Changes in the Properties of Spilt Oil over Time
Tsutomu Tsukihara
Marifu Refinery
KOA OIL Co.,Ltd.
Introduction
Crude oil spilled in the sea by any reasons, including collision, wreckage of crude oiltanker,etc.,will transform various state, such as forming emulsion, moose by wind andwaves or dispersing into the sea as small particles or precipitating its heavy portion. Forsmooth and appropriate response activities on spilt oil, it is required that proper
selection of equipment and materials corresponding to properties(especially viscosity) oftransformed oil is essential. Therefore, we have to precisely review and examine
properties of transformed crude oils before hand. In this context, PAJ installed acirculating water channel simulator at Marifu Refinery, KOA OIL Co.,Ltd., in order toobtain such properties of various kind of transformed crude oil, and commenced tests
since 1993FY. In this paper, we would present results obtained on twenty six (26) crude
oils and one (1) heavy fuel oil(JIS.fuel oil C) as the continued efforts of “Fate of the spiltoil” Project for FY1997.

Figure 1

Circulating Water Channel

Test Oils
As indicated in the Table 1, 26 crude oils categorized into, “light”, ”Medium” and“Heavy”, from some 80 kinds of currently imported into Japan and one heavy fueloil(Fuel Oil C,JIS spec.) in view of potential spillage, were selected.

Table１ Test oils
Production area
Middle East

Quality
Low pour point
Light-gravity

Low pour point
Medium-gravity

Low pour point
Heavy-gravity
Southeast Asia

China
MexicoAustralia
Japan

Low p. pt,Light-gravity
Medium p. pt, Light-gravity
High p. pt, Light-gravity
High p. pt, Medium-gravity
High p.pt,
Heavy-gravity
High p. pt, Heavy-gravity
Low p. pt,
Medium-gravity
Low p. pt,
Heavy-gravity
Low p. pt,
Heavy-gravity

Oil
Berri Crude
Mubarras Blend Crude
Murban Crude
Qatar Marine Crude
Umm Shaif Crude
Arabian Light Crude
Arabian Medium Crude
Dubai Crude
Forozan Blend Crude
Hout Crude
Iranian Light Crude
Iranian Heavy Crude
Kuwait Crude
Oman Crude
Upper Zakum Crude
Arabian Heavy Crude
Khafji Crude
Wafra(contains Ratawi)crude
Attaka Crude
Light Seria Crude
Sumatra Light Crude
Labuan Crude
Duri Crude
Shengli Crude
Isthmus Crude
Wandoo Crude
Fuel Oil C

Test Conditions
The test conditions for these tests are shown in Table 2.
Table２ Test conditions of experiment
Test conditions

Case1(Summer) Case2(Summer) Case3(Winter)

Case4(Winter)weak waves

strong waves

weak waves

strong waves

5〜910〜15

5〜910〜15

1

0.5

1

0.5

wave rank

1

2

1

2

Wind Speed (m/s)

2.6

6.4

2.6

6.4

Amount of s.water (t)

44

4

4

S.water dephth(cm)

60

60

60

60

S.water temp.
Amount of oil（℃)

2525

1010101010101.4

1.41.4

1.4Height (cm)
Wave Cycle(sec)chargedThickness of oil (mm)Before conducting tests, we assumed typical climatic sea conditions for the experiments
as follows:“Summer” sea water temperature

25℃“Winter” sea water temperature

10℃

Other parameters which affecting transformation of spilt oils also assumed as indicatedin the Table 2.
As for the one of parameter, wave, we set 2 types of wave referred to “the waveranks(wave height)” specified by the Japan Meteorological agency, however, waves
generated for the test have larger energy than the waves specified in the “wave ranks”.
Anyhow, we defined waves generated in the channel as follows:“weak wave” represents calm sea condition.
“strong wave” represents rough sea condition.
The Figure 2 and 3 shows “weak wave” and “strong wave” respectively.

Figure 2

Weak Wave

Figure 3Strong Wave

Test Procedure
For this test, crude oil(heavy fuel oil) was poured on the sea-water in the circulatingwater channel which have generated designed waves. Samples of crude oil(heavy fueloil) which going to be transformed were taken from the surface of sea-water in thechannel at designated interval for 96 hours. Then, the samples were tested for watercontent,viscosity,densityandevaporation

rate.

Further,

weappliedagas

chromatographic technique for measuring evaporation rate.

