(control de la migración de finos en agua de alta corte nigeria oil pozos problemas y soluciones

8/13/2019 (Control de la migracin de finos en agua de alta Corte Nigeria Oil Pozos Problemas y Soluciones

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W m . .I Society of Petmieum EngineersPE 39482

Fines Migration Control in High-Water-Cut Nigerian Oil Wells:roblems and Solutionsoni Ezeukwu, Ashland Oil Nigeria Company, R.L. Thomas, Schlumberger Dowellnd Terje Gunneroed, Schlumberger Dowell Nigeria

p~ght 1996, SWistY of Petroleum Engimsra, k.tis paper was weparad W Presantatm at the 1W SPE International Symposium wrmation Damage Control held inLafayette, Louisiana, 16-19 Febnmry 1996.hi s papar was sahdd for pmserdatl on by an SPE Pmgranr Commi ttaa fol lowti ravi aw &nfcfma~m wntainad in an abatrad wbmiied by b author(s). Controls d the paper, asresented, have not * reviawed by the S4ty of Patroti Engineen and are aubjad toorrti~ by tha autti(s) The materiat, as presented, does not nmssarily reW anYsiti on of the Social y of Petfobm Enginaars, its tiws, m manrbam PaPars presantad atPE meatings are subject to publbtti mviaw by Edktil Camitt~s of the q detroleum Enghriars, Electronic rww~, ditiMi, w stwage of my part of his wor ccinmercial pu~saa wtihwt tha wTittM asant d the Swety of Petrol eum Engbaara i srtitritad. Permission to repmd- in print i8 rsstided to an &s&* of Mt more than Words illuslratiis may not ba mpiad Tha abstract must mntarn conaplcuous~owladgment of WMR and by whom the paper was ~asented, Write LiWlan, SPE, PO.OX8338%, Rtiardson, TX 75063 -3S%, U S.A, f~ 01-972-952-%35 .

lthough fines migration has been investigated in theaboratory and the field for more than 30 years, severeoss of production resulting from fines migration stillxists in countless reservoirs. This field study evaluatedand inorganic clay-control agents to determineheir effectiveness to eliminate fines silt and clay)igration in high production-rate wells. Four gravel-acked wells that exhibited severe fines migrationroblems subsequent to conventional hydrofluoric acidF) treatments were overflushed with an organicolymeric clay-control agent. The wells were acidizedgain after production had significantly decreasedecause of fines migration and overflushed with an

agent to compare their performanceescriptions of the =ndidate selection and designrocedures are provided with the chemistry of the clay-ntrol systems and their control mechanism.This paper supports previous laboratory results that

organic polymeric clay-control agents are notffective in eliminating fines migration owing toechanical dislodgement. In most cases, productioneclined 50 to 90 within one year following organiclay-control treatments. Additionally, the onset of waterroduction further increased the production decline rateecause of increased fines migration. Following the

inorganic clay-control treatments, fines migration wagreatly decreased although the wells were producinghigher rates with higher water-cuts. The oil productionone year after the modified treatments was more thadouble the production at one year following the organiclay-control treatments. Five to six years after thinorganic fines-controltreatmentproductionwas equal ohigherthan the one year rate followingthe organic claycontrol treatments.IntroductionFines silt and clay) migration has long been recognizedas a problem in oil and gas wells producing fromsandstone reservoirs. 1 It was previously noted in cortests that fines dislodge at high flow rates and in fieltests rapid production declines occur when wells arflowed above a critical flow rate.2 These phenomena arattributed to fines migration into the wellbore arecaused by mechanical dislodgement rather than cladispersion as a result of ionic shock. Formation finecan migrate during production and workover operations.During the production of oil or gas, fines can migrateonce a critical flow rate is reached, when wateencroaches the reservoir or two-phase flow oil/water)exists. During workover or completion operations, finemigration can occur because of changes in water salinityandlor high drawdown during a well test. A decrease iwell performance occurs whether fines migrate owing twater salinity problems or high flow rates. 3S4567Numerous clay-control agents have been developed t

minimize fines migration. S,9,1OHowever, most of themignore the problem of fines migration caused by higproduction rates of oil or gas and focus on the watesensitivity of clay Additionally, they ignore the problemof silt migration by focusing on the ,migration of clayskaolinite, illite, chlorite, mixed-layer clays). Sicomprising 4-to 62-micron size feldspar, mica, silica and

