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Interaction of phosphonates onto the immobilized surface: Nan Zhang Rice University [email protected] March, 2013 Application to scale control in oil and gas flow assurance

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Interaction of phosphonates onto the immobilized surface:

Nan Zhang

Rice University

[email protected]

March, 2013

Application to scale control in oil and gas flow assurance

Outline

• Background and previous batch study

• Hypothesis/Objectives

• Challenges and Methods

• Results

• Conclusions

Scale in oil and gas flow assurance (CaCO3,

FeCO3 ,CaSO4, BaSO4, SrSO4 , etc.)

Changes of temperature and pressure.

Variations of pH and CO2/H2S partial pressure during

operation.

Mixing of incompatible waters.

Effect of other constitnents.

Fouling in heat exchanger (CaCO3, CaSO4, etc.)

Fouling on the membrane surface (CaSO4,

BaSO4 ,etc.)

Scale in water transporting system

How much scale could potentially form ?

esprecipitat calcite and ated"supersatur" 0,

formt doesn' scale and m"equilibriu" zero,

dissolves calcite and ated"undersatur" 0,

SI

Scale tendency

Scale control with threshold inhibitor

Conventional onshore and Unconventional offshore reservoir

Pushing and fixing inhibitors into the formation via squeeze

treatment

Inject trace inhibitors downhole via a treat string

Unconventional onshore reservoir

Inject trace inhibitors with the fracturing fluid

DTPMP

(methylene phosphonic acid)

NTMP

(Methylene phosphonic acid)

Inhibitor return after squeeze treatment

Well NameDownhole

Temperature (F)TDS (mg/L)

Ca

(mg/L)ΔSI

Minimum

Inhibitor

Needed

Gladys

McCall298 96340 4130 1.04 0.18

N.R. Smith 160 50899 480 0.43 <0.7

0

1

10

100

1000

3.E+01 5.E+05 1.E+06 2.E+06

Ph

osp

ho

na

te (

mg

/L)

Volumes of Produced Water (bbl)

N. R. Smith

0

1

10

100

1000

3.E+01 1.E+07 2.E+07

Ph

osp

ho

na

te (

mg

/L)

Volumes of Produced Water (bbl)

Gladys McCall

Inhibitor return concentration is dropping to a few mg/L level in the early flowback stage,

but the interaction mechanism between the phosphonate inhibitor and scale is unclear,

so the return concentration of the inhibitor is unpredictable.

Phosphonates attachment to calcite surface(Previous Batch Study)

Crystal growth

Langmuir adsorption

CaCO3

Amorphous growth

Kan et al., JCIS, 2005

0.01

0.1

1

10

100

1000

10000

100000

0.00001 0.001 0.1 10 1000

Solution Phase Na4H2NTMP Conc. (mmol/L)

So

lid

Ph

ase N

TM

P C

on

c.

(m

ol/

m2

)

1, Langmuir adsorption

2, Crystal growth

3, Heterogeneous crystal growth

Tomson et al., SPE, 2003

Adsorption

precipitation

Solution Phase Na4H2NTMP Conc. (mmol/L)

Solubility of Ca-Inhibitor precipitates (Previous Batch Study)

Inhibitor Stoichiometry Solubility product

PKsp at 1 M

I, 70 ºC

Solubility1

(mg/L)

NTMP CaH4P

Ca2.5HP (am)

Ca2.5HP (cr)

Fe2.5HP (aged) )K(T/1315)M(I18.2)M(I6.14- 39.54

)K(T/2023)M(I76.1)M(I5.32- 32.92

)K(T/2380)M(I17.2)M(I6.88-32.96

46.32

32.46

21.31

23.46

31.74

22502

174

0.92

0.0953

DTPMP Ca3H4P (am)

Ca3H4P (cr) )K(T/5.2084I(M)0.04858.95

C70 I, M 2-1 @ 0.55

50.5

52.9

250

1.05

BHPMP Ca4H2P (am)

