U.S. patent application number 14/143497 was filed with the patent office on 2014-10-30 for pumice-containing remedial compositions and methods of use.
This patent application is currently assigned to Halliburton Energy Services, Inc.. The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to James R. Benkley, D. Chad Brenneis, Jiten Chatterji.
Application Number | 20140318419 14/143497 |
Document ID | / |
Family ID | 51788148 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140318419 |
Kind Code |
A1 |
Chatterji; Jiten ; et
al. |
October 30, 2014 |
Pumice-Containing Remedial Compositions and Methods of Use
Abstract
Methods and compositions are provided that utilize pumice and
various additives. Embodiments provide pumice-containing remedial
compositions. One of the pumice-containing remedial composition
embodiments comprises pumice; a calcium activator; and water,
wherein the pumice-containing remedial composition has a density of
less than about 13.5 pounds per gallon, and wherein the
pumice-containing remedial composition is free of Portland
cement.
Inventors: |
Chatterji; Jiten; (Duncan,
OK) ; Brenneis; D. Chad; (Marlow, OK) ;
Benkley; James R.; (Duncan, OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Assignee: |
Halliburton Energy Services,
Inc.
Houston
TX
|
Family ID: |
51788148 |
Appl. No.: |
14/143497 |
Filed: |
December 30, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13873905 |
Apr 30, 2013 |
|
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14143497 |
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Current U.S.
Class: |
106/676 ;
106/698; 106/705; 106/792; 106/810; 106/811; 106/813; 106/814;
524/2 |
Current CPC
Class: |
Y02W 30/92 20150501;
C04B 2111/1037 20130101; Y02W 30/91 20150501; C04B 28/18 20130101;
Y02W 30/94 20150501; C09K 8/428 20130101; E21B 33/13 20130101; C09K
8/467 20130101; E21B 33/138 20130101; C04B 28/18 20130101; C04B
14/047 20130101; C04B 14/108 20130101; C04B 14/108 20130101; C04B
14/16 20130101; C04B 14/18 20130101; C04B 16/085 20130101; C04B
18/08 20130101; C04B 18/101 20130101; C04B 18/146 20130101 |
Class at
Publication: |
106/676 ;
106/814; 106/811; 106/813; 106/705; 106/698; 524/2; 106/810;
106/792 |
International
Class: |
C09K 8/467 20060101
C09K008/467; C09K 8/42 20060101 C09K008/42 |
Claims
1. A pumice-containing remedial composition comprising: pumice, a
lime, perlite; wherein the perlite is present in the
pumice-containing remedial composition position in an amount of
about 0.1% to about 50% by weight of the pumice, and water; wherein
the water is present in the pumice-containing remedial composition
in an amount of about 40% to about 150% by weight of the pumice;
wherein the pumice-containing remedial composition is foamed to a
density of less than about 10 pounds per gallon; and wherein the
pumice-containing remedial composition is free of Portland
cement.
2. The composition of claim 1, wherein the pumice-containing
remedial composition further comprises shale and zeolite.
3. The composition of claim 1, wherein the lime is present in an
amount of about 0.1% to about 25% by weight of the pumice.
4. The composition of claim 1, wherein the lime is hydrated
lime.
5. The composition of claim 1, wherein the water is present in an
amount in a range of from about 40% to about 100% by weight of the
pumice.
6. The composition of claim 1, wherein the pumice-containing
remedial composition further comprises at least one additive
selected from the group consisting of shale, zeolite, amorphous
silica, fly ash, metakaolin, rice hull hush, a swellable
particulate elastomer, and any combination thereof.
7. The composition of claim 6, wherein the at least one additive is
present in an amount in a range of from about 0.1% to about 100% by
weight of the pumice.
8. The composition of claim 6, wherein the at least one additive
present in an amount in a range of from about 50% to about 100% by
weight of the pumice.
9. The composition of claim 1, wherein the pumice-containing
remedial composition further comprises shale in an amount of about
40% to about 100% by weight of the pumice, and wherein the
composition further comprises zeolite in an amount of about 40% to
about 100% by weight of the pumice.
10. The composition of claim 1, wherein the pumice-containing
remedial composition further comprises metakaolin in an amount of
about 40% to about 100% by weight of the pumice.
11. The composition of claim 1, where the pumice-containing
remedial composition further comprises at least one additive
selected from the group consisting of a strength-retrogression
additive, a set accelerator, a set retarder, a lightweight
additive, a gas-generating additive, a mechanical property
enhancing additive, a lost-circulation material, a fluid loss
control additive, a foaming additive, a defoaming additive, a
thixotropic additive, and any combination thereof.
12. The composition of claim 1, wherein the pumice-containing
remedial composition further comprises at least one additive
selected from the group consisting of crystalline silica, fumed
silica, a silicate, a salt, a fiber, a hydratable clay, shale,
calcined shale, vitrified shale, a microsphere, diatomaceous earth,
natural pozzolan, cement kiln dust, a resin, and any combination
thereof.
13. The composition of claim 1, wherein the pumice-containing
remedial composition is foamed using a foaming additive and a
gas.
14. The composition of claim 1, wherein the pumice-containing
remedial composition is free of any additional cementitious
components.
15. A pumice-containing remedial composition comprising: pumice, a
lime, wherein the lime is present in an amount of about 0.1% to
about 25% by weight of the pumice, perlite; wherein the perlite is
present in the pumice-containing remedial composition in an amount
of about 0.1% to about 50% by weight of the pumice, and water;
wherein the water is present in an amount in a range of from about
40% to about 150% by weight of the pumice; wherein the
pumice-containing remedial composition has a density of less than
about 13.5 pounds per gallon; and wherein the pumice-containing
remedial composition is free of Portland cement.
16. The composition of claim 15, wherein the lime is hydrated
lime.
17. The composition of claim 15, wherein the pumice-containing
remedial composition further comprises at least one additive
selected from the group consisting of shale, zeolite, amorphous
silica, fly ash, metakaolin, rice hull hush, a swellable
particulate elastomer, and any combination thereof.
