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  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    1/8

    Design of Muds for Carrying Capacity

    R. E. Walker SPE AIME LamarU.

    T. M. Maye s

    SPE-AIME Milchem Inc.

     ntrodu tion

    Hole cleaning  san important function

    of

    a drilling liquid.

    The ability to predict the degree of cleaning possible for a

    given mud and flow rate is a definite advantage in plan

    ning and completing a successful drilling operation. The

    prediction is normally made by calculating the transport

    velocity the difference in the annular velocity and the

    slip velocity of the particles by assuming the slip veloc

    ity is equal to the terminal settling velocity

    of

    the particle

     

    a stationary liquid. The settling velocity

     s

    easily calcu

    lated if the annular flow  s turbulent or the particle settles

    in the turbulent regime. Under these conditions the slip

    velocity depends on the density difference between the

    mud and the particle and on the particle shape and size.

    The slip velocity  s not a function of the liquid viscosity.

    However these settling velocities may be high up to 74

    ft/min for a shale sphere Vs in. in diameter and high

    annular velocities are needed to clean the hole.

    There are many cases where high annular velocities are

    unavailable and/or undesirable. Annular velocities may

    be low because of pump limitations or an enlarged hole

    o r may be low where risers are used. Also it may be

    necessary to restrict annular velocity

    t

    minimize the

    equivalent circulating density or to maintain laminarflow

    opposite drill collars. If turbulent-regime slip velocities

    are too high forthe annular velocities the viscous proper

    ties of the liquid must be increased until the particle falls

    in a transition or laminar regime where slip velocities are

    influenced by viscous forces. Unfortunately none of the

    methods proposed in the literature for predicting terminal

    settling velocities in the transition or laminar regimes are

    suitable for field application. Most of the theoretical and

    experimental work

     s

    with s p h e r e s 1 ~ 8 1 0 ~ 1 3 ~ 1 4 or with liq-

    uids that are almost Newtonian. In work using non

    Newtonian liquids the rheological measurements are not

    sufficient for defining properties in the experimental

    range

    6

    or

    the prediction equations use rheological mod

    els with constants defined in a shear-rate range different

    than that of the experimental work.

    4

    One study 9 uses

    viscosities not associated with that of the liquid surround

    ing the particle while another stud

    y

      provides a solution

    so complex that it

     s impractical for field use.

    An assumption that the terminal settling velocity will

    be the same as the slip velocity

     s

    questionable because of

    the complex motion of the particle in the annulus. The

    moving liquid has a velocity profile near parabolic in

    form that  s affected by hole geometry liquid flow

    properties and pipe rotation.

     

    The particles tilt with the

    velocity profile which in turn affects their settling veloc

    ity. Drillpipe rotation introduces a centrifugal force caus

    ing radial migration

    5

    and some particles are also

    trapped near the

    p i p e 1 8 ~ 1 9

    If

    the mud

     s

    non-Newtonian

    the viscosity

    of

    the liquid around the particle

     s

    depen

    dent on the settling velocity and the flowing- velocity

    profile. An additional complication  s the various shapes

    a cutting or caving may have.

    Improvement in methods for predicting successful

    hole cleaning  s dependent on a better understanding

    of

    how viscous forces retard particle settling. Practical ap-

    The ability to predict the degree ofhole cleaning possible with a given mu n flow rate is an

    advantage   successfully planning and completing a drilling operation. A simple reasonably

    accurate mathematical prediction technique

     s

    developed that can be used in the field.

    JULY 1975 893

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    2/8

    plications

    of

    methods for improving hole cleaning require

    a simple approach. The objectives

    of

    this

    paper

    are. to

    relate the size, density,

    and

    slip velocities

    of

    cuttings

    and

    cavings to the shearstress

    vs

    the shearrate relationship

    of

    the l iquid and to establish a simple mathematica l pro

    cedure applicable to field use.

      ttling

     elocity

    The

    settling velocity of any particle depends on a number

    of

    factors such as the density and flow properties

    of

    the

    liquid and the volume, density, and shape of the particle.