Ca4H2P (cr) )K(T/2998I(M)2.60- 48.46

)K(T/3448I(M)2.65-48.11

35.41

37.12

385

7.0

PPCA Ca3(A·A·A)2

(aged) 16.35 + 0.24·I(M) –252.1/(T( K) - 252.1) 13.82 1.45

Kan et al. Biogeochemistry of chelating agents chapter 15, 2005

The formation of CaPhn/FePhn precipitates with a low solubility may contribute to the

low inhibitor return concentrations

Inhibitor may deposit and retain on the surface by working with

the possible scale, such as CaCO3

Scaling risk can be controlled with a pulse injection of inhibitor

Objectives

1. Develop a CaCO3 pre-coated steel tubing for studies of

CaCO3 crystal growth kinetics and inhibition kinetics.

2. Evaluate the attachment kinetics of inhibitor on the surface

3. Investigate the detachment kinetics and equilibrium of

inhibitor from the surface and its inhibition impact on the

CaCO3 scaling to the pipe.

Hypothesis

Challenges No robust experimental method for kinetics study

Difficult to convert beaker result to real prediction

Limited information on inhibitor performance

MethodConventional

free drift

Rotating

disc

Constant

composition

Plug flow

reactor

Modified

Plug flow

reactor

(this study)

Surface area Variable Constant Variable Variable Constant

Saturation index Variable Variable Constant Constant Constant

Ionic strength Variable Variable Constant Constant Constant

pH Variable Variable Constant Constant Constant

Hydraulic

conditionNo Yes No Yes Yes

Ultra High

Temp/PressureHard Hard Hard Easy Easy

Modified Plug flow reactor Modified carbon steel tube (AISI1010, 5in length, ¼ in OD)

1. Coat the outer surface with rust-oleum for corrosion control

2. Polish inner surface with sandpaper to create a smooth surface for

CaCO3 deposition

Modified Plug flow reactor 3. Precoat uniform CaCO3 layer on the subsurface

Provide constant surface area

Eliminate initial preferential attachment

Time (hr)

0 2 4 6 8 10 12

C/C

0

0.84

0.86

0.88

0.90

0.92

0.94

0.96

0.98

1.00

1.02

Ca Conc.

Tubing surface area

A=18.3 cm2

Crystal surface area

A=55 cm2

Aragonite

Calcite

Water Bath

75 psi

Sample Collection & Analysis: ICP, ICP-MS

Soln. B NaHCO3+ NaCl

Apparatus

y = 0.001xR² = 0.999

00.10.20.30.40.50.6

0 200 400 600

Inte

nsi

ty

P conc. (ug/L)

ICP_MS STD P

100

% C

O2

Soln. A CaCl2+ NaCl

Parameter Value

Flow rate 10 -250 ml/min

Reactor I.D. 1/8 inch

Reactor Length 5 inch

Temperature 70 °C

Reactor volume 2.09 cm3

Residence time 75sec- 12.6 min

Reynolds’s

number9-100

Reactor:

Carbon steel AISI1010 tubing pre-

coated with CaCO3

pump

pump

Inhibitor attachmentC0= 680ppm, ΔSI_CaCO3= 0.6, 0.2-1330 mg/L DTPMP, pH= 5.9, 70C, Q=100ml/h for 1 hr

• The break through occurs in 20 min

• Inhibitor cannot accumulate on the surface with time

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50

DT

PM

P E

fflu

ent

C/C

0

Time (min)

0.2 mg/L 2.5 mg/L 5 mg/L 50 mg/L

100 mg/L 363 mg/L 1331 mg/L K tracer

Inhibitor conc. effect on the attachment

.

