Investigation on Water Wetting in Large Diameter Horizontal. and Slightly Inclined Oil-Water Pipe Flows

Transcription

1 Investigatin n Water Wetting in Large Diameter Hrizntal and Slightly Inclined Oil-Water Pipe Flws Xuanping Tang, Francis Ayell, Chng Li, Jiyng Cai" and Srdjan Nesic Institute fr Crrsin and Multiphase Technlgy Ohi University 342 W. State St., Athens, OH U.S.A Fax: cai@bbcat.ent.hi.edu C. Ivan T. Cruz' and Jamal N. Al-Khamis' Saudi Aramc Oil Cmpany Bx 6891 Dhahran, Saudi Arabia Fax: czarivan.cruz@aramc.cm;jamal.khamis@aramc.cm ABSTRACT Internal crrsin in il prductin and transprtatin pipelines is always assciated with the presence f crrsive water, and the likelihd f crrsin generally increases with the vlume fractin f water. When crrsive water wets the pipe internal wall, crrsin is pssible. On the ther hand, crrsin is free nly when water entrainment ccurs. This paper utlines sme results f phase wetting determinatin f mdel il (LVT200) and extra light crude (AXL) il testing series in large diameter hrizntal and slightly inclined pipe flws. In this study, fur main techniques (flw pattern visualizatin, wall cnductance prbes, crrsin mnitring and wall sampling) were used t determine the phase wetting n the internal wall f pipe at varius superficial il & water velcities and pipe inclinatins. TIrree types f phase wettings (stable water wetting, intermittent wetting and stable il wetting) were bserved. Based n the verlapping infrmatin frm these techniques, cmprehensive phase wetting maps fr mdel il and AXL crude il tests were btained at different pipe inclinatins. It was fund that the il type has a significant effect n the transitin frm stable il wetting t intermittent wetting. Stable il wetting ccurs at much lwer superficial il

2 velcity fr AXL il than that fr LVT200 il. It is clear that pipe inclinatin als has a big effect n this transitin line. In the upward inclined flw, increasing pipe inclinatin leads t an ccurrence f stable il wetting at lwer superficial il velcity. This trend is als true with decreasing the pipe inclinatin in the dwnward inclined flw. Based n the results f crrsin mnitring, it was fund that a cmplete absence f crrsin ccurs nly when il wetting exists. Crrsin exists when stable water and intermittent wettings prevail. Keywrds: internal crrsin, il-water tw-phase flw, crude il, phase wetting determinatin 1. INTRODUCTION Crude il and grund water with cmplex water chemistry are transprted simultaneusly in the il pipelines. Different il-water flw patterns, which lead t different distributins f il and water phases n the crss-sectin f pipe, culd exist. At lw il-water mixture velcity, water phase culd flw as a water layer n the bttm f the pipe. Hwever, at high il velcity, water phase culd be entrained by the flwing il phase and flws as drplets in the cntinuum f the il phase. Since sme crrsive gases, such as C02 and H2S, disslve in the water phase and water is crrsive. In the fields, mst f crude il transprt pipelines are made f carbn steel. Once crrsive water wets the pipe inner wall, crrsin culd exist in these transprtatin lines. The likelihd f crrsin generally increases with the vlume fractin f water. Of curse, the wetting behavir f water phase and crrsin is affected by ther factrs: the water chemistry, type f il, additives, flw regime, velcity and surface cnditin f pipe wall, etc. Crrsin is absent nly when crude il wets the internal wall f pipeline. Typically, this ccurs nly when water entrainment (il wetting) happens. With increasing water cut and decreasing the il velcity, water drplets interactin each ther and calesce int bigger ne. Gradually bigger drplets will 'breaks' ut, and eventually frms a cntinuus water layer n the bttm f pipe at certain flwing cnditins. Hwever, water wetting is ne f the missing links in ur current understanding f internal crrsin in il and gas industry. In the past, the effect f these parameters has been cnsidered nly in a qualitative sense. N extensive experimental studies n this tpic have been dne. It is a great challenge fr crrsin engineers t determine mre precisely the flw cnditins leading t crrsin and cnversely the cnditins leading t entrainment f the free water layer by the flwing il phase. During last three decades, little experimental and numerical mdeling wrk has been

