Buoyancy Driven Motion of Crude Oil Droplet within Aqueous Solutions

Transcription

1 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: 3 12 Buoyny Driven Motion of Crude Oil Droplet within Aqueous Solutions Eis AlMtroushi * nd Mmdouh T. Ghnnm Deprtment of Chemil nd Petroleum Engineering, United Ar Emirtes University, Al-Ain, P.O , United Ar Emirtes Astrt The flow ehvior of the rude oil droplet motion within different queous solutions ws studied in terms of severl prmeters. These prmeters re the effet of surfe tive mteril, slt onentrtion, nd polymer onentrtion. The rude oil droplet motion under low Reynolds numer ws investigted in terms of rising veloity, stedy shpes, nd dimensionless geometri prmeters. Different Newtonin nd Non-Newtonin queous solutions were used s ontinuous phse. The droplets motion due to uoyny effets ws exmined in pillry tue positioned vertilly. The moility of the rude oil droplet nd the stedy shpe deformtion re influened y the presene of the surftnt whih, in turn, ffets surfe tension of the droplets. Presene of slt in the ontinuous phse lso ffets the rude oil droplet shpe. Keywords: droplet motion; surftnt; non-newtonin fluids, rude oil, uoyny effet. Introdution The droplet motion of one immisile fluid within ontinuum phse of nother fluid is of gret importne in severl industril nd tehnologil pplitions suh s extrtion of liquid liquid mixture, rekup of emulsions, pipeline trnsporttion of liquid liquid mixture, nd in the oil industry where oil nd wter re often produed nd trnsported together. The knowledge of the flow motion ehvior of the rude oil droplet within immisile queous solution is essentil for the trnsported industril proesses s in mss, het, nd momentum trnsfer. The intertion etween the dispersed nd ontinuous phses plys n importnt role in the droplet flow ehvior hrteristis. The fores reted from the ontinuous phse due to the motion of oil droplet tend to deform the oil droplet, however, the interfil tension nd visosity of the oil droplet ounterts the externl effet nd tends to stilize it. 1 The investigtion of drops nd ules motion through Newtonin fluids hs een found in severl experimentl nd theoretil studies. Tylor 2-3 ws one of the first to study the drop deformtions through the investigtion of fluid visosity ontining smll drops of nother fluid. Koh nd Lel 4-5 rried out n experimentl investigtion on the stility of visous drops through quiesent fluid. They found tht single drop would not regin spheril shpe if the initil deformtion ws suffiiently lrge. Arivos 6 studied the rekup of smll droplets in sher flow environment, nd he reported tht the droplet rekup will our t ritil vlue of pillry numer whih depends upon the physil properties nd the imposed fluid flow. Stone nd Lel 7 investigted the relxtion nd rekup of n initilly extended droplet in quiesent fluid. The droplet motion within the surrounding fluid retes stremlines whih diverge from the xis of symmetry on the upfront side nd onverge on the triling side. This ehvior will fltten the leding droplet nd use the triling droplet to streth. 8 Numeril simultion using three dimensionl oundry integrl method of lrger droplet moving pst smller one whih eomes strethed nd finlly reks up or eomes entrined nd finlly olesent hs een investigted Brton et l. 13 studied the liquid droplet migrtion in vertil temperture grdient. This droplet migrtion n e ttriuted to the effet of temperture to lower the interfil tension. Therefore, the liquid droplet will move towrd wrmer regions, whih is lled thermo-pillry migrtion. H et l. 14 investigted the effet of nonioni surftnt on the deformtion nd rekup of liquid droplet in n eletri field. It is reported tht the nonioni surftnt ffets the degree of deformtion nd the modes of rekup through the Mrngoni flow resulting from the non-uniform distriution on the droplet interfe. Olriht nd Kung 15 studied the deformtion nd rekup of liquid droplets in low Reynolds numer flow through stright irulr pillry tue for pillry numer rnge of.5-1. nd for three order of mgnitude of visosity rtio. If the visosity rtio is smll, n indenttion in the droplet triling side will grow nd entrin the ontinuous phse inside the droplet oundries. However, the droplet strethes long the tue xis until it reks if the visosity rtio rehes order of 1.. Ho nd Lel 16, Olriht nd Lel 17, nd Borhn nd Pllinti 18 studied experimentlly the reep motion of smll immisile droplets through irulr tue. Their experimentl dt for droplet speeds re over predited y the nlysis of Mrtinez nd Udell. 19 This disrepny n e referred to the presene of surftnt in the