Test Results
As indicated in the Table 3, crude oils tested are classified into 9 groups based on their
dominant properties, i.e, density, kinematic viscosity and pour point.
A series of test results for each crude oil are summarized in the Table 3.
By this classification, we recognized that respective group has characteristic tendency
on change in properties.

Table 3Group

①Low Pour Point,
Extra Light Gravity

Range of properties
Density
Kinematic Vis. Pour Point@15℃(g/cm3)@15℃ (cSt)(℃)
0.79〜 0.84
1.1〜 4.2-60〜 -5

Crude oil

Murban,UmmShaif,
Q.Marin,Berri,
Mubarras,Attaka
Arabian Lt,Dubai, Hout,
Iranian Lt, Isthmus,
U-Zakum
Oman,Iranian Hy, Kuwait,
Forozan B,Arabian M
Arabian Hy,Khafji,Wafra,
WandooLabuan,Lt Seria② Low Pour Point,
Light Gravity

0.85〜 0.87

4.1〜 6.1-55〜 -20③ Low Pour Point,Medium Gravity④ Low Pour Point,
Heavy Gravity⑤ Medium Pour Point,
Extra Light Gravity⑥ High Pour Point,
Extra Light Gravity⑦ High Pour Point,
Light Gravity⑧ High Pour Point,
Heavy Gravity⑨ High Pour Point,
Extra Heavy Gravity

0.85〜 0.88

6〜 10-45〜 -10

0.89〜 0.92

10〜 36-40〜 -25

0.79〜 0.87

1.8〜 2.1

7.5〜 -12.5

0.77〜 0.84

1.7〜 3.0

15〜 300.83〜 0.85

6〜 15

22.5〜 40

Sumatra Lt

0.86〜 0.90

22〜 100

30〜 -40

Shengli

0.92〜 0.97

150〜 600

5〜 17.5Duri① Group 1: Low pour point-extra light gravity
・ Increase of viscosity does not exceed 1,000 cp even after 96 hours.
・ Tend to disperse into sea water by “strong waves”.
・ In cold climate (winter), tend to form fragile emulsion impregnated with air

bubbles.
・ As for paraffin rich crude from southern region, lighter fraction is evaporated in ashort time period and solidified.
The figure 4 shows the changes of viscosity on crude oil belonged to Group 1.
Figure4

QM

200

US

Be

1000

1200

800

Mur

100

Mur

400
200

0US

600

QMMubBe

A tt

24487296M ub
Q M
Be

600
300

24time(Hrs)

48

72

6009624time(Hrs)

USBe200

M urAtt

US0Q M400

M u rA tt
00

800

90000

（Winter,StrongWave)
M ub

1500

Vis.(cP)

300

1200

Vis.(cP)

Vis.(cP)

400（Summer,StrongWave)

1400(Summer,Weak Wave)

Mub
A tt

Vis.(cP)（Winter,Weak Wave)
500

0
48

72096

2448

72

96time(Hrs)time(Hrs).

② Group 2: Low pour point-light gravity.
③ Group 3: Low pour point-medium gravity.
・ As for these two groups, the change in properties are quite different depending ontheir origins. Some are forming unstable emulsion while the others are forming
stable emulsion of which tend to transform firm mousse.
・ As can be seen on Dubai and Forozan Blend crude, the change in properties are
extremely varied by different conditions.
The Figure 5 and 6 shows the changes of viscosity of Group 2 and Group 3 oils
respectively.

Figure5（Winter,WeakWave)

30000

15000
10000
5000

Ist
Dub
IL
ALUZa
Ho

00 24 48 72 96time(Hrs)

80000

Ist

15000
12000
9000

IL UZ
AL HoaDub

6000
300000244872time(Hrs)

96Vis.(cP)20000（Winter,StrongWave)
12000018000

Vis.(cP)

Vis.(cP)

25000(Summer,StrongWave)

60000

Ist

40000

IL Du
AL
Ho
Uza

20000
00244872time(Hrs)96

Vis.(cP)(Summer,Weak Wave)

Ist

80000
40000

DubIL
AL
Ho
Uza

00

24 48 72 96time(Hrs)Figure6(Winter,Weak Wave)

IH
AM
Ku
Fo
Om

0Vis.(cP)

Vis.(cP)

10000050000(Summer,StrongWave)

40000

Ku
20000

AM
10000

40000

180000

IH

30000(Winter,StrongWave)

Om
Fo

IH
12000000 24 48 72 96

0 24 48 72 96

time(Hrs)time(Hrs)

Ku
AM Fo

60000

Vis.(cP)（Summer,WeakWave)