3 perfrmed. The first simplified water wetting mdel, which was used t predict the critical il velcity needed t sweep ut the settled water in the pipe, was prpsed by Wicks and Fraser! (1975). This mdel was nly based n limited experimental results. It was suitable fr predicting the critical velcity primarily fr very lw water cut situatins. At high water cuts, the mdel significantly underestimated the critical velcity needed fr entrainment. In 1987, L.M. Smith et al. 2 pinted ut that the ability f ils t carry water is up t a 20% water cut, if flwing at velcities larger than 1 mls. C. de Waard and Ltz 3 (1993) argued that the presence f the hydrcarbn phase was accunted thrugh a s-called water-wetting factr. Based n the riginal experiments f Wicks and Fraser! a binary predictin factr was extracted suggesting that il-wetting will ccur nly fr water cuts less than 30% and il velcity larger than 1 mis, when all water can be entrained in the il phase. In anther mdel published the same year (1993), Adams et al. 4 pinted ut that three types f phase wettings culd ccur and estimated that belw 30% water cut the tubing will be il-wet; frm 30-50%, intermittent water wetting ccurs, and ver 50% the tubing is water wet. Obviusly, these are very crude criteria that neglect r versimplify the effects f varying prperties f the il and water phases, the flw regime and the flw gemetry. Furthermre, field experience suggests that in sme cases crrsin was btained at water cuts as lw as 2%, in thers n crrsin was btained fr water cuts larger than 50%. Wu 5 in 1995 mdified the Wicks and Fraser! mdel; hwever n majr advancement was achieved. C. de Waard et al. 6 (2001 and 2003) updated their riginal empirical mdet3 and prpsed a new empirical mdel using an analysis based n the emulsin breakpint apprach. A link between API gravity, emulsin stability and water wetting f steel by an il-water mixture was cnsidered by taking int accunt the changes f interfacial tensins in an il-water-steel system. This was a majr step frward frm the riginal mdel. Hwever, while agreeing reasnably well with the specific pl f field cases used fr its calibratin, this new mdel remains an empirical crrelatin built n limited field data with an uncertain ptential fr extraplatin. Mre imprtantly, this mdel des nt cnsider the effect f pipe diameter, il density, il viscsity and system temperature n the critical velcity f the flwing il phase required fr entrainment. As a part f Ohi University's newly released sftware package MULTICORP V3.0 7, a mechanistic mdel (Cai et al. 8-9 ) f water wetting predictin in ilwater and gasilwater systems is included. The effects f pipe diameter, pipe inclinatin, il density, il viscsity and system temperature n the critical velcity f the flwing il phase required fr entrainment are cnsidered in that mdei 8-9. It shuld be pinted ut that the mdel has nt been verified in the gas-il-water three-phase flw and des nt cnsider the effect f gas, steel surface state, chemical additives and type f crude il n water wetting because f the lack f experimental and field data. Since 2004, a series f cmprehensive experimental studies n water wetting with mdel il and different types f crude ils in large diameter hrizntal and inclined il-water pipe flws have been carried ut in the Institute fr Crrsin and