18. A pumice-containing remedial composition comprising: pumice, a
hydrated lime; wherein the hydrated lime is present in an amount of
about 0.1% to about 25% by weight of the pumice, perlite; wherein
the perlite is present in the pumice-containing remedial
composition in an amount of about 0.1% to about 50% by weight of
the pumice, and water; wherein the water is present in an amount in
a range of from about 40% to about 200% by weight of the pumice;
wherein the pumice-containing remedial composition is foamed to a
density of less than about 10 pounds per gallon; wherein the
pumice-containing remedial composition is free of Portland cement;
and wherein the composition is foamed using a foaming additive and
a gas.
19. The composition of claim 18, wherein the pumice-containing
remedial composition further comprises shale in an amount of about
40% to about 100% by weight of the pumice, and wherein the
composition further comprises zeolite in an amount of about 40% to
about 100% by weight of the pumice.
20. The composition of claim 18, wherein the pumice-containing
remedial composition further comprises metakaolin in an amount of
about 40% to about 100% by weight of the pumice.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 13/873,905, entitled "Pumice-Containing
Remedial Compositions and Methods of Use," filed on Apr. 30, 2013,
the entire disclosure of which is incorporated herein by
reference.
BACKGROUND
[0002] The present invention relates to cementing operations and,
more particularly, in certain embodiments, to methods and
compositions that utilize pumice and various additives.
[0003] In cementing operations, such as well construction and
remedial cementing, settable compositions are commonly utilized. As
used herein, the term "settable composition" refers to a
composition that hydraulically sets or otherwise develops
compressive strength. Settable compositions may be used in primary
cementing operations whereby pipe strings, such as casing and
liners, are cemented in well bores. In a typical primary cementing
operation, a settable composition may be pumped into an annulus
between the exterior surface of the pipe string disposed therein
and the walls of the well bore (or a larger conduit in the well
bore). The settable composition may set in the annular space,
thereby forming an annular sheath of hardened, substantially
impermeable material (e.g., a cement sheath) that may support and
position the pipe string in the well bore and may bond the exterior
surface of the pipe string to the well bore walls (or the larger
conduit). Among other things, the cement sheath surrounding the
pipe string should function to prevent the migration of fluids in
the annulus, as well as protecting the pipe string from corrosion.
Settable compositions also may be used in remedial cementing
methods, such as in squeeze cementing for sealing voids in a pipe
string, cement sheath, gravel pack, subterranean formation, and the
like.
[0004] In remedial cementing, settable compositions may be used for
sealing voids in a pipe string or a cement sheath. As used herein
the term "void" refers to any type of space, including fractures,
holes, cracks, channels, spaces, and the like. Such voids may
include: holes or cracks in the pipe strings; holes, cracks,
spaces, or channels in the cement sheath; and very small spaces
(commonly referred to as "microannuli") between the cement sheath
and the exterior surface of the well casing or formation. Sealing
such voids may prevent the undesired flow of fluids (e.g., oil,
gas, water, etc.) and/or fine solids into, or from, the well bore.
The sealing of such voids, whether or not made deliberately, has
been attempted by introducing a substance into the void and
permitting it to remain therein to seal the void. If the substance
does not fit into the void, a bridge, patch, or sheath may be
formed over the void to possibly produce a termination of the
undesired fluid flow. Substances used heretofore in methods to
terminate the undesired passage of fluids through such voids
include settable compositions comprising water and hydraulic
cement, wherein the methods employ hydraulic pressure to force the
settable composition into the void. Once placed into the void, the
settable composition may be permitted to harden.
[0005] Remedial cementing operations also may be used to seal
portions of subterranean formations or portions of gravel packs.
The portions of the subterranean formation may include permeable
portions of a formation and fractures (natural or otherwise) in the
formation and other portions of the formation that may allow the
undesired flow of fluid into, or from, the well bore. The portions
of the gravel pack include those portions of the gravel pack,
wherein it is desired to prevent the undesired flow of fluids into,
or from, the well bore. A "gravel pack" is a term commonly used to
refer to a volume of particulate materials (such as sand) placed
into a well bore to at least partially reduce the migration of
unconsolidated formation particulates into the well bore. While
screenless gravel packing operations are becoming more common,
gravel packing operations commonly involve placing a gravel pack
screen in the well bore neighboring a desired portion of the
subterranean formation, and packing the surrounding annulus between
the screen and the well bore with particulate materials that are
sized to prevent and inhibit the passage of formation solids
through the gravel pack with produced fluids. Among other things,
this method may allow sealing of the portion of the gravel pack to
prevent the undesired flow of fluids without requiring the gravel
pack's removal.
[0006] A broad variety of settable compositions have been used
heretofore, including cement compositions comprising Portland
cement. Portland cement is generally prepared from a mixture of raw
materials comprising calcium oxide, silicon oxide, aluminum oxide,
ferric oxide, and magnesium oxide. The mixture of the raw materials
is heated in a kiln to approximately 2700.degree. F., thereby
initiating chemical reactions between the raw materials. In these
reactions, crystalline compounds, dicalcium silicates, tricalcium
silicates, tricalcium aluminates, and tetracalcium aluminoferrites,
are formed. The product of these reactions is known as a clinker.
The addition of a gypsum/anhydrate mixture to the clinker and the
pulverization of the mixture results in a fine powder that will
react to form a slurry upon the addition of water.
[0007] There are drawbacks, however, to the conventional
preparation and use of Portland cement. The energy requirements to
produce Portland cement are quite high, and heat loss during
production can further cause actual energy requirements to be even
greater. These factors contribute significantly to the relatively
high cost of Portland cement. Generally, Portland cement is a major
component of the cost of hydraulic cement compositions that
comprise Portland cement. Recent Portland cement shortages,
however, have further contributed to the rising cost of hydraulic
cement compositions that comprise Portland cement.
SUMMARY
[0008] An embodiment provides a method of remedial cementing in a
subterranean formation comprising: providing a lightweight settable
composition comprising pumice, a calcium activator, and water,
wherein the lightweight settable composition has a density of less
than about 13.5 pounds per gallon and is free of Portland cement;
and using the lightweight settable composition in a remedial
cementing method to seal one or more voids in a well bore.
[0009] Another embodiment provides a pumice-containing remedial
settable composition comprising: pumice; a calcium activator; and
water, wherein the lightweight settable composition has a density
of less than about 13.5 pounds per gallon, and wherein the
lightweight settable composition is free of Portland cement.