    Nonnally

    the relations are correlated

    by

    plotting a drag

    coefficient vs a Reynolds number. The drag coefficient is

    defined as twice the net vertical force volume times

    density difference) divided by the product of the particle

    velocity squared, projected area of the particle, and the

    liquid density. The Reynolds number contains a liquid

    viscosity

    t rm

    convenient for Newtonian liquids,

    bu t

    unsuitable for non-Newtonian liquids.

    Work

    with Newtonian liquids shows that the drag

    coefficient vs the Reynolds-number relation can be di

    vided into three regimes: turbulent, laminar, and transi

    tion.

    In

    the turbulent regime, the only resistance slowing

    the fall of the particle is causedby the

    momentum

    forces

    of

    the liquid; viscosity plays no part. Thus, if a particle is

    falling

     

    the turbulent regime, increasing the

    mud

    viscos

    ity will not slow the settling rate until the viscosity is

    increasedsufficiently to force a change from the turbulent

    to the transition or the laminar regime. In the laminar

    regime, the entire resistance slowing the fall is caused by

    the viscous forces of the liquid; the momentum forces are

    negligible.

    The

    drag coefficient in this regime varies

    inversely with the Reynolds number.

    Between

    the two

    regimes is the transition regime, where both viscous

    and

    momentum

    forces retard the falling particle.

    If

    the flow in anannulus is turbulent, a particle slips in

    turbulence. If

    the flow is laminar, a particle may slip in a

    turbulent, transition,

    or

    laminar regime depending

    on

    its

    geometry and on the viscous proptrt ies of the liquid.

    Work with Newtonian l i q u i d s ~ indi ca te s tha t the

    laminar-transition-regime change for a particle occurs at

    a Reynolds number between 0.1 and

    0.3 and

    the change

    from

    the transition to turbulen t

    regime

    occurs

    at

    a

    Reynolds n\lmber of 100.

    The

    approach used in this paper to develop a useful

    method forpredicting slip velocities is to assume a simple

    set

    of conditions and develop predictive equations. The

    results are compared with laboratory experiments and

    with the results

    of

    the work

    of

    others.

    The problem is simpl if ied by assuming a disk shape

    that is the simplest shape consistent witha cutting form. It

    also assumes that the qisk falls flat ,side down, which

    represents the condition for the highest terminal settling

    velocity. Drag coefficients are established

    fo r

    this disk

    shape and orientation, and the relations with Reynolds

    numbers for each flow regime are assumed from Newto

    nian l iquid data. An assumption is then made about the

    viscosity term in the Reynolds number to develop the

    settling-rate equation as a function of the liquid shear

    stress and the shear rate.

    E,quation  evelopment

    Terminal sett ling velocity equations are developed by

    combining the drag coefficient and the Reynolds number

    894

     

    1

    = 2

     3 4

     

    4

    JOURNAL OF PETROLEUM TECHNOLOGY

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    3/8

    +

    25

    895

    Fig. l-Comparison

    of calculated with measured settling

    velocities.

    -

    25

    b ------1

     1-

    0

      4 0 L 6 0 ~ ~ 8 O ~ I ~ O ~ ~ 1 2 ~ o ~ l ~ o

    OBSERVED SETTLING VELOCITY,

    Ft

    /min

    CONTROL

    LIMITS

    ..

    . . :  : .

     

    • 

    .

     

    .

     

    -

    20

    of

    20

    - 10   - - - - - - - - - - - - - - - - - - - -

     

    - 15 •

    f/

    ::>

    z

    i

    + 15

    + 10

    Discussion of

    Experimental Data

    The method used

    to

    evaluate the accuracy of the equa

    tions considered the difference between measured and

    calculated settling velocities. The measured particle ve

    locity was used to calculate the Reynolds number.

    There are

    87

    sets

    of

    useful experimental data, with

    10

    additional sets negated because

    of

    unstable fall. The data

    include a Reynolds-number range from

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    4/8

     

    \

    \

    TABLE

    2A-EXPER-IMENTAlRESULTS

     DIFFERENCE B ETWEEN OBSERVED

    AND

    CALCULATED SLIP VELOCITIES

    Liquid 2

    l iquid

    3

    Terminal Velocity

    Terminal Velocity

    (ft/min)

    Reynolds

    (ft/min) Reynolds

    Observed Difference* Orientation

    Number .Observed Difference*

    Ori-entation Number

    113.

