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Fedorovo: Prospects for the USSR's Third-Largest Oilfield
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Fcclororo: Prospects for ilic USSR's Tliird-Largest Oilfield*
three decades of rapid growth. Soviet oil production has reached at
emporary plaleauittle more thanillion barrels per dayr justillion metric tons per year. Produclion is currently declining at most of the giant and supergiant fields that generated the steady increases of. To offset this decline, the USSR must work much harder lhan in the past, particularly if i( is to meetth Rve-Ycar Plan goal6he outcome of the Soviets' efforts will hinge, in large measure, on the performanceumber of fields in western Siberia, the largest oil-producing region in lhc USSK
With the possible exception of Samotlor, no field in western Siberia wilt be more Critical lo Soviei success thanupergiant that is already lhc ihird-largcst producer in the nation. We estimate that Fedorovo originally contained overillion barrels of oil in itsccording to our analysis,illion barrels will be recoverable wiih available technolocy and with the facilities no* bcine developed at the field
lhc Soviets have invested considerable resources- in the form of drilling
rigs and an expensive gas-lift systemroman aucmpl lo maximize Output from the field. Our analysis indicates lhai ihis effort has succeeded. The currenl five-year plan calls for production at the
field lo rise lojusln6 perceni of naiional oillo slay at this high levele tudge thaiwill meet or exceed these goals Indeed, assuming thai drilling and
gas-lift installation continue ai their current pace, the field could be Operatedroductionbove these plan
target-
Wc do not anticipate that production liom Fedorovo will begin io decease Significantly6 al lhc earliest.owever, the field will piobably be entering an advanced stale of decline, wiih pioducnonnd dropping rapidly. The Sovicis might then consider initialing an enhanced recovery program for poriiom of the field or
Sivnysk,(null oillo,,caily ictatcd iot ineluotdoil-in-nUcci.-noi -in Tr.
expanding development to less productive reservoirs. In either case, such an effort could temporarily moderate the decline, and,ufficient resource commitment, might possibly restore production to the level of the
In spite of the inevitable decline in production at the end of this decade. Fedorovo haselcome bright spot for the Soviets on whal appears to be an increasingly troublesome oil horizon. The Soviet Ministry of Petroleum Industry has amassed sufficient personnel and equipment for (he field to achieve its production potential without the need for heroic measures or additional major investments. Its success in developing Fedorovo hasey role in Moscow's continued ability to maintain national oil production neaievel
FcdoroTu: 1'iospecls for lhc USSR's Third-[jirKosI Oilfield
From World Wm ii inio (be, the USSR maintained consistently hif.li rales of growth inproduction. Since then. Soviet oil productiontagnated at slightly note (banillion barrels per day) or (usiillion metric loos per year The reasons areecline in exploitable reserves, ihe remote locations ot" newer oil deposits, drilling problems, and serious equipmentin exploration and fluid-lift operations.Moscow needs to maintain positive rates of giowth ir. oil produclion lo fuel iit domestic economy,in badly needed hard currency Trom expoits. and to provide energys client Hates inrope, Cuba, and Southeast Asia. The Soviei desire to beep oil output fro-it it also molivatedctire lo maintain the first-place positron of the USSK tn world oil production, which wc believe hasine: of national prestigeSoviet eyes a'symbo! of the superiority of ibe Sovietsystem
Toih Five-Year Plan goal6he Soviei Union needs, among other things, io slow ot postpone the inevitable declines in production at ihe large mature lields lhat generated (he steady production incieases ofo date weassessed the curienl pciform ance and predicted fuluie recovery for three suchSamoUof. Romashkino. and Arlan. Ourindicates that despne ihe best Soviet cfToilv. production from tbese ihice fields alone could fall by as much0 levelsk middle of this decade
