Tap cM Khoa hoc va Cong nghe Bien; Tap 14, So 2; 2014 187 194 ISSN 1859 3097 http //www vjs ac vn/index php/jmst MO PHONG MpT SO KICH BAN TRAN DAU KHU VUC DAO C O N CO Tran Anh Tii*, Le Dire Cufrng Vi[.]
Trang 1ISSN: 1859-3097 http://www.vjs.ac.vn/index.php/jmst
MO PHONG MpT SO KICH BAN TRAN DAU
Tran Anh Tii*, Le Dire Cufrng Vien Tai nguyen va Moi trucmg Bien-Vien Han lam Khoa hoc va Cong nghe Viet Nam
E-mail: tula@imer.ac.vn Ngay nhan bai: 2-1-2014
TOM TAT: Ddo tien tieu Con Co dong vai trd quan trong Irong chien lucre phdt trien kinh te
vd an ninh qudc phdng cua nude ta Nhu cdu ndng luong-ddu md tren the gidi ngdy cdng tdng, kem theo su van chuyen ddu tren bien ciing tdng theo Vdi vi tri gdn tuyen dudng van chuyen ddu tic
ky ihudl ludi long cua mo Innh Delfl3D, mot so kich bdn trdn ddu (100 tdn) theo cdc hudng gio khdc nhau cda khu vuc ddo Con Co dd duac mo phong Ket qud linh todn vdi trudng hop gid hudng Dong Bdc vet ddu dnh hudng tic 9-14 ngdy: trudng hap gio hudng Nam vet ddu dnh hudng tic 6-9 ngdy vd trudng hap gio huong Tdy Nam vet ddu dnh hudng tic 12-14 ngdy Kit qud nghien cuu se Id
CO sd tham khdo cho cdc dan vi qudn ly moi trudng bien vd cdc ngdnh Uen quan
Tir khoa: Ddo lien lieu, trdn ddu
MO DAU
Bien va dai duang co vai tro quan trong doi
vai su song cila loai nguoi noi chung va Viet
Nam noi rieng Viee phat trien nhieu nganh
kinh le bien khac nhau nhu hang hai, thuy san,
khai thac dau khi, du lich, cac qua trinh do
deu tao ra cac nguon gay 6 nhiem bien Thuc le
cho thay cac vu 6 nhiem bien do dau thuang
gay ra cac thiet hai rat lan, dien tich rat rpng
(1 tan dau co the loang pliii mot dien lich lai
12 km^ mat nuoc.l gam dau co the lam ban_2
tan nuac [1]) Bien Dong noi chung va bien
Vi?t Nam noi rieng la bon chiia cac loai dau
thai tir nhieu nguon goc khac nhau (ro ri tir khai
thac, v^n ehuyen, tai nan tren bien va nguon
dau thai dua ra lir luc dja), Nhieu tai lieu da noi
den vai tro rat lan ciia nguon dau thai tir cac
ho?t dpng tren tuyen hang hai quoc le di qua
truong tren bien do Cue Bao ye Moi trucmg
quan ly tir nam 1995 den nay deu cho thay xu
huong ham lupfng dau gay 6 nhidm trong nuac
bifin CO xu huang tang dan tir bo ra khoi xa, co
lien quan den hoat dpng tau thuyen tren cac tuyen hang hai De giam thieu anh huong den trinh da dupe nghien ciru ve vet dau doi vai Bien Dong va khu vuc vinh Bae Bp Tuy nhien, chua e6 nhieu cong trinh n_ghien cuu Iran dau anh huong den cac dao tien lieu thupc viing bien Viet Nam Dao Con Co (tinh Quang Tri)
la mpt trong nhirng dao tien lieu ciia Viet Nam, dau tir Trung Dong ve Dong Bae A [3] Vai vj tri nay, dao Con Co chiu nhieu anh huong khi
CO su CO Iran dau xay ra De co duoc buc tranh chung ve su lan truyen ciia vet dau theo cac huong gi6 khac nhau, cong trinh nay da sir dung mo hinh Delft3d mo phong mpt so kich ban tran dau khu vuc dao Con C6
TAI LIEU VA PHU'ONG PHAP Tai lieu
