NHNG NG GP MI V MT HC THUT, L LUN CA LUN N TIN STn lun n: NGHIN CU XY DNG H CHT HOT NG B MT BN NHIT NG DNG TRONG CNG NGH TNG CNG THU HI DU TI M BCH H V M RNG Tn chuyn ngnh: Vt liu cao phn t v t hp M s: 62 44 50 10 Tn nghin cu sinh: L TH NH Kho o to: 2007-2010 Chc danh khoa hc, hc v, tn ngi hng dn: PGS.TS. Nguyn Phng Tng Tn c s o to: Vin Khoa hc Vt liu Nhng ng gp mi v mt hc thut, l lun ca lun n: Do c th a cht ca cc m Bch H v ng Nam Rng, cho n nay, cha c sn phm cht hot ng b mt thng mi no ph hp iu kin p sut cao, nhit cao: 140oC i vi mng Bch H, 91oC i vi mng ng Nam Rng, chu c mui v cng cao trong nc bin bm p v h mng nt n, hang hc. Do vy, xy dng thnh cng h cht hot ng b mt bn nhit bm p nhm tng cng thu hi du cc m Bch H v ng Nam Rng l kt qu ca qu trnh ti u ha vic s dng phi hp cc cht hot ng b mt thng mi c la chn trn c s nghin cu cu trc ha hc, cc tnh cht, c trng vt l, ha hc, gi thnh, bng cch pht huy tnh hp tri (ch yu gim sc cng b mt lin din du-nc), gim thiu cc nhc im ca tng cht hot ng b mt khi s dng ring l (gi thnh, tng hp, bn nhit, ha tan, hp ph, ). i vi m Bch H, xy dng c h cht IAMS-M4 gm bn cht hot ng b mt anion h sulfonate: LAS, AOS, ALAX, XSA-1416D vi t l phi trn ti u l 50:200:525:125 (theo khi lng), c kh nng gia tng h s thu hi du ln khong 3,3%, y l mt con s ng khch l. i vi m ng Nam Rng, iu kin tuy t khc nghit hn nhng du li c nht cao hn lm gim hiu qu y du ca nc bm p, xy dng c h cht IAMS-M2-P gm cc cht hot ng b mt

anion h Sulfonate l AOS, h Sulfate l EO, loi nonion l phenol ethoxylate v ph gia l polymer h polyacrylamide vi t l phi trn ti u l 132:395:273:200 (theo khi lng) c kh nng tng h s thu hi du ln n 6,9%. Kt qu t c ny l h qu ca vic tng cng ng thi h s y du (do tc ng hp tri ca cc cht hot ng b mt lm gim dunc xung gi tr nh nht 0,19mN/m) v h s qut du (do polymer AN125 c b sung ng vai tr ph gia ci thin nht ca dung dch bm p). Vic nghin cu thnh cng gii php tng cng thu hi du cho m Bch H v m ng Nam Rng s l tin thun li pht trin ng dng cho cc m khc ti thm lc a Vit Nam v khu vc ln cn trong nhng nm sp ti. Mt khc, qua kho st cc tnh cht c trng nhng hn hp ca ht nano SiO2 kt hp vi h cht hot ng b mt, bc u cho thy tc ng hp tri ca mt s hn hp c tim nng ng dng trong tng cng thu hi du vi kh nng lm gim sc cng b mt lin din gia hai pha du-nc xung t 103 n 104 ln nng tng 1000 ppm. y thc s l nhng h keo a phn tn rt phc tp m n nh ca cc h ny - th hin qua gi tr th zeta - ph thuc vo bn cht cng nh tng tc gia pha phn tn (cc ht nano SiO2, cc phn t cht hot ng b mt) v mi trng phn tn (nc bin). Kt qu nghin cu cho thy in tch b mt m ca ht nano SiO2v h phn tn ca ht nano SiO2 trong nc bin NR rt khng n nh, gn nh ri vo im ng in (IEP). Bn cnh , s bin i th zeta ca cc h phn tn ca ht nano SiO2 theo mui chng t cc tc ng khc nhau ca cc ion ha tr mt v ha tr hai trong cht in li n s p lp in tch kp. Cui cng, s thay i quy trnh chun b cc h phn tn cho thy, th zeta ph thuc rt nhiu vo phng thc phi trn cc ht nano SiO2 vi cc cht HBM v nc bin. T c th xc nh quy trnh chun b cc hn hp hp tri ny nhm ng dng hiu qu trong bm p tng cng thu hi du. Ch k v h tn ca NCS