[0010] Yet another embodiment provides a system for remedial
cementing comprising: a lightweight settable composition comprising
pumice, a calcium activator, and water, wherein the lightweight
settable composition has a density of less than about 13.5 pounds
per gallon; mixing equipment for mixing the lightweight settable
composition, and pumping equipment for delivering the lightweight
settable composition to a well bore.
[0011] 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, such changes are
within the spirit of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0012] Embodiments of the present invention disclose lightweight
settable compositions comprising pumice, a calcium activator, and
water, wherein the lightweight settable compositions are free of
Portland cement. Other additives that may be included in the
lightweight settable compositions include shale, zeolite, amorphous
silica, fly ash, metakaolin, perlite, rice hull ash, and/or
swellable particulate elastomer. One of the many potential
advantages of embodiments of the lightweight settable composition
is that pumice is a relatively inexpensive component in comparison
to traditional cements such as Portland cement. Another advantage
is that pumice manufacture and subsequent use in a settable
composition is less environmentally damaging as compared to cements
such as Portland cement. Therefore, a pumice settable composition
would have a smaller carbon footprint. One more additional
advantage is that the pumice-containing settable compositions are
lightweight and fast setting. Accordingly, embodiments of the
lightweight settable compositions may be used in a variety of
subterranean applications for remedial cementing operations such in
squeeze cementing for sealing voids in a pipe string, cement
sheath, gravel pack, subterranean formation, and the like.
[0013] In some embodiments, the lightweight settable compositions
may comprise pumice. Generally, pumice is a volcanic rock that
exhibits cementitious properties, in that it may set and harden in
the presence of a calcium activator and water. The calcium
activator may be used in combination with the pumice, for example,
to provide sufficient calcium ions for the pumice to set. The
pumice may also be ground, for example. Generally, the pumice may
have any particle size distribution as desired for a particular
application. In certain embodiments, the pumice may have a mean
particle size in a range of from about 1 micron to about 200
microns. The mean particle size corresponds to d50 values as
measured by particle size analyzers such as those manufactured by
Malvern Instruments, Worcestershire, United Kingdom. In specific
embodiments, the pumice may have a mean particle size in a range of
from about 1 micron to about 200 micron, from about 5 microns to
about 100 microns, or from about 10 micron to about 50 microns. In
one particular embodiment, the pumice may have a mean particle size
of less than about 15 microns. An example of a suitable pumice is
DS-200 lightweight aggregate available from Hess Pumice Products,
Inc., Malad City, Id., having an average particle size of less than
20 microns. In some embodiments, a total amount of cementitious
components in the settable composition may consist essentially of
and/or consist of the pumice. One of ordinary skill in the art,
with the benefit of this disclosure, will recognize the appropriate
amount of the pumice to include for a chosen application.
[0014] In some embodiments, the settable compositions may comprise
a calcium activator. The term "calcium activator" refers to a
material that generates calcium ions when mixed with water. The
pumice reacts with the calcium ions to react and form a hardened
mass. The calcium activator may be included in the settable
compositions to provide calcium ions for activation of the pumice,
thus providing a settable composition that will react with the
water to form a hardened mass in accordance with embodiments of the
present invention. Any of a variety of suitable calcium activators
may be used that are capable of generating calcium ions when
dissolved in the water. Examples of suitable calcium activators
include calcium formate, lime (e.g., hydrated lime), and any
combination thereof. In some embodiments, the calcium activators
may be present in the settable compositions in an amount in the
range of from about 0.1% to about 25% by weight of the pumice. In
further embodiments, the calcium activator may be included in an
amount in the range of from about 1% to about 10% by weight of the
pumice.
[0015] In some embodiments, the settable compositions may be free
of Portland cement. In some embodiments, the settable compositions
may be essentially free of any additional cementitious materials,
such as hydraulic cements, including, but not limited to, those
comprising calcium, aluminum, silicon, oxygen, iron, and/or sulfur,
which set and harden by reaction with water. Specific examples of
hydraulic cements include, but are not limited to, Portland
cements, pozzolana cements, gypsum cements, high alumina content
cements, silica cements, and any combination thereof. In some
embodiments, the Portland cements are classified as Classes A, C,
H, or G cements according to American Petroleum Institute, API
Specification for Materials and Testing for Well Cements, API
Specification 10, Fifth Ed., Jul. 1, 1990. In addition, in some
embodiments, the hydraulic cement may include cements classified as
ASTM Type I, II, or III. In some embodiments, the settable
compositions may comprise additional cementitious materials in an
amount less than about 1% by weight of the pumice and,
alternatively, less than about 0.1% by weight of the pumice.
[0016] The water used in embodiments of the settable compositions
of the present invention may include, for 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 compositions.
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%
by weight of the pumice. In some embodiments, the water may be
included in an amount in a range of from about 40% to about 150% by
weight of the pumice.
[0017] Embodiments of the lightweight settable compositions may be
foamed with a foaming additive and a gas, for example, to provide a
composition with a reduced density. In some embodiments, the
lightweight settable composition may be foamed to have a density of
less than about 12 pounds per gallon ("lbs/gal"), less than about
11 lbs/gal, or less than about 10 lbs/gal. In some embodiments, the
lightweight settable composition may be foamed to have a density in
a range of from about from about 4 lbs/gal to about 12 lbs/gal and,
alternatively, about 7 lbs/gal to about 9 lbs/gal. The gas used for
foaming the lightweight settable compositions may be any suitable
gas for foaming the lightweight settable composition, including,
but not limited to air, nitrogen, and combinations thereof.
Generally, the gas should be present in embodiments of the foamed
lightweight settable composition in an amount sufficient to form
the desired foam. In certain embodiments, the gas may be present in
an amount in the range of from about 5% to about 80% by volume of
the foamed lightweight settable composition at atmospheric
pressure, alternatively, about 5% to about 55% by volume, and,
alternatively, about 15% to about 30% by volume.
[0018] Foaming additives may be included in embodiments of the
lightweight settable compositions to, for example, facilitate
foaming and/or stabilize the resultant foam formed therewith.
