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    Society

    of

    PetroleumEngineers

    SPE 24931

    Simulation of a Successful Polymer Flood in the Chateaurenard Field

    Sunao Takaqi, G.A. Pope* and Kamy Sepehrnoori,*

    U.

    of Texas; A.G. Putz,* Elf Aquitaine;

    and Hichem BenDakhlia,*

    U

    of Texas

    SPE Members

    Copyright 1992 , Society of Petroleu m Engineers Inc.

    This pape r was prepared for p resentation at the 67th Annual Techn ical Conferenc e and Exh ibition of the Society of Petroleum Engineers held in Washington,

    DC

    October 4-7, 1992.

    This paper was selecte d for pres entation by an SP E Program Comm ittee following review of information containe d in an abstract submitted by the author@ ). Contents

    of

    the paper,

    as prese nted, have not been reviewed by the Society of Petroleum Enginee rs and are subject to correction by the author(@ . The mater ial, as presente d, does not necessarily reflect

    any position of the Society of P etmleum Enginee rs, its officers, or me mbe rs. Papers presented at SPE meetings are subject to publication review by Editorial Committees of the Society

    of Petmleum Engineers. Permission o copy is restricted to an abstract of not more than 3 00 word . Illustrations may not be copied. The abs tract should contain conspicuous acknowledgment

    of where and by whom the paper is presented. Write Librarian, SPE, P.O. Box

    833836

    ichardson.

    TX

    750834 836 U.S.A. Telex, 730989 SPEDAL.

    BSTR CT

    Early results of a successful polymer project started in

    1985 in the Courtenay sand of the Chateaurenard field located

    south of Paris, France, were presented at the fall 1988 SPE

    meeting. We update these data and show that subsequent

    performance has confirmed the highly favorable oil recovery

    behavior of this project. The objective of this paper is

    to

    report

    the results of a detailed compositional simulation study

    conducted to understand this favorable result. Both alternative

    reservoir and process characteristics were investigated in these

    three-dimensional simulations. n particular, both a classical

    layered reservoir description and a geostatistical reservoir

    description were investigated. The latter represents a new

    approach to the interpretation of polymer flooding and played an

    important role in our study since the attenuation of reservoir

    heterogeneities is known to be an important attribute of polymer

    flooding. We also evaluated the importance of permeability

    reduction and adsorption of the polymer on process performance.

    After obtaining a good match of the production of oil, water and

    polymer, we then investigated the importance of design factors

    on the oil recovery performance. The actual polymer flood

    consisted of injecting a large polymer slug followed by five

    smaller slugs of decreasing polymer concentration

    to

    decrease the

    time that a study of this type with an accurate compositional

    simulator has been reported for polymer flooding. The

    combition of better reservoir characterization methodology and

    accurate process simulation of polymer flooding should aid in the

    successful exploitation of this technology in the future.

    This

    project clearly shows the high potential of polymer flooding

    under the appropriate reservoir conditions and with good design

    and implementation methods.

    INTRODU TION

    polymer flood pilot test1 in the Courtenay sand of

    the Chateaurenard field was started in 1985. This pilot test is

    characterized by high oil recovery

    1.5

    bbl oil per lbm polymer)

    and high retention of polymer in the reservoir. The performance

    of this pilot was simulated using a compositional chemical

    simulator called UTCHEM developed at The University of

    exa as Actual field

    data

    and available physical property data

    were used as much as possible to evaluate simulation input

    parameters. UTCHEM is a three-dimensional, compositional,

    multicomponent, multiphase, finite-difference simulator.

    third-order correct in space finite-difference method3 with a flux

    lirnitefi is used to approximate the partial differential equations.

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    2

    SIMUL TION OF SUCCESSFUL POLYMER FLOOD INT HE CH TE UREN RD FIELD

    SPE

    24931

    Geology and Reservoir Characteristics

    The Chateaurenard field is located 100 km south of

    Paris, France, and is divided into three main structures: Saint-

    Firmin, Chuelles, and Courtenay. There have been several

    polymer and microemulsion pilots and a commercial-scale

    polymer flood conducted by Elf Aquitaine in the Chateaurenard

    field.lv6-l2

    Elf Aquitaine started a polymer pilot in the Courtenay

    reservoir sand of the Chateaurenard field on October 1, 1985.

    The sand was deposited on an already pre-existing structure of

    channels and basins, which explains rapid pay thickness changes

    even though the top of the formation is essentially flat.

