.1

.

SPE- SPE 22831

Renovate Produced-Water-Treating Facilities To Handle IncreasedWater Cuts

,

D.G.K. Murti* and H.R. A1-Nuaimi, Qatar General Petroleum Corp.

●SPE Member rI

CoPYWIt1sS1,Societyof petroleumEnsmaafsInc.

rhb PSPOIwss WCPSWJ fortwo-tatbn d theS6fhMwd T*hnj~l CMfWMCS@ E~h~t~ oftm *MY ofpmf*~ EIWIWS ~d in Dallas,TX, ~t~r 69, 1~1.

rhispaperwasadactadforprasantatbnbyan SPEProgramComrnittaaMowhs rewewofhformatkmwntainadInan abstrsasubrnmedbytheaumor(s).Contentsofthepaper,aspasintad, haVSnotban reviewadbymaSOCiatYo!PetmkwmEIVMSIWSm SMs@I@ 10-tire bytheauthor(a).ThernalHW = Pfmntti, *S II@n=eriW remrlny@itIon ofthe&oiatYofParfoiaurrrEnWmem.IMoffii. ormembers.paws waled ●t SPEmasfmsswe suWed10WMcstm 10vWWFJYEdrofhlCommmOOSof~ Mtipw*~. P~w*h*dwm~d M-*mti. Mr-my MM*. --d~w~w~01 whew SM by whom the PWH IS Ixawttad. Writs PIAMkaWnSMaMw, SPE,P.O.SoxS3SS3S,Flich#daorr,TX 7S4SS.SSSSU.S.A.Tabx, 730SS9SPEOAL.

k WIEF WSORIP11ON W WERATION

Tha modlf led skirmner tanks have consistent IY Flq. 1 shows a typical process t low diaaram otdemonstrated superior oi 1 recovery character st lcs a tank battery systam. [he tank DatterY cons 1st.s Otcanwared to convent tons I desl gn ~n an 011 fi e Id tdnk gas-oil separators, t ree-water-knocK-out vesse Is,battery system. The madltled tanks have baen in heaters, wash tanks, surge tanks and sKumner tankS.cent inuous service for mare than a years in one of It may a I so have enhanced water t rest Ifw units sucnths oldest oil fields in the Arabian Gulf. The new as tlotatlon units or coalesces, dawnst ream ofdealgn has helped recover sklfrwsd 011 fran a mere 6 sklsmtrer tanks. A tsrlet aescrlotlott ot various eaul -bpd (1.0 m3) to more than 65 bDd (8.7S m3) from Dmant 1s sufrmIar?zed below to have a better under-Draducad water In a tank battery system alOne. Tha standing of assomated Problems+recovery is exoected to unorove by uoto 200 bfId(31.6 m3,) unce skirmner tanks in all tha tank batte- Ues-oil separator : rhis 1s normally tha tlrstries are upgraded to tha new deslqn. ma.lor processing eaulpment WhlCh a wall straarft

Swrcounters after COsIin9 out ot the sub-surtace.wmoummru Separators may he aesl!lned as tWO-DnaSe or trtree

-phase and may b9 either horizontal. VertlCal orThe maser 011 fields throughout the world ara SPherlCal in COnf!gUratl@n.

typically 40 to 50 years old. These fleids have avast ,varlatv of oil, processing eciuifxttant ifWIUdlt’tq Free-water-knook-out (l_WKU) VeSSel : Ine 011-tanks. The tanks ttave many fuilctlons llke washing water mixture after removal ot associated ~as In aof crude oil, sklnsmnq of 011 tram csraduced water separator anters the FWKU vessel. Ihe E’wtii3may be aand providing sufficient storage capacity for sala- harizontal or a vartlcal vessel. Ins FWKLI mav bsblSi oil. tlttea with “coalescer Packs to lmProve 011-Water

separation. 011, WhlCh Is” removed t’rom tiie too Ot’Over tha years, praductlon Patterns hOVe the vessel, was to wash tank: and tne water 1S

changed considerably for many oil fields. This airected to a nearby SkWtffW3r tank. lvplcal allsituation has, ift turn, resulted in drastic chan!?as carrvov9r in water varies trun IWO to NW mmin gas/oil ratios and hjgherl.water cuts. The side tlooo to 3000 cm3/m3), oepsnain~ on manv factors,effect is a gradual detefioration””ln ths efficiency including whather the vessels ara tltted with coale-of field tanks, making tank internal deS19n obsolete seer Packs or nOt. .,in many cases.

