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Chemical EOR Potential in the Mangala Field

Barmer

Basin

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Outline

EOR Snapshot

Introduction to Mangala Field

Laboratory Analysis Update

Simulation Study Update

EOR Pilot

Plans

Summary

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EOR Snapshot

Screening studies by Surtek and Knowledge Reservoir

Mangala is a textbook candidate for application of Chemical EOR

Laboratory evaluation at SURTEK

IFT based

chemical

screening;

Linear

&

Radial

Corefloods

Incremental Recovery over waterflood : P(15%); ASP (30%)

Sector model studies using STARS

Incremental Recovery

over

waterflood

: P(5

‐10%);

ASP

(10

‐20%)

Closely spaced 5‐spot pilot planned

Additional Laboratory Evaluation at University of Texas, Austin

Refinement of Chemical selection

Phase Behavior; Long linear corefloods; Simulation using UTCHEM

Very low final residual oil saturations; Incremental over waterflood

(40%)

EOR pilot

wells

drilling

underway

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Crude Characteristics

•

Medium gravity

~27

o

API•Moderate Viscosity 10‐20cp

•Low sulphur

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Chemical Flooding : Polymer and ASP

AdditionofPOLYMER totheinjectedwatercan

increasetheinjectedfluidviscositytothesame

levelasthatoftheoil.Thismoreviscous

injectionfluidwillnotbreakthroughrapidly,contactmoreoftheinsituoilandsignificantly

increasethesweepefficiency.

Additionof LK LI ND

SURF CT NT totheinjectedfluidwill

reducetheresidualoilsaturationleftinthe

sweptzone(increasedisplacementefficiency)afterwaterorpolymerflooding.

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Initial Laboratory Work

Studies :

• Fluid – Fluid interaction studies

• IFT measurements, Phase behaviour screening, Polymer

rheology, Thermal stability

• Rock‐Fluid

interaction

studies

• Static adsorption, Dynamic adsorption, Polymer Rheology

• Flooding

Experiments• Linear coreflood

• Radial coreflood

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0 1 2 3 4 5 6 7 8 9 10Cumulative Produced Fluids VP

0

10

20

30

40

50

60

70

80

90

100

C u m u l a t i v e O i l R e

c o v e r y ( % O O I P )

O i l C u t ( V o l u m e % )

U n s o f t e n e d P r o d u c e d W

a t e r w i t h C a

2 + a t 0 . 9 6 f t / d a y

1

8 1 5 m g / L F l o p a a m 3 6 3 0 S a t 0 . 9 6 f t / d a y

U n s o f t e n e d T h u m b l i W a t e r a t 0 . 9 6 f t / d a y

0

1

10

100

0 10 20 30 40 50 60 70 80 90 100Cumulative Oil Recovery (%OOIP)

0

1

10

100

O i l C u t ( V o

l u m e % )

incremental

oil recovery

cumulative

oil

Oil Cutwaterflood

Mangala Polymer Flood Experiment

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0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0Cumulative Produced Fluids VP

0

10

20

30

40

50

60

70

80

90

100

C u m u l a

t i v e

O i l R e c o v e r y

( % O O I P )

O i l C u

t ( V o l u m e

% )

U n s o f t e n e d P r o d u c e d W a t e r w i t h C a 2

+ a t 0 . 7

4 f t / d a y

1 . 5 w t % N a

2 C O

3 + 0 . 0

5 w t % O R S - 5

7 H F + 0 . 0

5 w t % S t e p a n t

a n A S - 1

6 1 8 +

1 8 1 5 m g / L F l o p a a m 3 6 3 0 S a t 0 . 7 4 f t / d a y

1 8 1 5 m g / L F l o p a a m 3 6 3 0 S a t 0 . 7 4 f t / d a y

U n s o f t e n e d T h u m b l i W a t e r a t 0 . 7 4 f t / d a y

0 10 20 30 40 50 60 70 80 90 100Cumulative Oil Recovery (%OOIP)

0

1

10

100

O i l C u t (

V o l u m e

% )

0

1

10

100

oil

cut

cumulative

oil

waterflood

ASP flood

incremental

oil recovery

Mangala ASP Flood Experiment

Mangala is

an

excellent

Candidate

for

Chemical

flooding

based

on fluid

‐fluid

& rock‐fluid interaction

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0.0

0.5

1.0

1.5

2.0

2.5

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

N o r

m a l i s e d C u m u l a t i v e O i l R e c o v e r y

( % P o r e v o l u m e / % P o r e V o l u m e W a t e r f l o o

d

Normalised Cumulative Produced Fluids (PV/PV Waterflood)