    Vertically this structure consists of three unconsolidated sand

    layers. The lower layer is the polymer flood pilot target. The

    reservoir thickness varies between 0 and 7 meters with an average

    of 3.2 m. The structure of the Courtenay is a monocline with a

    low dip of 2 to the northwest. In the southeast direction, the

    structure is terminated by fingered stratigraphic traps with the

    reservoir becoming increasingly shaly. In the northwest

    direction, the oil zone is limited by a very large aquifer. This

    reservoir is an unconsolidated sand with a small percentage of

    clay (2 to 15 ), mainly composed of kaolinite. The porosity

    is nearly uniform and about 30 . The field permeability varies

    from 800 to 3,000 md and the mean value is estimated to be

    1,600 md in the pilot area.

    The original oil in place was 11.7 million m3 (73.6

    million bbl) in the Chateaurenard field of which 1.3 million m3

    (8.2 million bbl) is in the Courtenay sand. The pore volume and

    original oil in place inside the five-spot used in the Courtenay

    polymer pilot were estimated to be 44,444 m3 (280,000 bbl) and

    27,555 m3 (173,000 bbl), respectively. A summary of original

    oil in place and pore volume of each area is given in Table 1.

    The oil viscosity is 40 cp at 3 0 ' ~ reservoir temperature) and the

    oil density is 0.89 (~~'API) .The wells do not produce free gas.

    The formation water is fresh with a total dissolved solids content

    of about 0.4 glliter. The water viscosity is 0.73 cp at reservoir

    temperature.

    Production History

    The Chateaurenard field was put into production in

    1960. By December 1987, the cumulative production was 3.8

    million m3 (23.9 million bbl). The total cumulative production

    from the Courtenay reservoir was 0.389 million m3 (2.5 million

    bbl). Well CY30 had been producing for five years with a total

    production of 25,000 m3 (157,000 bbl), and wells CY40, CY41,

    and CY42 had been producing for three years with a production

    of about 11,000 m3 (69,000 bbl) for each well before the

    polymer project.

    well (CY543) was drilled for polymer injection in 1984. The

    well pattern is shown in Fig. la.

    The injected polymer was a partially hydrolyzed

    polyacrylamide. The pilot operation consisted of successive

    injections of a slug of 1,000 ppm polymer concentration,

    followed by a tapered concentration as shown in Table 2. After

    the final slug of 200 ppm polymer solution was injected, chase

    water was injected. The total volume of polymer solution

    injected was 47,200 m3 (297,000 bbl), which is 1.06 times the

    pore volume of the five-spot, and the total amount of polymer

    injected was 37.3 metric tons (82,300 lbm). The four producing

    wells were kept at about the same producing rate and the total

    production rate from the wells has been almost the same as the

    injection rate.

    Pilot Performance

    The polymer solution injection started on October 1,

    1985, and the injection rate was increased from the level of 50

    m3/d (314 BID) until it reached 100 m3/d (629

    BID

    at the

    beginning of 1987 after which it was kept nearly constant. Both

    injection and production volumes in this paper refer to standard

    conditions.

    A distinctive characteristic of the injection well was that

    the wellhead pressure of 18 bars (260 psia), which corresponds to

    about 1,100 psia bottomhole pressure, did not increase even

    when the injection rate increased or when the injection viscosity

    was suddenly increased. This indicates that the injector was

    operating above the parting pressure of the sand at least part of

    the time. The very good injectivity of polymer is one of the

    most favorable characteristics of this successful polymer pilot.

    Putz

    et

    a1.l reported that 18,300 m3 (115,000 bbl) of

    oil were produced from the Courtenay sand reservoir by 1987.

    The average field oil cut was then 16.6 , with 38 for the

    polymer pilot and 11 for the other wells. By June 1989, the

    cumulative oil production from the pilot was 26,013 m3

    (164,000 bbl), (about 94 of the initial oil in place inside the

    five-spot; see Table 1) and the produced polymer was only 0.3

    tons. Corlay t a1.13 estimated that the additional oil recovered

    in the polymer pilot was 19,000 m3 (120,000 bbl), which is

    about 1.5 bbl oil per Ibm of polymer, a very favorable result.