The new prcljction neededover the decline from established Heidi anddd ihepecified tnth FtseYear Plan must comeumber of young fields, moil of them in western Siberia, fedorovo. already ihe ihiid-largest oilm ihe country and second lai gest in western Siberia, is one of these key fields ffiguic l|
Geologic Setting
Fedorovo Oilfield is located in the Westillion square kilometers, one of ihe largest siructufal-scdjmentary basins in the worldhe basin deepens asymmetrically to the north and is traversed by major riven meandering northwardarshy, lake-strewn plain to the Arctic Ocean. Environmental conditions in the basin are harsh, especially in the central and northern parts, where most of the oil and gas fields are located Winters are frigid, and activity in (he summer months is hampered by swampy, poorly drained terrain These eondiiions seriously inhibit Ihe establishment of ihe required transportation infrastructure and commonly limit offload vehicular traffic to the winter months when ihe ground surface is frozen The per ma frost conditions in (he northern half of Ibe basin and the recurrent freezing and thawing of (he surface force the Sovietsse expensive construction techniques in the oilfields of the region. Wells must be clustered on large drilling pads designed to withstand Ihe severe environment and io reduce (lie expense and ease the construction of well sitct
The geologic history of the West Siberian Basin makes it one of (he more favorable locations tn ihe world lor accumulation of hydrocarbon deposits The basin hasuiet, lelairvtly undisturbed tectonic history under geologic conditions conducive ioformation and accumulation The sedimentary rock layers are thick and fairly uniform, consisting of marine and continental sediments of the Jurassic. Cretaceous, and Paleogene overlaideneer of more recent glacial, lake, and alluvial deposits Excei-lent petroleum source beds- pariioilaily the Barh-enovnumeious subsurface structuralnecessary io nap and accumulate oil from the source beds are present in motl of the basin. One notable feature is Ihe Khaniyominant
subsurface structure thategional oil mjgra-tion and collection system. Superimposed on this reeional hied arc additional uplifts, such as ihe Surgut and Nizhncvartov arches, which in turnlocalized and smaller individual domes andfeatures. The Fedorovo structure, site of lhc Fedorovo and Savuysk oilfields, is oneumber of smaller uplifts on the Surgut arch containing oil and natural gas (figure ?)
1Jarmo ind Sa-unlon rSc unit uiilill. are
rxtxluiiac lien lhc| mm and arcnait nn<>
HXtificilly (litre oihciwor ill iiultlu pcffauiiiiErw ilutmi.,i
We conductedanalysis of the Fedoi-
ovo structure to supplement and to validate the geologic information found in the ^'J" literature
Methodology
assessment of ihe produclion potential of any Soviei oilfield is hinderedaucity of open-source production and reserves dala. Data on reserves have been stale secrets since World War U, and accesshis information is highly controlled even wilhin the Geology and Petroleum Ministries. Field-by-field produclion figures, sparseirtuallyseveral years ago when Moscow became aware thai the United Stales was scrutinliing lis oil
To overcome ihis lack of information, we havemethodologies thai allow us to estimateconfidence ike reserves, current production,yields of Soviei oilfields. Considerableand reservoir data are available in Soviettechnical literature and fromn con/unction
with these other sorts of data, can be used to irack field development and estimate oil in place and reserves. Finally, we canariety of both simple and sophisticated techniques of reservoir engineering
analysis to estimate field performance and recovery potential under different development scenarios.