De thuc hien cong trinh nay, so lieu duong
Trang 2nghien cuu duac so hoa lai tir cac ban do dia
hinh UTM ty le 1: 25.000 do Cue Do dae Ban
do xuat ban (2005), day la nhirng ban do voi he
tpa do nha nude VN-2000 So lieu do sau
(hinh 2) dugc lay tir nguon ca sa dir lieu
GEBCO -1/8 (General Balhymelric Chart of
the Ocean) cua Trung lam tu lieu hai duang
hpc vuang quoc Anh-BODC (British
Oceanographie Data Centre) [4] So lieu ve dao
dpng muc nude tren cac bien ma phia bien
dugc tao tir mo dun TIDE tir hang so dieu hoa
lay tir bp hang so dieu hoa toan cau FES2004
cua du an Topex/ Poseidon voi do phan giai 1/8
dp va dugc hieu chinh vai du' lieu do dac tai
cac tram hai van Irong vinh Bac Bp nhu Hon
Dau, Hon Ngu, Da Nang,
Cac lai lieu ve khi tugng, hai van, chat
luang nuac dugc lay lu de lai VAST 06.03/
12-13
Phumig phap
De mo phong qua trinh tran dau khi c6 sir
CO trim dau xay ra, da su' dung mo dun
Delfl3D-PART trong bo mo hinh Delft3D ciia Ha Lan
Ngoai ra, mo dun Delfl3D-FL0W da dugc sir
dung de eung cap thong lin thiiy dpng luc ciia
khu vuc nghien ciiu
Delft3D-PART la module nam trong bp mo
hinh Delit3D, co chiic nang tinh loan va du bao
su bien dpng, phan bo ve ham lugng ciia vat
chat theo thdi gian bang phuang phap Monte
Carlo [2]
Doi vdl viec tinh loan Iran dau, vdi gia thiet
rang dau dugc dua vao Ihiiy vuc tir mot ngudn
lien tue hoac tire thdi, pham vi lan truyen ciia
dau dugc xae dinh bang phuang trinh (Fay va
Houll, 1971): '
trgng cua nude (kg/m^); g - hang so hap din
(m/s"); v^: do nhdt cua nude; ki, kj hang 56
Fay
Tdc do lan truyen cua dau Q(kg/mVs) dugc xae dinh theo phuang trinh sau:
P - Po
Q= ]Q{d)dd (2)
Trong do' K„ : the tich ban dau ciia dau Iran
(m ), p,_, - ty trpng cua dau (]<g/m^); p^,; ty
Q(d) = C" D°f F„N(d)d' (3)
N(d) = N„d-" (4)
D„=0.0034p„gHj42 (5)
„ 0.234C/J,
H,= (6)
g
^ = — ; ' , = 8 1 3 C / , / g ;
P
/ , = max(0.0;0.032(f/„ - 5.0)) Vdi: Q(d) la tdc do lan truyen tren mpt don
vi vdl gipl dau dudng kinh d(kg/m"/s); d,n,n-dudng kinh gigt dau nho nhat (m); dmax-dudng kinh gipl dau ldn nhal (m); C -hang sd hieu chinh (phu thudc vao tirng loai dau); N(d)-ham phan bd kich thudc ciia phan tiJ dau; N(i -ham phan bo lieu chuan; D^ -lieu hao ciia nang lugng song tren mgi dan vi dien tich
be mat (J/m"); F^c -sd sdng do tren mgt chu ky
song, lp -chu ky sdng cue dai (s); Uw -van toe gid (m/s); fw -phan bien dugc bao phii bdi song bae dau [2]
Trien khai mo hinh
Thiet lap mien vd luai linh
Khu vu'c nghien cuu khdng cd sd lieu quan trac tren bien, vi vay can xay dung cac dieu kien bien Dieu do chi cd thg thuc hien tinh loan tren mien ldn ban (loan bg Bien Dong), sau do trich xuat sd lieu tai ranh gidi khu vuc nghien ciiu
Mien linh bao gdm hai khu vuc: a) Khu vyc
Trang 3toan CO tga dg 99"E d^n I 2 1 " E va 01**N den
sd dieu hoa thuy trieu tai: eo Dai Loan, eo
Bashi va eo Malaca, b) Khu vuc dao Con Cd