Cumulative

Oil

Recovery

versus Normalised Cumulative Produced Fluids

1R ‐ 1 .0 wt% NaOH + 0.1 wt% SS B 20280 + 1815 mg/L Flopaam 3630S

2R ‐ 1.25 wt% Na2CO3 + 0.067 wt% B‐100 + 0.033 wt% AS‐1618 + 1815

mg/L Flopaam 3630S

3R ‐ 1815 mg/L Flopaam 3630S

5R ‐ 1 .5 wt% Na2CO3 + 0.1 wt% Agnique PG ‐8166 + 1815 mg/L Flopaam

3630S6R ‐ 1 .5 wt% Na2CO3 + 0.05 wt% ORS‐57HF + 0.05 wt% Stepantan AS

1618 + 1815 mg/L Flopaam 3630S

7R ‐ 1815 mg/L Flopaam 3630S

8R ‐ 1.25 wt% Na2CO3 + 1815 mg/L Flopaam 3630S

10R ‐ 1.75 wt% Na2CO3 + 0.1 wt% ORS‐57HF + 0.1 wt% Stepantan AS‐

1618 + 1815 mg/l Flopaam 3630S

Chemical FloodWaterflood

Summary of Mangala Radial Corefloods

• Fluid‐fluid experiments and linear corefloods have identified several chemical

systems that work well for Mangala.

• Radial core

floods

show

typical

incremental

recoveries

over

waterflood of

+15% STOIIP for polymer and +33% STOIIP for ASP.

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Additional Laboratory Evaluation

Phase Behavior

Evaluation

• Water & oil mixed with

surfactant and alkali

Volume &

Quality

of

micro

‐emulsion

evaluated

• Solubilisation ratio ( ) = (Vo/Vs &

Vw/Vs) IFT = C/ 2 ; C ~ 0.3 dynes/cm (After C.

Huh)

• Solubilisation ratio more than 10

sufficient to

mobilise waterflood

residual oil

• Aqueous stability of the

formulation checked

Co‐solvents used

% Sodium Carbonate0.0 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 2.75 3.0 3.5 4.0

0.2% Surfactant; 0.6% NaCl; 30% Oil

Type-I Type-III Type-II

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Solubilisation Ratio

Plot

• Vo & Vw curves intersection gives optimal

solubilisation ratio ( ) & optimal salinity

• ( ) decreases with decreasing oil ratio whereas optimal

salinity increases

30% Oil

% Sodium Carbonate0.0 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 2.75 3.0 3.5 4.0



10% Oil

40% Oil 50% Oil

20% Oil


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Phase Diagram

5040302010 60

Oil Cut, %Coil / Csurfactant

N a 2 C O 3 ( p p m )

0

10,000

20,000

30,000

40,000

50,000

60,000

0 50 100 150 200 250 300

Type I

Type III

Type II

Coil / Csurfactant

N a 2 C O 3 ( p p m )

0

10,000

20,000

30,000

40,000

50,000

60,000

0 50 100 150 200 250 300

Coil / Csurfactant

N a 2 C O 3 ( p p m )

0

10,000

20,000

30,000

40,000

50,000

60,000

0 50 100 150 200 250 3000

10,000

20,000

30,000

40,000

50,000

60,000

0

10,000

20,000

30,000

40,000

50,000

60,000

0 50 100 150 200 250 3000 50 100 150 200 250 300

Type I

Type III

Type II

5040302010 60

Oil Ratio, %

% Sodium Carbonate

0.0 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 2.75 3.0 3.5


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Corefloods

• Long (1ft) Berea & Native corefloods

• Vertical floods (gravity stable)

• Water flooded initially to residual oil

• 0.3 PV of ASP Slug

• 2 PV of Chase Polymer Slug

• Effluents analysed

for

oil

‐cut,

pH

&

surfactant

Typical Formulation

• 0.1 wt%

C16

ABS

(Alkyl

Benzene

Sulphonate)

• 0.1 wt% C20‐24 IOS (Internal Olefin Sulphonate)

• 1 wt% DGBE (Diethylene Glycol Mono Butyl Ether)

•

2.75

wt%

Na2CO3• 0.3 wt% Polymer

Out to

Fraction Retriever

Inlet

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0

1

2

3

4

5

6

7

8

9

10

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0

p H

C u m u l a t i v e

O i l R

e c o v e r y ,

O i l C u t & O i l S

a t u r a

t i o n

Pore Volumes

Cum Oil

Oil Cut

So

pHEmulsionbreakthrough

Berea Coreflood(A=2.75;S=0.2;P=0.3;µ=30cp)