DTPMP

(injected)

DTPMP

(retaine

d)

q

mg/L mg/m2

0.22 0.20

2.5 2.01

5 7.05

10 18.73

47 56.89

102 107.39

363.6 127.10

1331.8 128.78

Inhibitor attachment on the calcite surface (surface area 55cm2)

f=129.4087*(1-exp(-0.0145*x))

DTPMP (mg/L)

0 200 400 600 800 1000 1200 1400

q (

mg/m

2)

0

20

40

60

80

100

120

140

Cca= 612-3833 mg/L, 100 mg/L DTPMP, pH= 6.2, 70C, Q=100ml/h

Ca conc. effect on the attachment

0

0.2

0.4

0.6

0.8

1

1.2

0 60 120 180 240 300 360 420 480

C/C

0

Time (min)

Ca=612 mg/L Ca=1704 mg/L Ca=3833 mg/L

• The break through didn’t occur

• Inhibitor can accumulate on the surface with time

Injected Ca (mg/L)

0 1000 2000 3000 4000

q (

mg

/m2)

500

600

700

800

900

1000

1100

SI_CaCO3

0.8 1.0 1.2 1.4 1.6 1.8

Ca vs q

SI_CaCO3 vs q

Ca conc. effect on the attachment

Ca

SI_

Ca3H4

DTPM

P

SI_

CaCO3

DTPMP

(retained

for 1 hour

injection)

q

mg/L mg %mg/

m2

612 1.76 0.9 3.4 33 618

1704 1.85 1.35 4.6 50 836

3833 1.77 1.73 5.3 52 1019

• Both Ca3H4DTPMP and CaCO3 precipitates affect the inhibitor attachment

CaCO3 facilitates phosphonate retention

Ca HCO3

SI_

Ca3H4

DTPM

P

SI_

CaCO3

q

mg/Lmg/

m2

579 1224 2.09 0.01 59.2

583 1770 2.02 0.34 60.64616

581 2538 1.86 0.66 71.1

612 3274 1.76 0.9 609

1704 3274 1.85 1.35 835

3833 3274 1.77 1.73 966

0

200

400

600

800

1000

1200

0.0 0.5 1.0 1.5 2.0

q (

mg

/m2

)

CaCO3 SI

• SICaCO3 > 0.9, Ca concentration control the inhibitor attachment

• SICaCO3 > 0.6, Phosphonates concentration control the inhibitor attachment

Inhibitor release

DTPMP return

• starts with a short desorption and then followed by a long term dissolution process.

• doesn’t change with the amount of inhibitor attachment on the surface conc.

0.01

0.1

1

10

100

60 80 100 120 140

DT

PM

P c

on

c. (

mg

/L)

Time (min)

102.5 mg/L DTPMP

47.4 mg/L DTPMP

10 mg/L DTPMP

2.5 mg/L DTPMP

0.25 0.02 mg/L

Cca= 680 mg/L, ΔSI= 0.6, No DTPMP, pH= 5.9, 70C, Q=100ml/h

q= 4.75 mg/m2

q= 27.9 mg/m2

q= 125 mg/m2

q= 267 mg/m2

“Memory effect” of inhibitor release

Time (min)0 500 1000 1500 2000 2500

DT

PM

P (

mg

/L)

0

20

40

60

80

100

Ca

(m

g/L

)

0

200

400

600

800

DTPMP

Ca

Time (min)0 100 200 300 400 500 600 700

DT

PM

P (

mg/L

)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Ca (

mg/L

)

0

200

400

600

800

DTPMP

Ca

DTPMP

(injected)

Injection

time

DTPMP

(retained)q

Protection

time

mg/L hr mg % mg/m2 hr

0.22 1 0.003 1.04 0.41 5.7

47.4 1 0.69 1.45 125 17

SI_CaCO3=0.59

Ca Concentration effect

• Ca precipitation and dissolution were both prevented.

• DTPMP failed when SI_CaCO3 > 1.1

• DTPMP return increased with a lower SI_CaCO3 .