4 Multiphase Technlgy f Ohi University. Fur very different techniques, wall cnductance prbes, wall sampling, flw pattern visualizatin and crrsin mnitring, have been used t determine the wetting behavir. In a recent paper published by Cai et al lo, the authrs pinted ut that the mdel (Cai et al s - 9, 2004) was in gd agreement with experimental results btained with the mdel il. Hwever, this mdel has nt been verified by the results btained under crude il-water flw cnditins. In rder t validate and imprve the mdel (Cai et al s - 9, 2004) with mre experimental data btained frm large diameter pipelines, cmprehensive experiments are carried ut t determine the phase wetting in this study with fur main techniques (wall cnductance prbes, crrsin mnitring, wall sampling and flw pattern visualizatin) at different superficial il and water velcities in large diameter hrizntal and slightly inclined mdel ivcrude il-water pipe flws. Based n experimental results, cmprehensive phase wetting maps fr different ils at different pipe inclinatins will be built. These phase wetting maps can be used as useful references and guidelines fr crrsin engineers and pipeline peratrs t manipulate il and gas systems under crrsin free cnditins. 2. EXPERIMENTAL SETUP The experiments have been cnducted at the Institute fr Crrsin and Multiphase Technlgy at Ohi University in a 200' lng, 4" ill multiphase flw lp munted n a fully inclinable rig, which is specially designed t investigate crrsin and multiphase flw under realistic flw cnditins fund in the field. FIGURE I shws the schematic f the fully inclinable multiphase flw rig. The same experimental setup was used fr experiments described previusly by Cai et al. 10. A brief descriptin fr the experimental set-up is intrduced in the fllwing sectins. Oil is stred in a 1.2 m 3 stainless steel strage tanle The tank is equipped with tw 1 kw heaters and stainless steel cling cils t maintain a cnstant temperature. Water with 1% wt. NaCI is stred in a 1.2 m 3 stainless steel strage tank. Oil is pumped thrugh the system using a Myn pump equipped with a variable speed mtr. The il flw rate is precisely cntrlled within a range f 0.5 t 3 mls with a cmbinatin f the variable mtr speed and a bypass system. One f the tw Myn pumps (with small and high flw rate) are used t pump water thrugh the system frm the water strage tank. Oil and water mix in the static T-mixer and then the il-water mixture flws thrugh a 3 m length flexible hse, which allws the inclinatin t be set at any angle fr this fully inclinable rig, and then enters the 10 cm (4 inches) LD., 14 m lng stainless steel pipeline and then flws thrugh a 2 m lng upstream test sectin, where all measurements are carried ut. Since the test sectin is set at 14 m dwnward frm the

5 static T-mixer, the pipe has enugh length fr the develpment f flw structure and fr the effects f pump and valves n flw structure t be elminated. The test sectin is made f carbn steel. A 2 m lng transparent pipe is cnnected t the carbn steel test sectin, which is used t visualize the flw pattern. After the il-water mixture flws thrugh a 180 degree bend, it enters int a 14 m lng stainless steel pipe and anther 2 m lng transparent pipe is cnnected t the stainless steel pipe sectin and the 2 m lng dwnstream test sectin, which is made f carbn steel. After the il-water mixture leaves the dwnstream test sectin, it flws thrugh a 20 m lng 4 inch I.D PVC pipe and enters int the il-water separatr, where the separatin prcess f il and water takes place. After il and water separate, water accumulates in the water bt and it flws thrugh the valve at the bttm f water bt back t the water strage tank. Separated il phase flws thrugh the il utlet pipe back t the il strage tank fr further circulatin. It shuld be pinted ut that all the cmpnents, except the test sectins in this multiphase flw rig, are made f crrsin-free materials (either stainless steel r PVC). Since crrsin measurement and mnitring is carried ut in this study, in rder t minimize the effect f xygen n crrsin prcess, the whle flw system is de-xygenated using pure carbn dixide (C0 2 ) befre water wetting experiments are started. The xygen cncentratin in the system is always cntrlled belw 25 ppb, which is allwable fr crrsin measurements under this envirnment. As abvementined, tw sectins are used in current study. FIGURE 2 shws the schematic f the 2 m lng carbn steel test sectin. During the experiments, the test sectin can be crrded which leads t an increase f Fe 2 + in cncentratin in the water phase. Five rws f wall cnductance prbes with staggered structure, ne set f high frequency impedance prbes, wall sampling prt and ER prbe hlder are installed and lcated at the dwnstream prtin f test sectin. The test sectin is cnnected with dwnstream and upstream pipe sectins with tw clamp flanges, which allw the test sectin being rtated in any angle. Fur main techniques (flw pattern visualizatin, wall cnductance prbes, crrsin mnitring and wall sampling) were used t determine phase wetting n the internal wall f pipe at different superficial il and water velcities in large diameter il-water hrizntal & inclined flws. All wall cnductance prbes are used t measure the wateril cntent very clse t the surface f the pipe internal wall. FIGURE 3(a) shws the wall cnductance prbes. The prbes are epxy-cated stainless steel pins with 0.45 mm O.D. threaded thrugh a 0.5 mm I.D. hle in the pipe. In the dwnstream test sectin, five staggered rws f 18 prbes (90 prbes) are flush-munted n the bttm half f the pipe wall circumference. Hwever, 5 staggered rws f 32 prbes (ttal 160 prbes) are flush-munted n the whle circumference f pipe inner wall in the upstream test sectin. FIGURE 3 (b) shws the staggered cnfiguratin f wall cnductance prbes.