Because Fedorovoelatively young fieldengthy production history, we elected toodified material-balance approach rather thanmore complex modeling. This approachetroleum reservoiringle, uniform lank of fluid foil, water, and gai) and does noi attempt lo account for variables such as fluid flow within the reservoir or individual wellbore effects. If reasonably accurate estimates of reservoir rock and fluidoil in place, and historical production are available, ihe material-balance techniqueeans of Inventorying reservoir fluids al various lime intervals in the production life of afield andihe amount of oil produced under differentstrategies. Material-balance analysis canpredict near-term production but often overestimates long-range production rales by not anticipating and accounting for reservoir problems thai occur as afield ages
Soviet geologic cross sections show that oil migrated into these structural highs, where it was contained by less permeable overlying sediments. The average thickness of the scdimcniary cover in the area of theseOO meters, with the pay zones located
OU meters The best producing zone at Fedorovo is thelocatedeptheters (fieure Sj This highly productive andreservoir produces in all pans of the field and contains approximately aj percent ol the original oil in place at Ihe field The shallowerorizon is even more widespread lhan thebut appears to have much poorci reservoir properties The US, and OS, reservoirs contain oil in thin and discontinuous pay zones: the other hydrocarbon-bearing reservoirs ai Fedorovo contain mostly gas or only localized oil
j :I
Oil in Place anil Reserves
The amount of original oil in place in an oilfield must be known oi estimated in orderssess (he field's production potential. We estimate lhai at the (imc it was discovered Fedorovo contained appro"mutelyillion barrels of oil. We arrived a( (his figure by calculating the volume of the oil-bcaiing strata in the structural highs and (hen adjusting for the volume occupied by gas. water, and (be rock itself.illion barrels of this oil were located in (hehorizon, with (he2 billion barrels in theecause ibe other oil-bearing horizons are of very poor quality, wc excluded them from the
The USSR claims an average recovery rale ofercent of original oil in place in fields where water injection ts used for secondaryfigure that is quite high even by US standards. In reality, Soviet recovery rates are often considerably lower because of the inability of Soviet drillers to devise workable solutions lo inevitable reservoire believe lhat the quality and homogeneity of thereservoir at Fedorovo will allow an ultimate recovery rate ofercent orto place recoverablereserves atillion barrels. These largeoil reserves in thealone would putin (he giant field category '
Traditional Soviet drilling and well-completion practices make estimating recoverable reserves in theore difficult task. The Soviet drillinghas not perfected the multiple completionthat allows simultaneous extraction of oil from more than one pay zone through only one wellborc. At presenl. nearly all the wells at Fedorovo have been drilled into the deeper and higher qualityand we believe that overercent ol the production is currenlly coming from that pay zone. As wells into ihebecome depleted, wc believe lhc Soviets will probably plug llicm just below theotizon and reperforate the well casings to produce oil fiom lhcith no flow laiesor production
history for (hehere is no way to evaluate the quality of (he reservoir or to estimate its recoverable reserves with great accuracy. Itipoorer reservoir properties, however, should make the recoveryconsiderably lower titan tha( obtained in (heecovery factor as low asoercent would still addillion barrelsillion barrels inaiseinto Ihe supergiant category.
Field Deieloptncnl and Production History The rate at which (he USSR is able lo extract theillion barrels of reserves at Fedorovo latgcly depends on how (he field isand produced. Wjtb onegas-lift system now beingSoviets have basically followed (heir traditional methods of field development at Fedorovo and have experienced many of the same problems previously encountered at Samotlor and other fields in the basin. In keeping wiih standard Soviet practices, Fedorovo is being worked intensively in an attempt to maximize current production
The Sovieu drilled the first successful well in the Fedorovo areas has been (he case with many other western Siberian fields, Ihe remote loca-lion. environmental problems, and some confusion over geophysical survey results delayed the start of development drillingnitial development drilling then proceeded slowly, primarily because of the special engineering and construction lechniqucs needed in the harsh environment of the field (figurel was noihen Fedorovo was assigned its own independent oil and gas directorate, that the pace of drilling began to increase rapidly In lhat year, the number of production wells jumped fromnd total wells. The high rate of drilling in subsequent years and the faci thaiigs arc now working in the fieldoviet desire to boost production a; Fedorovo as tepidly as possible
U'l'tionsideredo ii" < rreovciahli mrr>ri of atall An barscl-.