dugc the hien tren hinh 1 Mien tinh dugc chia thanh 251 x 251 d ludi; kich thudc cac 6 ludi: Ay=Ax= 100 m
Dieu kien bien
Tai bien Idng: muc nude thiiy trieu duac
tinh loan theo hang sd dieu hda thiiy trieu Tai
bien ciing: eho dieu kien khdng chay qua (van
toe phap tuyen = 0) Kel qua tinh toan thiiy
dgng luc cho toan bg Bien Dong sau do dugc
truy xuat la dieu kien bien cho md hinh chi tiet
doi vdi khu vuc nghien cuu, Ky thuat ludi long
trong Delft-3D duoc ap dung
K t T QUA MO PHONG
Hifu chinh mu hinh
Sau nhieu lan linh toan, so sanh van tdc va
hudng ddng chay giila sd lieu tinh toan va thuc
do (d^ tai VAST 06.03/12-13) tai phia Tay dao
C6n Cd dugc the hien tan lugt tren hinh 2 va
hinh 3 Vdi h? sd tuang quan ctia thanh phan
v^n tdc cd gia trj la 0,73 Nhu vay viee hieu
chinh cho ket qua tdt, cd the sii dung bd cac
tham sd hieu chinh nay de dua vao cac tinh
toan khac
I g g $ g g g ! g g g g g I £ I
Hinh 2 So sanh van toe (m/s) ddng chay tinh toan vdi thuc do lai phia Tay dao Cdn Cd
Hinh 3 So sanh hudng (") dong chay linh loan
Trang 4Dong chay
Trudng ddng chay khu vuc dao Cdn Cd la
long hgp cua cac thanh phan ddng trieu, ddng
chay gid gay ra Trong dd, ddng trieu tuan hoan
cd vai trd quan trgng quyet dinh den tinh chat
chung cua ddng chay tdng hgp
Hinh 4 Tru'dng dong chay khu vuc dao Cdn
Cd khi trieu len (gid Ddng Bac)
trong pha U-iSu len va Nam, Tay Nam^ trong pha triSu xudng Vao thdi di6m ehan trieu va dinh trieu hudng ddng chay bj phan tan manh ve hudng, tdc dp ddng chay dat gia tri ldn nhat tai khu vuc ven dao (0,5 m/s) Trong thdi ky chuyen pha trieu ddng chay thudng cd hudng Tay vdi tdc do vao khoang 0,1 -0,3 m/s Tai khu
•vuc sat ven bd dao hudng ddng chay cd xu hudng son^ song vdi dudng bd, trong thdi ky giua pha trieu len (xudng) ddng chay d khu vuc sat ven bd phia Bac (Nam) dao cd gia trj kha nhd (0,1-0,2 m/s) va phan tan manh ve hudng (hinh 4, 5)
Hinh 5 Trudng dong chay khu vuc dao Cdn
Co khi trieu xudng (gio Ddng Bac)
Toe do ddng chay ldn nhat la 0,55 m/s
trong thdi ky giij'a pha trieu len va trieu xudng,
rr.;-."™- ;i,?=;r, „
m.^
Hinh 6 So do vi tri gia dinh xay ra su cd tran dau
Kich ban chay md hinh lan truyen dau do
su cd tran dau tai khu vue phia Bae Tay Bac ciia dao Cdn Co ddi vdi loai dau DO (ty trgng
la 850 kg/m^ do nhdt la SxlO'" mVs d 20"C_) Vdl gia thiel khdi lugng dau Iran la 100 tan theo cae kieh ban xay ra trung vdl thdi diem pha trieu len va pha trieu xudng vdi cae hudng gid khac nhau (45", 180" va 225") Trong trudng hgp dau DO, thanh phan dau bam day duge xem nhu khdng dang ke, do ly trpng nhe nen dang ton tai ndi tren mat nude la ehinh Lugng dau ndi dugc xae dinh la Idp dau mdng phia tren eiing be mat cdt nude cd dan vj linh la kg/m^ loai dau rai xudng day va bam vao dat