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Mangala Coreflood(A=2.0;S=0.2;P=0.25;µ=23cp)

0.0

2.0

4.0

6.0

8.0

10.0

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

p H

C u

m u l a t i v e O i l R e c o v e r y ,

O i l C

u t & O i l S

a t

u r a t i o n

Pore Volumes

Cum Oil

Oil Cut

So

pH

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Coreflood Simulation using UTCHEM

0%

10%

20%

30%

40%

50%

60%

70%

80%90%

100%

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0Pore Volumes

C u m

O i l R

e c o v e r e

d ( % ) a n d O i l

C o n c e n t r a t i o n

oil recovered, coreflood

Oil Cut, coreflood

Oil Recovery, Case 6

Case 6 oil cut

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Coreflood Simulation using STARS

Mangala Berea Coreflood #2

Oil Cut SC - % Producer1 M2Stars3Rel1PolyViscRF1Nc.irf Oil Cut SC - % Producer UT1.fhf Cumulative Oil SC Producer UT1.fhf Cumulative Oil SC Producer1 M2Stars3Rel1PolyViscRF1Nc.irf

Time (min)

O i l

C u

t S C

- %

C u m u l a t i v e

O i l

S C

( c m 3 )

0 500 1,000 1,500 2,0000

20

40

60

80

0

10

20

30

40

50

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I1

I2

I3

I4

I5

I6

I7

P1

P2

P3

P4

P5

P6

P7

P8

I1

I2

I3

I4

I5

I6

I7

P1

P2

P3

P4

P5

P6

P7

P8

Mangala FM1 Sector Model

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

OI L S

A T URA T I ON

ASP Flood:

Better Sweep &

Lower Sor

Waterflood:

Reasonable

Sweep & Sor

Water Vs. Chemical Flood : Simulation Results

Permeabil ity Display

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Water Flood

Water Vs. Chemical EOR Flood ‐ Simulation

ASP Flood

Oil Saturation Display

Top Layer

EOR by ASP – You will see:

Better sweep

efficiency

Reduced residual oil saturations

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Oil Saturation Display

Bottom Layer

Water Flood

ASP Flood

EOR by ASP – You will see:

Better sweep

efficiency

Reduced residual oil saturations

Water Vs. Chemical EOR Flood ‐ Simulation

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Mangala EOR Pilot Design

Ten Wells

4 injectors

1 Producer

3 logging observation wells

2 post‐pilot core hole wells

Planned Injection Sequence in Pilot

This will provide quantitative data

Sweep & displacement efficiencies

Chemical consumption

Direct operational data

Base

Waterflood

Polymer

Slug

ASP

Slug

Chase

Polymer

Slug

Chase

Waterflood

100m

70m

Injector

Producer

Logging Obs Well

Post-pilot core hole

Symbols

~2.5 acres

100m

70m

Injector

Producer

Logging Obs Well


Symbols

Injector

Producer

Logging Obs Well


Symbols

~2.5 acres

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0 100 200 300 400 500 600 700 800 900

TIME

0

250

500

750

1000

1250

1500

O I

L P R O D U C T I O N

R A T

E

( B / D )

OIL PRODUCTION RATE (BOPD)

POLYMER-ASP FLOOD POLYMER FLOOD WATER FLOOD

Comparative Pilot Performance – Simulation Results

WATER FLOOD RESPONSE

POLYMER ONLY FLOOD RESPONSE

“ POLYMER – ASP” FLOOD RESPONSE

Incremental

by Polymer

I n c r e m e n t a

l

b y A

S P

Polymer ASP Polymer

Polymer

(Polymer-ASP

Case)

(Polymer Only

Case)

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Expected Logging Well Response

W e l l D

e p t h ,

f t

IL_1

IL_2 IL_3

IL_4

PL_1

Well Closer to Injector Well Closer to Producer

Initial

Water FloodPolymer Flood

ASP Flood

Chase Polymer

Chase Water

Oil Saturation

W e l l D e

p t h ,

f t

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Summary

A new

hydrocarbon

basin

under

development

Mangala is a textbook candidates for application of EOR methods such as

polymer (P) or alkaline‐surfactant polymer (ASP) flooding

Laboratory and Simulation studies present very encouraging results to

implement chemical EOR in Mangala

Conventional 5‐spot

pilot

(4

injectors

and

1 producer

with

100

m

spacing)

is

being considered for pilot testing the process.

Drilling of Pilot Wells underway

Staged expansion planned based on pilot results

Field scale incremental Recovery of ~5‐10% by Polymer and ~10‐20% by ASP

are envisaged by application of chemical EOR

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