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2 Toni Ezeukwu, R.L. Thomas and Terje Gunneroed SPEother particles can be the predominate migratoryspecies.sIt was reported in core flow tests designed to exceed

the critical flow velocity for fines migration that migrationis not restricted to clay. Fines in the tests werecomposed of silica 50Yo), feldspar 11 Yo and variousclays (3970). Additionally, fines can migrate in thenonwetting phase with migration enhanced in a two-phase system. Subsequently, Grabriel and Inamdarperformed a Iaboratoty study directed at chemical watersensitivity) and mechanical native fines migration duringproduction) fines migration.l They concluded that o~anicclay stabilizers cationic polymers) are not effective ineliminating fines migration resulting from mechanicaldislodgement. This paper addresses the application ofo~anic and inofganic fines-control systems during thematrix acidizing of several Nigerian oil wells.Clay and Fines-control SystemsOrganic Agents. Polyquatemary amines have beenused for more than a decade to stabilize clay insandstones during matrix acidizing and fracturingoperations. Their positive charge attracts them to theclays surface, resulting in charge neutralization; i.e.reduced swelling smectite) and/or migratory kaolinite,illite, chlorite) characteristics. 1011 However, organic clay-control agents are not effective in eliminating finesmigration resulting from mechanica dislodgment.l Thispaper supports this observation./norganic Agents. Polyvalent inorganic cations werepreviously reported to provide clay-control in sandstones.Similar to a cationic o~anic polymer, becometenaciously attached to the surface of the clay, resultingin stabilizaiton.ag Although they are applied in matrixacidizing operations, they cannot be used in mostfracturing operations and are not commonly used today.Additionally, zirconium oxychloride and hydroxy-aluminum focus on c ay and not si/t and clay-control.However, fluoboric acid, an ino~anic system, has beenused for 20 years to provide silt and clay-control.1213This paper focuses on a field study that incorporatedfluoboric acid in the matrix treatments. A discussion ofnumerous laboratory and field studies reporting on theapplication of fluoboric acid as a fines stabilizationsystem follows.In one study, gas wells located offshore Louisiana

were matrix acidized with mud acid and subsequentlyexhibited a rapid production declines. Subsequently theywere treated with a mud acid treatment overflushed withfluoboric acid in an atiempt to sustain production at anacceptable lever. A turbulence plotwas used in the studyas an evaluation tool to determine the effectiveness offluoboric acid to eliminate further fines migration. Theresults indicate fiuoboric was effective in removing the

silt and clay damage and stabilized production.that typically exhibited a decrease in production ofthan 50 to 75 within one year following a treatremained on line for three years without fines migroccurring.14The results of a Iaboratoty study on Kuparuk

formation cores indicate that mud acid partially dissosilt and clay, resulting in the release of migratoryAn SEM study showed that fluoboric acid cementedundissolved clay to the framework, eliminating themigration potential. The authors concluded thafluoboric acid treatment was the best approach forbearing sandstones.lsA case study of an oil well that produced 2200 Bupon completion but exhibited a rapid production deto 400 BOPD in six months because of fines migrwas also reported.3 To bypass the damage the wellreperforated, resulting in increased production toBOPD followed by a rapid production decline. Aacid treatment was performed to remove the silt anddamage that had migrated into the wellboreAlthough the treatment resulted in improved producfor a short time, production declined again, indicatinfines migration. As a result, a fluoboric acid treatmwas performed to eliminate fines migration. The autreported the well was producing 1900 BOPD five yfollowing the treatment. The rapid decline resultingfines migration was eliminated by the fluoborictreatment, resulting in sustained production.Silt and clay exposed to the reaction products

fluoboric acid are bound together into a single pawith a much smaller surface area. 12,14Thjs results indrag force on the silt and clay during production. Uclay-control agents that adsorb rapidly on the clay iwellbore area, the spent fluoboric acid penetratesinto the formation 3 -5 ft) to react with the undissosilt and clay. Live fluoboric acid is not required to ofines-control. Additionally, the cation exchangeswelling characteristics of smectite have been repoto be essentially destroyed by exposure to fluobacid.12 The mechanism for fines-control is attributedthe formation of a borosilicate material throughtopochemical liquid/solid) reaction with the silt andThe reaction, specific to the fines, does not resuprecipitation products on the sand grains or withinpore throats.14Treatment DesignThe treatment designs for the ofganic and inorgfines-control treatments were similar. When the orgclay-control system was applied, it was incorporatedthe main fluid and overflush at 27 by volume.appropriate additive package was used in all cases