wash rahk : The wash tank, as the nema lmPlles.This paper descrlbas various precautions to ba washes CrUd9 oil to rsmave suspended water Particles

taken while uograding the Produced water handl~nr4 frun oil. Crude oil enters the tank through afacilities and modifications to skimmar tank degasser boot. The degasser Oaat removes excess gasinternal design to improve Quality and yield of from the crudst 011. The oil then enters tha tanKrecovered oil. Tns approach autlliwsd In this paper tffrough a scrreader ring lnstelled at an elevatlan O*would be particularly useful for oil fields handling 18” (450 nsrd from tank bottom. “Iha spreader ringlarge Quantities of producad water. allows crude 011 to oarcolate SIOWIY tnrawn a Kd

of water. Oil is taken out tram tha top ot theReferences and illustrations at end Ot DaPer. wash tarw to ed.latent surge tanks. rhs tree water

. --... . . .. J ,.

2. -ATE FROOUCED MATER TREATIMQFACILITIES TO WANGLEIMCREASEOWATERCUW SPE 22831

recovwed in the tank is drained out constantly Therefore, al l!%ting mors rstontion t$me thanthrough a W-l control valve ●nd routed to the required, ts not a good solutlon.sklsuner tank. The lovol control valvo allws ●fixed 10VC1 ofatit 5’-0” (1624 ssn) ofwatcr In the (b) The mre concentrated the dlsperaed phasewash tahk. (larger value of 0), the lesser the rosidenca

time needed to grow a given partlclo 812.. ThatSurfp Tank : These aro final product tanks frcm 1s, coalasconco occurs mm rapidly In a con-

uhero crude oil Is pmped to the roffnery/shiwlng contrated dispersion.taminal. Indlcatlve uf their names, surge tanksprovide sufflciant surge capacity to ensure adequate These are very important conclus~ons and high-hesd and trouble free wmplngof crude oil. A small llght the need to study the entire process train andamount of water settled In the tanks is periodically theequlpment very carefully.removed through semi-autuaetic decanting valves and

,.

routed to sklnmw tanks. SKIMlERTANKOESIi3N ,1-

Sklmer Tank: This tank receives produced water A sklmer tank Is one of the simplest forms offrom FWKGS and little iauantlties from wash and surge water treating equipment. It Is nonnallydeslgnedtanks. Water, after retsntlon In skltmner tanks, la to provide a long retention time, to ailow coale-generally disposed off in a suttable manner. Crude sconce and gravity separation to occur. Sklnmr can011 recovered In skinmmr tank msy be either routed be designed either as a pressure vessel, or ●s ,an”back to wash tank, If SS6W level Is high, or may atmtwherlc tank: the latter destgn Is recommended.be piped to surge tanks, If of salable quality. Atmospheric tanks offer large capacltles” at lower

costs, and are particularly suited for oil fieldsThts oaper describes extensive modifications having htgh water production rates. An atmospheric

done to skfnmsr tanks to fmprove their efficiency. tank Is oft~n the final stage ofwat.r treatment.The wash and surge tank Internals have ●lso beenmodified, as s part of a tank replacement program. The final treatment of Produced water atThe. paper does not cover these details. atmospheric pressure is reccmended to ●nsure lower

quantity of dissolved 011. Hlghsr the treatingCIL-WATER SEPARATI~THEORY pressure, higher would be the mount of dissolved

hydrocarbons. Note that dlasolved hydrocarbons can-The seoeration of 011 and water ahaaes Is one not be rmoved by gravity eepsratlon alone. Env$ron-

of the most consnon but least understood processes In ment Protection Agency (EPA) regulations do nota production faclllty. account separately for the dissolved 011.