Examples of suitable foaming additives include, but are not limited
to: mixtures of an ammonium salt of an alkyl ether sulfate, a
cocoamidopropyl betaine surfactant, a cocoamidopropyl dimethylamine
oxide surfactant, sodium chloride, and water; mixtures of an
ammonium salt of an alkyl ether sulfate surfactant, a
cocoamidopropyl hydroxysultaine surfactant, a cocoamidopropyl
dimethylamine oxide surfactant, sodium chloride, and water;
hydrolyzed keratin; mixtures of an ethoxylated alcohol ether
sulfate surfactant, an alkyl or alkene amidopropyl betaine
surfactant, and an alkyl or alkene dimethylamine oxide surfactant;
aqueous solutions of an alpha-olefinic sulfonate surfactant and a
betaine surfactant; and combinations thereof. An example of a
suitable foaming additive is ZONESEALANT.TM. 2000 agent, available
from Halliburton Energy Services, Inc.
[0019] As previously mentioned, embodiments of the lightweight
settable compositions may include one or more additives selected
from shale, zeolite, amorphous silica, fly ash, metakaolin,
perlite, rice hull ash, and/or swellable elastomers. These
additives may be included in the lightweight settable compositions
to improve one or more properties, including mechanical properties
such as compressive strength.
[0020] In certain embodiments, the lightweight settable
compositions of the present invention may comprise shale in an
amount sufficient to provide the desired compressive strength,
density, and/or cost. A variety of shales are suitable, including
those comprising silicon, aluminum, calcium, and/or magnesium.
Suitable examples of shale include, but are not limited to,
PRESSUR-SEAL.RTM. FINE LCM material and PRESSUR-SEAL.RTM. COARSE
LCM material, which are commercially available from TXI Energy
Services, Inc., Houston, Tex. Generally, the shale may have any
particle size distribution as desired for a particular application.
In certain embodiments, the shale may have a particle size
distribution in the range of about 37 microns to about 4,750
microns. In some embodiments the shale may be vitrified shale. In
some embodiments the shale may be calcined shale. In certain
embodiments, the shale may be present in the lightweight settable
compositions of the present invention in an amount in the range of
from about 0.1% to about 100% by weight of the pumice. In some
embodiments, the shale may be present in an amount ranging between
any of and/or including any of about 10%, about 20%, about 30%,
about 40%, about 50%, about 60%, about 70%, about 80%, about 90%,
or about 100% by weight of the pumice. One of ordinary skill in the
art, with the benefit of this disclosure, will recognize the
appropriate amount of the shale to include for a chosen
application.
[0021] In certain embodiments, the lightweight settable
compositions of the present invention may comprise zeolite. Zeolite
may be used in conjunction with the shale in some embodiments. In
other embodiments, zeolite may be an alternative to shale. The
choice may be dictated by a number of factors, such as total extent
of compressive strength of the cement, time for cement composition
to develop compressive strength, and density of the composition.
Zeolites generally are porous alumino-silicate minerals that may be
either a natural or synthetic material. Synthetic zeolites are
based on the same type of structural cell as natural zeolites, and
may comprise aluminosilicate hydrates. As used herein, the term
"zeolite" refers to all natural and synthetic forms of zeolite. In
certain embodiments, the zeolite may be present in the lightweight
settable compositions of the present invention in an amount in the
range of from about 0.1% to about 100% by weight of the pumice. In
some embodiments, the zeolite may be present in an amount ranging
between any of and/or including any of about 10%, about 20%, about
30%, about 40%, about 50%, about 60%, about 70%, about 80%, about
90%, or about 100% by weight of the pumice. One of ordinary skill
in the art, with the benefit of this disclosure, will recognize the
appropriate amount of the zeolite to include for a chosen
application.
[0022] In certain embodiments, the lightweight settable
compositions of the present invention may comprise amorphous
silica. Amorphous silica is generally a byproduct of a ferrosilicon
production process, wherein the amorphous silica may be formed by
oxidation and condensation of gaseous silicon suboxide, SiO, which
is formed as an intermediate during the process. An example of a
suitable source of amorphous silica is SILICALITE.TM., available
from Halliburton Energy Services, Inc. In certain embodiments, the
amorphous silica may be present in the lightweight settable
compositions of the present invention in an amount in the range of
from about 0.1% to about 40% by weight of the pumice. In some
embodiments, the amorphous silica may be present in an amount
ranging between any of and/or including any of about 10%, about
20%, about 30%, and about 40% by weight of the pumice. One of
ordinary skill in the art, with the benefit of this disclosure,
will recognize the appropriate amount of the shale to include for a
chosen application.
[0023] Fly ash may be included in embodiments of the lightweight
settable compositions of the present invention. A variety of fly
ashes may be suitable, including fly ash classified as Class C and
Class F fly ash according to American Petroleum Institute, API
Specification for Materials and Testing for Well Cements, API
Specification 10, Fifth Ed., Jul. 1, 1990. Class C fly ash
comprises both silica and lime so that, when mixed with water, it
sets to form a hardened mass. Class F fly ash generally does not
contain sufficient lime, so an additional source of calcium ions
may be required for the Class F fly ash to form a settable
composition with water. In some embodiments, lime may be mixed with
Class F fly ash in an amount in the range of about 0.1% to about
25% by weight of the fly ash. In some instances, the lime may be
hydrated lime. Suitable examples of fly ash include, but are not
limited to, POZMIX.RTM. A cement additive, available from
Halliburton Energy Services, Inc. Where present, the fly ash
generally may be included in the lightweight settable compositions
in an amount sufficient to provide the desired compressive
strength, density, and/or cost. In certain embodiments, the fly ash
may be present in the lightweight settable compositions of the
present invention in an amount in the range of from about 0.1% to
about 100% by weight of the pumice. In some embodiments, the fly
ash may be present in an amount ranging between any of and/or
including any of about 10%, about 20%, about 30%, about 40%, about
50%, about 60%, about 70%, about 80%, about 90%, or about 100% by
weight of the pumice. One of ordinary skill in the art, with the
benefit of this disclosure, will recognize the appropriate amount
of the fly ash to include for a chosen application.