2 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: 3 13 Imge nlysis experiments (AlMtroushi nd Borhn, 2 Borhn nd Mo, 21 Johnson nd Borhn 22 ). The ojetive of the urrent investigtion is to study experimentlly the rude oil droplets stedy motion nd their deformtion within different queous solutions. This investigtion employed low visosity rude oil for liquid droplets with different dimeters. Severl queous solutions will e used s ontinuous phse suh s glyerol, Triton X- 1, NCl, nd Aloflood polymers of AF1235 nd AF1285. Experimentl Work Light soure Cmer Fig. 1. Shemti illustrtion of the experimentl setup. Fluid drop Injeting syringe Experimentl setup is designed to study the stedy motion hrteristis of the rude oil droplet flowing through different queous solutions of Newtonin nd non-newtonin ehvior. A shemti digrm of the experimentl setup is shown in Figure 1. The experimentl system onsists of n outer retngulr tue with se dimensions of 1 x 1 m with 1 m height of Plexigls mteril. An inner irulr tue is mde of glss with n outside dimeter of 8 m nd 12 m height. The nnulr spe etween the inner glss tue nd the outer retngulr Plexigls tue ws filled with sodium iodide solution. In order to minimize the optil distortions due to the light refrtions, the refrtive index of the sodium iodide solution ws mthed with tht of the glss tue. A rude oil droplet of ontrolled volume is injeted through mirometer syringe fitted t the enter line of the ottom setion of the inner glss tue. A wide rnge, 5-7 µl, of rude oil droplet volume ws overed in this study. Crude oil from Bu-Hs oil field-united Ar Emirtes is employed throughout this investigtion. The rude oil ontins.42 wt % nd 1.33 wt % sphltene nd sulphur, respetively. The dynmi visosity nd density of the rude oil t 25 o C re 4.79 mps nd 827 kg / m 3, respetively. The pprent visosity of rude oil ws investigted versus sher rte over the rnge of.1-1, s -1 to study the flow ehvior. Crude oil ppers to exhiit Newtonin ehvior with onstnt visosity of 4.79 mps t 25 o C. The inner tue ws filled with different queous solutions to the height of 8 m. Tle 1 Tle 1. Physil Properties of Exmined Aqueous Solutions Aqueous Solution Density kg / m 3 Interfil Tension mn / m Visosity mp.s m n 1% glyerin % glyerin % glyerin % glyerin % gly.+.5% surf % gly. +.1% surf % NCL-Wter % NCL-Wter % NCL-Wter % NCL-Wter ppm AF ppm AF ppm AF ppm AF shows the physil properties of ll exmined queous solutions. The shpe of the rude oil droplet ws reorded through high-resolution olor video mer from SONY (DCR- PC1E) t vrious height positions. A powerful light soure is employed for the photogrphy reording purposes. All experimentl imges were reorded t room temperture of 25 o C. Imge-pro imge nlysis system softwre ws used to hrterize nd nlyze the rude oil droplet shpe y mesuring the perimeter, mximum xil nd rdil dimensions. The terminl veloity of the rude oil droplet ws estimted y determining the elpsed time required to trvel ertin vertil distne. The terminl veloity ws determined over region wy from the droplet inlet to void the entrne effets. Severl queous solutions were seleted refully to over wide rnge of different physil properties s reported in Tle 1. Pure glyerol from BDH Middle Est L.L.C., United Ar Emirtes ws employed to represent Newtonin ehvior. Six different onentrtions of glyerol solutions were used over the visosity rnge of mp.s to investigte the role of visosity on the rude oil droplet deformtion. Density of ll exmined solutions ws mesured y pynometer, however, Ostwld visometer is employed to mesure Newtonin visosity. Nonioni surftnt of Triton X-1 (iso-otylphenoxypolyethoxy ethnol from BDH Middle Est L.L.C. United Ar Emirtes) in the rnge of -.1 wt % ws used with glyerol solutions to ontrol the interfil tension quite signifintly. The interfil tensions of rude oilqueous solutions were mesured y spinning droplet tensiometer (from Core Lortories In., model 15, Dlls- USA). Brine solutions of -3 wt % NCl onentrtion were exmined s well. To investigte the flow ehvior of rude oil droplet within non-newtonin ehvior solutions, two Aloflood polymers were used. These Aloflood polymers, AF1235 nd AF1285 were otined from Ci Speilty Chemils (Brdford, West Yorks, Englnd). Aloflood polymers re high moleulr weight polyrylmide opolymers supplied in grnulr powder with ulk density of 8 kg / m 3. The intrinsi