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SPE 39482 Fines Migration Control in High-Water-Cut Nigerian Oil Wells: Problems and SolutionsOil Well Case HistoriesWell Overview. The wells in this study were drilledoffshore Nigeria between 1985 and 1990 in water depthsof 6 ft into the Biafra formation of lateMiocene/Pliocene age. The Biafra formation is a deltafront and delta slope deposit comprising of alternatingsand and shale sequences. The wells are deviated, andthe productive sands are occur between 5000 and 6800ft. Generally, the sands exhibit a systematic variation inreservoir properties from top to bottom. The uppersands are predominately fine grained, whereas the lowersands are predominantly medium to coarse grained.Compared with the upper sands, the lower sands arericher in detrital clay. The matrix is primarilymonocrystalline quartz 23A - 79Yo), with minorpolycrystalline quartz 1YO-1O ). Potassium feldsparand mica exhibit 6-43 and less than 3Y0, respectively.Detrital clay in the matrix-rich portions of the reservoiroccurs in proportions as high as 40Y0. Siderite occurs insmall amounts 170 3Y0, authigenic pyrite at tracelevels 5Yo) and kaolinite in trace levels. An X-raydiffraction study of the whole rock indicated that the bulkof the detrital clay consists of i llite and il lite/smectite.Resemoir Characteristics. The average reservoirporosity ranges between 23 and 30Y0. The bulk of theporosity is intergranular with minor intragranular porosityevident within partially leached grains of potassiumfeldspar. Because of the paucity of matrix cement,especially in the matrix-poor sand bodies, permeability isexcellent at up to 2500 millidarcies. The matrix-richsands, however, have slightly lower absolutepermeability ofl 500 millidarcies. The initial irreduciblewater saturation for the samples studied ranged from12.8 to 17.9 with an average of 15.37. pore space.Drilling and Completion. Saline mud was used to drillthe wells to protect the clay minerals in the productivesands. These wells were deviated, so tight spots andsloughing shale problems were inevitable. But the holeswere generally stable, as evident from the caliper logs.Electrical logs were also obtained and the casingsuccessfully cemented. Constraints of offshoreoperations prevented employing casing movement toensure good primary cementation.Adjacent prodl~ctive sands were isolated by block

squeezing as a secondary measure to protect the payzones. Consequently, displacement losses wereinevitable, particularly because of the high porosity andpermeability. Poor consolidation because of the paucityof matrix cement and high permeability did not favorunderbalance perforation; hence, the perforated intervalswere shot overbalance and then slowly flowed clean onsmall chokes sizes of 10/64 - 20/64 in. Underbalanceperforation in these poorly Iithified and low-compressive-strength sands could create a hydrodynamic surge,

cause shear failure and possibly aggravating saproduction problems. Tubing conveyed and casing gsystems with a high shot density of 8 -12 spf weemployed to minimize production draw-down pressubecause of the high flow capacity arising fromexcellent reservoir permeability. Gravel-pack sancontrol measures were also put in place using 10 15 strength hydrochloric acid pumped ahead ofsand slurry. In most cases gas lift facilities were ainstalled at the inception of completion.Production History. Upon initial completion in twater-drive reservoir, several of the wells experiencerapid production declines even at low water-cproduction. Initial attempts to stimulate the sands wmud acid treatments overflushed with organic polymerclay-control agents showed initial gains but sodeclined to pretreatment rates within 12 months. Asresult of the failure of the organic clay-control to minimizsilt and clay migration, an investigation was initiatedevaluate an inorganic agent. As shown in this paper tinorganic silt and clay-control system outperformed torganic system. This extended the life of the field aproduced more than f.3 rni//ion barre s of incrementalThe following case histories discuss four of the wellsthe study.