“l)~sperslon” and “Coalescence” are frequently An atmospheric sklmer tank Is generally desig-used in describing the separation process. Olsper- ned to give a retenthn time of up to 30 ❑inutes.s~on refers to the process of ● discontinuous phase; It may have coeleecer pecks, or serpentine pathe.g., 011 befng sollt Into small droplets anddistributed throughout the continuous phase, such as

pecks inside the tank or upstrernto Iwrove Itsperfonnsnce,

water *n present case. O+spersion occurs, when alarge amount of energy is put Into the system In a Fig. 2 (right side) shows a conventional designshort period of time. of a typical skimw tank. PrCdUCSd water from FWKO

vessel enters the tank central pen tangentially.Coalescence, the opposite of dlsperslon, is the Water Is distributed radially and moves towards

process of small droplets collld~ng and ccmbin~ng r~ser PIPSS locatsd near the ,tank periphery. ThsIhto larger droplets. Coalescence In water treating central pan gives a vortex motion to water and helpssystem is more time dependent than dispersion. The in ralaasing any excess gas. The oil droplets riseeuuations below help understand the separation upwards counter current to the downward flow oftheory analytically. water. The small amount pf flash gas breaks out of

the solution and rises quickly. The gas bubbles actThe timfto grow a droplet size through coales- simllar to dissolved gas In a flotation unit and

csncs can be estimated by the followlng simplified helpoll droplets float to the surface. Water movesand approximate squation: downward towards riser pipes. Riser Pipes are 10

each, 6“ (150mn) diemter located avenly at thed4 tank periphery. Water so collected at annular

t = chamber is taken out through a trunk located at the(2*@l*K~) . . . . . . . . . . . . . . . . . . . . . . (1) outer periphery of the tank. This water Is directed

towards a disposal well.Unfortunately, the equation cannot be solved

directly, since nefther KS nor s Is known for any Tta central pan has a 4“ (100 M) sludge drainparticular treating system. However, it Is possible connection. It is used for Periodic ”flushlngofto draw certain important conclusions ●s follows: solids buildup In the pen.

(a) After an tnitlal Period ofcoelescence In_ a Ofl collected at top falls beck to 011 colle-treatlng device such as a ski-r tank, the ctlon ctwunber through 3 each rectangular slots cutebllity of addit.tonal retent@n time to cause In the.oil weir. 011 was taken. out through a 4“additional coalescence and captureof smell 011 (100 SUS) oil outlet plpetoadjacent wash tenk fordroplets diminishes rapidly. For ex~le, reprocessing. This operation was periodic due to’doubling the slzeof a sklrnr tank! (i.e., opsrating problems. Any ●xcess 9ss was venteddoubltng the retention titi) wI1l cause onlY through the breather valve located central.lyon the18.9s fncrease In themeximm size droplet. roof of the tank. ,.

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WE 22831 “ D.&K. MU?TI s HMAOR. AL-UUAMI 3

TAMK ~ & OPERATIMQPIWB@fS adjusted to havo a desired oil pad thicknass.It Is nonsally t 1/2” (401MI) higher than the

The convontlonal skimsar tank design though watm walr. A rectangular manway is provldadvary stmpl~, gavo many operating problasa for past at the tank roof too for ease of weir adjust-1S-20 years. Thaproblams rolato to surge In flow mant.caused by operational upsets upstream of the tank.Additionally, the tank was deaigned for automatic (s) A 6“ (150 IIM) WldS SUPPl~ntarY 011 W@lrspill over of sklsssad 011 through the we’irs, It installed behind the sheen baffle. This weirnever gave the Intended performance due to faulty directs the 011 collocted behind the sheendesign ofoll weir andwator rlaar P$pas. A low 2“ baffle to the 011 collection chamber. To(60nws) oil Pad thickness allcwad Intha original slmpllfy the construction, the supplementarydesign was the culprtt. Note that aucha low 011ftlmthlckness nevorstabillzes in any water treat-

oll walr maY be substituted by nipples. Install3 nos. 3/4” (20 nss) nipples at different

ing equipment duetoaurga flow. Only oil/water elevations. Aftarestablishfng tha height ofemulslon can be expected to float at the top oil pad, the required nipple maY be kept opensurface. With a low oil pad thickness, recovered to drain off tha oil to the oil collectionoil cannot be successfully ski@nsd without the chamber. The other two nipples may be plugg8ddanger of water ccmingwlth it, for future use.

