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Tuygn tap bao c^o Hoi nghj KHCN "30 nam Phu khi Viet Nam Co" hoi m6i, thach thuc moi" 495 DAC DIEM T R A M TICH TANG CHLTA CAT KET MIOCEN Dir6l MO SET TtT DEN Pham Thj H6ng, Pham Hai Van Viin Ddu Khi[.]
Tuygn tap bao c^o Hoi nghj KHCN "30 nam Phu Viet Nam: Co" hoi m6i, thach thuc moi" 495 DAC DIEM T R A M TICH TANG CHLTA CAT KET MIOCEN Dir6l MO SET TtT DEN Pham Thj H6ng, Pham Hai Van Viin Ddu Khi TOM T A T Bdo cdo ndy trinh bdy nhirng nghien ciru vi thgch hoc trdm tich cua tdng Bl tudi Miocen s&m md Su Tu Den vd mdi lien quan din chdt lugng chua cua tdng Thdnh phdn vun Q/F/R trung hinh tuong irng la 46,5%/45%/8,5% Id mdt ddu hiiu di suy dodn ngudn vgt lieu Id cdc khdi granitoid Trong sd thdnh phdn vun, thdnh phdn thgch anh bin vdng hon k-fenpat Chung la ddu hiiu du dodn cdt kit tdng Bl cd chat lugng chira tdt Mdi tru&ng trdm tich xen ke giira ddng bdng chdu thd vd ven biin da tgo edt kit tdng Bl cd CO hgt trung binh din thd, v&i lua chon tir trung binh din rdt kem Ngodi cdn cd it glauconit vd anhydrit Cdc dge tinh trdm tich niu tren tgo ede via cd chat lugng chua tdt, ddc biit & cdc khodng sdu 1720m - 1765m, 1750m - 1778m, 1752m - 1792m & cdc giing khoan tuong ung 15-1-SD-lX, SD-3X, SD-4X Biin ddi thu sinh & tap BI gdm xi mdng hod vd nen ep hgt vun ldm gidm mdt phdn rdng nguyin sinh cua da Mirc mdt rdng qud trinh nin ip la chu yiu vd mgnh hem mire mdt rdng xi mdng hod Cd su tdng rdng vi phia Tdy Nam tir 25% din 29% cung v&i su tdng chiiu ddy hiiu dung theo hu&ng d& tir 6,63m t&i 9,25m VAI NET VE VI TRI DIA LY VA KIEN TAO CUA MO SlJ TLT DEN Mo Su Tir Den thuoc 16 15-1 nam phan Bae - D6ng Bae bon triing Cim Long, thim luc dja Nam Viet Nam, co toa dja ly khoang 9° - 11° vT B I C , ° ' - 109° kinh D6ng, each Tp Ho Chi Minh 180km ve phia D6ng Nam va trai rong tren dien tich 1634km^ Cac phat hien ciia mo nam a phan D6ng cua 16, dge theo huong Tay Bae doi nang Rong - Bach H6 - Rang D6ng - Ruby (Hinh 1) Ljch sir kien tao ciia mo gan lien voi ljch sir kien tao ciia bon trung Cim Long, la loai b6n dugc hinh qua trinh tao rift Qua trinh dugc chia lam ba thoi ky chinh: - Thori ky truoc tao rift hinh ting mong truoc De tam - Thai ky d6ng tao rift xay tir cuoi Eoxen - Oligocen - Thai ky sau tach gian xay vao Mioeen som din hien 496 Dac aigm trhm tich ting chua cat kgt Miocen duoi mo Su- Tii Oen Tuygn tap bao cao Hoi nghj KHCN "30 nam Dau Viet Nam: Co- hoi moi, thach thuc moi" Hinh 2: Ban dang sau noc tap Bl 497 Dac digm tram tich tang chiia cat kgt Miocen duoi mo Sa Tii Oen 498 TRt1 CDP h a s 1,086 50 1()0 19a 2^ pMfl IlKKI 11050 I I iji^ 15 i - S D - X ( g T ) ^ | - g D ^ > ! 