[0024] Metakaolin may be included in embodiments of the lightweight
settable compositions of the present invention. Generally,
metakaolin is a white pozzolan that may be prepared by heating
kaolin clay, for example, to temperatures in the range of about
600.degree. C. to about 800.degree. C. In certain embodiments, the
metakaolin may be present in the lightweight settable compositions
of the present invention in an amount in the range of from about
0.1% to about 100% by weight of the pumice. In some embodiments,
the metakaolin may be present in an amount ranging between any of
and/or including any of about 10%, about 20%, about 30%, about 40%,
about 50%, about 60%, about 70%, about 80%, about 90%, or about
100% by weight of the pumice. One of ordinary skill in the art,
with the benefit of this disclosure, will recognize the appropriate
amount of the metakaolin to include for a chosen application.
[0025] Perlite may be included in embodiments of the lightweight
settable compositions of the present invention. Perlite is an ore
and generally refers to a naturally occurring volcanic, amorphous
siliceous rock comprising mostly silicon dioxide and aluminum
oxide. Perlite suitable for use in embodiments of the present
invention includes expanded perlite and unexpanded perlite.
Examples of suitable perlite include expanded and/or unexpanded
perlite. The expanded or unexpanded perlite may also be ground, for
example. In certain embodiments, the perlite may be present in the
lightweight settable compositions of the present invention in an
amount in the range of from about 0.1% to about 100% by weight of
the pumice. In some embodiments, the perlite may be present in an
amount ranging between any of and/or including any of about 10%,
about 20%, about 30%, about 40%, about 50%, about 60%, about 70%,
about 80%, about 90%, or about 100% by weight of the pumice. One of
ordinary skill in the art, with the benefit of this disclosure,
will recognize the appropriate amount of the perlite to include for
a chosen application.
[0026] Rice hull ash may be included in embodiments of the
lightweight settable compositions of the present invention. In
general, rice hull ash is the ash produced from the burning of rice
hulls, which are the hard coverings of grains of rice, and may
comprise primarily silica and carbon. In certain embodiments, the
rice hull ash may be present in the lightweight settable
compositions of the present invention in an amount in the range of
from about 0.1% to about 100% by weight of the pumice. In some
embodiments, the rice hull ash may be present in an amount ranging
between any of and/or including any of about 10%, about 20%, about
30%, about 40%, about 50%, about 60%, about 70%, about 80%, about
90%, or about 100% by weight of the pumice. One of ordinary skill
in the art, with the benefit of this disclosure, will recognize the
appropriate amount of the rice hull ash to include for a chosen
application.
[0027] A swellable particulate elastomer may be included in
embodiments of the lightweight settable compositions of the present
invention. Particulate elastomers suitable for use in embodiments
of the present invention may generally swell by up to about 100% of
their original size at the surface when contacted by oil. Under
downhole conditions, this swelling may be more, or less, depending
on the conditions presented. For example, the swelling may be at
least 10% at downhole conditions, in some embodiments, the swelling
may be up to about 50% under downhole conditions. However, as those
of ordinary skill in the art, with the benefit of this disclosure,
will appreciate, the actual swelling when the particulate elastomer
is included in a lightweight settable composition may depend on,
for example, the elastomer concentration, downhole pressure, and
downhole temperature, among other factors. Some specific examples
of suitable particulate elastomers include, but are not limited to,
natural rubber, acrylate butadiene rubber, polyacrylate rubber,
isoprene rubber, chloroprene rubber, butyl rubber (HR), brominated
butyl rubber (BIIR), chlorinated butyl rubber (CIIR), chlorinated
polyethylene (CM/CPE), neoprene rubber (CR), styrene butadiene
copolymer rubber (SBR), styrene butadiene block copolymer rubber,
sulphonated polyethylene (CSM), ethylene acrylate rubber (EAM/AEM),
epichlorohydrin ethylene oxide copolymer (CO, ECO),
ethylene-propylene rubber (EPM and EDPM), ethylene-propylene-diene
terpolymer rubber (EPT), ethylene vinyl acetate copolymer,
fluorosilicone rubbers (FVMQ), silicone rubbers (VMQ), poly
2,2,1-bicyclo heptene (polynorbornene), alkylstyrene, and
crosslinked vinyl acrylate copolymers. In certain embodiments, the
swellable particulate elastomer may be present in the lightweight
settable compositions of the present invention in an amount in the
range of from about 0.1% to about 100% by weight of the pumice. In
some embodiments, the swellable particulate elastomer may be
present in an amount ranging between any of and/or including any of
about 10%, about 20%, about 30%, about 40%, about 50%, about 60%,
about 70%, about 80%, about 90%, or about 100% by weight of the
pumice. One of ordinary skill in the art, with the benefit of this
disclosure, will recognize the appropriate amount of the swellable
particulate elastomer to include for a chosen application.
[0028] Other additives suitable for use in subterranean remedial
cementing operations may also be added to embodiments of the
lightweight settable compositions, in accordance with embodiments
of the present invention. Examples of such additives include, but
are not limited to, strength-retrogression additives, set
accelerators, set retarders, lightweight additives, gas-generating
additives, mechanical property enhancing additives,
lost-circulation materials, fluid loss control additives, defoaming
additives, thixotropic additives, and any combination thereof.
Specific examples of these, and other, additives include
crystalline silica, fumed silica, silicates, silicalite, salts,
fibers, hydratable clays, shale, microspheres, diatomaceous earth,
natural pozzolan, 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.
[0029] Strength-retrogression additives may be included in
embodiments of the lightweight settable composition to, for
example, prevent the retrogression of strength after the settable
composition has been allowed to develop compressive strength when
the settable composition is exposed to high temperatures. These
additives may allow the settable compositions to form as intended,
preventing cracks and premature failure of the cementitious
composition. Examples of suitable strength-retrogression additives
may include, but are not limited to, amorphous silica, coarse grain
crystalline silica, fine grain crystalline silica, or a combination
thereof.
[0030] Set accelerators may be included in embodiments of the
lightweight settable compositions to, for example, increase the
rate of setting reactions. Control of setting time may allow for
the ability to adjust to well bore conditions or customize set
times for individual jobs. Examples of suitable set accelerators
may include, but are not limited to, aluminum sulfate, alums,
calcium chloride, calcium sulfate, gypsum-hemihydrate, sodium
aluminate, sodium carbonate, sodium chloride, sodium silicate,
sodium sulfate, ferric chloride, or a combination thereof.