Figure 6
Fedorovo Drilling aod Oil Production
omplete set ot year-by-yearfor Fedorovo is unavailable, acan be pieced together f
at Fedorovo started3 and began to grow rapidly with the intensification of drilling7 and the onset of production from the Savuysk poolc estimate (hat production from Fedorovoillion (ons)0illion (ons)hen it accounted forercent of Soviet national oil oulpul.
Tne development plan designed for Fcdoiovo C
similar to (hose at other western Siberian fields. Water injection has been used to stimulate the rccov. cry process since (he early stages of development. The Soviets rely on waterflooding to maintain reservoir pressure and improve production and ultimate oilater injection programield the size of Fedorovouge volume of water, which, under ideal circumstances, should match as closely as possible the chemical and temperature characteristics of the reservoir water. Despite reservoir problems thai have occuffed at Samotlor and other fields, atthe Soviets are apparently injecting some surface water into (he reservoir after only minimal treatment Although we are not aware of any reservoir damage yet. the use of surface water without filtering and proper chemical and heat treatment can causemaintenance problems and can reduce Ihe amount of oil ultimately recovered
Another problem the Soviei Union has frequently encountered with water injection is prematurely high water cuts from producingo far. however, this problem has not occurred at Fedorovo lC
0 watercut (or the fieldhole was onlyeasonable figureedotovo's current stage of development
'Tbe "sitrem uibe propinkmol *aiei in tbe ntiiiurr of uiier. oil. iml tucjliacledllibe vaurcvt niu.
in tmreaiinjflukh mutt Ik li'ird from ihe well' tn
iven amounloil
Ai Fcdoiovo the Sovieu have also continued theii practice of developing and producing oil from tbe largest and most promising geologic structure before delineation drilling is cxsmpletedf* ^jThtsmay be responsible for some ol the earlyand conflicting estimates of (he productionof Fedorovo.as delineated inhich encompasses the most promisingwas developed fiiSt and is (he most intensively drilled area or (he Field. C
r
Drilling activity in sectors B, C.ags behind that in sector A. Neveriheleti.ave already been drilled close to the margins of tbeir respectivc structural higbs and will probably be the scene of intensive development drilling dunr.: he nexi several yean Sector D. the least de*elo.rea, will probably not be dulled as densely as the -est of tbe field because of the presence of several large lakes The Soviets normally build cause-ays terminated by mar made islandsrill in fiestiwater lakes, an eipensive and laborious process that Is not siaricd until development is well under way It is instructive to note (hat atield criticalhe USSR's near-term oil production goals, (he Soviets seem tomade no efforts to employ new leclinologics that would allow cheaper and more effective drilling in these lakes
The only significant departure from normal Soviet field development stiaiegy has been the instal' 'lion in
he Fedorovo sector of Ihe fieldas-lift *em boughi fromhe Soviels have state si the Savuysk pool is not scheduled for gas lift VV under gas ltd are made to (low faster by the iniecii of compressed gas inio Die bottom of ihe hole, iftercby lightening Ihe fluid column and incicasing total fluid production ool of individual wells by as much as JOield under gas lift will nor necessarily produce move oil ewer its lifetime lhan one eiplo-.ted with mechanical pumen and wale' insection. bui it willargei percentage of its ol earlier in iu
rirf So--ill PrixLinl
ntern of|.>
rootii ibex aad a< uxialil'
oUma douieiixall. Jewkuj-dGas lift also permits the production of larger volumes of fluid, which lends (sMInbilize oil output as watercuis increase with time
C_ induslry sooices indicate lhat the USSR originally planned tocll gas-lift systemt about lhc time when Fedorovo became the locus of an independent oil and gas association and the pace of drilling beganncrease. According io these same sources, lhai plan was discarded and replacedore ambitious one catling for tbe installation of gas liftellsIdditional wellsy comparison.upergiant field currently producing five limes as much oil as Fedorovo. is slued foras-lifi -cits
Last year the Soviet Minister of Petroleum Industry announced on two occasions ihai ihe Fedorovo gas-bf; project was falling behind schedule
-jthat (heof gns lift will not occur asThree of the foui main compressorbeen constructed along with the gasand the pipelines to transport recoveredthe compressor nations Installation of theequipmeni and the pipelines lo Iransporlgas to ihe individual wellheads, however,behind schedule At the current rate ofof downhole equipment, ihe full system will . jl until the end4 or so. Pipelinewill probably progress at aallowing gas lift to begin in7 The Soviels are aKcmpting iofoe Ihe loss ol rxodstciion caused by the
an infdl drilling program is under way in sector A. the oldest pari of the field where production may have begun to decline The greater density of producing wells in thai sector will achieve the same effect as gat lift- in inctease in oil ptodueiion
Production Fo tec all
Annual production at Soviet oilfields is normally keyed lo goals contained in national five-year plans,dorovo is nociception Oillicld production chiefs arc canceledeet plan goals and often lo
exceed Iheseih rough "counter plans" unlessproduclion mightremature declineplan shortfall later in ihe productionIhecuircni plan
for Kedoiovo Calls for yearlyfili.
