279

Zhao Fenglan1, 2, 3 , Zhang Lei1, 2, 3, Hou Jirui1, 2, 3 and Cao Shujun1, 2, 3 1

2

3

Abstract: 2

2

2

Key words: 2

2in ultra-low permeability reservoirs

CO2

for CO2 2

2

2

2

the use of CO2

2

1 Introduction2

2 2 2

2

2 2

2

the effect of CO2

of CO2

280

2

2

2 2

2

CO2

2

2

2 Experimental

2.1 Experimental equipment and materials

2

2

2 2 2 2

2

2.2 Experimental methods

2

channels.2.2.1 Chemical reaction of ethylenediamine with CO2

2

2.2.2 Measurement of ethylenediamine injectivity

-3 2

2

Carbon

dioxide

Pressure

containerReaction

container Organic

amine

Air bathValve

Pressure pump

Fig. 1 2

281

2.2.3 Measurement of swept volume by ethylenediamine

-3

2

2.2.4 Oil displacement tests before and after profile improvement

-3 -3 2

-3 2

2

2

2

3 Results and discussion

3.1 Chemical reaction of ethylenediamine with CO2 3.1.1 Morphologic characteristics of reaction products

2 are

3.1.2 Reaction mechanism of ethylenediamine and CO2

2

2

Fig. 2

Pressure sensor

Backup pressure valve

Am

ines

Water

Carbon dioxide

Core holder

Air bath

Liquid collector

Separator

Six-way valve

Gas m

eter

Pressure pump

Six-way valve

282

2

Fig. 3 2

H2N CH2 CH2 NH2

H

H

NCH2 CH2N

COOH

H

CO2

H2N CH2 CH2 NH2 2CO2

HOOC

H

NCH2 CH2N

COOH

H

H2N CH2 CH2 NH2 3CO2

HOOC

H

NCH2 CH2N

COOH

COOH

2 2 2 2 4CO2 2 2

2

2

2

H2N CH2 CH2NH2

-OOC

-OOC

NCH2 CH2N

COO-

COO-

yCOOH xR

-OOC

-OOC

NCH2 CH2N

COO-

COO-+NH3 CH2 CH2NH3

+

283

2

2 in the

Fig. 4

Fig. 52

2 2 COO--OOC

22 22 COO--OOC

2

2

reservoirs.

3.2 Injectivity of ethylenediamine

2

2

2

2

3.3 Swept volume

－2＋

2 2 2＋

－

2

2

284

Fig. 7

0

1

2

3

4

5

0 0.05 0.10 0.15 0.20 0.25 0.30

Inje

ctio

n pr

essu

re, M

Pa

Injection volume, PV

45 °

65 °

85 °

100 °

Swept region by ethylenediamine

(a) 0.1 PV (b) 0.2 PV (c) 0.3 PV

Swept region by ethylenediamine

Swept region byethylenediamine

Fig. 8

Table 1

cores 10-3 2 ratio

Core 1 1.47.1

10.0

Core 2 10 4 180

-3 2

Fig. 6

2

3.4 Oil displacement results of the plugged cores3.4.1 Heterogeneous cores

2 injection.

Table 2

10-3 2Oil recovery after

1 0 32

Fig. 9

0

1

2

3

4

5

6

7

8

0 50 100 150 200 250 300

Inle

t pre

ssur

e, M

Pa

Time, min

2

2

3.4.2 Sealed fracture core2

4 Conclusions2

CO2

2

CO2

Acknowledgements

References2

2

CO2

2

a CO2

for CO2

effect of CO2

CO2

2

2

2

2

2

2

2

2

2

2

CO2

2 injection.

2

2

2

alternating-CO2

2

2388-2399

2

area for CO2

CO2

(Edited by Sun Yanhua)