As a makeshift arran9&ant, the akinwned oil was (h) The water inlet Pan has hen provided with 16removed manually. The practice was to keep the oil nos. baffles. These bafflas help equal distri-outlet valve closed all the time. This valve was bution of water and reduce short circuiting.OPSnSd periodically WhSI’I&UffiCient oil film Dad, asseen from gauge glass, had davelopad. The practice (i) The inlet water cons hasbaen loweredto allowwas time consuming, tedious and required constant an undlsturbad oil pad thicknessof i2”’. (305operator attention. Sasidas, the oil recovered M) to is” (460 mm). The top elevation ofcould not be directed to final product tanks (aurga cone is about t2” (30S mm) lower than thetanks) as sarm amount of water would always escape oll/watar interface as shown in the. fig. 2with oil. (left aide). This ensures that the oil/water

interface is not disturbed by the inccsning~IFIEDDESIGN influant.

Fig. 2 (left side) shows thamodifted sklnmw (j] Gas equallzer holes 3/4” (20mn) diameter 24tank. fiote the following “major changes in design each drilled throughout the wall aiwwating 011which are detafled In the fig. 3: and clean water chambers. Thts is to release

(a) The existing clean water riser pipes that usedthe gas liberated in ttw’clean water chamber.

to provlda unstable fountain type head, have (k) Few small oil dfoPlets msY finallY ●acaWbeen cut flush with the bottom plate. through the clean water riser Pipaa. These oil

(b) Inlet of clean water riser Pipes that waaparticles can still be captured by Installingcross baffles In the clean water annular

axtending almost up to tank center ?ine has chanhr. The cross baffles would allow waterbeen cut near the tank periphery to reduce to pass below and capture floating otl dropletsshort circuiting and provide longer path. on surface. However, note that there is no

(c) -Number of riser Pipes increased from 10 nos. topractical way to recover the oil collected atcross bhfflas. The oil maY only be removed

20 nos. In practice, as large a number of riser during tank shutdowns.PIPSS as practical should be provided to reduceturbulence and to avoid stagnant areas. (1) Ths open type water outlet trunk has ~nTheoretically, a doubla walled tank allowing a cloaed witha bolted cover. This ensures lesscontinuous peripheral outlet would @ th Ideal amount of dissolved alr in the disposal water.choice, though considered impractical.

(m) PrOPSr lavel gauge glasses have baen installed(d) :Ut;gt (305 rmn) high weir installed at water to monitor thaoil/watew interface, both in the

This wair extands throughout the tank main tank and behind the sheen baffle. Siliconcircum;erance. This weir establishes oil/water coated non-stickin9 We %auiw 91ass tu~s haveinterface in the tank. It is also used to been used.measure tha approximate produced water flowrate in the tank battery system. OESIGM.CALUJLATIONS 1

(e) A 6* (f50m) Witi’” sheen baffle installed at Tha oil and water weirs installed in thethe water outlat. This baffle captures the skinmasr tenk Uae thS dOSi9n concOPts of tYPicalSSS11 oil droplets that misht escape thrw9h 3-phase separator. Thaheight of oil Weir frcm thethe clean watar riser pipes. tank twttcmcontrols theworklng level of fluids in

the tank. The net elevation difference between the(f) Threa each fixed height slots found intha oil oil and water weirs and the specific gravity differ-

weir have been replaced with a single 12” (305 once controls the thickness of oil ~d.mm) long oil weir, This weir is of boltedccnstructia with a seal ing gasket and The required elevation difference between oilinstalledin a 18- (460smd WidSOil collecti~ and water weirs is calculati by thaewation (2).box . The haightof this weir with respect to The equation isdavelcped by Wuatin9 t~ staticfixed circumferential water weir can be heeds at tank bottm as ahcwn in fig. 4.

