influence of brine composition on c/b/r interactions and

The IEAEOR 33rd Annual Symposium August 26 to 30, 2012Regina, Saskatchewan, Canada

Influence of Brine Composition on C/B/R Interactionsand Oil Recovery in Low Permeability Reservoir Coresand Oil Recovery in Low Permeability Reservoir Cores

Xi Q Li Qi ji M D h W Ji hXie Quan, Liu Qingjie, Ma Desheng, Wu Jiazhong

State Key Laboratory of Enhanced Oil Recovery

(Research Institute of Petroleum Exploration & Development, CNPC)

August 27, 2012

Outline

• Background

• Experiments

• Results and discussions• Results and discussions

• Summary

Background

Proposed mechanisms and Definition • Mobile fine particles playing a key role (Tang,

G.Q., Morrow, N.R. 1999)Alk li t fl di (M G i t l 2005)• Alkaline waterflooding (McGuire et al. 2005)

• Multi-component ionic exchange (MIE) (Lager, A., Webb, J.K., 2006)Webb, J.K., 2006)

• Electric double layer expansion (Nasralla, A., Bataweel, 2012)

• LosalTM , DWF …

IMWF (I i M t hi W t fl di )• IMWF (Ionic Matching Waterflooding)

Background

Challenges

• Waterflooding scenario in China

• Most oilfield waterflooded by surface water• Most oilfield waterflooded by surface water

• Spontaneous Low Salinity Effect

I ti ti th i t f ti d i t d

Objectives • Investigating the impact of cation and anion type and

concentration on the zeta potential.

• Feasibility especially for low permeability reservoir

Outline

• Background

• Experiments


• Summary

Experiments

Air permeability Porosity

• Core samples

• Crude Oil

Air permeability Porosity 0.3-1.5mD 9.0-12%

Density Viscosity Reservoir Temp.0.81g/cm3 9.0mPa.s 65

• Crude Oil

Sources ingredients（mg/l) Total• Brine

Salinity

(mg/l)

K++Na+ Ca2+ Mg2+ Ba2+ HCO3- Cl- SO4

2-

Formation 19249 2460 317 876 308 35220 0 58430Formation brine

19249 2460 317 876 308 35220 0 58430

Cation : Potassium sodium calcium magnesium barium Anion: bicarbonate chlorine sulphate

Experiments

The relative content of minerals

• Mineral and Clay

Sample

Mineral types and content（%） Total clay

minerals（%）

The relative content of minerals（%）

quartzFeldspar

I K C（%）quartz I/S Iillite

Kkaolinite

Cchlorite Potassium Plagioclase

1 44.8 7.1 21.5 26.5 30 14 27 292 43.2 11.9 20.9 23.6 32 12 28 283 41.7 13.8 16.7 27.1 33 11 30 264 37.6 13.9 19.2 28.4 36 15 24 255 35.2 13.6 21.8 28.3 37 15 24 246 45.2 11 24.8 11.4 36 16 24 247 41.1 9.8 23.8 25.1 38 13 22 27

Average 41.3 11.5 20.7 34.1 14 24.7 27.2

montmorillonite

Experiments

• Zeta Potential：Surface Chemistry Study

Zetasizer Nano ZS manufactured by Malvern Electrophoretic LightZetasizer Nano ZS manufactured by Malvern Electrophoretic Light Scattering, tested in room temperature

• Contact angle: Drop Shape Analysis (DSA)

Tested in room temperature

Experiments

Coreflooding testg

ISCO100-DX

Triaxial core holder Triaxial core holder

DXD Series Digital

Pressure TransducerPressure Transducer

Air Springs BPR (BP-100)

Tested at 65 Tested at 65

IFT Measurement

TX550A,Tested at 65

Outline

• Background

• Experiments


• Summary

Results and Discussions

Zeta potential measurement• Zeta Potential：Surface Chemistry Study

The montmorillonite for all the solutions is negatively charged.

Th f h f hl it i iti ith th 5 t% C Cl dThe surface charge of chlorite is positive with the 5wt% CaCl2 and MgCl2 solution.


• Zeta Potential：Surface Chemistry StudyZeta Potential：Surface Chemistry Study

The surface charge of kaolinite with the CaCl2, and MgCl2 solutions at concentration of 1wt% and 5wt% are positive.p

Na2SO4 solution is not sensitive to the zeta potential with different types of clays except for illite.