6 This particular arrangement with a large number f spatially distributed prbes is used t minimize the errrs that plagued such similar effrt in the past such as the effect f a water phase "snaking" arund islated prbes. Als, this redundant cnfiguratin is very useful fr characterizing the 'gray zne' (intermittent wetting) between stable il wetting and stable water wetting and fr eliminating utliers. Visual recrding were dne at the transparent test sectin just dwnstream f the main carbn steel test sectin. Artificial clring f the water was used t enhance the cntrast between il and water phases. The visual technique wrks very well with clear mdel ils and is nt suitable fr the tests with crude ils. A wall sampling methd, which is used t verify and check the results frm the wall cnductance prbes, is used t measure the wateril cntent very clse t the surface f pipe inner wall by extracting the fluid frm the bttm f pipe. A cmbinatin f a very precisely cntrlled needle valve and a slenid valve used t extract the fluid very clse the wall surface thrugh the wall sampling prt is shwn in FIGURE 2. The instrumentatin is carefully calibrated s the prper extractin time and suctin is applied t minimize errneus readings. Since a CO2 saturated wateril mixture is circulated thrugh the flw lp it is straightfrward t cnduct crrsin masurements n mild steel test sectin. The crrsin prcess enables an alternative way t determine water wetting. If water wetting ccurs in a given test, crrsin happens as well. This will manifest itself as a rise in disslved ferrus in (Fe 2 +) cncentratin in the water phase, which can be easily detected by sampling the water and emplying a standard clrimetric technique. An ER prbe munted in the test sectin can als used t mnitr the crrsin rate and indirectly determine the water wetting. It is anticipated that by using at 4 very different techniques fr detectin f water wetting as abvementined, verlapping infrmatin will reinfrce ur cnfidence in the verall results and yield a strnger base fr water wetting mdeling. 3. RESULTS AND DISCUSSIONS In this study, tw main test series f experiments were cnducted by using LVT200 mdevaxl crude il and 1 wt% NaCI brine saturated with CO 2 Different flw cnditins were applied in hrizntal & slightly inclined pipe flws. The mst imprtant parameters and test matrix are shwn in TABLE 1 belw. The prperties f the ils f LVT200 and AXL at 25 C are listed in TABLE 2. It is seen that the prperties faxl crude il are clse t thse f LVT200 mdel il.