[0031] Set retarders may be included in embodiments of the
lightweight settable compositions to, for example, increase the
thickening time of the settable compositions. Examples of suitable
set retarders include, but are not limited to, ammonium, alkali
metals, alkaline earth metals, borax, metal salts of calcium
lignosulfonate, carboxymethyl hydroxyethyl cellulose,
sulfoalkylated lignins, hydroxycarboxy acids, copolymers of
2-acrylamido-2-methylpropane sulfonic acid salt and acrylic acid or
maleic acid, saturated salt, or a combination thereof. One example
of a suitable sulfoalkylated lignin comprises a sulfomethylated
lignin.
[0032] Lightweight additives may be included in embodiments of the
lightweight settable compositions to, for example, decrease the
density of the settable compositions. Examples of suitable
lightweight additives include, but are not limited to, bentonite,
coal, diatomaceous earth, expanded perlite, fly ash, gilsonite,
hollow microspheres, low-density elastic beads, nitrogen,
pozzolan-bentonite, sodium silicate, combinations thereof, or other
lightweight additives known in the art.
[0033] Gas-generating additives may be included in embodiments of
the lightweight settable compositions to release gas at a
predetermined time, which may be beneficial to prevent gas
migration from the formation through the settable composition
before it hardens. The generated gas may combine with or inhibit
the permeation of the settable composition by formation gas.
Examples of suitable gas-generating additives include, but are not
limited to, metal particles (e.g., aluminum powder) that react with
an alkaline solution to generate a gas.
[0034] Mechanical-property-enhancing additives may be included in
embodiments of the lightweight settable compositions to, for
example, ensure adequate compressive strength and long-term
structural integrity. These properties can be affected by the
strains, stresses, temperature, pressure, and impact effects from a
subterranean environment. Examples of mechanical property enhancing
additives include, but are not limited to, carbon fibers, glass
fibers, metal fibers, mineral fibers, silica fibers, polymeric
elastomers, and latexes.
[0035] Lost-circulation materials may be included in embodiments of
the lightweight settable compositions to, for example, help prevent
the loss of fluid circulation into the subterranean formation.
Examples of lost-circulation materials include but are not limited
to, cedar bark, shredded cane stalks, mineral fiber, mica flakes,
cellophane, calcium carbonate, ground rubber, polymeric materials,
pieces of plastic, grounded marble, wood, nut hulls, formica,
corncobs, and cotton hulls.
[0036] Fluid-loss-control additives may be included in embodiments
of the lightweight settable compositions to, for example, decrease
the volume of fluid that is lost to the subterranean formation.
Properties of the settable compositions may be significantly
influenced by their water content. The loss of fluid can subject
the settable compositions to degradation or complete failure of
design properties. Examples of suitable fluid-loss-control
additives include, but not limited to, certain polymers, such as
hydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose,
copolymers of 2-acrylamido-2-methylpropanesulfonic acid and
acrylamide or N,N-dimethylacrylamide, and graft copolymers
comprising a backbone of lignin or lignite and pendant groups
comprising at least one member selected from the group consisting
of 2-acrylamido-2-methylpropanesulfonic acid, acrylonitrile, and
N,N-dimethylacrylamide.
[0037] Defoaming additives may be included in embodiments of the
lightweight settable compositions to, for example, reduce tendency
for the settable composition to foam during mixing and pumping of
the settable compositions. Examples of suitable defoaming additives
include, but are not limited to, polyol silicone compounds.
Suitable defoaming additives are available from Halliburton Energy
Services, Inc., under the product name D-AIR.TM. defoamers.
[0038] Thixotropic additives may be included in embodiments of the
lightweight settable compositions to, for example, provide a
settable composition that can be pumpable as a thin or low
viscosity fluid, but when allowed to remain quiescent attains a
relatively high viscosity. Among other things, thixotropic
additives may be used to help control free water, create rapid
gelation as the slurry sets, combat lost circulation, prevent
"fallback" in annular column, and minimize gas migration. Examples
of suitable thixotropic additives include, but are not limited to,
gypsum, water soluble carboxyalkyl, hydroxyalkyl, mixed
carboxyalkyl hydroxyalkyl either of cellulose, polyvalent metal
salts, zirconium oxychloride with hydroxyethyl cellulose, or a
combination thereof.
[0039] Those of ordinary skill in the art will appreciate that the
lightweight settable compositions generally may be characterized as
lightweight in that the settable compositions have a density that
does not exceed about 13.5 lb/gal. Because the settable
compositions are lightweight, they may be used in applications
where heavier compositions may not be suitable, for example, those
with fracture gradients that would be exceed by the heavier
compositions. Lightweight settable compositions may also be used,
for example, to prevent the collapse of depleted zones that may
results from a heavier composition. In an exemplary embodiment, the
density of the settable compositions is about 12.5 lb/gal. Those of
ordinary skill in the art, with the benefit of this disclosure,
will recognize the appropriate density for a particular
application.
[0040] The components of the lightweight settable composition may
be combined in any order desired to form a settable composition
that can be placed into a subterranean formation. In addition, the
components of the settable compositions may be combined using any
mixing device compatible with the composition, including a bulk
mixer, for example. In some embodiments, the settable compositions
may be prepared by combining the dry components with water. Other
additives may be combined with the water before it is added to the
dry components. In some embodiments, the dry components may be dry
blended prior to their combination with the water. In some
embodiments, a dry blend may be prepared that comprises the pumice.
The dry blend may also comprise one or more of shale, zeolite,
amorphous silica, fly ash, metakaolin, perlite, rice hull ash,
and/or swellable particulate elastomer. The calcium-ion source may
be added, for example, to the water or the dry blend. Other
suitable techniques may be used for preparation of the setting
compositions as will be appreciated by those of ordinary skill in
the art in accordance with embodiments of the present
invention.
[0041] In remedial cementing embodiments, the lightweight settable
compositions may be used, for example, in squeeze-cementing
operations. By way of example, the settable compositions may be
placed in a well bore to plug a void or crack in the formation, in
a gravel pack, in the conduit, in the cement sheath, and/or a
microannulus between the cement sheath and the conduit.
