL TREATMENT - Separation

Separation pressure at the different stagesRule of thumb n-1

R=

P sep. HP P storage

n = number of stages + storage Examples GOR < 20 m3/m3 1 3-7 bara : 2 Storage : 1 :10-20 bara 2 2-6 bara : 3 Storage : GOR > 200 1 20-40 bara : 2 5-15 bara : 2007 ENSPM Formation Industrie - IFP Training

GOR < 150 m3/m3

3 2-5 bara : 4 Storage :

PRO01198 CRUDE OIL TREATMENT - Separation

EXAMPLE OF APPLICATION

PALANCA FIELD (ANGOLA)

Separation efficiency = final stock tank oil mass / mass of hydrocarbonsentering the processing unit

at P = 25, 20, 15 & 10 bar at T = 105 90 75 C, C, C Determination of the optimal P & T and number of separation stages to get the higher separation efficiency

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

PALANCA separation output 2nd stageSep. Efficiency (%) 76.5 76 75.5 75 74.5 74 73.5 2007 ENSPM Formation Industrie - IFP Training

75 C

90

73 72.5 0 5 10 15 20

105

25 Pressure (bars)

PRO01198 CRUDE OIL TREATMENT - Separation

PALANCA separation output 3rd stageSep. Efficiency (%)77.5 77 76.575 C

76 75.5 75 74.5 74 2007 ENSPM Formation Industrie - IFP Training

90

73.5 73 0 3 6 Low pressure separator pressure 9 12

105

15 Pressure (bars)

PRO01198 CRUDE OIL TREATMENT - Separation

PALANCA separation output 4th stageSep. Efficiency (%) 77.575 C

77

76.5

76

90

75.5

75

2007 ENSPM Formation Industrie - IFP Training

74.5 3 0 6 Medium pressure separator pressure 9 12

105

15 Pressure (bars)

PRO01198 CRUDE OIL TREATMENT - Separation

PALANCA separation output T=75 COutput (%) 78

77.54 stages

77

76.5

significant gain between 2 & 3 less gain between 3&43 stages 2007 ENSPM Formation Industrie - IFP Training

76

ECONOMICS COMPROMISE0 5

2 stages

75.5 10 15 20 25 Pressure (bar)

PRO01198 CRUDE OIL TREATMENT - Separation

Influence of separation temperatureEFFECT ON RECOVERY ( )

Temperature Low Average High

+Liquid Economy Water Gas H2S treatment

Gas

Price 2007 ENSPM Formation Industrie - IFP Training

in general, the lower the T the higher the liquid recovery (but other parameters interfere on final Process T chosen : e.g. oil/water separation which is enhanced by high T C)PRO01198 CRUDE OIL TREATMENT - Separation

Influence of separation T & P : example 1

ASHTARTGas

13b - 110 C 1b - 85 C

Gas

Oil Gas

5b - 40 C 1b - 35 C

Gas

GAIN 9 % OIL at lower T

Oil

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

Influence of separation T & P : example 2BREMEFlare

4b 40 C 1b

Gas

Oil

Flare

3.5 b 30 C 4b 40 C 1bGas 2007 ENSPM Formation Industrie - IFP Training

Oil

GAIN 2.6 % OIL from flare gas recoveryPRO01198 CRUDE OIL TREATMENT - Separation

3- Separator sizing

2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

Sizing of a separator

INCREASING COMPLEXITY OF FIELD INSTALLATIONS WITH THE AIM TO MAXIMISE RECOVEY AND OPTIMISE ALL PRODUCTION UNITS

INTRODUCTION TO GENERAL PRINCIPLES AND METHODS OF SIZING AND TYPICAL VALUES

SPECIFIC INSTALLATIONS AS HEATER-TREATER, CYCLONIC SEPARATORS, etc. ARE DETERMINED BY MANUFACTURERS 2007 ENSPM Formation Industrie - IFP Training

PRO01198 CRUDE OIL TREATMENT - Separation

Sizing of a separator

DIMENSIONS FOR GAS AND LIQUID FLOWRATES ARE CALCULATED SEPARATELY

FOR GAS FLOWRATE, SPEED LIMITED TO PREVENT GAS FROM ENTRAINING DROPLETS OF LIQUID smallest diameter possible

FOR LIQUID FLOWRATE, RETENTION TIME SIZE TO ENSURE THAT THE GAS IS COMPLETELY RELEASED FROM IT 2007 ENSPM Formation I

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