cd ciing dan vi_ la kg/m^ loai dau la lirng trong col nude do kel qua cua qua trinh xao Iron va nhii tuang hda cd don vi linh la kg/m^ Loai dau Irong nude la san pham ciia qua trinh xao Iron nude be mat (do gid, sdng gay nen) dii manh lam cho dau ndi di vao trong nude, mat
Trang 5kien cho qua trinh nhu tuong hda diln ra nhanh
ban Trong dieu kien toe do gid nhd, sdng nhd
thi qua trinh dau di vao nude khong dang kg
Vi tri gia su xay ra su cd tran dau dugc thi
hi?n nhu hinh 6 (tga dg dang UTM-WGS84:
748.217,38 m; 1.899.652,80 m Trong cac kich
ban tinh toan, tdc do gid khoang 4 m/s nen Idp
nude be mat it xao trpn (gay ra bdi gid va
sdng), loai dau DO sau khi tran ra chu yeu ton
tai d dang dau noi
Gid hir&ng Bong Bac: vdi kich ban su co
tran dau DO xay ra khi trudng gid cd hudng la Ddng Bae vdi tdc dp la 4 m/s, khdi lugng dSu tran la IOO tin Vet dau chi anh hudng trong pham vi tinh toan khoang 9 ngay khi su cd xay
ra vao thdi diem pha trieu len va 14 ngay khi su
cd xay ra vao thdi diem pha trieu xuong Cac dac trung (ham lugng, hudng di ehuyen, viing anh hudng) ciia vet diu bien ddi theo thdi gian dugc the hi$n trong hinh 7 va bang 1
Khoang cSch i Khoang each
(a) , (b) Hinh 7 Su cd Iran diu (hudng gid Dong Bac, pha trieu len) sau 1 gid (a) va sau 6 gid (b)
Bang \ Cac dac trung ciia \et dau vdi trudng htrp tinh cho hudng gid Ddng Bac (45")
Thoii Hirang dl ctiuyin c
gian v f t dau Viing anh htrang
trung vol ttiot diem pha liiiu len
1 h V4 phia ray
6 h
12h
24 h
36 h
V4 phfa l a y Tay Nam
V4 phia Tay Nam
Mn' ri^ng len phia Tay
B^c va Phia Dong
Md ring len phia Tay
B^c va Phia Gang
trungr voi thoi diem pha trieu xuong
6h
12 h
24 h
Xu^ng phia Tdy Nam
Nam Tay Nam
L6n phia B^c
Ibn phia aac
0,025-0,026 1,2-10"' 5,1 '10"*
2.4 • 10""
1,8- 10"*
0,019 1,3 "10"'
5,5" 10"*
3,0 » 10"*
TCr VI tri Iran dau ma rpng v i phia Tay Tay Bic cua dao
Ma rpng tir phia Tay Bic dfen Tay TSy Nam cSch tir ba ra phia ngoai khoang 5 km
Toan bo goc 'A mo rpng lie phfa Tay den phia Nam cua To^n bg goc '/ ma rpng \if phfa Tay din phia Nam cua
dao, ma rpng sang phfa Dong va len phfa Baccua dao each
ba khoang 10 km,
Khu v\/c phia Cdng Bac ciia dao cach bo khoang B km khong b( anh hi/ong, con I31 cac khu v^rc khac d^u b| anh
hi/ang Tir ven ba ra phia ngoai khoang 2 km, pham v\ vgl dau vao khoang Z • 2 km
Pham VI vel dau mo rpng xij6ng phia Nam Tay Nam, li/ ven
bo ra phfa ngoai 7 km Goc '/ phia Tay Nam khu vi/c Ifnh loan, mgi phin len phfa Dong cua dao-lif bo ra phia ngoai khoang 3 km
Toan bp V, phgm v linh loan - l i j phia Bac-Tay-Nam cua
dao, mgt phin nho mo rpng sang phia Opng ciia dao
Trang 6Gio hur&ng Nam: vdi kich bin su cd tran
dau DO xay ra khi trudng gid cd hudng la Nam
vdi toe dp la 4 m/s, khdi lugng diu tran la 100
tan Vet dau chi anh hudng trong pham vi tinh
loan khoang 9 ngay khi su ed xay ra vao thdi
diSm pha tri^u len va 6 ngay khi su co xay ra vao thdi diem pha trieu xudng Cac dac trung (ham lugng, hudiig di chuyen, viing anh hudng) cua vet dau bien ddi theo thdi gian dugc the hien trong hinh 8 va bang 2