3 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: % 9 % 75 % 5 % 25 % U * x Fig. 2. Effet of glyerol onentrtion on the rise veloity of rude oil droplet in systems with Bo= visosities of the two polymers of AF1235 nd AF1285 re 12 nd 24 respetively. The Aloflood polymers re mnuftured for the enhned oil reovery progrms floods. AF1235 hs good hndling hrteristis to promote etter injetion into low to medium permeility reservoirs (5-5 md), wheres AF1285 is utilized for high permeility reservoirs. Both polymers offer good hndling hrteristis with exellent visosity ltertion power in wter. The rheologil ehvior of the Aloflood queous solutions ws investigted extensively y Ghnnm nd Esmil 23 using RheoStress RS1 from Hke. A wter th ws onneted to the RS1 to ontrol the pplied temperture in the rheometer system. The drive shft of the RS1 ws entered y n ir ering to pply the speified stress on the tested smple without ny frition. The RS1 offers operting modes of ontrolled rte (CR) mode, ontrolled stress (CS) mode, nd osilltion (OSC) mode. One of the importnt speifitions of RS1 is its pility to pply sher stress with extremely low inerti. The operting mode of RS1 n e esily swithed etween CR & CS modes, nd it n lso pply osillting stress nd frequeny sweep. The mesurements dt ws olleted using one-plte sensor. The sensor system onsisted of stinless steel one nd plte with 35 mm dimeter nd 4 o of one ngle. Different polymer onentrtions in the rnge of 1-5 ppm were used. Power lw model suffiiently fits the flow ehvior of AF1235 nd AF1285 solutions for the reported onentrtions. Power lw model n e presented s η = m γ& n-1 [1] where η is visosity in mp.s, γ& is sher rte in s -1, m is onsisteny index in mp.s n, nd n is flow ehvior index. The results of modeling nlysis in terms of m nd n re reported in Tle Fig. 3. Stedy shpes of oil droplets rising in glyerol-wter system; () 1% glyerol with Bo =.13; () 75% glyerol-wter with Bo =.9 nd () 25% glyerol-wter with Bo =.11; where vlue under eh imge indites droplet size rtio. Results nd Disussion In this setion, we present the experimentl results in terms of the effet of surftnt onentrtion, slt onentrtion nd polymer onentrtion on the stedy shpe nd terminl veloity of rude oil droplets. The Reynolds numer sed on the terminl veloity of the oil droplet ws less thn.1 in ll of the experiments reported here. The Bond numer, Bo = ρgr 2 /σ, vried in the rnge.11 Bo.13, where ρ nd σ represent the density differene nd interfil tension etween the two phses, respetively. R is the tue rdius, nd g is the mgnitude of the grvittionl elertion. We first onsider the effet of the queous glyerol onentrtion on the motion of rude oil droplets. The dependene of the dimensionless terminl veloity on droplet size is shown in Figure 2 where the droplet size is mde dimensionless with the tue rdius nd the veloity U is sled with ρgr 2 /µ (µ denotes the visosity of the suspending fluid). The solid, dotted nd dshed urves in this Figure represent the est fits to the experimentl dt in the glyerol-wter system with no ddition of surftnt to the ontinuous phse, tking into ount the ft tht U must vnish s the ule size tends to zero. Typil profiles (in the meridionl plne) of the stedy shpes of rude oil droplet in surftnt free system re shown in Figure 3 for vrious droplet sizes with different glyerolwter systems. Smll droplets hve spheril shpe in ll three glyerol-wter onentrtions shown in Figure 3. The stedy shpe of n oil droplet, in 1% glyerol system, pprohes n ellipsoid s the droplet size inreses, with slight loss of fore nd ft symmetry. Reduing glyerol onentrtion to 75% results in rdil deformtion of lrger oil droplet nd the droplet develops into n olte shpe. As the droplet size inreses in 25% glyerol-wter system, the