    2.6 Flat 203.

    68.

    4.3

    Flat 50. 88. 10.1 Flat

    100.

    27.9

    4.1 -Flat 8.1

    48.5

    3.6

    Flat , 50.

    Unstable 1.1 29.2 5.5

    -Flat

    23.9

    5.3

    1.2 Edge

    0.4 16.4

    2.8 Flat

    12.6

    _101.

    (4.8)

    Flat 71.

    48.2

    0.0 Flat

    17.8

    -67.

    6.9 Flat 37.9

    . Unstable

    2.6 38.4

    4.3

    Flat

    20.0

    12.8

    6.0

    Edge

    0.8 21.7 3.7

    Flat 8.9

    19.3

    (11.9)

    Stable

    3.2 35.9

    (5.7)

    45° 10.6

    8.9

    (2.7)

    Edge- 0.6 Unstable

    5.9

    2.8

      1.5)

    Edge

    0.1

    Unstable

    2.5

    .22.2

    3:9

    Edge 5.1

    39.7 1.6 Flat 39.2

    8.5 1.6 Edge

    0.8

    24.7

     

    4.2

    Flat

    20.0

    4.1

    (9.8)

    Flat

    0.5  25.4

    (3.5)

    Edge 12.6

    1.9 (3.3)

    Edge

    0.1

    16.3

    0.7

    Flat

    6.6

    0.44

    (3.4)

    Stable

    .

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    5/8

    ceed t hese l imit s, six are i n t he t ur bulent r egime; in .each

    c as e, the d iffere nce is less t ha n 20 p erc en t

    of

    the mea

    sured velocity. The four remaining cases-occurred with

    disks wh ose thickness was equ al to or o n e ~ h a l f of th e

    diameter; in each i nstance, t he par ti cl e was i n t ransit ion

    fall.

    Terminal velocities

    of

    thfee non disk shapes were

    measured

    in L iq uid s 4 and 5. All were

    made

    from

    lA-in.-thick plastic. One

    s h a p e ~ a s

    a s qua re w it h I- in .

    s id es ; a no th er w as a t ri an gl e m ad e b y c ut tin g t he s qu are

    along a diagonal; and the third was a  

    x

    Vz-in.rec

    tangle. The dif ferences i n vel ocit ies wer e in

    the

    _sa me

    ra nge as those obtained for disks when the effective

    d ia me te rs w er e c al cu la te d by the hydraulic-diameter

    equation:

    3

    d

     

    == . . _

      10)

     

    c

    In summary

    the e qu at io ns p re di ct ed t he v el oc it y

    within ±10 ft/min for 88 percent of the test sets and closer

    t ha n e it he r  10 ft/min or 20 p erc en t -of the m ea su re d

    velocities

    over

    95

    percent

    of the time.

    The

    over-all error

    could b e r ed uc ed b y m od if yi ng th e e qu at io n fo r t he tur

    bulent r egime, as t he dif ference i n this r egime averages

     4.2

    ft/min, and

    by

    alt er ing t he equat ion i n t he ~ a m i n a r

    re gi me , w he re the a ve ra ge -e rr or is ft/min.

    The

    corr elat ion is

    deemed

    s uf fi ci en tl y a cc ur at e f or f ie ld

    application.

    Disk

    o ri en ta ti on a pp ea rs to b e i nf lu en ce d

    by

    many

    factors. Within

    the

    limits of

    this

    study, f lat fall always

    o cc ur re d a bo ve a R ey no ld s n um be r of 13 and edge fall

    occurred predominantly below H ow ev er , w he n t he

    disk thickness equaled its diameter,

    flat

    fall occurted at

    a R ey no ld s n um be r

    of

    2 and s tab le fall occu rred at a

    Reynolds

    number

    of 1

    When

    unstabl e fall occur red, i t

    was in t h e R e y n o ~ d s

    number

    range

    of

    2. 5 to 10. The

    largest errors in the predicted-to-observed velocities in

    t he l aminar and t ransit ion r egimes occur red wit h disks

    having thickness-to-diameter ratios

    of

    0.5,and 1.0. Thi s

    w as p ro ba bl y b ec au se t he e qu at io ns do n ot a cc ou nt fo r

    the viscous drag

    on

    the peripheral area

    of

    the disk.