Vis.(cP)

IH

IH
Ku

30000

Om

10000

Om

0AM

20000

Fo00 24 48 72 96024 48 72 96

time(Hrs)time(Hrs)④ Group 4 : Low pour point-Heavy gravity
・ Crude oils origined in the Middle East tend to form similar firm mousse, regardlessof conditions.
・ Wandoo crude origined in Australia does not form emulsion, but disperses into
seawater with “strong waves”.
The Figure 7 shows the changes of viscosity on Group 4 oils.
Figure7(Winter,Weak Wave)(Summer,StrongWave)

60000

150000100000
50000

AH

Kf
Waf

40000

AH20000

Wan

Wan

00 24 48 72 96time(Hrs)

200000Kf
Waf
Vis.(cP)

Vis.(cP)

200000Vis.(cP)

250000(Winter,StrongWave)
100000150000Kf Waf

100000

AH

50000

Wan

000 24 48 72 96time(Hrs)024 48 72 96time(Hrs)⑤ Group 5: Medium pour point-extra light gravity
・ Only unstable emulsion is formed.
・ In cold climate (winter), the oil solidifies.
・ The oil disperses into seawater with “strong waves”.
The Figure 8 shows the change of viscosity on Group 5 oils.

80000

Vis.(cP)（Summer,WeakWave)

Kf
Waf
AH

60000
40000
20000

Wan0024 48 72 96time(Hrs)Figure8LSe（Summer,StrongWave)(Winter,StrongWave)

150

200150Lab1000Lab100LSe

50150
100500024487296

Lab

Vis.(cP)

200Vis.(cP)

Vis.(cP)

300（Winter,WeakWave)

Vis.(cP)(Summer,Weak Wave)time(Hrs)

24487296time(Hrs)

La50LSe

LSe00

100002448 7296time(Hrs)024 48 72 96time(Hrs)⑥ Group 6: High pour point-extra light gravity.
Group 7: High pour point-light gravity.
Group 8: High pour point-Heavy gravity
Group 9: High pour point-Extra Heavy gravity.
As to the high pour point groups (Group 6 to 9), they tend to form a range of semisolidified to solidified lump or patch contacting with seawater which has relatively
cold temperature compared to their own high pour points. Also, since it appears noremarkable changes in properties, we do not touch them further in this paper.

Conclusion
・ Emulsion forming tendency of spilt oils seem to be depending on their origin whichclosely related to its composition. (Refer to the Attachment Table 1)・ In general, crude oil having high asphaltene content tends to form emulsion easily.
There is a positive correlation between asphaltene content and emulsification
tendency.(Refer to the Attachment
Figure 1)・ Crude oils classified to Group 1 (low pour point-extra light gravity) form only
unstable emulsion, and tend to disperse into seawater.
・ Crude oils classified to Group 3 (low pour point-medium gravity) tend to form
various type of emulsion.
・ Crude oils classified to Group 4 (low pour point-heavy gravity) which usually havehigh asphalten content tend to form firm mousse.

A prospect for further study
It is beneficial and important for us that grasping change in properties of all crude oils
being imported to Japan, they are more than 80 kinds, for preventing or responding
potential hazard caused by those crude oils.
At this time of period, we have gathered 27 sets of data for “change in properties” of spilt
oils, however, we are going to accumulate another same sets of data for establishing acomprehensive data-base and simulation software to predict any kind of ”Fate of spiltoil” in the near future.
Now we are making efforts to develop the said simulation software effective even forunknown sources.

Attachment
Attachment Table 1 Emulsions forming tendency by origin and gravity
Production area
Tendency to form emulsions
Characteristics
Light‑gravityMedium‑gravity Heavy‑gravity
Middle EastHigh aroma, resin and★
★★
★★
asphaltene contents.
MexicoHigh aroma, resin and★
★★
★★
asphaltene contents.
Southern
Saturated HC rich, high wax★
★★
★
regions
content.
China
Saturated HC rich, high wax★
★
★
content.
Australia
Saturated HC rich, low wax★
★
★
and low asphaltene content.
Note: The number of ★ shows, emulsion forming tendency.

Relationship between the asphaltene content andthe emulsion forming tendency.

50000
W af

AH

40000
V is .(c P )Attachment Figure 1

Kf
IH

30000
20000

Kuw
Is t hAMUZaO m
A LF o r o
W a nB e M u Hb o D u b0 L a bM uQr M

100000IL246A s p h a lte n (m a s s % )