Note: Descriptions are shown in the official language in which they were submitted.
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iMETLIODS FOR DETERMINING REACTIVE INDEX FOR CEMENT KILN
.DUST, ASSOCIATED COMPOSITIONS, AND METHODS OF USE
BACKGROUND
[00011 The .present invention relates to -cementitious components and, More
particularly, in certain embodiments, to methods of .determining a reactive
index for
cementitious components,
[00021 In general, well treatments include a Wide variety of methods that may
be
performed in oil, gas, geothermal and/or water weiis. such Its
driilingcompletio.n. and
-workover Methods.. The drillingõeOmpletion and-workoVer.melhods May include,
but are not
10. limited to, drilling, .fracturingnacidizing, logging, cementing, gravel
packing, perforating and
conformance methods, :Many Of these Well treat-runts are designed to enhance.
and/or
facilitate the recovery of desirable fluids from a subterranean well. These
fluids may include
hydrocarbons such as oil andlotgas.
10003.] in cementing methodsõ such as well construction and remedial
cementing,
settable compositions are Commonly utilized. As used herein,. the term
"settable
composition" refers to .a 'compOsieton(S) that hydraulically Sets aIr
otherWise develops
compressive strength Senable.compositions may be used in primary cementing
operations
whereby pipe strings, Such as casing. .and liners, are cemented in well bores
in performing
primary cementing, a. sellable composition may be pumped into an annulus
between
.subteuTanean formation and the pipe string dispOSed in the subterranean
formation or
between :the pipe. string and a larger conduit disposed in the subterranean -
formation. The
settable composition should. set in the annulus, thereby forming an annular
sheath of
hardened. cement .(04., a ceraerit sheath) that -should support and position
the pipe string in
the well bore:and bond the exterior surface. of the pipe string to. the walls
of the well bore or
2..5 to the larger conduit. Settable compositions also may be used in
remedial cementing
methods, such as the placement of cement plugs, and in squeeze cementing for
sealing voids
in a pipe string, cement:sheath, gravel pack, formation, and the like.
.Settable compositions
may also be used in surface .applications, for-example, construction
cementing.
1.000411 Settable compositions for use in subterranean formations may
typically
include a ccmentitious.compottent which hydraulically sets, of
otherwiSehardens,.to develop
compressivestrength.. Examples of cementitious components that can be included
in .settable
compositions include Portland cement,. calcium. MultiMate cement, cement kiln
dust,. lime
kiln dust, fly ash, slag, pumice, and rice-hull ash, among others. The
performance of these
differeacementitions components in settable compositions may vary and can even
vary fOr
a particular ce-mentitions component depending, tbrexampIe, on the particular
type or-source
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of the, component. For example, -certain of these cementitious components may
have
undesitabla properties that can make them unsuitable for use in well
treatments. In addition,
variation of the performance tbr the cementitions components can lead to lack
.of
predictability and consistency for the cementitious components when used in
treatment
fluids This lack of predictability consistency nlay even be apparent for the
same
cementitious.componcnt, for example, if sourced from different locations..
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SUMMARY
[0005] The present invention relates to cementitious components and, more
particularly, in certain embodiments, to methods of determining a reactive
index for
cementitious components.
[0006] An embodiment discloses a method of treating a well comprising:
providing
a treatment fluid comprising a base fluid and a blended cementitious
component, wherein the
blended cementitious component comprises kiln dust from two or more different
sources;
and introducing the treatment fluid into a well bore.
[0007] Another embodiment discloses a method of cementing comprising:
providing
a settable composition comprising water and a blended cementitious component,
wherein the
blended cementitious component comprises kiln dust from two or more different
sources;
and allowing the settable composition to set to form a hardened mass.
[0008] Another embodiment discloses a method of cementing comprising:
providing
a settable composition comprising water and a blended cementitious component,
wherein the
blended cementitious component comprises kiln dust and an additional
cementitious
component, the kiln dust and the additional cementitious component each have a
determined
reactive index; and allowing the settable composition to set to form a
hardened mass.
[0009] Another embodiment discloses a method of preparing a blended
cementitious
component comprising: providing a first kiln dust, the first kiln dust being
from a first
source; providing a second kiln dust, the second kiln dust being from a second
source; and
blending at least the first kiln dust and the second kiln dust to form the
blended cementitious
component.
[0010] Another embodiment discloses a method of measuring reactivity of a kiln
dust comprising: measuring a parameter of the kiln dust, the kiln dust having
a specific
surface area; and dividing the measured parameter by the specific surface area
of the kiln
dust to obtain a reactive index for the kiln dust.
[0011] Another embodiment discloses a well treatment fluid comprising: a base
fluid; and a blended cementitious component comprising kiln dust from two or
more
different sources.
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[0011a] In accordance with another embodiment, there is provided a method
of
treating a well comprising: providing a treatment fluid comprising a base
fluid and a
blended cementitious component, wherein the blended cementitious component
comprises
kiln dust from two or more different sources; and introducing the treatment
fluid into a
well bore, wherein the kiln dust comprises a first kiln dust from a first
source and a second
kiln dust from a second source, and wherein the first kiln dust and the second
kiln dust
have different reactive indexes.
[0011b] In accordance with another embodiment, there is provided a method
of
cementing comprising: providing a settable composition comprising water and a
blended
cementitious component wherein the blended cementitious component comprises
kiln dust
from two or more different sources; and placing the settable composition into
a
subterranean formation penetrated by a well bore; and allowing the sellable
composition to
set to form a hardened mass, wherein the kiln dust comprises a first kiln dust
from a first
source and a second kiln dust from a second source, wherein the first kiln
dust and the
second kiln dust have different reactive indexes.
[0011c] In accordance with another embodiment, there is provided a well
treatment
fluid comprising: a base fluid; and a blended cementitious component
comprising kiln dust
from two or more different sources, wherein the kiln dust comprises a first
kiln dust from a
first source and a second kiln dust from a second source, and wherein the
first kiln dust
and the second kiln dust have different reactive indexes.