[0042] An example of a method of the present invention is method of
sealing a portion of a gravel pack or a portion of a subterranean
formation. An example of such a method may comprise providing a
lightweight settable composition; introducing the lightweight
settable composition into the portion of the gravel pack or the
portion of the subterranean formation; and allowing the lightweight
settable composition to form a hardened mass in the portion. The
portions of the subterranean formation may include permeable
portions of the formation and fractures (natural or otherwise) in
the formation and other portions of the formation that may allow
the undesired flow of fluid into, or from, the well bore. The
portions of the gravel pack include those portions of the gravel
pack, wherein it is desired to prevent the undesired flow of fluids
into, or from, the well bore. Among other things, this method may
allow the sealing of the portion of the gravel pack to prevent the
undesired flow of fluids without requiring the gravel pack's
removal.
[0043] Another example of a method of the present invention is a
method of sealing voids located in a pipe string (e.g., casing,
expandable casings, liners, etc.) or in a cement sheath. Generally,
the pipe string will be disposed in a well bore, and the cement
sheath may be located in the annulus between the pipe string
disposed in the well bore and a wall of the well bore. An example
of such a method may comprise providing a lightweight settable
composition; introducing the lightweight settable composition into
the void; and allowing the lightweight settable composition to set
to form a hardened mass in the void.
[0044] When sealing a void in a pipe string, the methods of the
present invention, in some embodiments, further may comprise
locating the void in the pipe string; and isolating the void by
defining a space within the pipe string in communication with the
void; wherein the lightweight settable composition may be
introduced into the void from the space. The void may be isolated
using any suitable technique and/or apparatus, including bridge
plugs, packers, and the like. The void in the pipe string may be
located using any suitable technique.
[0045] When sealing a void in the cement sheath, the methods of the
present invention, in some embodiments, further may comprise
locating the void in the cement sheath; producing a perforation in
the pipe string that intersects the void; and isolating the void by
defining a space within the pipe string in communication with the
void via the perforation, wherein the lightweight settable
composition is introduced into the void via the perforation. The
void in the pipe string may be located using any suitable
technique. The perforation may be created in the pipe string using
any suitable technique, for example, perforating guns. The void may
be isolated using any suitable technique and/or apparatus,
including bridge plugs, packers, and the like.
[0046] In some embodiments, the lightweight settable compositions
may set to have a desirable compressive strength for remedial
cementing operations. Compressive strength is generally the
capacity of a material or structure to withstand axially directed
pushing forces. The compressive strength may be measured at a
specified time after the settable compositions have been positioned
and the settable compositions are maintained under specified
temperature and pressure conditions. 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 in
a 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 Cement Analyzer ("UCA"), available from Fann Instrument
Company, Houston, Tex. Compressive strengths may be determined in
accordance with API RP 10B-2, Recommended Practice for Testing Well
Cements, First Edition, July 2005.
[0047] By way of example, the lightweight settable compositions,
may develop a 24-hour compressive strength--after mixing of the dry
blend with the water--in the range of from about 100 psi to about
165 psi, alternatively, from about 80 psi to about 165 psi, or
alternatively from about 100 psi to about 600 psi. In some
embodiments, the lightweight settable composition may develop a
compressive strength in 24 hours of at least about 20 psi, at least
about 100 psi, at least about 500 psi, or more.
[0048] The exemplary lightweight settable compositions disclosed
herein may directly or indirectly affect one or more components or
pieces of equipment associated with the preparation, delivery,
recapture, recycling, reuse, and/or disposal of the disclosed
settable compositions. For example, the disclosed settable
compositions may directly or indirectly affect one or more mixers,
related mixing equipment, mud pits, storage facilities or units,
composition separators, heat exchangers, sensors, gauges, pumps,
compressors, and the like used generate, store, monitor, regulate,
and/or recondition the exemplary settable compositions. The
disclosed settable compositions may also directly or indirectly
affect any transport or delivery equipment used to convey the
settable compositions to a well site or downhole such as, for
example, any transport vessels, conduits, pipelines, trucks,
tubulars, and/or pipes used to compositionally move the settable
compositions from one location to another, any pumps, compressors,
or motors (e.g., topside or downhole) used to drive the settable
compositions into motion, any valves or related joints used to
regulate the pressure or flow rate of the settable compositions,
and any sensors (i.e., pressure and temperature), gauges, and/or
combinations thereof, and the like. The disclosed settable
compositions may also directly or indirectly affect the various
downhole equipment and tools that may come into contact with the
settable cement compositions such as, but not limited to, wellbore
casing, wellbore liner, completion string, insert strings, drill
string, coiled tubing, slickline, wireline, drill pipe, drill
collars, mud motors, downhole motors and/or pumps, cement pumps,
surface-mounted motors and/or pumps, centralizers, turbolizers,
scratchers, floats (e.g., shoes, collars, valves, etc.), logging
tools and related telemetry equipment, actuators (e.g.,
electromechanical devices, hydromechanical devices, etc.), sliding
sleeves, production sleeves, plugs, screens, filters, flow control
devices (e.g., inflow control devices, autonomous inflow control
devices, outflow control devices, etc.), couplings (e.g.,
electro-hydraulic wet connect, dry connect, inductive coupler,
etc.), control lines (e.g., electrical, fiber optic, hydraulic,
etc.), surveillance lines, drill bits and reamers, sensors or
distributed sensors, downhole heat exchangers, valves and
corresponding actuation devices, tool seals, packers, cement plugs,
bridge plugs, and other wellbore isolation devices, or components,
and the like.
EXAMPLES
[0049] To facilitate a better understanding of the present
invention, the following examples of some of the preferred
embodiments are given. In no way should such examples be read to
limit, or to define, the scope of the invention.
Example 1
[0050] The following series of tests were performed to evaluate the
mechanical properties of the lightweight settable compositions.
Twelve different lightweight settable compositions, designated
Samples 1-12, were prepared using the indicated amounts of water,
pumice, lime, shale, and/or zeolite. The amounts of these
components are indicated in the table below with percent by weight
of blend ("% bwob") indicating the percent of the component by
weight of the blend of pumice, shale, and/or zeolite. The pumice
used for the tests was either DS 200 or DS 325 lightweight
aggregate available from Hess Pumice Products, Malad City, Id. The
lime used for the tests was Texas lime from Cleburne, Tex. The
shale and zeolite used for the tests were supplied by Magnablend,
Inc., Waxahachie, Tex. Sample 1 was a comparative composition that
did not include lime as a calcium activator. This sample did not
set (DNS) and therefore possessed no measurable compressive
strength (0 psi).