4. REMOVATE ~ED WATER TREATIHQ FACILITIES TO HANOLE INCREASEDWATER CUTS SPE 22831

[

u~

1the Influent Increases, This phancmenon conforms to

‘W: HO,* l-— + %2 -Ho2#’ . ..(2) the Interpretation of equation no. 1.

h b-LUBI~ ‘

This equation la flow aansltlva, It requiresprior knowledge of producod water and expected oil At tima, on flndlng poor perfonaance ofrecovory rates. However, by chooslngoll walr width sklmar tanks, recmnendations are made to installso that the head over oil ●nd water weirs is seam,

si@ified~~~~~&8can M ne910Cted, T~

additional skiawdng capacity. The fact that thethe factor coalescence in a water troatlng systm is more time

: dependent than the dispersion, leads one to believethat the larger the capacity of a skimaar tank, the

[

b 1bstter would be its separation efficiency. . .

6H=HoiS i-— . . . . . . . . . . . . . . . . . ...(3)

b Here sophisticated suggestions are to upgradeupstream facilities such as retrofitting coalescer

The head over oil and water weir can be DaCkS in FUKO VOSS61S or installation of SP packscalculated using any weir formula such as Bazin’s downstream of FWKO vessels.formula. Velocltyof approach is neglected.

Note that neither of these retrofits or2 additional skiming capacity may do any good to the

Q=— gcx Bz42gx H3/2 . . . . . . . . . . . . ...(4) system. The problem should be studied in more3 detai 1. Study should include the piw sizing and

configurations, all major processing equipment andSimple ccmputer programs in Bsslc language have the skimmer tank internal design itself.

been developed to establish the height of adjustableoil weir with respect to water weir and to calcu- ktany manufacturers of water treating equ~piwmtlate approximate water and oil flow rates. The recmmnand an oil Dad thicknass ranging from i/4” (6Programs are listed In the appendix A and B. m) to 6“(i50 ass). The reason for this criterion is

that the primary purpose of a water treating equiP-OPERATIW RESULTS mant is to remove 011 frcm water and produce water

as clean as possible. the quality and quantity ofRefer to tablo no. 1 which summarizes equipment skisawid oil is considered of secondary importance.

online status and table nos. 2, 3, 4 and 5, whichshow performance of, equipment in various combina- Note that a thin oil pad is not racosmanded duetions, AS tb SP pack was received at SitO WhOfI to reasons explained under operating problems. Usethe modifications to skimer tank were already in a minimum i2’” (30S m) to i8° (460 m) oil pad. Thaprogress, no tests could be conducted with the old design ia slightly comprcsaising on water side.skimnar tank and SP pack in circuit. But, tha nat gain isontheoll side. The oil would

be practically free fran B.S.&W. and maybe shippedIt is observed thattha modified skismar has directly to the customer without any further

shown an oil removal efficiency of upto 91% without processing.the assistance of any enhanced water treating o@Jibmant upstream. The higher the oil concentration, In case of,major breakdmms in a water treatingthe batter the Parfonsence. train, pay more attention to the downstream

equipment first. If any particular equipatant is outA comparison of table 4 and S shows that t

P !lPof service, it would only increase the concentration

pack has added a marginal 134 Pm (134 cm /m ) of oil dispersed phase downstream. As a result, theimprovement in the final effluent quali y$. In terms performance of downstream equiptsent will improveof net recovery, about 6 barrels (1.0 m ) of oil is unexpectedly. Experiment by taking out of stree%added par day by SP pack, Tha payback pOriOd at $26 various water treating equipment individually and in/barrel ($150/m3) crude oil Price, is about 240 various combinations. Naasure the oil concentrationdays. in the influent and the effluent. Results meY be

surprising. The study may Prove some Water traatin9An Important observation is the deterioration equigmant redundant. Such equipment may be rel-

in quality of water aftar cofmnisaioning of new catad elsewhere without any appreciable deterio-gas-oll aaparators. ‘h ‘il carryover ‘as inc!ieasd undgr study

ration in the quality of the effluent in the plantfrom an average of 2000 P* (2jO0 ~ /m ) to

Ppm (4500-5500 cm3/m ). The reason.