Case 1:0 335 MMBO Incremental Reserves W1 is one of five active completions draining the reservoir at a depth between 6220 and 6360 ft trvertical depth TVD). It is separated by a sealing fafrom the main sand body and is not under pressumaintenance. The perforations at 7475 to 7504measured depth MD) are 17 feet above the base of tsand with a permeability of 352 md. It produces 31 Agravity oil with no gas from a gravel-packed zone withft of net pay.Sidewall core analysis and electric log data indica

that the formation is an unconsolidated, very fine grainesilty sandstone with 13 clay illite, smectite akaolinite).Production commenced from this completion in M

1986 Figure 1) with the aid of gas lift after all effortsflow the well naturally failed. Two remedial workoverwere performed in the past. The first was in 1987repair and isolate the upper gas producing lobes. Thsecond workover was performed in 1988 with tobjective of pulling tubing to remove stuck SCSSV on tlong string.As shown in Figure 1, the from inception of productio

through the last period of the workover, Well 1 hexhibited periods of rapid production decline.conventional Mud Acid treatment incorporating 2organic polymeric clay-control agent overflush waperformed in June 1989, resulting in production increasfrom 194 to 1300 BOPD and O BWPD. Six months late

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4 Toni Ezeukwu, R.L. Thomas and Terje Gunneroed SPEwater production occurred and oil production declinedrapidly to approximately 100 BOPD, indicative of finesmigration. Subsequently, a faulty subsurface safetyvalve SSV) was replaced resulting in a tempora~increase in production. Systems analysis indicates acompletion efficiency of 0.26 spf although the well wasshot with 12 spf. The production potential of Well 1 was460 and 1800 BLPD with 3 and 12 spf completionefficiency, respectively.In January 1991 a fluoboric acid treatment was

performed because fines migration was suspected andthe organic clay-control agent had tiiled to provide siltand clay fines) control. The goal was to avoid frequentacid treatments and improve cumulative production byminimizing fines migration.Following the fluoboric acid treatment, production

increased from 518 to 1358 BLPD 1.7 spf completionefficiency). As indicated in Figure 1, the fines-controlfluoboric acid) treatment resulted in a large increase incumulative production, indicating fines stabi lization. Theoil production six months following the fluoboric acidtreatment was more than double that obtained at thesame time period following the treatment incorporatingthe organic polymeric clay-control agent. Two yearsafter the fluoboric acid treatment, the well was producing779 BLPD with 275 BOPD. Six and a half years after thefluoboric acid treatment the well was producing 188BOPD. In comparison, within 9 months after the organicpolymeric clay-control treatment in June 1989,production was only 183 BOPD.Cumulative production to December 1996 was 1.223

MMBO . Incremental reserves resulting from thefluoboric acid treatment is approximately 0.335MMB0,which contributed to extending the life of the field beyond1992.

Case 2:0.427 MMBO /ncren7enfa/ Reserves. Well2 is one of six completions draining reservoir C and wascompleted dually in two zones, A and C, as the short andlong strings, respectively. The perforations are situatedapproximately 13 ft above the original oil-water contactOWC). No gas-oil contact was visible during the initialcompletion and the level was credited with 32 ft of net oilpay. Sidewall core results coupled with electric log dataindicates that the sand is an unconsolidated sandstone,silty and fine grained in texture. An X-ray petrographystudy of the mineralogy of the sand indicated that themain framework grains are quartz and feldspar, with thebulk of the clay matrix composed of illite andillite/smectite. Authigenic minerals are rare; a thin-section study revealed small quantities of pyrite, sulfurand kaolinite. Gravel pack was employed as a sand-control measure during initial completion of the zone.The well was on stream in January 1986 with initialproduction of more than 500 BOPD and gas/oil ratio

OR) of 400 scf/STB on 1/2 choke. Six months aproduction commenced, the water-cut increased towhich caused a decline in total liquid production to b600 BLPD. Figure 2)In June 1989, a conventional mud acid treat

incorporating 270 organic polymeric clay-control aoverfiush was performed to improve producProduction increased from 339 BLPD to more thanBLPD, but the gain could not be sustainedproduction declined to 522 BLPD in June 1990.decline was attributed to fines migration intoimmediate wellbore area and the gravel pack.Following a pressure survey in July 1990, it

difficult to obtain adequate production becausemalfunctioning SSV. A workover was performed in1990 to correct this problem. After the workoproduction continued to decline at preworkover rSystems analysis indicated severe wellbore dami.e. a vety high completion pressure drop andeffective shot density).In January 1991, a two-stage foamed diverter m

treatment was performed to improve productionprovide fines-control. It consisted of a 10 HCI pref10.57. - 1.5 HC1/HF mud acid and an ovefflushfluoboric acid for fines-control. The treatment resultean increase from 225 BOPD/493 BLPD toBOPD/1 236 BLPD Figure 2). This represents awater cut. Although the water-cut increased over thefive years to approximately 90 , the daily oil producremained above 268 BOPD. Only seven months aftthe organic polymeric clay-control agent applicationJune 1989 the oil production had dropped to 119 BOIn comparison, at 7 months after the inorganic fcontrol treatment, production was 315 BOPD. Thus,inorganic fines-control system eliminated migration oand clay.Well 2 has recovered cumulative production of 1MMSTBO since completion in 1986. Incremereserves of 0.421 MMSTBO are attributed tofluoboric acid treatment, which extended life of thebeyond 1992.