4 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: % TX-1.5% TX-1.1% TX U * x Fig. 4. Effet of surftnt onentrtion on the trnsltionl veloity of rude oil droplet in 1% glyerol-wter systems with Bo = droplet shpe eomes olte with flttened front. This shpe hnges from ellipsoid to olte is refleted in oil droplet terminl veloity s shown in Figure 2 where rdil reformtion of the droplet redues the terminl veloity espeilly for lrger droplet. The presenes of surftnt in the 1% glyerol-wter system results in retrding effet on the rude oil droplet trnslting veloity s shown in Figure 4. The trnslting veloity grdully dereses with surftnt onentrtion where the effet of surftnt is more pronouned t lrge vlue of. The ddition of surftnt to the system leds to the development of Mrngoni stresses on the surfe of the rising oil droplet s surftnt monomers diffusing to the oil droplet surfe re swept to the triling end of the oil droplet y surfe flow. These Mrngoni stresses oppose the surfe flow nd retrd the motion of the oil droplet s whole in the sme mnner s tht oserved for the rise of ules in n unounded fluid. Therefore, the redution in the terminl veloity in Figure 4 is due to the development of Mrngoni stresses whih eome more pronouned with inresing surftnt onentrtion. The ddition of surftnt to the 1% glyerol-wter system results in n xil droplets deformtion s the size of the oil droplet inresed ove =.3. This deformtion is shown in Figure 5 for vrious droplet sizes with different surftnt onentrtions. Smll droplets hve spheril shpe in ll surftnt onentrtion systems. As the rude oil droplet size inreses, slight deformtion in the xil diretion strts to pper nd the droplet loses fore nd ft symmetry. However, the presene of surftnt in 75% glyerol-wter system enhnes oil droplet deformtion in the rdil diretion s the size of the oil droplet inresed s illustrted in Figure 5- nd Figure 5-. Fig. 5. Surftnt effet on stedy shpes of oil drops rising in glyerolwter system; () 1% glyerol with.1 TX nd Bo =.12; () 75% glyerol with. TX nd Bo =.9; () 75% glyerol with.5 TX nd Bo =.26; where vlue under eh imge indites drop size rtio. U * x , PPM 1, PPM 2, PPM 3, PPM Fig. 6. Effet of NCl onentrtion on the rise veloity of rude oil droplet in systems with Bo= To investigte slt effet on rude oil droplet deformtion nd motion, different onentrtions of NCl-wter system re used in this study. Figure 6 reflets the effet of slt onentrtion on the rude oil droplet trnslting veloity. The presene of NCl in the system enhnes the rude oil trnslting veloity for ll. This inrese in trnslting veloity n e ttriuted to the effet of slt on the interfil tension etween rude oil-queous phses. The presene of slts in the queous phse, up to 2, ppm, hs strong ility to inrese the umultion of the surfe-tive speies, whih re ville in rude oil, t the rude oil-

5 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: PPM AF PPM AF , PPM AF , PPM AF U * x Fig. 8. Effet of polymer onentrtion on the rise veloity of rude oil droplet in systems with Bo = Fig. 7. Stedy shpes of oil droplets rising in NCl-wter system; () 1, PPM with Bo =.6; () 2, PPM with Bo =.1 nd () 3, PPM with Bo =.11; where vlue under eh imge indites droplet size rtio. queous phse interfe. These tivities redue the interfil tension, from 48 to 27.2 mn/m, nd therey enhne the trnslting veloity. However, further ddition of NCl up to 3, ppm will lower the rude oil trnslting veloity elow the upper limit. The further ddition of NCl eyond the 2, will inrese the repulsive eletrostti doule-lyer fores whih will slightly lower the droplet trnslting veloity. This redution in trnslting veloity leds to the droplet rdil deformtion even t smll droplet size. The rude oil droplet mintins stedy shpe s the droplet pssed through the tue. Figure 7 shows shpe deformtion for NCl-wter system, where inresing rude oil droplet size results in rdil deformtion with redution in the front urvture for lrger droplets. For lrger rude oil droplet size, deformtion ws slightly ffeted y high onentrtion of NCl. Suh deformtions enhned t low NCl onentrtion nd s the NCl onentrtion inresed, the front urvture of the