4500-6500attributed to this phenomenon is that the new GOSP Check all chokes and control valves in theis oversized to take care of future requiraaIants. circuit. Avoid low openings of ~alves and c@kes.AS a result, -~tha control valve tinatr- of ~p If the iines are oversized resulting in low valveramalns only 15 to” 20S open under cur~nt fl~ openings, raducetha line size gradually and installCondltims. Thie results in large Pressure drew in valves which shall r-in open to the maxiu ●xtenta relatively small distance and formation of smaller under normal operating conditions. Bee fig. 5 fordi~ter oil droplets. This situation should be an explanation. Nota that partially 0P9n ValVaS/avoided hs amallor dropl~ts result in Poor coal- chkes result in unfavorable oil particle size andsconce in downstream equirsaant. distribution as well, for the downstremmuimnt.

The data in ●ach table has bean arranged in The field experience has shcm that a proPerlYrising order of oil concentration in the influant. dasignsd skiur tank is capableof handling lareaFrom all the tables, it’isob-rved t~t th r~val mount o+ dispersed oil. A skimr tank can offer●fficiency improves as the oil dispersed phase In removal ●fficiency upto 90%, which cmres WS1l

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SPE 22831 D.G.K. WRTI & NANAD R. AL-NUAIHI 5J

with &y comercfally avaflable, but exrwsive from Produced Water,”’; Production Facilttywater treating eauitxasnt. The required conditions to 8ookware Soriea, ItiRDO, Bcston, HA 02116, USA.achieve good performance f:- the skinner tanks are,optimum daslgn of the upstream piping ●nd other (3) Arnold Ken. and Haurlce StOUa!t. Jr.: “Oesignlng●ssociated equl~nt and the skimsar tank internals. Oil and Gas Production Systems,”: World Oil

(March 1985) P69-78, (May 1985) P91-98..Note that an oversized aystam by Itself, helPs

separation of 011 ●nd water prior to reaching the (4) Correspondence betweanlturtl D.G.K. and” Arnoldintended equipment, But, a flow reatrlctlon or a Ken.: Paragon Enginaar*ng services Inc; Houstonlevel contro? device, such as a control valve in the Texas 77040, USA regarding design of 3-DhiIS9circuit, may neutralize the potential banef~ts. Separators, (March 1987).

~ENCLATLRE APPENDIX-A : Program listing for adjusting Oil VsWater bfelr

‘t: TMIS taken to grow a droplet - sacondd : Oil particle size- micron 10 INPUT “Water Flow Rate (bpd):”;Sl0: Volume fraction of 011 in water continuous 20 INPUT “0~1 Flow Rate (bpd):-;B2

phase 30 INPUT ““Water Weir Length (feet):’’:B3

% : Empirical parameter for a Particular water 40 INPUT “Oil Weir Length (feat):’”;B4system 50 INPUT “OasiredOll Pad Thickness (inch):’’:B5

MO : Oensity of oil - gn/cm3

: Flow rate m /se~o%a3

60 INPUT “Water Swclfic Gravity:’’;B6

%: Oanslty ofbfaer

.870 INPUT “Oil Specific Gravity:’’:B780 B9=0.008887*(Bl/(B3-O.005))”.867-O.036

c: Weir constant 90 BIO=0.009*(B2/(B4+0.007))-.667-0.036B : Width of weir- mater 100 Bll=B5*(l-(B7/B6))+B?:BiO*(B7/B6)

: Ciravitationa! constant - 9.81 m/see-see 110 PRINT ‘“Results:”’~ : Haad over the weir - meter 120 PRINT ‘“Head Over Water Weir (inch):’”:B9

130 PRINT “HeadOverOil Weir (inch):’’:BlOfor LiH, HOI, H02, \.l and %2, ri!Jfer fi9. 4. 140 PRINT “Oil/Water Weir Differential (inch):’’:Bil

160 STOPACKJWLELWNENT

APPENOIX-B: Program listin9 for calculating WaterThe authors thank (jatar. General Patroleum and Oil Flow Rates:

Corporation (Onshore Operations) for permission topublish this paper. to INPUT “water Weir Len9th (feet):”:Bl