I Old Five-Year Plan.ighnd (osiay ai or nearlevel over ihc rest ofth Five-Year Flan period (sec table
i; ; ;has the-espialsess lift io exceedlarjci. Suffic'cn drillingdrill pads aie in place al the field todrilling it iaicto lhal of theyears. If ihcndeed-ill be able :e> maintain production allhc presentore-
over.liic addition of ihc extra capadiy provided
by lhc gas-liftinstalled inells wiihdditional wells being convened eachFedorovo should be able lo exceed plan goals during Ihis period. The upper limit, or maximum efficient ralel which lhc field could be operated during (he remainder of ihe current five-year plan is represented in figureperating al Ihe MER. Ihe Soviels couldroduction plateauevelbove ihe plan goalsapid and premature produclionduringh Five-Year Plan
For ihe MER lo be reached, lhc gas ltd must nari up in increments as the downhotc equipment is installed, and it must operate ai its design capacity. The Soviets will probably achieve an incremental startup or ihe gas lift. They have reported lhai one or thestations at Fcdoiovo is already operating, implying that part of the field is now under gas lilt. Wc think it unlikely, however, that the gas-lift equipment will be operated at peak efficiency. Moreover, someo IS percent of ihe wells at Soviet oilfields are noty shut in al any one time for routine maintenance or repairs. Thus, produclion from Fedorovo will probably fall somewhere between the plan rate and the MER. Nevertheless, the gas-lift program should provide some excess oilpioduction capacity upon which the Soviets could draw if unexpected problems develop at oilier fields. There are some indications lhat Fedorovohave to draw upon ihis excess capacity. The Soviet journal Socialist Industry reported in January, for example, that the oilfield workers at Fedorovo arc committed to exceed2 plan by.
. the period of the next five-year plan, theeservoir will begin to experience problems, including falling production, higher watercuis. and decreasing reservoir energy We expeci that themay uy io offset Ihese problems by increasing the number of wells on gas lift, intensifying infill drilling, or drilling the lakes lo the same density as ihe rest of lhc field. None of these options would be cosi effective if the resources consumed -ere io come at the expense of investment al other, younger fields with high-quality reserves. Alternatively, ilic Soviets could try n> drill separate wells into Iheeservoir lhai is not
a faigh^ualily reservoir, however, and wc doubt the Soviets would elect to drill il as long as better reservoirs were available dscw/ac/e.