1;aô6 1550 1,25CL IMO ,1,760 2,000 2.0flOL 2^50 2M0 ã tlmô.prôtôl( TMVSSE 2M Tlmô ã / ' JPH '*^|t,ằ-.3 Hinh 3: Mat c^t dja chin qua cac gieng khoan SD-2X-ST, SD-IX, SD-3X, SD-4X _2M Tuygn tap bao cao Hoi nghj KHCN "30 nam Phu Viet Nam: Co' hoi moi, thach thuc moi" DAC TRU^NG T A N G CHLTA 499 Bl Ting B1 la ting chira nim he tang Bach H6 tu6i Miocen som Noc ciia lap cat Bl xuit hien a sau 1650m (Hinh 2) g6m nhieu via cat m6ng, co t6ng chieu day cac via cat tir 15m - 26,9m (o gilng khoan 15-1-SD-IX), dugc xac djnh la dai chira dau (Hinh 3) Cac tap da chua gIm chii yeu cat ket xen it hot ket va set ket Chat lugng tang chiia rat t6t, r6ng cao (do r6ng tir 17 - 31%), va tham t6t (do tham 2,2 - 3,0D) Chung dugc hinh vao sau qua trinh tach gian va dac trung boi m6i truang tram lich tii' s6ng h6 chau th6 a phan Tay Nam den bien ven bo o phan D6ng Bae va dugc phii chom len loan bg boi tang set bien tien Rotalia Trong tang Bl g6m c6 cac tap chira ehinh la B9, BIO Tap da chu'a B9 g6m mgt s6 via cat ket mong xen ke voi bgt ket va set ket Cac via cat ket bai s6ng va long s6ng phan b6 dien hep va chieu day thay d6i nhieu Tap da chira B9 gap o gieng khoan I5-1-SD-3X (khoang sau 1750 - 1760m), a gilng khoan 15-1-SD-IX (khoang sau 1720 - 1730m), va gilng khoan 15-1-SD-4X (khoang sau 1752 - 1765m) Tap chira cat ket BIO phat hien gieng khoan 15-1-SD-IX khoang sau 1745 - 1765m, o gieng 15-1-SD-3X khoang sau 1762 - 1778m va o gilng 15-1SD-4X khoang sau 1778 - 1792m Tap phan b6 rong nhat cac mo, t6n tai a dang mgt dai nang cau tao theo huong D6ng Bae - Tay Nam tir kinh 108''26'E toi 108^22'E Noc tap chira BIO a chieu sau 1710m Cae dirt gay tang chua co huong Tay Bae - D6ng Nam thuong keo dai kh6ng qua 3000m Hoat dgng diit gay giam manh ve s6 lugng va bien chinh a tap chan ben tren tap set Rotalia DAC DIEM THACH HOC CUA T A N G B, HE T A N G BACH HO - MIOCEN SOM He tang Bach H6 g6m cat ket xen ke hot ket va set ket Thanh phan cat ket phan Ion la acko theo phan loai R.L Folk, 1974 (Hinh 4) Q = Thach anh A ACKO F = Penpat • Miu khoan SD-3X • Miu khoan SD-lX • Mau khoan SD-4X A LrrHAKENJT R = Manh da Hinh 4: Bieu phan loai di cat kit Miocen du-oi (theo R.L Folk, 1974) 500 Dac digm tram tich tSng chua cat ket Miocen duoi mo Su Tu Oen Thanh phin hat vun gIm 29,0 - 47,4% thach anh 17,6 - 24.0% fenspat kali, 1.8 - 8.2% plagiocla, 3,4 - 24,8% manh da granitoit, 1,4 - 5,2% manh da vi quaczit 0.4 - 2,7% mica 2.4 - 8,0% cac manh da phun trao, da silic va da phien Vat chit vun lip diy 6,0 - 11% khoang vat set Xi mang g6m khoang vat set: - 5% carbonat; - 10,5% anhydrit va vet glauconit Ngu6n