20 INPUT ‘“Head Over Water Weir (inch):’’:B2REFERENCES 30 INPUT “Oil weir Length (fact):’’:B3

40 INWT “Head Over Oil Weir (inch):’’:B4(1) Nurti D,G.K., A1-#iaskati A.H., Sood L.K.: 50 B6=(112.524*B2+4.05)”1.5*(BI-O.005)

“ImDroved Dis’wsal Water Treatment at Bahrain 60 B7=(I12.524*B4+4.05)”1.5*(B3-O.006 )Oil Fields,’”: SPE ProductIon Engineering (Nov. 70 PRINT “Results:”1988) P677-682. 80 PRINT “AUProx. Water Flow Rate (bpd):’’:B6

90 PRINT “APProx. Oil Flow Rate (b@):’’:B7(2) Arnold Kenneth E. and Lew Skaug: “Treating Oil iOO STOP

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TABLE-l : Equipment Online Status

EQulpmalt old Modiliad NW S.P.

mails SWIM TSnk BklmmefTank GOSP PXkTsbla 2 v- No No NoTable 3 No Y* No NoTti 4 NC Yas Ye NoT@a 5 No Yes Yw Y*

la7

SPE 22831’

TABLE-2: OtdSkimmerTank in Senfice

Sarnpfafua No. 1 No. 2 No. 3 No. 4 Avaraga

Sall@ing Dataa ?2-1-33 le-1-m 5-2-S9 1-2-33 Fwdin@B

Upafraam of Skfmmar Tank 2207 234a 2410 2439 2334

Downatraam of SkimmarTank 1932 2033 2031 2143 2064

Parcantage Ranlwai 12.5% l&296 la79b 13.9% 13.1%

TABLE-3: ModifiedSkimmerTank inService

- No. No. 1 No. 2 No. 3 No. 4 Avaraga

Sampfhlg C)@aa 13-3-33 23-3-33 2-7-39 25-e-e9 Ftaadinga

Upatraam of 3kimmar Tank 1773 1395 2013 m 1933

Downsfraarn of 3kimmar Tank 4eo 494 433 450 431

TABLE4: ModifiedSkimmerTank&New GOSP inService

lBarnola No-- I *I [ No.2 ] No.3 I No.4 lAvaraoa

3ampfingDafe 5-11-39 11-11-53 13-11-39 13-11-33 Raadinga

UpaWam of Skimmar Tank 3929 4437 4343 %70 5357

DowmWaam of Skimmar Tank 543 419 435 e35 533

TABLE-5: ModifiedSkimmerTank, NewGOSP& SP Packin Service

Sampi@ No. No. 1 No. 2 No. $ No. 4 Avaraga

Sampiing Dama 17-12-39 7-1-30 25-11-39 3-12-33 Raatfinga

Upatraam of Skimmar Tank 4143 4230 45W 4923 4473

flownatraam of 3kimmar Tank 433 405 335 337 393

Parcanfaaa Ramaual 83.4% 33.4% 91A% 923% 91.1%

110(J3UY9)3U “

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~ OIL COLIECllON BOX

’42/GAS EQUAL!ZER HOLES

“*’N “L ‘E’R\. & ~uPP. OIL WEIR

/-SHEEN BAFFLEBAFFLE

OVER

Existing Details , Modified Details ~

Fig. 3- Modification Details

-46H

011 WEIR

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wATER wEIR

H02- ,..

Hoi’ \,,.., +;f.,-Hw2....,:.:.:.......... +:.:.::::,.,...........................................................................,~-::,::..:::::::~.::::,:.:.:.:.:....................+>:.:.:......-.:.:.:.x.:.>.........:::::”””.”...............:.:.:.:.;,:.::::?:::::;.:::.:::::::>.::::::.:,::y.:::::::::::::::::.:.:.:.:,::<.:::::::,:...:.:.:.:.:.:.>..:.:::::::HWI........................................................

TANK:.:.:.:.::.:;:::::::::::::;::::::::.:,:.

‘OTTO”-

Fig. ~- Weir Calculations

NOT RECOMMENDED

RECOMMENDED

Ni

wD+

Fig.51 Piping Arrangement

...,