Case 3: 0.159MMB0 Incremental Reserves3 was drilled, tested and suspended in March 1984.well was entered in 1988 and completed as a singleproducer in two lobes. Perforations were at 5302-529and 5272 - 5263 ft with 16 ft of net pay anpermeabil ity of 455 md.Results of sidewall core analysis and electric logs

indicate that the zone is an unconsolidated fine-graishaley sand. The mineralogical composition wasavailable. There was no defined fluid contact onelectric logs. Both lobes were gravel-packed to asand production.Production commenced on July 12, 1988, a poor

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SPE39482 Fines Migration Control in High-Water-Cut Nigerian Oil Wells: Problems and Solutions

unstable production rate. The sliding sleeve across theupper lobe was subsequently opened and the lobes werecommingled in October 1988. A conventional mud acidtreatment incorporating 2 polymericclay-controlagentoverflushwas performed, resultingin productionof 753BOPD and 59 BWPD. Once the water-cut increased to20 Nov. 1988) a production rapidly declined to only290 BLPD December 1990. Subsequently, Well 3 wasplaced on gas lift to sustain production and a systemsanalysis was performed. The analysis indicated 850 psidifferential pressure across the completion because ofmigratoy fines and heavy hydrocarbon deposits withinthe wellbore region. The systems analysis studyindicated that production could be significantly increasedto about 580 BOPD from 220 BOPD if the damage isremoved.In January 1991, the well was stimulated with toluene,

15 HCI, 13.5 -1.5 mud acid and overflushed withfluoboric acid for fines-control. The well responded totreatment with the liquid rate increasing to more than1050 BLPD from its pretreatment level of 450 BLPD.However, as a result of further water-cut increases overthe next two and a half years, the rate declined to 350BLPD by June 1993. In this case the inorganic fines-control system yielded a decline similar to that asexperienced with the organic clay-control system yet at amuch higher water-cut.A systems analysis indicated an effective shot density

of 0.69 SPF with a 583 psi pressure drop across thecompletion. A sensitivity test to simulate the effect ofincreased shot density indicated a potential productionrate of 460 BOPD at 3 spf. The completion pressuredrop at 3 spf is approximately 200 psi. The analysisshows no additional benefits at shot densities higher than3 Spf.In July 1993, a two-stage 10 HCI, 10 - 1.5 mud

acid treatment overfished with fiuoboric acid wasperformed. The well was placed on gas lift after thetreatment resulting in production increase from 190BOPD and 449 BLPD to 422 BOPD and 1039 BLPDFigure 3). Four years later Well 3 production issustained at 194 BOPD/663 BLPD. The reduction in rateis partly due to an increase in the producing GOR fromthe gas gap and reduced reservoir pressure.Cumulative production from this well through

December 1996 was 0.870 MMBO. Because of the 19API gravity and high viscosity of about 9 cp, recoveryfrom this zone has been generally low. The incrementalincrease in reserves of 0.159 MMBO because of thefluoboric treatment has helped to increase the life of thefield. Horizontal wells are currently being dtilled toimprove recovery from the heavy crude reservoirs.

Case 4:0.35 MMBO Incremental Resetves Finalcompletion of well 4 was conducted in Februa~ 1989 as

a single-string oil producer. Figure 4 showsproduction history of this 2.5 darcy oil well with a gravpack completion. The sand was perforated from 72927302 ft 6963 - 6972fi true vertical depth ~D] with 52of gross height. Results of sidewall core analysis aelectric logs indicated that the reservoir consistsunconsolidated sand and siltstone, with interbedsshale.Production from the well began in May 1989 with