    Equation Evaluation

     

    Experiments that simulate continuous

    t r a n ~ p o r t

    i n a well

    bor e and provi de rheologi c al i nfo rmat ion are l imit ed.

    Field dat a _containing r equi si te i nf or mati on are almost

    nonexistent. - ,

    Williams and Bruce

    18

    measured the ,transport rate for

    disks in an annulus with Newtonian fluids where pa.rticle

    sli p was t ur bulent . The t er mi nal s e t t U n g v e l o c i ~ y ,eqia

    tion, Eq. 6, is equivalent to the slip-velocity equation

    developed in their work. .

    Sifferman et al measured, the transport velocity

    of

    simulated cavings carried up an annulus with gel muds. A

    comparison between their c a l c u l ~ t e d slip veiocities; es- ,

    tablished by subtracting the t ~ a n s p o r t velocity from the

    bulk-liquid velocity, and the terminal settling velocities

    predi ct ed wit h Eqs. 6 and 8 are l isted

    in

    Table 3. Evalua

    tion was limited to four sets of data; one set

    ~ h e r e

    par ti cl es wer e i n t ur bulent f al l, one set i n t ransit ion fall,

    a nd tw o sets i n

    laminar

    fall. Agreement was excellent for

    t he t ur bulent and t ransit ion r egimes, but not as .good for

    the laminar regime. The laminar conditions were calcu

    lated for two differentparticle orientations because a shift

    TABLE 2B-EXPERIMENTAL RESULTS DIFFERENCE BETWEEN OBSERVED AND CALCULATED

    SLIP

    VELOCITIES

    L iq uid 4

    L iq uid 5

    Particle Shape

    Terminal Velocity

    Terminal Velocity

    Diameter

    Thickness Specific ft/min)

    Reynolds

     ft/min.)

    Reynolds

      in.) , in.)

    _ Q ~ ~ t _

    Observed Difference* Orientation

    Number

    Observed Difference*

    Orientation

    Number

     

    Disk

    1

     

    2.83 128

    18.0

    Flat

    348.

    117.

    6.5

    Flat

    .833.

    Disk 1

    2.83 90.

    11.9

    Flat

    211. 78.

    0.3 Flat 4 8 7 ~

    Disk

    1

    l/

    s

    2.83 56. 1.2 Flat

    115.

    54.

      1.5)

    Flat

    277.

    Disk 1

    1/16

    2.83

    38..8

    3.4

    FIClt

    71.

    Disk 1

    1/32

    2.83

    24.0

    3.0

    Flat

    44.0

    Disk

    1/

    2  

    2.69 123. 8.7

    Flat

    162.

    111.

      3.4)

    Flat

    390.

    Disk

     

    2.83

    83.

      3.5)

    Flat

    97.

    98.

    13.6 Flat

    303.

    Disk

      s

    2.83

    49.1 1.4

    Flat

    50.

    Disk

     

    1/16

    2.83 29.8 2.9

    Flat

    27.3

    41.0

      1.5) Flat

    94.

    Disk V4

    V4 2.68

    51.

      6.3)

    45°

    28.6

    85.

    1.7

    Flat

    117.

    Disk

    V4 Vs

    2.68

    33.8

    1.2 Flat

    17.2

    47.2

      4 .5) Flat

    61.

    Disk V4

    1/16

    2.68

    23.8 5.5 Flat

    10.9

    Disk

    1

      1.38

    52.

    0.1 Flat

    95.

    61.

    10.8

    Flat

    282.

    Disk

    1

    V4 1.38 32.5

    1.7

    Flat

    60.

    39.

    3.4

    Flat

    178.

    Disk

    1/

    2

     

    1.38 36.3

      3.1)

    Stable

    33.2

    60.

    5.5

    Flat

    137.

    Disk V

    1/

    4 1.38

    24.6

    1.2

    Flat

    22.5

    38.2 1.2

    Flat

    87.