L Th Nh

NEW CONTRIBUTIONS IN ACADEMIC ASPECT AND ARGUMENTS OF DOCTORAL THESIS

Thesis Title: DESIGN OF THERMOSTABLE SURFACTANT SYSTEMS FOR

ENHANCED OIL RECOVERY USE IN THE WHITE TIGER AND DRAGON BASEMENT RESERVOIR. Name of speciality: Polymeric materials and combinations Code: 62 44 50 10 Name of PhD student: LE THI NHU Y Duration of thesis: 2007-2010 Academic titles, degrees and name of the tutor: Prof. Dr. Nguyen Phuong Tung Name of institution: Institute of Materials Science The new contributions in academic aspect and arguments of thesis: Due to the geological characteristics of the White Tiger (WT) and the Dragon South-East (DSE) basement reservoirs, until now, there have not been any commercial surfactants which are stable to high pressure, high temperature conditions (140oC for WT reservoir, 91oC for DSE reservoir), resistant to salinity as well as high hardness of the injected brine and suitable to the fractured basement. Therefore, design with success of thermostable surfactant systems for enhanced oil recovery (EOR) in WT and DSE reservoir is the result of optimization process in the combination of commercial surfactants selected. That was based on studying the chemical structure, the physical and chemical characteristics, cost, ... by promoting the synergy (decrease the oil-water interfacial tension) and minimizing the disadvantages of each surfactant when used alone (cost, compatibility, thermal stability, solubility, adsorption, ...). For the WT reservoir, IAMS-M4 system was built by the combination of four anionic surfactants of sulfonate group: LAS, AOS, ALAX, XSA-1416D with the optimal weight ratio of 50:200:525:125. It can increase the oil recovery factor to about 3.3%. This is a commendable figure. For the DSE reservoir, the conditions are less severe, but oil has higher viscosity. That causes a decrease in the sweep efficiency of water injection.

Therefore, IAMS-M2-P system built by the combination of anionic surfactants (AOS sulfonate, EO - Sulfate), a nonionic surfactants (phenol ethoxylate) and an additive (AN125 - polyacrylamide) with the optimal weight ratio of 132:395:273:200 can increase the oil recovery factor up to 6,9%. This result was achieved due to the simultaneous enhancement of displacement efficiency (because the synergistic effect of surfactants reduces oil-water interfacial tension (oilwater) to ultra low value, with oilwater 0.19 mN/m) and the sweep efficiency (because AN125 polymer additive improves viscosity of the injection fluid). The successful research on EOR solution applied for the WT and the DSE basement reservoir will be the first favorable impetus to develop applications for the other reservoirs in the continental shelf of Vietnam and the neighboring regions in the coming years. On the other hand, researching on the characteristics of the blends of the polysilicon nanoparticle (PN) with surfactants, initially showed the synergistic effect of some blends with great potential applications in EOR to reduce the interfacial tension between oil and water phases from 103 to 104 times at a concentration of 1000 ppm. These blends are really complex colloidal dispersed systems. Their stability, which is evaluated by zeta potential value, depends on the nature as well as the interactions between the dispersed phase (PN, surfactant molecules) and the dispersion medium (brine). By measuring the zeta potential of the PN suspensions with different solutions, surface charge of PN was obviously confirmed being negative and the PN suspension exhibited the extreme instability in the DSE brine, almost approached the isoelectric point (IEP). Furthermore, the variation of the zeta potential of the PN suspensions with the salinity proved the different compression effects on the double layer of the divalent ions and monovalent ions in the electrolytes. Finally, zeta potential of the PN suspensions were found highly dependent on mixing modes of the PN, the surfactant and the brine. Thence a modified preparation of PN suspensions was proposed to achieve the efficient injection for EOR. Signature and name of PhD student

LE Thi Nhu Y