[0012] The features and advantages of the present invention will be
readily
apparent to those skilled in the art, while numerous changes may be made by
those skilled
in the art.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These drawings illustrate certain aspects of some of the embodiments of
the
present invention,, and should not be used to limit or define the invention,
[0014] FIG, 1 is a chart showing measured reactive indexes for various supply
Sources Of cement kiln dust,
[0015] FIG. 2 is a chart Comparing actual versus predicted compressive
strength for
dry blends of cement kiln dust.
[0016] FIG. 3 is a chart comparing actual versus predicted volume average
apparent
viscosity at 51 I see for dry blends of cement kiln dust,
[0017] FIG, 4 is a chart comparing actual verSos predieted volume average
apparent
viscosity at 51 sec for dry blends of cement kiln dust
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DESCRIPTION OF PREFERRED EnRommENTs
[0018] The present invention relates: to. cementitious components and, more
particularly. M certain embodiments, to methods of determining a reactive
index: .for
cementitious components, By determining the reactive index for cementitious
components,
blends of cementitions components may be used. in well treatments., according
to particular
embodiments, that can provide more predictable and consistent performance. in
addition,
additional embodiments may include using the determined reactive index to
provide blend
of .cementitions components in which one or more.. parameters have been
optimized,
including compressive .strength, Young'S Modulus,. fluid logs, and/or
thickening time, for
example,.
[00191 Without being limited by theory, the reactive index of a cementitious
component may be referred to as a measure.of the eementitious component's
reactivity as
adjusted for differences. in ..surfilet area. Example techniques for
determining the reactive
index may comprise measuring a parameter of the cementitious component, and
then
dividing the measured parameter by the specific surface area of the
cementitious component.
In some embodiments, the reactive index for a cementitious component may be
calculated in
accordance with the following ovation:
= MP / SSA
wherein RI is the reactive index, MP is the measured parameter of the
cementitious
component, and SSA is the specific surface area. of the eementitiouseomponent
In general,
specific surface area is a property Oa particulate solid and, as used herein,
is defined as the
total surface area of the .cementitious component divided by the mass of the
cementitious
component or the total surface .area divided by the bulk volume of the
cementitious
component.
[00201 in general, ceinentitiouS. components are particulate: solids that
hydraulically
:set, .or otherwise harden to develop compressive strength in the presence of
Water. Non-
limiting examples of cementitious components that may be suitable for use in
embodiments
.of the present invention include Portland cements, calcium aleminatee,
gypsum, pozzolanic
materials., and kiln dust. Mixtures of one or more ditit.rent cementitious
components may
also be .used, In some embodiments, the cementitious. component may be
combined with
lime.
[0021] in some .einbodiments,:the teinentitions component may comprise
Portland
cement. Portland cement is a commonly used .cementitious component that
hydraulically
reacts with water to develop compressive strength. Example Of suitable
Portland cements
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may include thoSe classified as Classes A, C C and H cements according to
American
Petroleum institutc.õ4JI SpoijkiviOt for Materiais ond TagiOg
(e.M.014, API
Specification 10, Fifth Edition, July I, 1990. In addition, Portland eetnents
suitable for use
in embodiments of the present invention may also include those classified as
ASTM Type I,
VII, 11,114 IV, or V> In some embodiments:, blends of cementitious
001'min:owls containing
Portland cement may be used,
[00221 In some embodiments, the cementitious component may comprise a calcium
aluminate. Calcium aluminate may hydraulically react with water to develop
compressive
strength. Calcium aluminate may be included in cements commonly referred to as
Calcium
aluminate :cements or high alumina content cements. calcium aluminate cements
my
prepared in a manufacturing process that includes mixing a calcium bearing
material
limestone) and an aluminum-hearing material (e.gõ bauxite).
[0023] In some embodiments, the Comentitious component may Comprise gypsum
Gypsum is 0 material that sets in the presence of water to develop compressive
P4rength,
Gypsum may be included in cements commonly referred to as gypsum cements. For
use in
cements, gypsum may, in some instances, be burned at eXtremely high
temperatures and then
ground, in particular embodiments, gypsum may be added to Portland cement.
[90241 In some embodiment's, the eementitious eoniponent may Comprise a
poz2olanic material. Pozzolanic materials that may be suitable for use include
a wide variety
of natural or artificial materials that exhibit cementitious properties in the
presence of
calcium hydroxide. Examples of suitable pozzolanic material that may be
suitable for use in
embodiments of the present invention include natural and artificial pozzolans,
such as fly
ash, silica fume, slag, burned shale, burned clay, metakaol in, pumice,
diatomaCeous earth,
volcanic ash, opaline shale, tuff, and burned organic materials, such as
agricultural waste
ash, municipal waste ash municipal solid waste ash), wastewater treatment
waste ash,
animal wage ash, TIOTA-1111Man-non-animal industrial waste ash, and
combinations thereof
Specific examples of agricultural waste ash include, for example, rice husk
ash, wood (e.g.,
sawdust, bark, twigs, branches, other waste wood) ash, tree leave ash, corn
cob ash, cane
(e.g., sugar cane) ash, bagasse ash, grain (e.g., amaranth, -barley, corn
flaxseed, millet, oat,
quinoa, rye, wheat ete) and related by-product(s) (e.g., husks, hulls, etc)
ash, orchard ash,
vine trimming ash, grass (e.g., Korai, Tifton, native :shiba, etc) ash, straw
ash, ground nut
shell ash., legume (e.g., soybean) ash, and combinations thereof
[0025] In 001i.te embodii.nenta, the cementitious component may comprise a
kiln
dust. One example of a kiln dust includes cement kiln dust Cement kiln dust,
as that term is
used herein, refers to a partially calcined kiln feed which is removed ttom
the gas stream and
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collected, fit example, in a dust collector durinu. the manufacture of cement:
The cement
kiln dust generally may exhibit cementitious properties, in that it may set
and harden in the
presence of water. Usually, large quantities of 'cement kiln dust. .are
collected in the
production cement that are commonly disposed of as waste. .Disposal of the
cement kiln
dust can add undesirable Costs to the .manufacture of the cement, as well as
the
environmental coneerns associated with its disposal. The chemical analysis of
the cement
kiln dust from various cement manufactures varies depending on .a number of
factors,
including the particular kiln teed, the efficiencies of the cement production
operation, and
the associated dust collection $ystems. Cement kin dust generally may comprise
a variety of
oxides, such as Si02, A1.203., Pe2Q,CaQ, MgO, $03, .NazO, and .K,20.