    Disk

    V4

    1/

    4 1.38

    14.9

      2.1)

    45°

    6.8

    26.6

      0.3) Flat

    30.5

    Disk 1

    1/32 8.77 51.

      6.1)

    Flat

    104.

    70.

    13.0

    Flat

    360.

    Disk V

    1/32 8.77 52.

    2.0

    Flat

    53.

    Disk

    1/

    4 1/32 8.77

    45.3

    8.9

    Flat

    23.2

    Square**

    1.04

    0.248

    1.42

    36.8

    3.3 Flat 70.

    38.3

    1

     

    3

    Flat

    183.

    Triangular***

    0.66

    0.247

    1.42 32.5

    4.4 Flat

    39.2

    39.9

    0.8

    Flat

    120.

    Rectangular

    t

    0.82

    0.236

    1.42

    33.2  3.6 Flat

    49.8

    33.9

      3.5) Flat

    127.

    Average velocity

    2.7

    2.55

    Standard deviation of velocity

    5.4

    5.4

    Standard error

    of

    the mean 1.1

    1.3

    *Observed min

    us

    calculated: ) minus.

    **Square plate, I-in. sides, l .04-in. effective diameter.

    ***45°

    isosceles triangle with

    I-in.

    sides, O.66-in. effectivediameter.

    t

    x V2 in rectangle, O.82-in. effective diameter.

    JULY 1975

    897

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

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    in orientation would be expected at a low Reynolds

    number.

    An

    assumption

    of

    e dg e fall, w hi ch i s li ke ly to

    occur under laminar conditions, more closely approxi

    mates experimental results .

    Additionalinformation

    is

    needed before drawing defi

    nite conclusions but, based

    on

    the available,data, termi

    nal settling and slip velocities can be considered the same

    and the predicted velocities are consistent with experi

    ments of others.

    Application

    Slip Velocities

    The developed equations can be more easily applied

    in

    the field by transposing to the following units:

    velocity - ft/min .

    density

    - lb /gal

    particle dimensions - in.

    shear stress  lb

    f

    /100 sq ft

    The specific gravity

    of

    the solids

    is

    a ss ume d to be 2 .5 o r

    20.8 Ib/gal.

    The first step in estimating the slip velocity

    is

    to calcu

    late the shear stress developed by the particle:

    T

    c

     

    7.9

    Yh

    c

      20. 8 -   c . 11)

    The

    particle thickness can be estimated from samples

      over

    the shaker, junk basket, viscous plugs,

    or

    offset

    wells). .

    The second step is to estimate whether the annular flow

    is

    laminar

    or

    turbulent.l

    6

    If

    it is laminar, skip to Step

    3; if

    it is turbulent, calculate the slip velocity for the turbulent

    regime:

     

    c

    =

    16.62 •••••••••• • •••••• ••   12)

    V;;;

    rhe

    third step

    is

    to determine the turbulent-transition

    rt

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

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    MAXIMUM SHEAR RATE

    FOR

    TRANSITION

    REGIME: SLIP

    FOR

    PARlICL 1

    1 0 0 - r - - - - - - - - - - - - r - : 1 / ~ - ; - - ,

    A-RT-IC-L E-S-l . . . ..----T-:?----

    899

    6 •

    1000

    8 100 2

    SHEAR

    RATE   SEC-I

      ig 2-Stress-rate

    relations for two field muds

    1

    1

    - - -P-OI -NT -S-- . . - - . .. - - ~ - t - - 7 - - - S H - e : A - R - S - T R - E - S S - D - E - V t - L O - P - E

     

    - : - = ~ - - -   -B Y RIVER GFtAVEL

      I   P ~ T ~ SHEAR STRESS Df :VELOPED

    I . I BY l iS

    SAND

    I I

    I I

    I

    I

    I

    I

    I

    0::

    « 8

    w

    ::I:

    CI

    6

    o

    Q

     

    .Q

     I

    2

    f./

    Cf

    W

    0::

    Cf

    omenclature

     

    e

    = projected cross-sectional area of

    particle, ft

    2

     

    = particle diameter, in.