7 TABLE 1 Main Test Parameters Oil Phase LVT200 il and AXL crude il Water Phase 1% NaCI slutin Superficial Water Velcity, V sw 0.22 ms Superficial Oil Velcity, V s ms Water Cut, E 020% Hrizntal (fr LVT200 test series) Pipe Inclinatin Hrizntal, :t2 and :t5 (fr AXL test series) Pipe Diameter 4" System Temperature 25 C System Pressure 0.13 MPa TABLE 2 Prperties f Oils at 25 C Prperties Density, (kgm 3 ) Viscsity, (cp) Surface Tensin, (dynecm) Interfacial Tensin, (dynecm) LVT200 Oil AXL Crude Oil Phase Wetting Maps All the results btained by the methds as abvementined were crss validated. Based n these experimental data, phase wetting maps fr LVT200 il and AXL crude il test series are generated at different pipe inclinatins LVT200 Oil Test Series FIGURE 4 shws the phase wetting map f mixture f LVT200 il and 1% NaCI water in hrizntal pipe flw. It is clear that. three types f phase wettings (stable water, intermittent and stable il wettings) exist. Intermittent wetting is dminant at il-water mixture velcity ranged frm 0.5 ms and 1.5 ms and water cut less than 10%. Water wetting ccurs when water cut is higher than 10% at same il-water mixture velcity range. Hwever, water entrainment (il wetting) ccurs when il-water mixture velcity is higher than 1.5 mls and water cut lwer than 10%. All water phase flws as water drplets in the il phase. Oil and water frm stable water-in-il dispersed flw. At the il-water mixture velcity lwer than 1 mis, increasing water cuts leads t a transitin frm intermittent wetting t stable water wetting since the calescence f water drplets is getting strnger and leads

8 t the frmatin f bigger water drplets. On the ther side, il phase culd nt affrd enugh energy t break up these bigger drplets. Mre big water drplets drp ut f il phase and gradually frm a stable water layer at the bttm f pipe. Hwever, at the il-water mixture velcity higher than 1.5 mis, increasing water cut leads t a transitin frm stable il wetting t intermittent wetting. Since the il-water turbulence is very high and prevents the calescence f small water drplets, it is very difficult t frm a stable water wetting at this il-water mixture velcity range since the il-water turbulence is very high and prevents the calescence f small water drplets AXL Crude Oil Test Series FIGURE 5 shws the phase wetting maps fr AXL il tests in hrizntal pipe flws. It is seen that three types f phase wetting (stable water, intermittent and stable il wettings) are clearly bserved. Water wetting prevails at il-water mixture velcity lwer than 1 mls and water cut higher than 5%. It disappears when the il-water mixture velcity is higher than 1 mls. When the il-water mixture velcity is higher than 1.0 mls and water cut lwer than 10%, il wetting is dminant. Hwever, il wetting still ccurs at il-water mixture velcity 0.7 mls with water cut arund 3%. Within current test cnditins, intermittent wetting nly exists in a narrw area. Increasing pipe inclinatin up t 2 degrees leads t an appearance f stable il wetting ccurring at much lwer il-water mixture velcity (FIGURE 6), cmpared t that fr hrizntal flw. It even ccurs at il-water mixture velcity f 0.6 mls and water cut arund 2%. It is clear that il wetting prevails at il-water mixture velcity higher than 1 mls and water cut up t 15%. Stable water wetting disappears at water cut lwer than 20% within current test il-water mixture velcity. Intermittent wetting dminates at il-water mixture velcity lwer than 1 mls. In 5 upward inclined flw (FIGURE 7), il wetting dminates at water cut lwer than 15% and il-water mixture velcity f 1.5 mls. Cmpared t the phase wetting map at pipe inclinatin f 2 degree, the stable il wetting area at pipe inclinatin f 5 degree is much bigger. Frm the phase wetting maps at pipe inclinatins f 2 and 5, it is seen that stable water wetting culd nt survive in the upward inclined pipe flw. It can be argued that water layer culd nt frm because f the effect f gravity frce. The phase wetting maps at pipe inclinatins f _2 and _5 are shwn in FIGURE 8 and FIGURE 9, respectively. At 2 dwnward inclined flw, stable water wetting ccurs at il-water mixture velcities ranged frm 0.6 mls t 0.8 mls and water cut higher than 15%. Within this il-water mixture velcity range, decreasing the pipe inclinatin t _5 leads t ccurrence f stable water wetting at water cut higher than 20%. Frm bth phase wetting maps, it is seen that stable water wetting disappears when the mixture velcity is higher than 0.8 mls. On the