rude oil droplet inresed. A few runs re mde to investigte the polymer onentrtion effet on rude oil droplet trnslting veloity s shown in Figure 8. Inresing the polymer onentrtion refleted in sustntil redution in the terminl veloity for oth polymers used in this study. Menwhile, t low polymer onentrtion of 1ppm, the rude oil droplet veloity shows lmost similr ehvior. A signifint deformtion is oserved for rude oil droplet motion in the polymer solution where the droplet developed triling usp s illustrted in Figure 9. With smll polymer onentrtion, the rude oil droplet develops into olte shpe Fig. 9. Stedy shpes of oil droplets rising in AF1235 polymer system; () 1 PPM with Bo =.23; () 1, PPM with Bo =.13 nd () 5, PPM with Bo =.1 ; where vlue under eh imge indites droplet size rtio. with flttened front. Inresing the polymer onentrtion to 1 ppm, results in usp pperne t the triling end of the droplet. This usp is due to polymer elstiity tht reported y severl studies. With high polymer onentrtion of 5 ppm, this usp disppers nd the rude oil droplet mintins its olte shpe. Ghnnm et l. 24 studied the visoelsti ehvior of the Aloflood polymers. They reported tht the onentrtion of 1 ppm, the Aloflood polymers show visous ehvior for frequeny of less thn.15 s -1, wheres predominntly elsti ehvior will e displyed for frequeny

6 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: 3 17 higher thn.15 s -1. For higher onentrtion, the AF1285 disply only elsti response, wheres AF1235 shows elsti response if the frequeny is higher thn.3 s -1. In order to quntittively hrterize the influene of surftnts on the stedy droplet shpes, deformtion prmeter D= P 2 /4πA is defined, where P nd A represent the perimeter nd re of the deformed droplet profile in the meridionl plne, respetively. This quntity provides mesure of devitions from spheril shpe (whih is hrterized y D=1), nd it is esily otined from digitized imges of rising rude oil droplets using the Imge-Pro imge nlysis softwre. Figure 1 shows the dependene of the deformtion prmeters on the dimensionless droplet size for different surftnt onentrtions. Also Figure 1 displys the geometri prmeters L A nd L R, representing the mximum xil nd rdil dimensions of the stedy rude oil droplet profile reltive to the tue rdius, respetively. The dshed lines in Figure 1 denote the vlues of the geometri prmeters for spheril droplets. Both the rdil nd xil dimensions of the droplet initilly grow linerly s funtion of droplet size with the first shpe trnsition ourring t droplet size of out =.3. D % TX-1.5% TX-1.1% TX-1.% TX-1.5% TX-1.1% TX-1 Conlusions L A The flow ehvior of rude oil droplet motion is studied in the presene of different queous solutions of glyerol, Triton X-1, NCl, Aloflood mterils of AF1235 nd AF1285. The flow ehvior is investigted in terms of rising veloity, stedy shpes, nd dimensionless geometri prmeters. The following onlusions n e mde: 1. For ll exmined queous solutions, the dimensionless terminl veloity inreses signifintly with the dimensionless droplet dimeter. 2. For ll glyerol solutions, smll droplets show spheril shpe. For 1% glyerol, the rude oil droplet pprohes ellipsoidl shpe s the droplet size inreses. Reduing the glyerol onentrtion uses rdil deformtion whih leds to olte shpe with flttened front. 3. The terminl veloity of the rude oil droplet dereses grdully with surftnt onentrtion due to the development of the Mrngoni stresses. 4. The presene of NCl in the queous phse inreses the droplet trnsltion veloity for ll droplet sizes up to onentrtion of 2, ppm. 5. A sustntil redution in the terminl veloity ws reported with polymer onentrtion for oth polymers of AF1235 nd AF The presene of polymer uses signifint deformtion for the rude oil droplet shpe. This deformtion depends upon polymer onentrtion. For the future of the urrent study, it is reommended to investigte the rude oil deformtion nd rising veloity for oth medium nd high visosity rude oil. In ddition it is importnt to inlude the effet of different temperture on the L R % TX-1.5% TX-1.1% TX Fig. 1. Vrition of the dimensionless geometri prmeters with drop size for systems with Bo = : () deformtion prmeter, D; () xil length, L A; () rdil length, L R.