050010001500200025003000350040004500

0.0

0.5

1.0

1.5

2.0

2.5

180 240 300 360 420 480

DT

PM

P (

mg

/L)

Time (min)DTPMP Ca

Ca

(mg

/L)

SI=0.74 SI=1.1 SI=-3.3 SI=-0.28

Ca HCO3 SI pH

mg/L mg/L

612.37 1643.73 0.29 5.89

1703.86 1643.73 0.74 5.90

3969.95 1643.73 1.11 5.92

0.175 1643.73 -3.25 5.88

163.69 1691.89 -0.28 5.88

SI=0.29

0

1

10

100

60 110 160 210 260 310 360

DT

PM

P (

mg

/L)

Time (min)

10 ml/hr

50 ml/hr

100 ml/hr

250 ml/hr

QLinear

Velocity

Return

DTPMP

Steady state

ml/hr cm/sec mg/L

10 0.017 1.3

50 0.08 0.4

100 0.17 0.25

250 0.42 0.12

Flow rate effect on the inhibitor release

Linear

Velocity

Return

DTPMP

Steady

state

Solubility

(cs)

Overall

Dissolution

rate

constant (k)

Mass

transfer

rate

constant

cm/sec mg/L mg/L sec-1 cm/sec

0.017 1.3

1.73 0.00182.86

E-4

0.08 0.4

0.17 0.25

0.42 0.12

Advection Dissolution

L/v £s(sec)

0 200 400 600 800

DT

PM

P S

.S.

Eff

luen

t C

on

c.

(mg

/L)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Pipe length at equilibrium (c=cs)

Q=1000 bbl/d,

I.D.=2.5-4 inch,

v=22.7-57.9 cm/sec,

km=2.86 E-4 cm/sec,

c/cs=1-exp(-3)=0.95

L=1250-3200 ft

0

0.2

0.4

0.6

0.8

1

1.2

0 1000 2000 3000 4000

c/cs(DTPMP)

pipe length (ft)

ID=4 inch ID=2.5 inch

Inhibitor-Saturation Index Relationship

At a specific T, SI, pH, and molar ratio (cation/anion) for

each specific inhibitor concentration, , there is a

unique saturation index value, , for those conditions.

These were solved for using Goal Seek. Illustrated here for

barite, the same applies for calcite.

32 40 1

2

31 2 4 5 10 2

4

10

0

10 ^

[ ]log

[ ]

1( / ) log

Barite

Barite Bartie

Barite

Inh Bartie

Barite Bartie

safety InhBarite

Inh Barite Barite

Inh

aa at a

SI TK SI TK

b Ba Mb b b SI b pH b

TK SO M

f tC mg L

b t

( / )Barite

InhC mg L

BartieSI

0.5

0.75

1

1.25

1.5

1.75

2

2.25

0

0.5

1

1.5

2

2.5

0 1000 2000 3000 4000 5000 6000

Ca

lcit

e a

nd

ba

rite

Sa

tura

tio

n I

nd

exes

DT

PM

P (

mg

/L),

blu

e d

iam

on

ds

Feet of flow in 2.5in. pipe with

Ca-DTPMP on steel surface

Barite

Calcite

Conclusion The phosphonate inhibitor layer was built up on the pipe

surface with CaCO3 pre-coated layer.

Amount of inhibitor attached is related with the DTPMP

adsorption on the CaCO3 surface.

CaCO3 can facilitate the inhibitor attachment on the

surface, may suggest the copercipitation of CaCO3 and

CaPhn crystal.

The DTPMP return is controlled by the dissolution of the

Ca3H4DTPMP precipitates attached on the surface with a

dissolution rate about 0.0018 cm-1.

Ca precipitation and dissolution were both prevented.

Acknowledgements

• Rice Brine Chemistry Consortium (BCC)

• Fellowship, China Scholarship Council

[Grant 2008102375] (2008-prsent)

• DOE (DE-FE0001910)

•Dr. Mason Tomson and Dr. Amy Kan