9 ther side, it is bvius that il wetting prevails at the mixture velcity higher than 1 ms and water cut up t 20%. The area fr intermittent wetting is much smaller than that fr il wetting. 3.2 Transitin Line between Stable Oil Wetting and Intermittent Wetting Based n the experimental results, it was fund that crrsin is eliminated nly when il wetting ccurs. Frm the crrsin pint f view, it is very imprtant fr crrsin engineers t determine the flwing cnditins, which lead t a transitin frm stable il wetting t intermittent wetting. In rder t clearly find ut this transitin, the phase wetting map as abvementined are re-pltted (FIGURE 10 - FIGURE 12) with respect t the relatinship between superficial il velcity and superficial water velcity. The slid line in these plts presents the transitin between stable il wetting and intermittent wetting. The effects f il type and pipe inclinatin n this transitin line are discussed in the fllwing sectins Effect f Oil Type FIGURE 15 shws the effect f il types n the transitin line frm stable il wetting t intermittent ne. It is clear that the il type has a significant effect n this transitin line. Within current test cnditins, it is seen that stable il wetting nly ccurs at il-water mixture velcity higher than 1.5 ms in LVT200 il-water hrizntal flw. Hwever, stable il wetting exists at il-water mixture velcity lwer than 1 ms fr AXL crude il tests. The stable il wetting area fr AXL il is much bigger than that fr LVT200 il test. Althugh mst f the physical prperties faxl il are very clse t thse f LVT200 il, the AXL il-water interfacial tensin is much lwer than that f LVT il and the chemical prperties faxl il are much cmplex than thse f mdel il, which lead t a big difference n phase wetting behavir. Mre experimental wrk is needed t investigate the effects f chemical prperties f crude il and il-water interfacial tensin n wetting behavir Effect f Pipe Inclinatin The phase wetting maps at pipe inclinatins f 0, +2 and +5 are shwn in FIGURE It is seen that the slid line (transitin frm stable il wetting t intermittent wetting) shifts lwer superficial il velcity with increasing the pipe inclinatin. At the same superficial water velcity, il wetting ccurs at lwer superficial il velcity with increasing the inclinatin. In the upward inclined flw, water phase has the trend t flw back and accumulate because f the effect f gravity frce. The cmpnent f the gravity frce f the il-water mixture ppsite t the flw directin increases with the increasing f the inclinatin, which will be beneficial t the back mixing f the water and il and cnsequently helps t frm il wetting.

10 The phase wetting maps at pipe inclinatins f _2 and _5 are shwn in FIGURE 13 and FIGURE 14. Cmpared t the phase wetting map at pipe inclinatin f 0, it is clear that the transitin line mves t the lwer superficial il velcity with decreasing f the inclinatin. It is easier t frm il wetting at inclined pipe flws. In the dwnward inclined flw, water phase mves faster that in the hrizntal flw at same flwing cnditins. The il-water mixing n the il-water interface in the dwnward inclined directin is strnger than that in the hrizntal rientatin. Mre water is entrained int il phase, which leads t il wetting ccurring at lwer superficial il velcity. The effect f pipe inclinatin n the transitin line fr the pipe inclinatins as abvementined is shwn in FIGURE 16. It is seen that pipe inclinatin has a big effect n the transitin line between il and intermittent wettings. Als, it can be fund that this effect is strnger in upward inclined flw than that in the dwnward inclined flw. 4. CONCLUSIONS Fur main techniques (flw pattern visualizatin, wall cnductance prbes, wall sampling and Fe 2 + cncentratin mnitring) are used t detect phase wetting at different superficial il and water velcities in large diameter hrizntal LVT200 il-water pipe flws and AXL il-water pipe flws at different inclinatins. Accrding t experimental results, the fllwing main pints can be cncluded: Extensive phase wetting maps fr a mdel il and AXL crude il were built based n the verlapping infrmatin btained frm these techniques. Three types f phase wettings (stable water wetting, intermittent stable il wetting) were determined. wetting and The il wetting area n the AXL crude il's phase map is much wider than that n the mdel il. The il type has a significant effect n the wetting behavir. Increasing the pipe inclinatin leads t a lwer superficial il velcity that leads t il wetting. ACKNOWLEDGEMENT Financial supprt frm Saudi Aramc C. fr Institute fr Crrsin and Multiphase Technlgy f Ohi University is gratefully acknwledged.