    Figure 2 shows the total oil production rate from the

    four producers in the pilot area after starting the polymer

    injection. After the start of polymer injection, the oil cut of the

    producing wells remained unchanged for 250 days, after which

    two wells encountered a sharp increase in oil cut. For well

    CY30, the oil cut increased from 18 to a maximum of 61 at

    500 days (Fig. 3). For well CY42, the oil cut increased from

    19 to a maximum of 50 at 450 days (Fig. 4). Well CY41

    experienced the arrival of the oil bank a little later, with an oil

    cut increase from 12 to 37 (Fig. 5). Only a weak response

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    SPE 24931

    S.TAKAGI H. BENDAKHLIA G.A. POPE,A. PUTZ

    ND K.

    SEPEHKNOORI

    3

    arrival of tertiary oil banks in five wells and a high concentration

    of polymer in one well have been observed.

    S I M U L A T I O N

    A complete description of the simulation input as well

    as the polymer models used for each polymer property are given

    in ~ a k a ~ i . l ~summary of the most important simulation

    input parameters is given below.

    Stat is t ical ly Dis tributed Permeabil i ty Field

    Heterogeneous permeability fields were generated by the

    method of moving averages or Matrix Decomposition Method

    (MDM) using a spherical variogram and a log-normal

    permeability distribution.15*16 A common measure of

    permeability variation is the Dykstra-Parsons coefficient (VD~).

    If the permeability distribution is log-normal, the Dykstra-

    Parsons coefficient is described as

    where k50 is the median permeability, kg4.l is the permeability

    one standard deviation below k50 on a log-permeability plot, and

    o nk is the standard deviation of log permeability.

    A correlation length scale, h is the parameter used to

    express spatial correlation. The degree of correlation between the

    permeabilities at two points decreases as the distance between

    them increases. The correlation length scale was normalized by

    the length of the side of the simulated area (500 m or 1,640.5 ft).

    For the base case, I 1,549 md, V D ~ 0.221, ~ D X

    h ~ y1.0, and DZ 0.33. These parameters represent

    relatively low permeability variations, a strong correlation in the

    horizontal direction, and a low correlation in the vertical

    direction. A verticaVhorizonta1 permeability ratio (kv /k~)f 1.0

    was used throughout this study. The permeability field generated

    by MDM for the 15x15~3rid is shown in Figs. 7 through 9.

    Unfortunately, these parameters had to be inferred from history

    matching rather than from core data or other measured reservoir

    data since these were not available on this sand.

    Injection Rate

    The four producing wells were constrained by a constant

    pressure of 100 psia, the same pressure as the initial reservoir

    pressure. The total injection volume of this pilot was about 6

    more than the total production volume from the four wells, so

    the injection rate was made the same rate as the total producing

    rate (Table

    3 .

    As a result, the total volume of polymer

    solution injected was 44,524 m3 (280,000 bbl), which was

    paper by Putz t a1.l with the calculated viscosity is shown in

    Fig. 10. The parameters that determine the effect of shear rate on

    polymer viscosity were obtained from data on partially

    hydrolyzed polyacrylamide.17 The polymer viscosity at the

    injected polymer concentration of 1000 ppm and 90 s-l is about

    20 cp. This gives a mobility ratio between the initial polymer

    slug and the oil bank of about 0.4.

    For modeling the polymer adsorption in the simulator,

    the salinity dependency was neglected since the salinity in the

    reservoir is essentially constant. The adsorption isotherm for

    both the base case and the final simulation are shown in

    Fig. 11.

    The permeability reduction was reported by Putz l a1.l

    as 1.3. However, in order to simulate the high oil cut of the

    producing wells, higher permeability reduction Rk than this

    value had to be used. Figure 12 shows the calculated Rk as a

    function of polymer concentration and permeability for the two

    assumed cases that we simulated. In the final simulation, the

    maximum gridblock permeability reduction was 9.182. The

    reason why higher values are needed to match the field behavior

    of this pilot is not known. Low values of permeability on a

    small scale is one possible explanation for these higher values.

    A value of 0.15 was used for inaccessible pore volume

    in all simulation runs. Longitudinal and transverse dispersivities

    were 1.0 and 0.0 ft, respectively.

    The oil relative permeability was based on the data by

    Putz

    t

    a1.l However, the water relative permeability was

    modified by changing the endpoint relative permeability to water

    and the residual oil saturation. The original values were 5.8

    and 27 , respectively, and the modified values were both 20 .

    Recent experimental research18 has revealed the fact that the

    residual oil saturation to polymer (Sorp) in heterogeneous cores

    is often about 6 lower than that to water (So,,) even when the

    capillary number for each coreflood is kept precisely the same.