    d

    eq

    = equivalent particle diameter, ft

    d

    p

    :=;;:

    particle diameter, ft

    d

    w

    :=: inside diameter of glass pipe, ft

     

    w

      wall-effect factor defined in Eq. 9

      T

     

    dimension factor, Ib

    f

    /100 ft

    2

    g

    ~

    acceleration of gravity, 32.17 ft/sec

    2

    g

    = gravitational constant,

    32.17

    Ibm

    -ft/ lb

    f

    -sec

    2

     

    h = particle thickness, in.

    h

    p

    =

    particle thickness, ft

    e

    = perimeter around projected area of

    particle, ft

      ed drag coefficient defined by Eq. 1

     Re

     

    Reynolds number

    V

    e

    =

    particle velocity relative to the liquid,

    ft/min

    V

    p

    = particle velocity relative to the liquid,

    ft/sec

    y   shear rate, sec-

    i

    velocity in

    95

    percent of the cases.

    2. Data for comparison is l imited, but the avai lable

    information indicates that the terminal settling velocities

    calculated by

    the proposed equations are numerically

    similar to slip velocities calculated from transport-rate

    measurements .

    3. Limited data indicate that the equations developed

    for disks can be used to predict slip velocities and hole

    cleaning for other shapes commonly encountered when

    drilling.

    4. These equations permit comparing hole-cleaning

    capabilities of muds with different flow properties and

    provide a method to adjust flow properties to clean an

    annulus.

    h

    =   I ~ O 2  15

    The effective particle thickness is 0.108 in. This gives

    a shear stress

    of

    8.6

    Ib/l00

    ft

    2

    in 10-lb/gal mud. The

    effective diameterof the largerparticles is estimatedat

    14

    in.

    To clean the hole, the larger particles must have the

    same or a lower slip velocity than the l/s-in. sand grains.

    The shear rate corresponding to a slip velocity of

    17

    ft/min for the

    14

    -in.-diameterparticles is, from Eq. 14, 33

    sec-i. The mud must be changed to give a shear stress

    equal to or greater than

    8.6Ib/l00

    ft

    2

    at a shear rate of

    33

    sec-

    i

     Point B in Fig. 2 .

    The hole was displaced with a prehydrated gel mud

    weighted

    in

    brine to 10 lb/gal. This mud, which cleaned

    the hole and allowed problem-free drilling to continue,

    closely matches the required shear stress at

    33

    sec-

    i

    , as

    shown in Fig. 2.

    In

    retrospect, the 14-in. gravel has a slip velocity of 45

    ft /min in 10-lb/gal brine and 30 ft/min in the guar-gum

    mud. In each mud the particles would be carried up the

    gauge hole to accumulate in the enlarged hole and would

    then fall back when the circulation stopped.

     onclusions

    1.

    A simple set of equations were developed that pre

    dict the terminal settling velocity of disks in turbulent,

    transition,

    or

    laminar fall for a wide range of test condi

    tions. The equations predict the terminal settling velocity

    within ± 10 ft/min in 88 percent of the cases and within

    either

    ±

    10 ft/min or 20 percent of measured settling

    JULY, 1975

    sand grains exert a stress of7 .5Ib/100 ft

    2

    in the 10-lb/gal

    mud. A spherical shape is used for the sand grains, and

    the effective thickness to use in Eq. 11 is two-thirds the

    sphere diameter. Slip velocity estimates for spheres are

    valid in the laminar and transition regimes becauseEqs. 4

    and 5 are valid for both spheres and disks, but Eq. 3

     turbulentregime is not valid for spheres. The flow in the

    annulus was laminar. From the shear stress vs shear rate

    plot shown in Fig. 2, the shear rate corresponding to a

    stress of

    7.5

    Ib/100 ft

    2

    is 91 sec-

    i

     Point A . This shear

    rate is less than the limit for the transition regime Line

    C , so the transition equation, Eq. 14, is used to calculate

    a slip velocity

    of

    17 ft/min. A mud velocity

    of

    27 ft/min

    might be considered necessary to clean the hole 17

    ft/min to overcome the slip and 10 ft/min to move the

    particles through the enlarged hole in a reasonable time .

    A 26lh-in.-diameter hole will have a bulk velocity

    of

    27

    ft/min, which is a reasonable hole size.