11 REFERENCES 1 Wicks, M., and Fraser, J.P., "Entrainment f Water by Flwing Oil", Materials Perfrmance, May 1975, pp L.M.Srnith, M.J.J. Simn Thmas and C. de Waard, "Cntrlling Factrs in the Rate f CO 2 Crrsin", UK. Crr.'87 Brightn, Oct., C. de Waard and U. Ltz, "Predictin f CO 2 Crrsin f Carbn Steel", Crrsin93, paper n. 69, (Hustn, TX: NACE Internatinal, 1993). 4 C. D. Adams, J. D. Garber, F. H. Walters, C. Singh, "Verificatin f Cmputer Mdeled Tubing Life Predictins by Field Data", Crrsin93, paper n. 82, (Hustn, TX: NACE Internatinal, 1993). 5 Wu, Y., "Entrainment Methd Enhanced t Accunt fr Oil's Water Cntent", Oil & Gas Technlgy, Aug. 28,1995, pp C.de Waard, L.Srnith and B.D. Craig, "The Influent f Crude Oil n Well Tubing Crrsin Rates", EUROCORR S. Nesic, Jiyng Cai, Shihuai Wang, Ying Xia and Dng Liu, Ohi University Multiphase Flw and Crrsin Predictin Sftware Package MULTICORP V3.0, Ohi University(2004). 8 Jiyng Cai, Srdjan Nesic and Crnelis de Waard, "Mdeling f Water Wetting in Oil-Water Pipe Flw", NACE 2004, Paper NO.04663, pp. 1-19, Srdjan Nesic, Jiyng Cai and Kun-Lin Jhn Lee, "A Multiphase Flw and Internal Crrsin Predictin Mdel fr Mild Steel Pipelines", NACE 2005, Paper NO Jiyng Cai, Srdjan Nesic, Chng Li, Xuanping Tang, Francis Ayell, C. Ivan T. Cruz and Jamal N. Kharnis, "Experimental Studies f Water Wetting in Large Diameter Hrizntal Oil-Water Pipe Flws", SPE 2005, Paper N PP.

12 Dwnstream Test Sectin Upstream Test Sectin Oil-Water Mixture Wat Main CO, Gas Fl!Cl.?,!Iine L'.)"",' T Main Venting: System. Oil. :. -. lj (. <;;.:. Knek-ut Tank :.) le T Oil Pump Water Pump FIGURE 1 - Schematic f 4-inch LD. fully inclinable multiphase flw lp Flw ' ','.' ',',' ',',' Wall Cnductance Prbes FIGURE 2 - Schematic f test sectin

13 (a) (b) FIGURE 3 - Wall cnductance prbes (a): wall cnductance prbes n the test sectin (b): 5 rws f staggered cnfiguratin f prbe hlders _.- _. - --_._.._ l1li III! -=u = 5.00 III II _---_ -._._-----_._--_._._-- II., III iii GIll l1li l1li II1II? 1I ". <> 0 liii Oil wetting Intermittent Water wetting Oil-Water Mixture Velcity I m1s FIGURE 4 - Phase wetting map fr LVT200 at different il-water mixture velcities and water cuts in the hrizntal il-water tw-phase flw