    This is consistent with the residual oil saturation to polymer of

    20 being lower than that to water of 27 needed to match this

    field pilot data. We consider this to be one of the most

    interesting and significant observations about this pilot study.

    When large amounts of highly viscous polymer are injected into

    heterogeneous rock containing oil above residual oil saturation,

    both laboratory and field data support the conclusion that the

    residual oil saturation in the swept zone will be lower to

    polymer than to water, so polymer flooding has the potential in

    some favorable circumstances of not only improving sweep

    efficiency and accelerating oil recovery, but also of reducing the

    ultimate oil saturation locally.

    For the simulated area of 1,640.5 ft x 1,640.5 ft shown

    in Fig. lb, a 15 x 15 grid with AX AY 109.367 ft was used.

    For the three vertical layers used for the base case, A was equal

    to 3.60858 ft. For the final match to the field data, variable

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    SIMULATION OF A SUCCESSFUL

    OLYMERFLOO N

    THE

    CH TE UREN RD

    FELD

    SPE 24931

    oil in place inside the five-spot was produced. The slope of the

    recovery w e ecame steeper aftcr 500 days because the oil bank

    formed by the polymer started to break through to the producing

    wells. To determine the effect of mesh refinement on the base

    case, one run with a 25 25 3 areal mesh refinement was

    made. The effect of this mesh refinement on the oil recovery

    efficiency is shown in Fig. 13. The areal mesh refinement

    resulted

    in

    a change of only 2.3 in the oil recovery. A vertical

    mesh refinement was done for the final field simulation shown

    later and resulted

    in

    even less change in oil recovery.

    Sensitivity of Oil Recovery to Adsorption

    The adsorption isotherm with one-half the maximum

    adsorption plateau of the base case (Fig. 11) was used for

    comparison with the base case. As shown in Fig. 14, the oil

    recovery for this Run PF2 increased 9 . The adsorption of

    polymer in mass units was 105 pglg. This level of adsorption

    resulted in 83.3 retention of the injected polymer for Run PF2,

    while for the base case Run PFO, with an adsorption of 118

    pgjg, 93.7 of injected polymer was retained. These retention

    values are based upon the pore volume inside the five-spot

    pattern. The actual local adsorption in any given gridblock

    varies but is lower. The lower adsorption of Run PF2 resulted

    in higher simulated polymer concentrations and earlier polymer

    breakthrough times as would be expected. Detailed analysis of

    s

    nd other results can be found

    in

    Takagi's thesis.14

    Sensitivity of Oil Recovery to Permeability

    Reduction

    The permeability reduction of the polymer was reduced

    from the base values as shown in Fig. 12. A comparison of the

    oil recovery for this Run PF3 with that of Run PFO is shown in

    Fig. 15. The oil recovery is about 9 less than that of Run

    PFO. Each well had a higher simulated polymer concentration.

    The maximum permeability reduction in any gridblock was 10.8

    for the base case but only 3.0 for Run PM. As expected, lower

    permeability reduction resulted in lower oil cut and lower oil

    recovery.

    Sensitivity of Oil Recovery to the Dykstra-Parsons

    Coefficient V D ~ )

    A

    VDP value of 0.5695 was used for the case of higher

    heterogeneity (Run PF4)

    th n

    the base case (Run PFO; V D ~

    0.221). A comparison of the cumulative oil recovery for Run

    PF4 with that for Run PFO is shown in Fig. 16. The oil

    recovery for Run PF4 is about 3 more than that for Run PFO.

    This result indicates that the higher heterogeneity (VD~)han the

    base case causes higher oil recovery, which was not expected.

    Recall that the vertical and horizontal permeabilities are equal,

    which is favorable for crossflow. The gravity number Ng)or

    regions free of polymer is about 0.006 based upon an aqueous

    viscosity of 0.73 and for regions with 1000 ppm of polymer is

    about 0.0003 based upon 20 cp aqueous viscosity. The effective

    This would not happen in most cases. Tables and contour plots

    showing precisely how and where this happened in this

    realization are given in Takagi's thesis.14

    Comparison Between Layered and Stochastic

    Permeability Distribution

    Next, a simulation was made using a reservoir

    description consisting of three permeability layers with 400 md

    on top, 4000 md in the middle layer and 400 md on the bottom.