cung cap vat lieu ciia tang phia Tay - Tay Bae la mien co kh6i granitoid c6 Cat kit hat tir nho den th6 (d6i cat chua san) vai kich thuoc trung binh (Md) tii' 0,16mm din 3,5mm Do lua chgn kem den rat kem So = 2,6 - 4.3 gieng khoan 15-1-SD4X, cat hat nho din trung kich thuoc hat trung binh tir 0,1 - 0.6mm, lira chgn trung binh den ill, So = 1,3 - 1,9 Hat vun phin Ion tir ban goc canh den ban tron canh (Anh ^ 4) 250|Lim 2nicon Anh I: Cdt kit hgt nhd din trung, lua chgn tdt Hgt bdn gdc cgnh den bdn trdn canh Thdnh phdn vun Id thgch anh (Q), octoela (O), mdnh dd granit (G), mdnh da silic (C), xi mdng thgch anh thir sinh (q) vd khodng vgt set (mui tin) Do sdu 1769, Om - thudc tap BIO- GK SD-3X 250|im nicon Anh 2: Thdnh phan hgt vun giong dnh Do rdng nguyin sinh giira cdc hgt phdn bd khdng diu Do sdu 1769,0m - Thude tap BIO - GK SD-3X Tuygn tap bao cao Hoi nghj KHCN "30 nam Phu Viet Nam: Co' hoi moi, thach thuc moi" 500|im 501 2nicon Anh 3: Cdt kit hgt trung din thd, lua chgn trung blnh din kem Hgt vun ehu yiu tir bdn gdc cgnh din bdn trdn cgnh Thdnh phdn vun Id thgch anh (Q), octoela (O), mdnh da granit (G), vd mdnh phun trdo (V) Do sdu 1914,2m - Thudc tdngBl - GK SD-3X Anh 4: Hgt thd din rdt thd, lua chon rdt kem Thdnh phdn vun Id thgch anh (Q), octoela (O), mdnh da grand (G), set kaolinit lap day (mui tin) vd xi mdng canxit (C) rdi rac Do sdu 2109,2m - thudc BI- GK SD-3X Moi truang tram tich: Cat kel Irong he ling Bach H6 chiim chii ylu xen vai set kit va bgi ket tao nhjp din len tren (trong phu ting Bach H6 duai co nhip phu tang Bach H6 tren co nhip) Tap set kit tren ciing co mau luc din mau xam xanh chira glauconit va rotalia Chiing dugc tao m6i truang biin khoi, img vai giai doan bien lien cue dai (Hinh 5) Tap cat kit nim sat vai tap set rotalia va la phin duai ciia nhip tren ciing Tu thay rang tap da chira diu B9, BIO dugc tao moi truong ven bien tiep can voi d6ng bang chau ihl D6 khoang hoa nuoc via liy lir llna chira "B," bina 40.000ppm 502 Oae diem tram tich tang chiia cat k i t Miocen du6im6^u^J^i^_5£I!- Tap CbKii MB rhmj dii be Bae 3KDg tthoan Giitiji kimwi (in> CiiKa^ tiinan 2.\ ^ ,, ki i A - 500 NocBI NocBl i-iMt.:fi-sraxj.> '3 za; - B, • ;' -1000 X'^ -' N('ic I E NocK! - B .ã,'"- ã "L?: j?iĐJ;;?*^?::-;;-: 1500 c >: c SSBiSp^ ;-v; '>,' -y-^"'- .< NocBI ' ' > ^ ' ' " ' • • ' • • • " • ' • • •5 -a x; 1- ;»oo • N(5cBl B, -Cl , ^ N « C c C , , ,, NocC -TT^!:rc—r ^^^ilr^^^i^ S.^.>ScD ; • - - _5 D o _ - ; ~^JJocD ' M'T'' « B s ZfiX) \ ^ ^ K Noel • > ; • • > > '.-." \ff^ '///.' f & o h ) - S ( « d A h i n k f i i < l i a t % t i c ji£ngU>oaB IA-2A-3A ""P"- I DacA,cal:fi(30?^70%) KSa D4 s