initial rate of 981 BOPD and a GOR of 278 scf/bbl on20/64 inch choke. However, the average productionMay 1989 was 257 BOPD with negligible water.conventional mud acid treatment incorporating 2organic polymeric clay-control agent overflush wperformed to improve production. Production increaseto 560 BOPD and 290 BWPD. Subsequently, waproduction increased rapidly to more than 50 and ttotal fluid production declined to 39 BLPD by June 19because of fines migration and emulsion blocking.Based on systems analysis, Well 4 exhibits a completioefficiency of 0.14 spf, although the well was shot withspf. Additionally, the plot indicates 2800 BLPD apossible at 12 spf completion efficiency. At the curreproduction rate, about 1322 psi was being expendeacross the completion as a pressure drop, resulting inlow productivity index of 1.08 BBUday/psi. Results frothe analysis indicate severe damage in the completionBecause fines migration was suspected and the cla

control agent had failed to provide fines-control,fluoboric acid treatment was performed following the fiyear of production. The goal was to avoid frequent actreatments and improve cumulative productionFollowing the fluoboric acid treatment the well wplaced on gas lift. Production increased to more th2500 BLPD 4 spf completion efficiency) and eventualincreased to more than 3000 BLPD with a water-cut80 Figure 4). Wereas production one year followinthe mud acid/organic polymeric clay-control treatmenwas only 39 BOPD, production one year following tfluobonc acid treatment was 150-200 BOPD. FigureFive years following the fines-control treatment, the wwas producing 129 BOPD with a 93 water cut 120BLPD). The previously observed rapid productiodecline was successfully arrested, indicating total finecontrol.Cumulative production from this well througDecember 1996 was 0.440 MMBO. Because of the lo

API gravity and high viscosity of about 1.6 cp, recoverfrom this zone has been generally poor. The incrementarecovery resulting from the inorganic fines-control/acidtreatment is more than 0.350 MMBO, which hextended the life of the field.Case History Summary. Figure 5 shows theproduction of the case study wells 1 year after t

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6 Toni Ezeukvvu, R.L. Thomas and Terje Gunneroed SPEorganic polymeric clay-control treatment and 1 to 5 yearsafter the inorganic fines-control treatment. A rapiddecline following the o~anic polymeric clay-controltreatment was observed in each well. However,sustained production for several years was observedafter the jno~anic fines-control treatment. Note, Well 3was treated twice with the inorganic fines-control system.The observed accelerated decline after the first inorganictreatment is attributed to the high water-cut, whichenhances fines migration.As a result of the inorganic fines-control treatments, thelife of the field was extended several years and morethan one million three hundred thousand barrels ofreserves were added to the field.Conclusions1

2.

3.

4.

This field study in high rate oil wells indicatesconventional organic polymeric clay-control agentsare not effective in stabilizing formation fines, i.e.they do not prevent post-treatment productiondecline due to plugging in the matrix and gravelpack.The inorganic fines-control system, fluoboric acid,was effective in preventing fines migration caused bymechanical and chemical dislodgement in high-water-cut oil wells.norganic fines-control treatments in oil wells resultedin significant improvements in production and highercumulative hydrocarbon production because ofminimization of fines migration. Production wassustained for several years in most cases.The life of the oil field used in this case study wasextended to yield more than 1.3 million barrels ofincremental oil. This was a direct result of theapplication of the inorganic fines-control systemcomposed of fluoboric acid.

AcknowledgmentThe authors thank Ashland Oil Nigeria Company,Schlumberger Dowell and Schlumberger Dowell Nigeriafor permission to publish this paper. Special thanks go toLois Westbrook for editing and preparing this manuscript.References1. Krueger R.F. Fischer P.W. Vogel L.C. 1967 Effectof Pressure Drawdown on the Cleanup-Up of Clay or Silt-

Blocked Sandstone. JP~ 397 403 AIME 2402. Gabriel G.A. Inamdar. G.R. 1983. An Experimental

Investigation of Fines Migration in Porous Media. PaperSPE 12168 presented at SPE Annual TechnicalConference and Exhibition San Francisco

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5.6.

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9.10.

11.

12.

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15.