Khoang each ^ ^gS Khoang each
(a)^ (b) Hinh 8 Su c6 tran diu (hudng gid Nam, pha lri6u xudng) sau 1 gid (a) va sau 6 gid (b)
Bang 2 Cac dae trung ciia vet dau vdi trudng hgp tinh cho hudng gid Nam (180 )
Tho'i Hu'O'ng di chuyer
gian cua vet dau
Ham l i r ^ n g dau max (kg/m^) V i i n g anh Hu'O'ng
S{F CO xay ra triing voi thcyi diim pha tri4u len
0,016-0,017 11,3 " 10"*
TiJ v[ tri xay ra si^ co ma rgng len phia Bac each bcr
khoang 1 km
5 36 h
Sy CO xiy ra triing
Ma rgng len phia
Bac, sang phia Tay 5,5
va xu6ng phia Nam
M o rgng ra khu vu'c
xung quanh dao
Ma rpng ra khu vuc
xung quanh dao
/o'/ thm diem pha trieu xuong
^ ' " ^ N V m ' ^ ^ ' 0,027
TCF VI tri xay ra s y co mo khoang 10 km Phgm VI m a rpng ILP b a
9 km
rpng len phia Bac each bo
n het bien phia Bac sang
1 xuong phia Nam khoang
Xuong phia Nam
,-2 L^ Ve phia Tay va phia
B§c
1 , 3 " IO"'
10 36 h
Ve phia Bac Tay
M o rpng ra phia
Hau nhif loan bg phgm vi tinh toan, chi mpt khu v\fc
nho khong bi anh hu'dng n§m a goc phia Dong Nam cua mien tinh - each b a khoang 9 km Toan bp pham vi tinh toan
Til' bo ra phia ngoai khoang 1,5 km - vk phia Tay
cua dao Til- bo ra phia tay cua dao khoang 2,5 km va keo dai xuong phia Nam each b a khoang 6 km Bao quanh dao ti> phia B^c sang phia Tay va phia nho lan ra phia Dong ciia Dao - lir b a ra phia ngoai khoang 5 km
l o a n bp khu vi/c goc V phia Tay Bac cua Dao, mpi phan bao xung quanh dao-Iif b a ra phia ngoai khoang 4-5 km
H 4 U nhu' loan bp phgm vi tinh toan, chi mpt khu w/c nho khong b| anh h u a n g nSm 6 goc phia Dong Nam
Trang 7tran
Tiy
tran la 100 tan Vet dau chi anh hudng trong viing anh hudng) cua vet dau bien ddi theo thdi pham vi tinh loan khoang 14 ngay khi su cd gian dugc th^ hien trong hinh 9 va bang 3
Hinh 9 Su co tran dau (hudng gid Tay Nam, pha trieu xudng) sau 1 gid (a) va sau 6 gid (b) Bang 3 Cac dac trung ciia vet dau vdi trudng hgp tinh cho hudng gid Tay Nam (225")
Tho'i Hu'O'ng di c h u y e n Ham l i f t i n g dau
gian ciia v f l dau max (kg/m^) Viing a n h h u v n g
S(f CO xay ra trung v6-i thai diem pha trieu len
1
2
3
4
5
S^r cc
7
6
9
10
1 h
6 h
1 2 h
24 h
36 h
xay ra triing
1 h
6 h
1 2 h
24 h
Len phia B i c
Len phia Bac,
va phia Tay Nam
Mcf rging ra xung
quanh dao
Ma rpng ra xung
quanh dap
Ma rpng ra xung
quanh dao
v&i thm diim pha trieu *
Ve phia Tay Tay
Nam
V e p h i a Nam va
Dong
M a rgng xung
quanh dao
M o rgng xung
quanh dao
Mo rpng xung
0,03 16,5 " 10"*
7,1 » 10"*
2,2 - 10"*
1 5 - 10'^
uong
0,025-0,026
2,0 - 10"'
5,5 X 10"*
2,5 - 10"^
Tip vj tri xay ra s y co ma rpng len phia BSc each bd' khoang 1 km
Phgm VI tiF phia B i c sang phia Tay xung quanh dao
- each bo khoang 5-6 km Xung quanh dao ti> bo len hel bien phia Bac va phia Nam, tii' bo ra phia ngoai khoang 10 km ve phia l a y cua dao va khoang 7 km ve phia Ddng ciia dao