Anotherekample ofa
kiln dust includes lime kiln dust. Lithe kiln dust, as that. term is used
herein, refers to . a
product generated in the manufacture of lime. The lime kiln dust may be
collected, for
'example, by dust control systems in the calcination of limestone;
100201 in some embodiments, one or more parameters of the cementitious
1.5 component may he measured and then used in determining the reactive
index. The
parameters may include a number of different parameters that may be measured
using
.standard laboratory testing techniques for a. settable composition comprising
a cementitious
component and water. Additional components may also be included in the
settable
compositions, for example, to vary One or more properties of the treatment
fluid. Parameters
of the .eernentitious component, or settable composition, contained theitin.,
that may be
measured include, for example, compressive .strength, Young's Modulus, fluid
thickening time, theological values. .(e,g., volume average apparent
viseOsity, plastic
viscosity, yield point, etc.) and/or free water,
[00271 Compressive strength is generally the capacity of a material or
structure to
withstand axially directed .pushing forces, The ..compressive strength of the
comentitious
component may be Measured. at a. specified time after the ceMentitious
component has been
mixed with water.and the .resultant treatment fluid is maintained under
specified temperature
and pressure. conditions. :For example.. compressive strength can be measured
at a. time in the
range of about 24 to About 48 hours after the ibid. is mixed and the fluid is
maintained at a
temperature. of 170 F and atmospheric pressure. Compressive strength can be
Measured by
either a destructive method or non-destructive method.. The destructive method
Physically
tests the strength of treatment .fluid samples at various points in time by
crushing the.samples
compression-testing machine. The. Compressive .strength is calculated .from
the failure
load divided by the cross-sectional area resisting the load and is reported in
units of pound-
force per square. inch (psi): Non-destructive methods typically may employ .an
Ultrasonic
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Cement Analyzer ("UCA''), available from Fann instrument Company, Houston, TX,
CompreSS.ive strengths may be determined in accordance with API RP 10B-2.
Recoinmend0
Practice for Msting Well Cemom, First Edition, July 2005.
[00281 Young's modulus also referred to as the modulus of elasticity is a
measure of
the relationship of an applied: stress to the resultant strain. in general, a
highly deformable
(plastic) material Wi I I exhibit a lower modulus when the confined stress is
increased. Thus,
the Young's modulus is an elastic constant that demonstrates the ability of
the *W(1 material
to withstand applied loadsõ A number of different laboratory techniques may be
used to
measure the Young's modulus of a treatment fluid comprising a cementitious:
component
after the treatment fluid has been allowed to set tbr a period of time at
specified temperature
and pressure conditions.
[0029] Fluid toss typically refers to loss of a. fluid such as a treatment
fluid into a
subterranean formation. A number of different laboratory techniques may be
used to
measure fluid loss of a treatment fluid to give an indication of the behavior
of the treatment
fluid in a well, Fluid loss may he measured using a static fluid-loss test,
with either a static
or stirred fluid-loSs in accordance with the atbre-mentioned API RP
Practice I 0B-2.
[0030] Thickening time typically refers to the time a fluid, such as a
treatment fluid,
comprising the eementitious component, remains in a fluid state capable of
being pumped,
A number of different laboratory techniques may be used to measure thickening
time to give
an indication of the aniount of time a treatment fluid will remain pumpable in
a well. An
example technique for determining whether a treatment fluid is in a. pumpable
fluid state
may use a high-temperature high-pressure eensistometer at specified pressure
and
temperature conditions, in accordance with the procedure for determining
cement thickening
times set forth in the afore-mentioned API. R.P Practice 10B-2. The thickening
time may be
the time for the treatment fluid to reach 70 Bearden units of consistency ("BO
and may be
reported in time to reach 70 13c,
[0031:1 Rheological values of a fluid may be determined to ehariicterize the
fluid
rheologieal behavior. Rheological values that may be determined include volume
average
apparent viscosity, yield point and plastic viscosity, among others: Plastic
viscosity is
typically a measure of the resistance of a fluid to flow, in some embodiments,
the yield
point may be a parameter of the Bingham plastic model, the yield point being
the slope of
the shear stress/shear rate line above the yield point. Yield point is
typically a measure Of
the point at which a material can no longer deform elastically, In some
embodiment* the
yield .point May be a parameter of the Bingham plastic model, the yield point
being the yield
stress extrapolated to a shear rate of zero. A. number of different laboratory
techniques may
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be used to measure theological values of a treatment fluid to give an
indication of the
behavior ofT the. treatment fluid, in a well. Rhe.ologieal Vallie; May be
determined in
accordance with the procedure set forth in API RP Practice 108-2.
[00321 Free water typically refers to any water in a fluid that is in excess
to what is
required to fully hydrate the components of the fluid. Free water can be
undesired as it may
physically separate from a cement composition as itsets. Freowater may also be
referred to
.as free fluid. A number of different laboratory techniques may be Used to
Measure free water
of a. treatment fluid to give an indication of the behavior of the treatment
fluid in a well.
Free water may be determined in accordance with the procedure.Set forth in
API.RP Practice
108,2.