    A comparison of the oil cumulative recovery for this Run PF5

    with that for Run PFO is shown in Fig. 17. The oil recovery for

    Run PF5 is about 5 more th n that for Run PFO. However,

    as shown in Takagi, the agreement with the water cuts and

    polymer production data from individual wells was not as good

    as for the final field case using a statistically generated

    permeability field as shown next and there is no easy mechanism

    for systematically assessing the uncertainty of the result as there

    is for the stochastic case.

    Simulated (Run PF6) and field oil production are shown

    in Figs. 2-6 and 18, and comparisons of the simulated water cuts

    and aqueous phase polymer concentrations with the field data for

    each producing well are shown in Figs. 19 through 22. For the

    base realization, the field oil recovery at 1,369 days after start of

    polymer injection was 94.4 of the initial oil in place inside the

    five-spot (26,013 m3 or 163,600 bbl).

    The simulated oil

    recovery at 1,369 days was 90.3 of the initial oil in place

    inside the five-spot (24,923 m3 or 156,600 bbl).

    Increasing the number of vertical gridblocks from three

    to six made almost no difference in these results. We also show

    on

    each of these figures another realization created by simply

    changing the seed for the random number generator. Again, there

    is little difference between this realization and the one labelled

    base realization that was used to generate all of the results shown

    in this paper. We did many more realizations with similar

    results. This reflects the insensitivity of the results to small

    changes in heterogeneity. The results of this fhal case differ

    from the base case because log based variable sand thicknesses

    were used rather than a uniform average thickness.

    The simulated and field polymer breakthrough times are

    very close. The simulated maximum polymer concentrations in

    wells CY30 and CY40 are close to the field values, whereas the

    simulated

    peak

    polymer concentrations for well CY42 and CY41

    are about 70 ppm too high. The simulated retained polymer was

    120 pg/g rock, or 95.0 of the injected polymer compared to

    99.2 field retention. Retention of polymer in pg/g rock is

    based on the rock volume inside the five-spot pattern. Local

    adsorption values vary but are lower than this average based upon

    the five-spot volume, which is used merely for a convenient

    reference. The maximum adsorption for any gridblock was about

    36 pgtg. This amount of adsorption is about the same as the

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    SPE

    24931

    S.TAKAGI.H. BENDAKHLIG

    G A

    POPE.A PUTZ

    AND K

    EPEHRNOORI

    of simulated water cuts to the field data. Thus, a comprom ise is

    required to simultaneously achieve a good agreement match of

    both water cut and polymer production.

    Field water cuts in well CY30 (Fig. 19) show a

    stronger oil bank than the simulated water cuts. A comparison

    of the simulated and field water cuts in well CY42 (Fig. 20)

    shows good agreem ent in the first 800 days, but the simulated

    water cuts are too high after 800 days.

    A comparison of the

    simulated and field water cuts in well CY41 (Fig. 21) show s that

    the simulated water cuts are too high except for the time period

    from

    4

    to 800 days. A comparison of the simulated and field

    water cuts in well CY40 (Fig. 22) shows good agreement most

    of the time.

    Polymer concentration grading is a strategy for

    decreasing fingering of the chase water through the polymer slug.

    The

    effect of graded polymer flooding was studied by comparing

    its results with those of a single-slug polymer flood of

    1,000 ppm polymer co ncentration. The single-slug polymer

    flood case was simulated with the same amount of polymer as

    the graded polymer case. The simulated area, the grid, the well

    pattern, and all other parameters were the sam e as for the base

    case.

    There was essentially no difference between the

    simulations for the base case (graded) and the ungraded

    simulation, so the results are not plotted here but c nbe found in

    Takagi, who also shows other simulations to study grading and

    fingering. This may seem like a surprising result given the high

    mobility ratio between injected polymer solution and chase water

    and thus the tendency for viscous fingering. However, detailed

    simulation studies of the unstable dis lacement of polymer

    solutions by water made by KruegerlBand ~ U ~ Os well as

    Takagi s results including some a t higher mobility ra tios and

    using finer grids have shown that decreasing polymer

    concentration gradually (polymer grading) often makes very little

    difference in oil recovery for a given total amount of injected

    polymer. Although space does not allow us to discuss these

    results in detail, the general nature of the result can be

    summarized as follows. Other factors may be so dominant that

    fingering has little effect. In the case of the Courtenay sand

    polymer flood, the dominant facto r was polymer adsorption. A

    secondary factor was heterogeneity. Large directional variations

    in

    permeability caused the chase water to channel rather than

    finger.