Paccaloni G. Tambini M. Advances in MStimulation Technology. Paper SPE 20623 presentthe Amual Technical Conference and Exhibition Orleans.Muecke T.W. 1979 Formation Fines and FaControlling Their Movement in Porous Media. JPZ50.Gruesbeck C. Collins R.E. 1982. SPN 847 56Kmeger R.F. Fischer P.W. Vogel L.C. 1967 Eof Pressure Drawdown on the Clean-Up of Clay orBlocked Sandstone. JPT 397 403 AIME 240.Jones F.O. Kr. 1964. Influence of ChemComposition of Water on Clay Blocking of PermeabJP~ 441 46.Veley. C.D. 1969. How Hydrolyzable MetalStabilize Clays to Prevent Permeability Reduction .1111-18.Reed M.G. 1972. Stabilization of Formation ClaysHydroxyaluminum Solutions. JPT 860 64. AIME 25McLaughlin, H.C., Elphigstone, E.A. and Hall,Aqueous Polymer for Treating Clays in Oil andWells, SPE 6008 presented at SPE 51* AnnFall Meeting, New Orleans, Oct. 3-6, 1976Coulter, A.W., Copeland, C.T. and HarrisbergW.H ., A Laboratory Study of Clay Stabilizers, J1979,267-269.Thomas R.L. Crowe C.W. 1981. Matrix TreatmEmploys New Acid Systems for Stimulation and Coof Fines Migration in Sandstone Formations. JPZ 11500.Schaible D.F. Akpan B Ayoub J.A. 1Identification Evaluation and Treatment of FormaDamage Offshore Louisiana. Paper SPE 14820 preseat the Formation Damage Control Symposium LafayeMcBride J.R. Rathbone M.J. Thomas R.L. 1Evaluation of Fluoboric Acid Treatment in the GrandOffshore Area Using Multiple Rate Flow Test. Paper8399 presented at the Annual Fall Technical Confereand Exhibition Las Vegas.Boyer R.C. WU C.H. 1983. The Role of ReserLithology in Design of an Acidization program: KupRiver Formation North Slope Alaska. Paper SPE 11presented at California Regional Meeting Venatura

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39482 Fines Migration Control in High-Water-Cut Nigerian Oil Wells: Problems and Solutions

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jOrganic ClaylControl Treatment

( D7..,...~;;raanic Fines i I

- Con;ol Treatment I

ihT& A -BOPD~BWPD +BLPD+ Ii IMay 86 May 87 May 88 May-89 May-SO May-91 May 92 May-93 May-94 May- 5 M8y.96 Way-97

Fiaure 1. Production of Oil Well 1 showing the rapid Production decline followin9 treatment ~th mud acid. U overtlushed with an organic polymeric clay-control agent and sustained production following the inorganicfines-control treatment.

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.l BOPD I1A AI--- BWPD I-_BLPD I -A . -* .-.LeT&----I

Jan-87 Jan-88 Jan-89 Jan-90 Jan-Sl Jan-92 Jan-93 Jan-S4 Jan-95 Jan-96 Jan-97

Figure 2. Production of Oil Well 2 showing the rapid production decline following treatment with mud acidoverflushed with an organic clay-control agent and sustained production following the inorganic fines-controltreatment. 535


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8 Toni Ezeukwu, R.L. Thomas and Terje Gunneroed SPE

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0JuI-88 JuI-89 JuI-90 JuI-91 JuI-92 JuI-93 JuI-94 JuI-95 JuI-9S

Figure 3. Production of Oil Well 3 showing the rapid production decline following treatment with mud acoverflushed with an organic clay-control agent and sustained production following the inorganic fines-control treatment. Note, gas lift was installed in early 1990.

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A. HZ % R +BwpD-~BOPD---- ..

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7Apr-89 Apr-90 Apr-91 Apr-92 Apr-93 Apr-94 A pr-9S Apr-96 Apr.07

Figure 4. Production of Oil Well 4 showing the rapid production decline following treatment with mud acioverfished with an organic clay-control agent and sustained production following the inorganic fines-control treatment. 536


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SPE 39482 Fines Migration Control in High-Water-Cut Nigerian Oil Wells: Problems and Solutions

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]= 1 yr. After Organic Polymeric Clay Control Treatment / 1 yr. After INORGANIC Fines Control Treatment

a~02 yrs. After INORGANIC Fines Control Treatment 3 yrs. Afier INORGANIC Fines Control Treatment 4 yrs. After INORGANIC Fines Control Treatment

2 3a 3b 4Well

Figure 5. Oil production of case study wells 1 year after the ofganic polymeric clay-controltreatments and 1 to 5 years after the inorganic fines-control treatments. Note, sustained productionfor several years after the ino~anic fines-control treatment (fluoboric acid).

(control de la migración de finos en agua de alta corte nigeria oil pozos problemas y soluciones

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