[00311 As previously mentioned, the reactivity of cementitious components: may
vary between different types of cementitious components or even between
different sources:
for a particular type of cementitious component. For .example, the reactivity
of Portland
cement and another cementitious component, such .as a ponolanie material, may
be
different. By way of further example, the reactivity of a cementitious
component may vary
.between different sources .fOr the tementitious component. In SC,lthe
embodiments, the.
reactive index of the cementitious component may 'vary betWeert two or more
different
sources by a factor .of at least about 21. For example, thereactive index of
the eetnentitions
component between different sources may vary . by an amount between any of
and/or
includiegarty of about 2 about 10:1, about 50:1, about 100A, about 250:4about
500:1, or
about 1000:1. Because the reactivity varies between different cementitious
components:. and
even between different sources for a vernentitiOtis component, the performance
of different
cementitious components may be unpredictable and may also lead to a lack of
consistency
for the cementitious components. when used in treatment fluids such as.
settah.le
'compositions. some. instances, the performance of a particular
cementitious. component
may have undesirable properties, which may make it unsuitable for use, for
example, a
cementitious component from a particular source may have properties making it
undesirable
for use.
[0034] in some embodiments, a blend of two or more different cementitious
.30 components may he used to provide, a blended cementitious component
that may have
properties = suitable fir use in a particular application. This may' be
particularly useful, for
.example, where one of the c'ementitious components in the blend may have
properties
making it unsuitable for particular applications. For example, a cementitious.
component
such as cement kiln dust from a first source may be blended with a
cementitious component
such as cement kiln dust from a .second sourcc, in some embodiments, one or
both of the
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.cementitious components may have. reactivities that are unsuitable for a.
particular
application. For example, the reaclivitieS: of. each cementitious component
may be
individually too.slow.or too fast for a. particular application. The blends:
of the cementitious
component .from the two .different: sources may form a blended cementitious
component
having. compressive strength properties that are suitable for the application.
In some
embodiments, the relative proportions. (e.g,õ weight fractions) of each
cementitious
component in the blended. cem.entitious component may then be adjusted to
adjust the
compressive strength properties of the blended cementitious component.
100351 The two or more cementitious components in the blended cementitiotis
component may include,. fc-a- example, two or more: different types of
cementitious
components, such .as Portland cement and cement kiln dusty Alternatively, the
two or more
cementitious components in the blended cementitious component may include,
.for example,
a :cementitious .component from two. or more different sources. For example,.
A. first
cementitious component may comprise cement kiln dust from a first source, and
the second
cementitious component may comprise cement kiln dust from a second source. It
Should be
understood that embodiments are not limited to only two different sources, but
may include a
cernentitious component, such as cement kiln dust, .from . three,. thur, five,
or even more
different sources. The two or .more different sources for the. cementitious
.component may
include different manufactures, different cement manufacturing plants, .and
the like. A
cementitious component:, such as cethent kiln dust which is al byproduct from
the cement
:manufacturing plant, may have a number Of different sources available
throughout the world.
For example, different sources for cement kiln dust may include different
manufacturing
plants throughout The world at which cement kiln dust can. be generated.
[00361 The two .or more cementitious components may be blended to: form the
2.5 blended cementitious component, thtexampie, prior to combination with
water and/or other
components of the treatment fluid. In particular embodiments, the two or more
cementitious
components may be dry blended to form a dry blend comprising the two or more
cementitious components. The dry blend may then be combined with water and/or
other
components, in any order, to firm the treatment fluid. floWever, the use of
the term "blend"
is not intended to imply that the two or tn.Cire cementitious components have
been dry
blended prior to .combination with water. For example, .the blend of two or
more
cementitious components may not be combined until after one, or even both, of
the
cementitious Components has already been blended with water.
[0037.] In some embodimeM, the reactive index may be used to optimize the
blended cementitious component, wherein the blended cementitious component
comprises
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MO or more cementitious components. For example, the reactive index may be
Used to
optimize one. or more paramcWr$! Of the blended cementitious component,
including
compressive strength, Young's Modulus, fluid loss, and/or thickening time.
Optimizing the
blended cementitious component may include determining the reactive index for
each of the
cementitious components in the blended cementitious component. The reactive
indexes tbr
the cementitious components may then be used to predict the performance of the
blended
cementitious component. The ratio a each cementitious component may be
adjusted to
optimize the performance, of the blended cementitious component. 71'he
performance of the
blended cementitious component May be optimized with the performance of the
blended
cementitious componentesti mated using the following equation:
ENwnd Evaix.s&itx fir
Wherein BP. .k the estimated parameter for the blended. cementitious
'component, i is.the
individual cementitious component from the set of cementitious components I to
n, n is an
integer, RI i is the reactive index for cementitious CoMponent i, SSA i is the
specific surface
area for cementitious component I, is the Mass fit:client of the cementitious
component
and m is ..a number from 1 to .10. The set of cementitious components may
:include lor more
diMrent.cernentitious components. The two or' more different cementitious.
component may
be different types of cementitious components, such as Portland cement and
slag, or May be
from diffc.tent sources, such as cement kiln dust from a. first ..source..and
cement kiln dust
from a second source. In some embodimentsõm may be. 1.. In alternative
embodiments, tri
may be
[00381 In some embodiments, the mean padicle size of the cementitious
component
may be altered from its original particle- size. The reactive index may then
be measured for
the altered cementitious component. The altered cementitious component may be
included
in a blended cementitious Component. In accordance .with present embodiments,
the mean
particle .size of the cementitious 'Component can be altered using any
Suitable technique,
including, without limitation, grinding or separating. to provide a material
having an altered
particle size.. Separating the .cementitious component may include sieving or
any other
suitable technique for separating the cementitious component to provide a.
mean particle size
that. has been altered from its original size. For 'example, sieving may be
used to produce
cementitious component having an increased or reduced mean particle size as
desired for .a
particular application. By way Of further example, grinding may be used to
decrease the
mean particle size of the cemeniitious...component. Combinations of grinding
and separating
may be used in some embodiments. The term "'ground" or "grinding" as used
herein means
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using a. grinder (e,g., ball mill, rod mill, etc.) to. tultice the particle
size of the Speci tied
component(s). An.exampk ofa Suitable -grinder is.an 8000 N4ixet1MiIf ball
mill, available
from SPEX. Sample Prep. In some, embodimcnts, .the cementhiou.s component may
be
ground for a time period in a range of from about .30 'minutes to about 1
hour.