14 20 11 j 15 <!> + :; u 10 5 II. Oil wetting II III II " <> 1} 4; III Intennittent m":.'%-. II III. Water wettin III 4). '<).. Iii " <e IiIII l!ii <>. <>.. <> IiIII l!ii $. <> <I> iii <> () III <> <> <> 18 <>++ <> <;;, Oil-Water Mixture Velcity I m1s FIGURE 5 - Phase wetting map fr AXL at different il-water mixture velcities and water cuts in the hrizntal il-water tw-phase flw II!-.&_li-fi-If , 15 :; u 10 5., "- Ill! + % ill <I> III iii III O , "'T""---r------r----i Oil-Water Mixture Velcity I m1s FIGURE 6 - Phase wetting map fr AXL at different il-water mixture velcities and water cuts in the 2 degree upward inclined il-water tw-phase flw

15 ::::-: l 15 '=U 10 <; 5 <: <> {> <> <> : I Oil-Water Mixture Velcity ms FIGURE 7 - Phase wetting map fr AXL at different il-water mixture velcities and water cuts in the 5 degree upward inclined il-water tw-phase flw 'ij. - -=u 10-0; 15 III liil 5. #>.$.". <> III.'>O%, + Oil wetting Intennittent Water wettin Oil-Water Mixture Velcity ms FIGURE 8 - Phase wetting map fr AXL at different il-water mixture velcities and water cuts in the 2 degree dwnward inclined il-water tw-phase flw

16 =u 10., -= 5 O DO O. Oil wetting Intermittent Water wetting -l ,----'"t"'""----j Oil-Water Mixture Velcity ms FIGURE 9 - Phase wetting map fr AXL at different il-water mixture velcities and water cuts in the 5 degree dwnward inclined il-water tw-phase flw U 0.15., -= C; 0.1 0e:; l;::., c * Oil wetting Intermittent Water wettin Superficial Oil Velcity ms FIGURE 10 - Phase wetting map fr AXL at different superficial il and water velcities in the hrizntal il-water tw-phase flw

17 % 5. (> Q 0; 0.15 ;;> -;., -; 0.1 'y If: C = en 0.05 '" 4;"> <> Superficial Oil Velcity ms FIGURE 11 - Phase wetting map fr AXL at different superficial il and water velcities in the 2 degree upward inclined il-water tw-phase flw Q 0; 0.15 ;;> -; -; 0.1 'y I,::. C = 0.2." (> en 0.05 * Superficial Oil Velcity ms FIGURE 12 - Phase wetting map fr AXL at different superficial il and water velcities in the 5 degree upward inclined il-water tw-phase flw

18 = -; 0.1 '0 l;:::: C Jl 0.05,', Oil wetting Intermittent Water wetting Superficial Oil Velcity ms FIGURE 13 - Phase wetting map fr AXL at different superficial il and water velcities in the 2 degree dwnward inclined il-water tw-phase flw e» ' = -; 0.1 '0 l;:::: C = rj.j 0.05 Oil wetting Intermittent Water wettin Superficial Oil Velcity mls FIGURE 14 - Phase wetting map fr AXL at different superficial il and water velcities in the 5 degree dwnward inclined il-water tw-phase flw

19 0.25 '" 0.2 e :! '" ; 0.1 0;:; If c. = '" 0.05 r Transitin line fr AXLil \ Transitin line fr LVT2000il Oil Wetting Superficial Oil Velcity I m1s FIGURE 15 - Effect f il type n the transitin line frm il wetting t intermittent wetting in the hrizntal pipe flw '----n! I! i I! :! '" -; 0.1.;:; If c. = '" I II ',: 1.( Intermittent '!.! I! -0 i I! -2 2, I 1 "Ij II-! I. :"! i t. :L f Jlj _50 Superficial Oil Wetting Oil Velcity I m1s FIGURE 16 - Effect f pipe inclinatin n the transitin frm il wetting t intermittent wetting fr AXL crude il tests