Hau h6l phgm vi tinh loan Hau h6l pham vi linh loan
Tir ba ra phia ngoai khoang 1 km - ve phia Tay ciia Dao
Khu VU'C til' ba xudng phia Nam ciia dao- each bo khoang 1-2 km
Xung quanh dao lip ba ra phia ngoai khoang 7
-10 km
H l u nhu" loan bg khu vyc linh loan
Trang 8Md hinh Delft3D da dugc sii dung de md
phdng cac kich ban tran diu theo cac hudng gid
khu vuc dao Con Cd Theo ket qui nghien ciiu
cho thay xu the vet diu ndi phu thuoc ro ret vao
eac pha trieu (len va xudng) Trong pha tri§u
len vet dau anh hudng tu 9 n^ay den 14 ngay
va trong pha triSu xuong vet diu anh hudng tir
6 ngay den 14 ngay Vdi trudng hop gid hudng
trieu xudng, vet diu cd xu hudng md rgng ra
phia Bac va phia Ddng ciia dio Trudng hgp
vdi pha trieu len, sau 1 ngay vet diu md rgng
toan bd xung quanh dao Trudng hap gid
hudng Tay Nam, thdi gian xiy ra sir co triang
vdi pha trieu xudng, sau 6 gid vet diu md rgng
ve phia Nam va phia Ddng ciia dao Tuy nhien
do chinh xae cua md hinh phu thuoc nhieu vao
cac yeu td khi tugng va trudng do siu Trong
nghien ciiu tiep theo nhung ban che nay cin
dugc khac phuc de ning cao do chinh xae ciia
md hinh
LM cam tm: Nhdm tac gii tran trgng cim on
Ban chii nhiem de tai "VATS 06.03/12-13:
Nghien cvu ban chdt hoan ltru ven ddo tgi mgt
so ddo tien tieu tren vinh Bdc Bo phuc yy bdo
ve moi truong, sinh thdi va phdt trien bin
vimg" (2012-2013) da tgo diSu kien cho v i ^
hoan thanh cong trinh nay
TAI U E U THAM KHAO
1 Trdn Anh Tii, Vu Duy Vinh Nguyin HGu
Cu, 2008 Md phdng qui trinh tran d4u khu
vuc dio Bach Long VT bang md hinh delft-3D Tuyen tip Tai nguyen v i moi trudng bien Tap XIII Nxb Khoa hoc v^ Ky thu$t HaNgi.Tr 342-351
2 WL\DelJi Hydraulics 1999
Delft3D-FLOW User Manual Version 3.05, Delft3D
- Waq User Manual Version 3.01, Delft3D
- Part User Manual Version 1.0 WL| Derft Hydraulics, Delft, Netho-lands
3 http://energyinasiablog.com
4 http://www.gebco.net/data_and_products/-gridded_bathymetry_data/
SIMULATION OF SOME OIL SPILL SCENARIOS
IN CON CO ISLAND AREA
Tran Anh Tu, Le Due Cuong Institute of Marine Environment and Resources-VAST
ABSTRACT: The Con Co Island plays an important role in the economic and security
development strategy of Vietnam The need for petroleum consume is more increasing in the world leading to the increase of petroleum transportation Located near the petroleum transport line from Middle East to North East Asia Con Co Island will be affected if oil spills happen By using Delft3D model and nesting technique, some scenarios of oil spill (100 tons) in different wind directions in Con Co area are simulated Calculating results show that, with the North-East wind case, the oil slick spreads in 9-14 days: m the case of southern wind, oil slick spreads in 6-9 days and the case of South West, oil slick spread in 12-14 days The results are reference for marine management agencies and related sectors
Keywords: Oil spill, scenarios