    A viscous plug was run in the well , removing ~ i n

    gravel. Because of the odd shapes of the gravel, the

    effective thickness was difficult to determine. The effec

    tive thickness was est imated by measuring the shear

    stress developed by the particles. This was done by tim

    ing the terminal settling velocity of a handful

    of

    the gravel

    dropped into water contained in a verticaI2-in.-diameter

    glass pipe

    10

    ft high. Since the flow regime is turbulent,

    Eq. 12 can be used to solve for part icle shear stress; the

    resul t can be substituted into Eq. 11 to calculate the

    thickness . Or, the effect ive part icle thickness can be

    calculated from Eqr 15, obtained by combining Eqs.

    11

    and 12, using the density of water.

  • 8/18/2019 Walker and Mayes - SPE-4975-PA

    8/8

      (B-1)

     

    (B-3)

    which is Eq.

    8.

    APPENDIXB

    Eq.

    13

    is developed starting with Eg. A-2, which is

    solved for shear rate and is squared to give

      T

    , . . (A-5)

     

    (B-2)

    100 (12)2/3

    gc

    F

    T

     100)2 ge d

    p

     

    VPLge

    FT

    100

    Eq.

    B- 2

    is solved for shear rate and the units are changed

    to those listed under Application to give

     y =

    8.62  N

     

    2/3

    de

    V;;;

    IfN

     

    =

    100, Eq. B-3 yields

      =

    186 , (B-4)

    de vP;-

    which is Eq. 13.

    Then, the shear-stress term is replaced with the right side

    of Eq. 7 and the velocity term

    is.

    replaced with the right

    side

    ofEq.

    8 to give

    (

    NRe J2

     

    =

    dpPL

    and the shear stress

    is

    replaced by the right side of Eq. 7

    to give

    N

    Re

    =   d

    p

    V

    p

    PL

    ;/ge (A-3)

    V 100F

    Th

    p

     Ps -

    PL

    g/ge

    Next, the right side

    ofEq.

    A-3 is used to replaceN

    Re

    and

    the right side

    of

    Eq. 1 is used to replace

    Ne d

    in Eq.

    A-I

    to give'

    [

    24

    v

    p

    2

    PL J =

    2g

    h

    p

     ps - PL

    100

    dpv

    p

    PL y 2  A-4

    100h

    p

     Ps - PL g

    ge

    FT

    Solving Eq. A-5 for velocity gives

    V

    p

    =   ~ 3 / 4 d

    p

      h

    p

     Ps -

    PL

    g

    24

    v p

    L

    FTge/

    lOO

    1

    =

    (N

    Re 

    2

     

    A-I)

     N

    ed

     3

     24 3

    Next, substitute for

    N

    Re andNe d . The viscosity term in the

    Reynolds number is replaced by shear stress divided by

    shear rate to give

    N

    Re

    =

    d

    p

    VPPLY , (A-2)

    T

    p

    APPENDIX A

    Eq. 8 is obtained by combining Eqs.

    1

    2, 4, and 7 as

    follows. First, Eq.

    4,

    the relation between the drag coef

    ficient and theReynolds humber, is inverted and cubed to

    give

     

    = shear rate corresponding

    toN

    Re

    = 100, sec-

    1

    IL =

    viscosity, lbm/ft-sec

    Pc = liquid density, I

    b

    m

    gal

    PL = liquid density, Ib

    m

    ft

    3

    Ps = particle density, Ib

    m

    ft3 .

    T

    e

    =

    shear stress, lb

    f

    /100 ft

    2

    T

    p

    =

    shear stress,

    Ib

    mft-sec

    2

    Acknowledgments

    The authors wish to express their appreciation to

    Mil

    chern, Inc., for permission to publish parts

    of

    this article

    and to the Lamar

    U.

    Research Committee for their

    support.

    References

    1. Ansley, R. W. and Smith, T. N.:  Motion of Spherical Particles in

    a BinghamPlastic, AIChE

    Journ.

    (1967) 13, 1193.

    2. Becker, H. A. :

     The

    Effects

    of

    Shape and Reynolds Number on

    Drag intheMotion

    of

    a Freely OrientedBody

    in

    an Infinite Fluid,',

    Cdn. J. Chem. Engr. (April 1959) 85.