[0039] The mean particle. Size of the eementitious component can be altered to
any
'size suitable for use in cementing operations. In SOMt embodiments, the mean
particle size
of the eementitiouscomponent may be altered frOnl. it original particle size
to. have a mean
particle size in a range of about 1 micron to about 350 microns. The mean
particle size
corresponds to d50 values as measured by partiele.sizoanalyzers such as those
manufactured
by Malvern Instruments, Worcestershire, United Kingdom.
[0040] in. some embodiments, the mean particle size of the eetnentitious
component
may be increased from its .original Size. For example, the mean particle Size
of the
CeMentitious component may be at lea*: 5% greater than its Original sizeõ in
some
embodiments, at :IOW a portion of the cementitious component may be increased
to a size
that is in a range of from about. 5% to about 500% greater than its
originaLsize. In some.
embodiments, the mean particle size may be increased to size. ranging between
any of
and/or including any of about 5%, about 10%, about .20%, about 30%, about 40%,
about
50%,. about 60%,about 70%õ about $0%,..abotit 90%, about 100%,..abont 200%,
about
about 400%, or about 500% Mater than itS Original size,
[0041] In some'embodiments, the mean .particle size of the cementitiou's
component
may be reduced from its original :size. For example, the mean particle size
may be reduced
in an amount sufficient to increase. the compressive strength of the
eementitions component.
In some embodiments, the-emend-nous component .may have a mean particle
siZelhat is at
least .5%. less than its original size,. In some :embodiments,. 41 iCast a
portion of the
cementitious component may be reduced to have a mean particle .size in a range
of from
.about 5% to about 95%. of its original. size. For example, the mean particle
size may be
reduced to a size ranging between arrs,,,, of .atidtor including any of about
5%, about 1:0%,
about 15%, about 20%, about i.25%, about 30%, about 3.5%, about 40%, about
45.%, about
50%, about 55%, about 60%, about 6%, about 70%, about 75%, about 80%, .about
90%, or
.30 about.
95%: of its original .size. =Byway of example, :the reduced particle .size
cementitious
component may have .a mean particle size .or less than about 15 microns. In
..some
embodiments, the reduced particle size cementitioas component may have a mean
particle
size ofless. than about 10 .micronS, less than about 5 microns, lea's than
about 4 microns, less
than about 3 'microns, less than about .2 microns ,.or less than about .1
micron, In specific
embodiments, the reduced particle size: cementitious component may have a mean
particle
CA 02888162 2015-04-10
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size in a range of from about 0.1 microns to about 15 microns, from about 0.1
microns to
about 10 microns, or from about 1 trilettn to about 10 microns. One of
ordinary skill in the
art, with the benefit of this .4isclosure, should be able to select a particle
Size for the
cementthous component suitable for a particular application.
[0042] in some embodiments, the mean particle size of the cement kiln dust may
be
reduced in An amount sufficient to provide an increase in compressive:
strength thr the
.settable composition: For example, the mean particle size may be reduced .to
provide an
increase in compressive strength of at least about 5%, about 25%, about 50%,
about 75%õ or
about 100%,
[0043] In accordance with present embodiments, the cemeinitious components may
be included in treatment fluids that Can be .uSed in a variety of operations
that may be
performed in: Subterranean formations: The cernentitious component may have
reactive
index calculated aecOrding to disclosed embodiments. In some embodiments, a
blended
cementitious component may be used. In some embodiments, the reactive index
may be
used in determining the eementitious components in a particular blended
.cementitious
component. As referred to herein, the term -treatment fluid" will be
understood to mean any
fluid that may be used in a subterranean application in conjunction with .a
desired function
and/or for a desired purpose. The term "treatment fluid" .is not intended to
imply any
particular action by the fluid. Treatment fluids Wien are used in, el.., well
drilling,
'd ompietion, and stimulation operations, Examples Of such treatment fluids
include drilling
fluids, well cleanup fluids, workover fluids, conformance fluids, gravel pack.
fluids, acidizing
fluids, fracturing fluids, cement compositions, spacer fluids,: and the like.
[0044] While embodiments of the compositions and methods may be used in a
variety of applications, they may be particularly useful for subterranean well
completion and.
remedial operations,. such as primary cementing of casings and liners in well
bores. They
also may be useful for surface cementing operations, including construction
cementing,
Operations,
Accordingly, embodiments of the present invention disclose sellable
compositions.co.mpri.sing.a.cementitious component and water.
[00451 The cenlentitiQUS component may be included in embodiments of the
settable
compositions in an amount suitable for .a particular application. In some
embodimentsõ:the
cementitious component may eomprise, cement kiln dust. The cement kiln dust
may be
present in an amount in a range of from about 0.01% to 100% by Weight of the
cementitious
component: ("bwoc"). For example, the. cement kiln dust May be present in an
amount
ranging between any of and/Or including. any Of about 0.01%, about 5%, about.