    Several papers21-23 have recently addressed the

    conditions under which channeling, fingering, or gravity

    segregation tends to be the dominant flow mechanism in

    miscible displaceme nts at unfavorable mobility ratios. High

    heterogeneity, especially high correlation length, tends to

    promo te channeling as opposed to fingering. Also, the very

    high value of RL of 50 tends to suppress fingers and promote

    cases, the dominant polymer design factors are likely to be the

    total amount of polymer and its initial concentration rather than

    grading. High concentrations and large amounts of polymer as

    used in this Courtenay pilot have been found to be the best

    approach to polymer flooding in the field cas es that Krueger and

    Liu have studied to date.

    ON LUSIONS

    Good agreement was obtained between the simulated and

    field performance of the Courtenay polymer pilot in the

    Chateaurenard field using a statistically generated permeability

    field. Better agreement with the field

    data

    and better ins ight into

    the behavior of the pilot was obtained using this approach rather

    than a reservoir description consisting of uniform layers. More

    information from logs, cores, tracers or other sources would have

    been very desirable to use in conditioning these stochastic

    permeability fields, but even in the absence of conditioning some

    insight into the uncertainty and importance of the reservoir

    heterogeneity was obtained by a combination of sensitivity

    studies and multiple realizations. Both areal and vertical mesh

    refinement indicated that these simulation results were

    numerically accurate since the oil recovery changed very little as

    the gridblock sizes decreased . Sensitivity studies showed that

    this polymer pilot was dominated by polymer adsorp tion. The

    oil recovery was surprisingly insensitive to change in the

    permeability distribution (heterogeneity as measured by the

    Dykstra-Parsons coefficient). Reduction of residual oil saturation

    by the polymer to values below that expected of water may have

    contributed to the good oil recovery in this pilot.

    Although the actual polymerflood pilot used a large,

    graded polymer injection scheme, comparisons w ith simulated

    resu lts for a single , large polymer slug with the same total mass

    of polymer indica ted that grading made very little diffe rence in

    this pilot, i.e., finge ring was not important. This result can be

    explained in terms of the dominant importance of polymer

    adsorption and fractional flow effects and to a lesser extent the

    effects of heterogeneity with large correlation length and large

    effective length to thickness ratio that promotes channeling

    rather than fingering. The exc ellent oil recovery of this pilot

    (1.5 bbl of incremental oil per lbm of polymer) was a result of

    using a large amount of polymer, favora ble reservoir conditions

    and good des ign and implementation of this technology.

    NOMENCLATURE

    kH

    Horizontal permeabiiity (md)

    k = Vertical permeability (md)

    =

    Endpoint relative permeability to aqueous

    phase

    0

    Ng = kxAp H Gravity

    Number

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    STMUL TIONOF

    A

    SUCCESSFULPOLYMER FLOO NTHECH TE UREN RD

    FIELD

    SPE

    2493

    Greek

    Symbols

    L

    correlation length scale (ft)

    p

    Viscosity of aqueous phase

    Porosity (fraction)

    ACKNOWLEDGMENTS

    We thank Ph. Corlay, Ph. DeLapace, J. Lecourtier, and

    1. P~ersonfrom IFP for their contribution to the paper.

    Financial support from the U.S. Department of Energy and the

    participating companies of the Enhanced Oil and Gas Recovery

    Research Program of the Center for Petroleum and Geosystems

    Engineering at The University of Texas at Austin is gratefully

    acknowledged. Computing resources for this work were provided

    by

    The University of Texas Center for High Performance

    Computing. Sunao Takagi would like to thank Japan China Oil

    Development Co. (JCODC) and Japan National Oil Co. JNOC)

    for the financial support during this study.

    Putz, A., J. Lecourtier, and L. Bruckert: Interpretation of

    High Recovery Obtained in a New Polymer Flood in the

    Chateaurenard Field, paper SPE 18093 presented at the

    63rd Soc. Pet. Eng. Annual Tech. Conf. and Exhibition,

    Houston, TX, Oct. 2-5, 1988.

    Datta Gupta,

    A.

    G.A. Pope, K. Sepehmoori, and R.L.

    Thrasher: A Symmetric, Positive Definite Formulation of

    a Three-Dimensional Micellar/Polymer Simulator, SPE

    Reser Eng.

    (Nov. 1986) 1 No. 4,622-32.