Zeta potential measurement• Zeta Potential：Surface Chemistry Study

Surface charge of sandstone with CaCl2 and MgCl2 at 1wt% and 5wt% are positive.

Zeta potential of sandstone with Na2SO4 is still negative with all of the t ti th th i l i thi t dconcentration the same as other minerals in this study.


Zeta potential measurement

• Surface charge at oil/brine Tested at the room temperature

interface is negative for all

solutions except 5wt% CaCl2 .

• The ion types and

concentration have the huge

impact on the zeta potential.


Contact angle measurement• The contact angle created by NaCl, Na2SO4 at the concentration of 0.1wt%

and 1wt% was lower than other solutions except for de-ionized water.

• Interfacial tension slightly changed with the increase of magnitude of pH at• Interfacial tension slightly changed with the increase of magnitude of pH at the given solution.


Magnitude of pH in oil/brine and minerals/brine solutions at 25

Brine Kaolinite Illite Mont. Chlorite Sandstone Oil

NaCl5% 5.3 8.1 8.2 9.9 8.7 6.51% 5.1 7.5 7.6 9.9 8.7 6.2

0.1% 4.9 7.1 7.4 9.7 8.3 6.3

CaCl2

5% 4.3 7.6 7.4 9.2 8.2 6.31% 4.2 7.1 7.1 9.2 7.8 5.92

0.1% 4.3 6.9 6.9 8.7 7.3 5.8

MgCl2

5% 4.7 7.9 7.6 9.5 9.0 6.21% 4.2 7.5 7.3 9.2 8.5 5.4MgCl2 1% 4.2 7.5 7.3 9.2 8.5 5.4

0.1% 4.5 7.1 7.0 8.7 8.0 5.0

Na2SO4

5% 5.7 8.3 7.8 9.9 8.7 6.01% 5 4 7 6 7 6 10 2 9 0 7 0Na2SO4 1% 5.4 7.6 7.6 10.2 9.0 7.0

0.1% 5.3 7.4 7.3 10.1 8.6 6.3De-ionized water 5.1 8.0 7.3 7.2 7.6 5.8


• Secondary mode coreflooding (starting at Swi )y g ( g )

synthetic formation brine : 30.0% IMW: 45.6%


• Tertiary mode Coreflooding (starting at Sorw) y g ( g )

Secondary IMW: 13.3% 14.5%


• The magnitude of pH of effluent fluid displaced by Ionic Matching

Waterflooding is higher than that displaced by synthetic formation

brine within increase of 1-3pH at the secondary and tertiary

8 5

9.0

9.5

10.0

8 5

9.0

9.5

10.0condition.

6 5

7.0

7.5

8.0

8.5

pH

core46#

core19#

6 5

7.0

7.5

8.0

8.5

pH

core23#:Ionicadjustment water

core40#:syntheticformation water

5.0

5.5

6.0

6.5

0 5 10 15 20 25 30 35 40

*Ionicadjustment water

*syntheticformationwater

5.0

5.5

6.0

6.5

0 5 10 15 20 25 30 35 40Total produced fluid，pore volumes

(A)

0 5 10 15 20 25 30 35 40Total produced fluid，pore volumes

(B)

Outline

• Background

• Experiments


• Summary

Summary

• Zeta potential results indicated that NaCl and

Na2SO4 changes electrical charge at both oil/brine 2 4 g g

and rock/brine interfaces to highly negative charge.

W t t i t f b f d ith i• Water-wet interface can be formed with an increase

of the zeta potential at both interfaces towards

highly negative charge.

Summary

• The types and concentration of cations and• The types and concentration of cations and

divalent in the injection water brine and the

minerals have a more dominant influence on the

wettability than the salinity.

• The ultimate oil recovery by the ionic matching

waterflooding improved to 37.8%~45.6%,waterflooding improved to 37.8% 45.6%,

compared with synthetic formation water.

Summary

Th it d f H f ffl t fl id di l d b• The magnitude of pH of effluent fluid displaced by ionic matching waterflooding is higher than that di l d b h i f i b i i hidisplaced by synthetic formation brine within increase of 1-3.

• Differential pressure was decreased at residual oil saturation invaded by ionic adjustment waterflooding compared to formation brine.

influence of brine composition on c/b/r interactions and

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