:10%, About
35. 20%,
about. 30%, 40%, about 50%, about 60%, about 70%, about 80%, about 90%, or
about
13
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100%. The eeinentitious component may be free or essentially .frm (for
example, no more
than 1%. by weight of the Cementitious component) of any additional
eementitiong
components other than the cementitious component. In some embodiments, the
cementitious
component may be essentially free of Portland cement. One of ordinary in
the art with
the benefit of this disclosure should be able to determine An appropriate
amount of the
cementitious.eomponent to include for a particular application.,
[0046] The water Used in embodiments of the settable compositions of the
present
invention may include, or example, freshwater,. saltwater (e.g., water
containing one or
more salts dissolved therein), brine (e.g.., saturated saltwater produced from
subterranean
formationS), seawater, or any combination thereof. Generally, the water may be
from any
source, provided, for example, that it does nOt contain an excess of compounds
that may
undesirably .affect other components in the settable, coMposition, in some
embodiments, the
water may be. included in an amount sufficient to form a pumpable slurry. in
some
embodiments, the water may be 'included in the settable Compositions of the
present
invention in an amount in a range Of from about 40%-to about 200% .bwoc: For
example, the
water may be present in an amount ranging, between any of and/or including any
of about
50%, about. 75%, about 100%, about .125%, about 150%, or about 175"4 by
.weight of the
cement. In specific embodiments, the water may be included in an amount in the
range of
from about 40% to about 150% bWoc. One of ordinary skill in the art, with the
benetit.of
this dis=closiire, recognize the appropriate amount of water .to include
for a chosen
application.
[0047] Other additiveS .suitable for Use in subterranean cementing operations
may
also be added to Ombodiments.of the.isettable compositions, in accordance with
embodiments
of the present invention. .Examples: of such additives .include, but are not
limited to, fluid-
loss-control additive, set retarder, strength-retrogression additives; set
accelerators,
weighting agents, tiahtweight additives, gas-generating additives., mechanical-
property-
enhancing: additives, lost,c=irc u ati on materials, filtration-control addi
dye's, %tuning
additives, thixotropic additives, and any combination thereoff. Specific
examples of these,
and other, additives include crystalline. Oita, amorphous = silica, finned
silica, salts, fibers,
hydratable clays, calcined shale, vitrified shale, microspheres, hollow- glass
spheres, fly ash,
diatomaceous earth, metakaolin, ground perliteõ rice, husk ash, natural
pozzolanõ
cement kiln dust, resins, any combination thereof, and the like. A person
having ordinary
Skill in the art, with .the benefit of this disclosure, will readily be able
to determine the type
and. amount of additive: useful for a particular application and desired
result
14
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[00481 Those of ordinary skill in the art will appreciate that embodiments of
the
settabie compositions generally should have a density suitable for a
particular application.
By way of example, embodiments of the settable compositions may have a density
of about
4 pounds per gallon (lb/gal") to about 20 ltVgal. in certain embodiments, the
settable
Compositions may have a density of about 8 to about 17 lb/gal. Embodiments
of the
settable compositions may be foamed or untbamed or may comprise other means to
reduce
their densities, such as hollow micrcispheres, low-density elastic beads, or
other density-
reducing additives known in the art. hi addition, the settable composition may
comprise
weighting agents or other means to increase their densities. Those of ordinary
skill in the art,
with the benefit of this disclosure, will recognize the appropriate density
for a particular
application.
[0049] in some embodiments, the settable compositions may have a thickening
time
of greater than about I hour, alternatively, greater than about 2 hours,
alternatively greater
than about 5 hours at 3,000 psi and temperatures in a range of from about 50 F
to about
400 F, :alternatively, in a range of from about 80 F to about 250*1, and
alternatively at a
temperature of about 140 F. in soffic embodiments; the settable composition
may have a 24-
hour compressive strength in a range of from about WO psi to about .10,000 psi
and,
alternatively, from about 350 psi about 3,000 psi at atmospheric pressure and
temperatures in
a range of from about 50 F to about 400 F, alternatively, in a range of from
about 80 F to
about 250 F, and. alternatively at a temperature of about 180 F.
[0050-1 The components of the settable composition may be combined in any
order
desired to form a settable composition that can be placed into p subterranean
formation. In
addition., the components of the gettable compositions may be combined using
any mixing
device compatible with the composition, including a bulk mixer,. for example.
In some
embodiments, a dry blend may first be formed by the cementitious component or
mixture of
=cementitious components. The dry blend may then be combined with water to
form the
settable composition. Other Suitable techniques May be used for preparation of
the gettable
compositions as will be appreciated by those of ordinary skill in the art in
accordance with
embodiments of the present invention.
100511 As will be appreciated by those of ordinary skill in the art,
embodiments of
the cement compositions of the present invention may be used in a variety of
cementing
operations, including surface and subterranean operations, Such as primary and
remedial
cementing In. some embodiments, a cement composition may be provided that
comprises a
cememitious component and water., and allowed set. in certain embodiments, the
cement
composition may be introduced into a subterranean formation and allowed to set
therein. As
CA 02888162 2015-04-10
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used herein, introducing the cement composition i.nto a subterranean lbrmation
includes
introductiOn into any portion of the subterranean II-Irina-tit* including,
without limitation,
into a .well bore drilled into the subterranean formation, into a near well
bore region
surrounding the well bore, or into both,
[0052] in primary-cementing. embodiments, .for example, embodiments may
comprise providing a cement composition, introducing the cement composition
into a well-
bore annulus; and allowing the cement composition to set in the annulus to
tbrm a hardened
mass. The well-bore annulus may include, for example, an annular space between
a conduit
(e,g.õ pipe. string, liner, etc;) and a wall of a well bore or between the
conduit and a larger
.10
conduit in the well bore. Generally, in most instances, the hardened
mass...should fix,. the
conduit in the well bOrcõ
(0053 ln reinedial-cementing embodiments,a cement composition may be used, for
example, in squeeze-cementing operations or in the placement ofeement plugs,
By :way Of
'example, the cement composition may be placed in a well bore to plug an
opening, such as.a
void or crack in the .formation, in a gravel pack, in the conduit, in the
cement sheath, andlora
microannulus between the cement sheath and the conduit or .formation. An
example of such
a method may comprise .placing the cement composition into the void, and
allowing the
content composition to set in the void.