    Saad, N., G.A. Pope, and K. Sepehmoori: Application of

    Higher-Order Methods in Compositional Simulation,

    SPE

    Reser Eng (Nov. 1990) 5 No. 4,623-30.

    Datta Gupta, A., L.W. Lake, G.A. Pope, K. Sepehmoori,

    and M.J. King: High-Resolution Monotonic Schemes for

    Reservoir Fluid Flow Simulation. In Situ (Sept. 1991)

    15 NO. 3, 289-317.

    Pope, G.A.: Mobility Control and Scaleup for chemical

    Flooding, DOE/BC/10095-4 Report prepared for the U.S.

    Department of Energy under contract no. DE-AC19-

    79BC10095, Bartlesville, OK (1981).

    Bourdarot, G., M. Sardin, and A. Putz: Chateaurenard

    Field Test Recovery Mechanism and Interpretation, paper

    SPE 12685 presented at SPE POE Symposium on

    Enhanced Oil Recovery, Tulsa, OK, Apr. 15-18, 1984.

    Chapotin, D., J.F. Lomer, and A. Putz: The

    Chateaurenard (France) Industrial Microemulsion Pilot

    Design and Performances, paper SPE 14955 presented at

    SPEPOE Symposium on Enhanced Oil Recovery, Tulsa,

    OK, Apr. 20-23, 1986.

    Putz, A. and R.C. Rivenq: Commercial Polymer

    Injection in the Courtenay Field, J

    Per Sci Eng

    (1992)

    7 15-23.

    Rivenq, R., M. Sardin, D. Schweich, and A. Putz:

    Sodium Carbonate Preflush: Theoretical Analysis and

    Application to Chateaurenard Field Tests, paper SPE

    14294 presented at the 60th SPE Annual Technical

    Conference and Exhibition, Las Vegas, NV, Sept. 22-25,

    1985.

    Corlay, P., P. Delaplace, J. Lecourtier, and I. Pierson:

    Champ de Chateaurenard Interpretation du Comportment

    du Pilote D'Injection de Polymere Courtenay (MDPl),

    A.R.T.E.P., CFP Total, ELF Aquitaine, I.F.P., Associe:

    G.D.F. (Mar. 1991).

    Takagi, S.: Field-Scale Simulation of Chateaurenard

    Polymer Pilot, M.S. thesis, The U. of Texas, Austin

    (1992).

    Wilson, J.L.: The Synthetic Generation of Areal

    Averages of Random Field, paper presented at the S o c m

    Workshop on Stochastic Methods in Subsurface

    Hydrology, New Mexico Institute of Mining and

    Technology, Socorro, Apr. 26-27,1979.

    Yang A.P.: Stochastic Heterogeneity and Dispersion,

    Ph.D. dissertation, TheU of Texas, Austin (1990).

    Ganapathy, S., D.G. Wreath, M.T. Lim, B.A. Rouse,

    G.A. Pope, and K. Sepehrnoori: Simulation of

    Heterogeneous Sandstone Experiments Characterized Using

    CT Scanning, SPE 21757 presented at the SPE Western

    Regional Meeting, Long Beach, CA,

    Mar.

    20-22, 1991.

    Wreath, D.G.: Polymer Flooding and Residual Oil

    Saturation, M.S. thesis, The U. of Texas, Austin (1989).

    Krueger, C.:

    Viscous Fingering, M.S. thesis, The U. of

    Texas, Austin (1989).

    Liu, J.: Ph.D. dissertation (in progress), The U. of Texas,

    Austin (1992).

    Chang, Y.B., M.T. Lim, G.A. Pope, and K. Sepehrnoori:

    Carbon Dioxide Flaw Patterns Under Multiphase Flow,

    Heterogeneous Field Scale Conditions, paper SPE 22654

    presented at the 66th Annual Technical Conference and

    Exhibition of the Society of Petroleum Engineers, Dallas,

    TX, Oct. 6-9, 1991.

    Ringrose, P.S., K.S. Sorbie, F. Feghi, G.E. Pickup, and

    J.L. Jensen: Relevant Reservoir Characterisation:

    Recovery Process, Geometry and Scale, paper presented at

    the 6th European IOR-Symposium, Stavanger, Norway,

    May 21-23, 1991.

    Waggoner, J.R., J.L. Castillo, and L.W. Lake:

    Simulation of EOR Processes in Stochastically Generated

    Permeable Media, paper SPE 21237 presented at the SPE

    1 th Symposium on Reservoir Simulation, Anaheim, CA,

    Feb. 17-20, 1991.