    3. Bennett, C. O. and Myers, J. E.:

    Momentum, Heat,

    and

    Mass

    Transfer, McGraw-Hill

    Book Co., Inc.,

    New York (1962) 174.

    4. Brookes, G. F . and Whi tmore , R. L .:  Drag Forces in Bingham

    Plastics,

    Rheologica

    Acta (1969) 9, 472.

    5. Carey, W. W.: Set tl ing of Spheres in Newtonian and Non

    Newtonian

    Fluids,

    PhD thesis, Syracuse U. , Syracuse, N.Y.

    (1970).

    6. Ha ll, H. N. , Thompson, H. , and Nuss, F.:  Ability of Drilling

    Mud

    to

    Lift BitCuttings,

    Trans.,

    AlME (1950) 189, 35-46.

    7. Lappe , C. E. and Shepherd, C. B .:  Calculation of Particle

    Trajectories,

    I

    and

    E Chem.

    (1940) 32, 605.

    8. Michael , Paul:  Steady Motion of a D isc in a Viscous Fluid,

    Physics ofFluids

    (1966) 9, 466.

    9. Rimon, Y.:  Numerical Solution

    of

    the Incompressible Time

    Dependent Viscous Flow Pasta Thin Oblate Spheroid,

    Physics

    of

    Fluids (1969) 12, SupII , II-65.

    10. Rimon, Y. and Cheng, S. 1.:  Numerical Solution

    of

    a Uniform

    FlowOver a Sphere at IntermediateReynolds Numbers, Physics

    of

    Fluids (1969)

    12,949.

    11. Savins, 1. G. and Wal lick , G. C.:

     Viscosity

    Profiles, Discharge

    Rates, Pressures and Torques for a RheologicallyComplex Fluid in

    a Helical Flow, AIChE Jour. (1966) 12, No.2, 357.

    12. Sifferman, T.

    R. ,

    Meyers, G.

    M.,

    Haden, E. L. , and Wahl, H. A.:

     Drill-Cutting Transport in Full-Scale VerticalAnnuli,

    J. Pet.

    Tech. (Nov. 1974) 1295-1302.

    13. Slattery, J. C. and Byrd,. R. B .:  Non-Newtonial Flow Past a

    Sphere, Chem. Eng. Sc. (1961) 16,231.

    14. Turian, R. M .:  A n Experimental Investigation of the Flow of

    Aqueous Non-NewtonianHigh PolymerSolutions Past a Sphere,

    AIChE Jour. (1967) 13, 999.

    15. Walker, R . E.: Migration

    of

    Particles to a Hole Wall in a Drilling

    Wall, Soc. Pet. Eng.

    J.

    (June 1969) 147-154.

    16. Walker, R. E. and Kor ry , D. E.:  Field Method of Evaluating

    Annular Performance

    of

    Drilling

    Fluids, J. Pet. Tech.

    (Feb.

    1974) 167-173.

    17. Walker, R. E. and Othmen, AlRawi :

     Helical

    Flow

    of

    Bentonite

    Slurries, paper SPE 3108 presented at the SPE-AIME 45th An

    nual FallMeeting, Houston, Oct. 4-7, 1970.

    18. Williams, C. E. and Bruce, G. H.:  Carrying Capacity of Drilling

    Muds, Trans.,

    AIME (1951) 192, 111-120.

    19. Zeidler , H. Udo:  A n Experimental Analysis

    of

    the Transport of

    Drilling Particles,

    S oc. Pet. Eng . J.

    (Feb. 1972) 39-48;

    Trans.,

    AlME, 253.

    Original m n uscriptreceived in Society of Petroleum Engineers office July 31 1974.

    Revised manuscript received   y 13, 1975. Paper SPE 4975 w s first presented atthe

    SPE-AIME

    49th

    Annual Fall Meeting, held in Houston, Oct . 6-9 , 1974. ©Copyright

    1975

    American Instituteof Mining, Metallurgical, and Petroleum Engineers, Inc.

    This paperwill be included in the 1975 Transactions volume.

    900

    JOURNAL OF PETROLEUM TECHNOLOGY


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