1.0054] While the preceding description is directed to the use of the
cementitious
component in Cementing method* it should be understood that embodiments of the
present
technique also encompasses the use of the cementitious component. in any of a
variety of
different subterranean treatments. The cementitious component may have a
reactive index
determined according to disclOsed embodiments. in some embodiments, a blended
cementitious component may be used.. In some embodiments, the reactive index.
may be
used in determining the amount of' cementitious components that are in a
particular blended
tementitious component. An example method may include a subterranean treatment
method
that comprises providing a treatment fluid comprising the cementitious
component and
introducing the treatment fluid into a subterranean formation, ror example, a.
drilling. fluid
may comprise the cementitious component, wherein .the drilling fluid may be
circulated
.30
downwardly through a drill pipe and drill bit and then upwardly through the
well bore to the
surface. The drilling. fluid .used may be any number of fluids (gaseous or
liquid) and
mixtures of fluids and solids (such as solid suspensions, mixtures, and
emulsions).
1.0055] In some embodiments, a spacer fluid may comprise the cementitious
component, which may have a determined reactive index according to disclosed
35.
embodiments. Spacer :fluids may be used, far exam*, in the displacement of
fluids from.
16
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well bore, In an embodiment, the fluid displaced by the spacer fluid.
comprises a drilling
fluid, By way of example, the spacer fluid may be used to displace the
drilling fluid from
the well bore. The drilling fluid may include, for example, any number of
fluids., such as
solid suspensions, mixtures, and emulsions. Additional steps in embodiments of
the method
may comprise introducina a pipe string into the well bOre, introducing a
ecinent compOsition
into the well bore with the spacer fluid separating the cement composition and
the first fluid.
in an embodiment, the cement composition may be allowed to set in the well
bore. The
Cement composition may include, for example, cement and water. In some
embodiments, at
least a portion of the spacer fluid may be left in the well bore, the spacer
fluid in the well
bore setting to -fbrm a hardened mass,
EXAMPLES
[00561 To facilitate a better understanding of the present invention, the
following
eXaMples of Certain aspeet$ or some embodiments are given. In no Way should
the following
examples be read to limit. or define, the entire scope of the invention.
Example I
[0057] The reaetiµv indexes for compressive strength for thirty-three
different
samples of cement kiln dust, designated Samples A through 00, were determined
and are
provided in FIG. 1. The CK.D samples are each from a different supply source.
The reactive
indexes =fbr thirty-three CKD samples were determined by dividing the
determined 24-hour
.compressive strength for a 8ettable composition by the specific surface area
of the CKD
sample. The specific surface area for each CKD sample was determined by
dividing the
total surface area of the particular CKD sample by the sample. mass. The
surface area Was
determined using a Malvern particle size analyzer. The 24-hour compressive
strength for
each CKD sample was determined by first preparing a senable composition that
comprised
the CKD sample in an amount of 100% bwoc and water in an amount sufficient to
provide a
density Of about 13 Ihigal. After preparation, the settable composition was
allowed to cure
fir 24 hours in a 2" x 4" metal cylinder that was placed in a water bath at
170W to %rm. set
cement cylinders. Immediately after removal from the water bath, destructive
compressive
strengths were determined using a mechanical press in accordance With API RP
1013-2,
Example 2
100581 Blended cementitioua components were prepared that comprised mixtures
of
the CKD samples from Example 1. as indicated in the table below. The
determined reactive
indexc.s for the MD sample$, Were then used in the following equation to
predict the
performance or each blended cententitious component.
17
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CSwend UtiASSAAfzr (RIASSAFOr atiO(SSAE)(fan
Wherein CSwend is the estimated compressive strength for the blended
cememitious
component. RI z is the reactive index for compressive strength for CKD Sample
Z and was
m is I, SSAz is the specific surface area for CKD Sample Z and was 2,32, fz,
is the mass
fraction of CKD Sample Z, RIF is the reactive index for compressive strength
for CKD
Sample F and was 105, SSAF is the specific surface area for CKD Sample F and
was 2.33, fy
is the mass fraction of CKD Sample F. RIE is the reactive index for
compressive strength for
CKD Sample E. and was 107, SSAE is the specific surface area for CKD Sample E
and was
3.6, and f, is the mass fraction of CKD Sample Li.
[00591 The estimated compressive strength valuesl for the blended cementitious
components were then compared with the actual 24-hour compressive strength
values for the
blended cementitious components. The 24-hour compressive strength for each
blended
cemeatitious component was determined by first preparing a settable
composition that
comprised the blended cementitious component in an amount of 100% bwoc.: and
water in an
amount sufficient to provide a density of 13 lb/gal. A cement dispersant (1C-
F11.-3"4 cement
fron reducer, from Hall iburton Energy Services, Inc.) in an amount of from
0.5% bwoc to
1.0% bwoc was added to some of the samples and should not impact determined
compressive strength values. Atter preparation, the settable composition was
allowed to
cure for 24 hours in a 2" x 4" metal cylinder that was placed in a water bath
at I40"F to form
set cement cylinders. Immediately after removal from the water bath,
destructive
compressive strengths were determined using a mechanical press in accordance
with API RP
1013-2.
10060] A chart of the actual compressive strength values versus the estimated
compressive strength values is provided on FIG. 2, As shown on FIG. 2, the
charted values
have an.R value of 0,952 and a slope of 0,9253. The estimated and actual
compressive
strength values for the blended cementitious components are also provided in
Table I below,
18
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Table I
CKID Sample CKD Sample CKD Sample Estimated Actual
F Compressive Compressive
(44 bwoe) bwoe) bwoe) Strength Strength
ist)
100 0 0 .16 16
75 25 0 73 51
25 75 0 187 183
0 .100 0 :244 244
75 0 25 108 84
25 50 0 50 200 192
0
292. 216
0 0 I 00 384 384
Example 3
[0061] The reactive indexes for volume Average apparent Viscosity at 511 Seel
and
51 see were determined for CKD Sa.mples Z, F, and E from Example 1 and are
provided in
5 Table 2 below. The reactive indexes for these samples were determined by
dividing the
determined volume average apparent viscosity for a .Settable composition by
the specific
surface area of the CK.0 sample. The specific surface area for each CKD sample
was
determined hy dividing the total surface area of the particular CKD sample by
the sample
mass. The surface area was determined using a Malvern particle size analyzer.