If no extraordinary measures arc uken. (heat Fedorovo will be entering an advanced stale of decline ai (Ik end of (his decade. Production willnd dropping rapidly. Watercuis will approachercent for Ihe fieldhole and will be higher in older wells. Even though lhc Soviets will besteadily increasing amounts of fluid, ihey will be extracting decreasing amounts of oil. Nevertheless, durine this decade Fedorovo is expectedeet (he goals of Soviet planners without heroic mcasuies or major infusions of additional manpower or
Our material-balance analysis indicates that thereservoir will be ncaring Ihe end of its producing lifetime in the. wiihoercent of ihe original oil in place recovered undet the present water injection program. This figure, which is somewhat higher lhan ihe recoveries we have calculated for other Soviet fields undei waterflood. is probably ioo optimistic. Material balance docs no! account for intcrwell effects such as -aler channeling andwater brcakihrough, which can increase -atei production and lower ihe oil-recovery percentage The Soviets experience these kinds of problems at most fields -here they employ water injection. Atsuch problems -ould probably begin tedticing production5 For (his icason. wc doubt ultimate recovery will exceedoerceni of the original oil in place in thereservoir
Ai some point in, lhc Soviets will probably try to slow or temporarily reduce lhc produclion decline at Fedorovo They will have iwo options either plugging back th; -ells above lhcreservoir and beginning production from ihe same wells in ihe shallowerorizon, or using an enhancedhehe sizable amount of oil lefl in the6 billionlhc quality of the icscivoir as well as likely improvements in enhanced recoveryead us io believe thai aneed recover)jinbe the opuo"
Among chc enhanced recovery techniques no* avail-able, carbon dioxidenfection and polymer flooding offer ihe most promise for increasingfrom (hessuming nuequalc CO, supplies wereO, program poienlially could recoveroercent ol" ihe remaining oil inoviet decision loould probably be heavily influenced by the resultsimilar program nowection of lhc much larger Romashkioo field in the Urals-Volga oil-producing region. Polymer flooding is equally promising and would probably be more cost effective Tbc technology is relativelyihe increased cost of production moderate, and the potential recovery percentage equal to that ob-laiced in CO, injection '
Neither of (hese lechniques has yet been fully proved in the field, even in more technologically advanced countries such as ihe United States. If the Soviei oil industry were to apply either process in the near future, its Success would be pfoblemalic wiihoul Western assistance By, however, asevolves and the Soviets gain more experience wiih enhanced recovery techniques, the silualion might be different. In anyecision to initiate an enhanced recovery process would ullimaielyon which of two funds menially differentstrategies Ihe USSR chooses to emphasize for its petroleum industry during the rest of this decade The Soviets could decide lo concenirate their efforts and inveslmenl resources on finding and developing new fields in new areas, in which case Fcdorovo would cease toignificant oil producer in ihelternatively, ibcy could decidetilize theirmanpower, capital, and equipment to sustain produclion al existing fields Thereservoir al Fedorovo would (heneading candidate for enhanced recovery.
'CO, mieiiKMii' .. im b*y null or in tonh -iterfloodiaif la milium prow,cp <f* oileservoir towardlac pinduttionUnlikeCO, mitts "tiloilluid thn mow* more caii'v ihiovrh iiu ion*he roeV
Polymer floooinir iii'olvonuiinifc. -alcrllood, il, Uriljried (nirmtali enhr-
polyiKCharidei or polfai'rlamiilei tu rni^on ihr alaliiv ol
c|ioiliht production
Outlook
The Soviet Union clearlyumber ofsci-backs in developing Fedorovo. Early fieldwas slower than expected, the gasjjfifell behind schedule, and Ihc Soviets achieved aa major technological breakthroughs or proceduralOur analysis indicates, however, that de-spile these setbacks, the Soviet Petroleum Ministry has now amassed enough personnel and material al the field to rnaxtmizc oil production soon. Fedorovo should easily achieveth Five-Year Plan targets,o major setbacks occur in the drilling and gas-lift programs, the field should be able to achievelevelsbove the plan. Thus we anticipate that Fedorovo willelcome bright spot for lhc Soviets on what may be an increasingly troublesome ail horizon If similar successes arc achieved at Older key western Siberian fields, Soviet near-term petroleum prospects winconsiderably, and ihc potentialownlurn in produclion in theould be lessened.
Original document.
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