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    Table 1. Pore Volume, OOIP and Cu mulative Oil Production

    f December 1987

    as of June 1989

    Table 2. Injection Scheme of Polymer Solution in the Chateaurenard Polymer Pilo t

    Table 3.

    Injection Schedule of Polymer and Chase Water used in Simulations

    Date started Time, t t

    Injection Rate Concentration

    Volume Polymer

    mo/day/yr)

    days)

    days) B P I

    [m3/dl

    PPm)

    @b l) [m31 Quantity

    tons)

    10/01/85 273 273 252 [40]

    334 [531

    408 [64.8]

    230 [36.6] 1,000

    555 [88.21 800

    622 98.91 625

    586 [93.1] 500

    537 B5.41 400

    531 [84.3] 200

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    Figure 1A Isopach map of the Courtenay field

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    0 200 400 600 800 1000 1200 1400 1600

    Time

    Days)

    Figure 2. Com parison of the total oil production rate for the final simulatio n

    PF 6) with the field data.

    ield data

    Base realization 15 x1 5~ 3)

    *

    Realization 3

    200 400 600 800 1000 I200 1400 1600

    Time

    Days)

    Figu re 4. Com parison of the oil production rate of well CY4 2

    for the final simulation PF6 ) with the field data.

    Time Days)

    Figure 3 Co mp arison of the oil production rate of well CY3 0

    for the final simulation PF6 ) with the field data.

    Time

    Days)

    Figure 5 Com parison of the oil production rate of well CY41

    for the final simulation PF 6) with the field data.

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    I l l l t l l l l l [ l l l { l l l l l r a l l l l r

    ield data

    Base rea li zat ion 15 x1 5~ 3)

    Mesh refinement 15 x15 ~6 1

    Realization 3

    Figure 6. Comparison of the oil production rate of well CY40

    for the final simulation PF 6) with the field data.

    x direction

    1 7

    4

    5

    8

    9

    I 0 1 1 1 2 1 3 1 4 1 5

    x

    direction

    1 2

    4

    5

    6 7 8

    9 1 0 1 1 1 2 1 3 1 4 1 5

    Figure 7. Permeability contour map for the top layer 1 5x 1 5~ 3) .

    Figure

    8

    Permeability contour map for the middle layer 15 x1 5~ 3) .

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    x direction

    I 2 6

    7 8 9 1 0 1 1 1 2 1 3 1 4 1 5

    Polymer concentration (wt 7c)

    Figure 10. Comparison of measured and modeled viscosities

    of polymer solution at zero shear rate.

    Figure

    9.

    Permeability contour map for the bottom layer 15x 15x3 ).

    Polymer concentration

    wtclc

    Figure I I. Polymer adsorption isotherms.

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    1 5 . I I

    ase case and at lOW md

    Base case and at 1500md

    - - - Base case and at 2000md

    -

    ow case and at 1000md

    - - - .

    Low

    case and at 1500md

    -

    Low

    ase and at

    2000

    md

    Polymer concentration

    ( ~ 1 )

    Figure 12. Permeability reduction factor for the base case and the low case.

    200 400 600 800 1000 1200 1400 1600

    Time Days)

    Figure 13. Comparison of the oil recovery for the base case PFO: 15 ~15x3) ith

    the oil recovery for the areal mesh refinement case PF1: 25x25~3).

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    0 200 400 600 8 00 1000 1200 1400 1600

    Time

    Days)

    Figure 15. Comparison of the oil recovery for the base case PFO) with

    the oil recovery for the lower permeability reduction case PF2).

    0 200 400 600 8 1000 1200 1100 I600

    Time Days)

    Figure 16. Comparison of the oil recovery for the base case

    PFO)

    with

    the oil recovery for the higher VDpcase PF4).

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    Time

    Days]

    Figure 18. Com parison of the oil recovery for the final

    simulatio n PF6 ) with the field oil recovery.

    200 400 h00 XI10 1000 1?00 1400 h l l

    me Days

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    0 2 0 0 OO 600 SO0 1000

    1200 1100

    Time Days)

    Figure 20. Comparison of simulated well performance PF6)with the field well

    performance in well CY42.

    2 0 0 400 600 8 0 0 I J00 12illl 11110 lh 00

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    SP 24931

    ield data

    Base realization l S x l h 3

    Mesh refinement

    1 5 x 1 5 ~ 6

    ........