The 24-hour
volume average apparent viscosity ("VAV") for each CKD sample was determined
by tint
preparing a settable composition that comprised the CKD sample in an amount of
100%
bwoc and water in an amount sufficient to provide a density of about 12
lb/gal. The volume
average apparent viscosities were measured at 511 !see and 51 see in
accordance with
API RP 1013-2
Table 2
CM) Sample Z CM) Sample F CKD Sample E
SSA 2.31 2.33 3.6
VAV at 511 Seel (cp) 11 62 123
RI at 511 See 5 27 32
VAV at 51 sec- (9?) 40 410 860
RI at St see-1 17 176 239
00621 Next, blended ccmentitiouS components were prepared that comprised
mixtures of OM .samples Z, F, E. as indicated in the table below. The
determined reactive
indexes At 511 see and 51 stel far the (11(1) samples were then used in the
following
equation to predict the :performance of each blended cementitious component.
(Riz)(SSAz)(V,(RI)(SSAAtir + (RIASSAO(V
19
CA 02888162 2016-10-13
Wherein VAVbiend is the estimated volume average apparent viscosity for the
blended
cementitious component, RIz is the reactive index for volume average apparent
viscosity for
CKD Sample Z, SSAz is the specific surface area for CKD Sample Z, fz is the
mass fraction
of CKD Sample Z, m is 7/3, RIF is the reactive index for volume average
apparent viscosity
for CKD Sample F, SSAF is the specific surface area for CKD Sample F, fF is
the mass
fraction of CKD Sample F, RIE is the reactive index for volume average
apparent viscosity
for CKD Sample E, SSAE is the specific surface area for CKD Sample E, and fE
is the mass
fraction of CKD Sample E.
[0063] The estimated volume average apparent viscosities at 511 sec-1 and 51
sec-1
for the blended cementitious components were then compared with the actual
volume
average apparent viscosities at 511 sec-1 and 51 sec-1 for the blended
cementitious
components. The volume average apparent viscosities for each blended
cementitious
component was determined by first preparing a settable composition that
comprised the
blended cementitious component in an amount of 100% bwoc and water in an
amount
sufficient to provide a density of 12 lb/gal. After preparation, the volume
average apparent
viscosities at 511 sec' and51 seciwere determined in accordance with API RP
10B-2.
[0064] Charts of the actual volume average viscosity values versus the
estimated
volume average viscosity values are provided on FIGS. 3 and 4. As shown on
FIG. 3, the
charted values at 511 sec-1 have an R2 value of 0.9894 and a slope of 0.9975.
As shown on
FIG. 4, the charted values at Si sec-1 have an R2 value of 0.9931 and a slope
of 0.9814. The
estimated and actual volume average viscosity values for the blended
cementitious
components are also provided in Table 3 below.
Table 3
CKD CKD CKD Actual Est. Actual
Est.
Sample Z Sample F Sample E VAV VAV VAV VAV
(/0 bwoc) ("/0 bwoc) ("/0 bwoc) @ 511 sec "I @ 511 sec -I @ 51 sec -I @ 51 sec
"1
(cp) (cp) (cp) (c13)
100 0 0 11.0 11.0 40.0
40.0
75 25 0 11.0 8.1 40.0
36.7
75 0 24.0 32.2 190.0 211.3
0 100 0 62.0 62.0 410.1 410.0
0 0 100 123.0 123.0 860.2 860.0
25 0 75 66.0 63.4 500.1
441.5
50 0 50 25.0 26.7 160.0 179.0
75 0 25 16.0 10.5 60.0
54.5
[0065] It should be understood that the compositions and methods are described
in
25 terms
of "comprising," "containing," or "including" various components or steps, the
compositions and methods can also "consist essentially of' or "consist of' the
various
CA 02888162 2016-10-13
components and steps. Moreover, the indefinite articles "a" or "an," as used
in the claims,
are defined herein to mean one or more than one of the element that it
introduces.
[0066] For the sake of brevity, only certain ranges are explicitly disclosed
herein.
However, ranges from any lower limit may be combined with any upper limit to
recite a
range not explicitly recited, as well as, ranges from any lower limit may be
combined with
any other lower limit to recite a range not explicitly recited, in the same
way, ranges from
any upper limit may be combined with any other upper limit to recite a range
not explicitly
recited. Additionally, whenever a numerical range with a lower limit and an
upper limit is
disclosed, any number and any included range falling within the range are
specifically
disclosed. In particular, every range of values (of the form, "from about a to
about b," or,
equivalently, "from approximately a to b," or, equivalently, "from
approximately a-b")
disclosed herein is to be understood to set forth every number and range
encompassed within
the broader range of values even if not explicitly recited. Thus, every point
or individual
value may serve as its own lower or upper limit combined with any other point
or individual
value or any other lower or upper limit, to recite a range not explicitly
recited.
[0067] Therefore, the present invention is well adapted to attain the ends and
advantages mentioned as well as those that are inherent therein. The
particular embodiments
disclosed above are illustrative only, as the present invention may be
modified and practiced
in different manners apparent to those skilled in the art having the benefit
of the teachings
herein. Although individual embodiments are discussed, the invention covers
all
combinations of all those embodiments. Furthermore, no limitations are
intended to the
details of construction or design herein shown, other than as described
herein. Also, the
terms herein have their plain, ordinary meaning unless otherwise explicitly
and clearly
defined by the patentee. It is therefore evident that the particular
illustrative embodiments
disclosed above may be altered or modified and all such variations are
considered within the
scope of the present invention.
21