7 Interntionl Journl of Engineering & Tehnology IJET-IJENS Vol: 12 No: 3 18 droplet veloity nd its deformtion. At the end, it is plnned to hve theoretil nd numeril simultion to study the flow ehvior of rude oil droplet deformtion within queous solutions. Aknowledgments Aknowledgment is mde to the United Ar Emirtes University for the finnil support of this reserh. Referenes (1) Angeli, P.; Hewitt, G. Drop Size Distriutions in Horizontl Oil Wter Dispersed Flows. Chem. Eng. Si. 2, 55, (2) Tylor, G. The Visosity of Fluid Contining Smll Drops of nother Fluid. Pro. R. So. London 1932, Ser. A 138, 41. (3) Tylor, G. The Formtion of Emulsions in Definle Fields of Flow. Pro. R. So. London 1934, Ser. A 146, 51. (4) Koh, C.; Lel, L. Stility of Drop Shpes for Trnsltion t Zero Reynolds Numer through Quiesent Fluid. Phys. Fluids A 1989, 1, 139. (5) Koh, C.; Lel, L. An Experimentl Investigtion on the Stility of Visous Drops Trnslting through Quiesent Fluid. Phys. Fluids A 199, 2, 213. (6) Arivos, A. The Brekup of Smll Drops nd Bules in Sher Flows. Ann. N. Y. Ad. Si. 1983, 44, 1. (7) Stone, H.; Lel, L. Relxtion nd Brekup of n Initilly Extended Drop in n Otherwise Quiesent Fluid. J. Fluid Meh. 1998, 198, 399. (8) Mng, M.; Stone, H. Buoyny-Driven Intertions etween Two Deformle Visous Drops. J. Fluid Meh. 1993, 256, 647. (9) Mng, M.; Stone, H. Colletive Hydrodynmis of Deformle Bules in Dilute Low Reynolds Numer Suspensions. J. Fluid Meh. 1995, 3, 231. (1) Zinhenko, A.; Rother, M.; Dvis, R. A Novel Boundry-Integrl Algorithm for Visous Intertions of Deformle Drops. Phys. Fluids 1997, 9, (11) Cristini, V.; Blwzdziewih, J.; Loewenerg, M. Drop Brekup in Threedimensionl Visous Flows. Phys. Fluids 1998, 1, (12) Dvis, R. Buoyny-Driven Visous Intertion of Rising Drop with Smller Triling Drop. Phys. Fluids 1999, 11, 116. (13) Brton, K.; Surmnin, R. The Migrtion of Liquid Drops in Vertil Temperture Grdient. J. Colloid Interfe Si. 1989, 133, 211. (14) H, J.; Yng, S. Effet of Nonioni Surftnt on the Deformtion nd Brekup of Drop in n Eletri Field. J. Colloid Interfe Si. 1998, 26, 195. (15) Olriht, W.; Kung, D. The Deformtion & Brekup of Liquid Drops in Low Reynolds Numer Flow through Cpillry. Phys. Fluids 1992, 4, (16) Ho, B.; Lel, L. The Creeping Motion of Liquid Drops Through Cirulr Tue of Comprle Dimeter. J. Fluid Meh. 1975, 71, 361. (17) Olriht, W.; Lel, L. The Creeping Motion of Liquid Drops through Cirulr Tue of Comprle Dimeter: The Effet of Density Differenes etween the Fluids. J. Fluid Meh. 1982, 115, 187. (18) Borhn, A.; Pllinti, J. Pressure-Driven Motion of Visous Drops through Cylindril Cpillries: Effet of Buoyny. Ind. Eng. Chem. Res. 1998, 37, (19) Mrtinez, M.; Udell, K. Axisymmetri Creeping Motion of Drops through Cirulr Tues. Fluid Meh. 199, 21, 565. (2) AlMtroushi, E.; Borhn, A. Surftnt Effet on the Buoyny-Driven Motion of Bules nd Drops in Tue. Ann. N.Y. Ad. Si. 24, 127, 33. (21) Borhn, A.; Mo, C. Effet of Surftnts on the Motion of Drops through Cirulr Tues. Phys. Fluids A 1992, 4(12), (22) Johnson, R.; Borhn, A. Pressure-Driven Motion of Surftnt-Lden Drops through Cylindril Cpillries: Effet of Surftnt Soluility. J. Colloid Interfe Si. 23, 261, 529. (23) Ghnnm, M.; Esmil, N. Flow Behvior of Enhned Oil Reovery Aloflood Polymers. J. App. Poly. Si. 22, 85, (24) Ghnnm, M.; Esmil, N. Storge nd Loss Moduli of Aloflood Polymers Used in Enhned Oil Reovery Proess. J. Chem. Eng. Jp. 21, 43 (2), 115.