[0051] After preparation, the samples were allowed to cure for
twenty-four hours in a 2'' by 4'' metal cylinder that was placed in
a water bath at 140.degree. F. to form set cylinders. Immediately
after removal from the water bath, destructive compressive
strengths were determined using a mechanical press in accordance
with API RP 10B-2. The results of this test are set forth
below.
TABLE-US-00001 TABLE 1 Components 24 Hr Water Pumice Lime Shale
Zeolite Comp. Density (% DS 200 DS 325 (% (% (% Strength Sample
(lb/gal) bwob) (% bwob) (% bwob) bwob) bwob) bwob) (psi) 1 12.5
75.06 -- 100 0 -- -- DNS 2 12.5 78.65 -- 100 5 -- -- 112 3 12.5
82.24 -- 100 10 -- -- 256 4 12.5 78.65 100 -- 5 -- -- 140 5 12.5
82.24 100 -- 10 -- -- 218 6 13.5 57.47 100 -- 10 -- -- DNS 7 12.5
81.38 50 -- 2.5 50 -- 110 8 12.5 94.97 50 -- 5 50 -- 162 9 12.5
77.18 50 -- 5 25 25 96 10 12.5 78.98 50 -- 7.5 25 25 338 11 12.5
80.78 50 -- 10 25 25 407 12 12.5 84.37 50 -- 15 25 25 459
[0052] Based on the results of these tests, the inclusion of lime
as a calcium activator in the settable compositions had a
significant impact on compressive strength development. Likewise,
the blending of the shale and zeolite additives with the pumice,
also produced significant compressive strength gains.
Example 2
[0053] The following series of tests were performed to evaluate the
mechanical properties of the lightweight settable compositions.
Seven different lightweight settable compositions, designated
Samples 13-19, were prepared using the indicated amounts of water,
pumice, lime, fly ash, metakaolin, or perlite. The amounts of these
components are indicated in the table below with percent by weight
of blend ("% bwob") indicating the percent of the component by
weight of the blend of pumice, fly ash, metakaolin, and/or perlite.
The pumice used for the tests was DNS 200 lightweight aggregate
available from Hess Pumice Products, Malad City, Id. The lime used
for the tests was Texas lime from Cleburne, Tex. The fly ash used
for the samples was POZMIX.RTM. pozzolanic cement, available from
Halliburton Energy Services, Inc. The metakaolin used for the tests
was METAMAX.RTM. pozzolanic cement additive, available from BASF.
The perlite used was ground, unexpanded perlite (IM-325), available
from Hess Pumice Products, Malad City, Id.
[0054] After preparation, the samples were allowed to cure for
twenty-four hours in a 2'' by 4'' metal cylinder that was placed in
a water bath at 140.degree. F. to form set cylinders. Immediately
after removal from the water bath, destructive compressive
strengths were determined using a mechanical press in accordance
with API RP 10B-2. The results of this test are set forth
below.
TABLE-US-00002 TABLE 2 Components 24 Hr Water Lime Fly Ash Perlite
Comp. Density (% Pumice (% (% Metakaolin (% Strength Sample
(lb/gal) bwob) (% bwob) bwob) bwob) (% bwob) bwob) (psi) 13 12.5
86.44 80 15 20 -- -- 162 14 14 51.68 50 15 50 -- -- 146 15 14 50.94
80 15 20 -- -- 88 16 12.5 89.97 50 10 -- 50 -- 233 17 12.5 93.57 50
15 -- 50 -- 579 18 12.5 76.58 50 10 -- -- 50 273 19 12.5 80.17 50
15 -- -- 50 259
[0055] Based on the results of these tests, the inclusion of
metakaolin provided the largest increase in compressive strength,
with the value scaling noticeably with the increase of lime.
Perlite showed a lesser increase. The fly ash showed either no
increase or a negligible increase as generally compared to the
earlier samples without additives (samples 4-6).
Example 3
[0056] The following series of tests were performed to evaluate the
mechanical properties of the lightweight settable compositions. Six
different lightweight settable compositions, designated Samples
20-25, were prepared using the indicated amounts of water, pumice,
lime, rice hull ash, amorphous silica, or swellable particulate
elastomer. The amounts of these components are indicated in the
table below with percent by weight of blend ("% bwob") indicating
the percent of the component by weight of the blend of pumice, rice
hull ash, amorphous silica, and/or swellable particulate elastomer.
The pumice used for the tests was DNS 200 lightweight aggregate
available from Hess Pumice Products, Malad City, Id. The lime used
for the tests was Texas lime from Cleburne, Tex. The rice hull ash
used for the tests is available from Rice Hull Specialty Products
Inc., Stuttgart, Ark. The amorphous silica used for the tests was
Silicalite.TM. cement additive, available from Halliburton Energy
Services, Inc. The swellable particulate elastomer used for the
tests was LIFECEM.TM. 100, available from Halliburton Energy
Services, Inc.
[0057] After preparation, the samples were allowed to cure for
twenty-four hours in a 2'' by 4'' metal cylinder that was placed in
a water bath at 140.degree. F. to form set cylinders. Immediately
after removal from the water bath, destructive compressive
strengths were determined using a mechanical press in accordance
with API RP 10B-2. The results of this test are set forth
below.
TABLE-US-00003 TABLE 3 Components Rice Hull 24 Hr Water Pumice Lime
Ash Amorphous Comp. Density (% (% (% (% Silica Elastomer Strength
Sample (lb/gal) bwob) bwob) bwob) bwob) (% bwob) (% bwob) (psi) 20
12.5 85.95 50 10 50 -- -- 176 21 12.5 89.55 50 15 50 -- -- 208 22
12.5 83.43 80 10 -- 20 -- 426 23 12.5 87.02 80 15 -- 20 -- 557 24
12.5 65.78 90 10 -- -- 10 194 25 12.5 69.37 90 15 -- -- 10 216
[0058] Based on the results of these tests, the inclusion of the
amorphous silica provided the largest increase in compressive
strength, with the value scaling noticeably with the increase of
lime. Both rice hull ash and the swellable elastomer showed a much
smaller increase in compressive strength.
Example 4
[0059] The following series of tests were performed to evaluate the
mechanical properties of the lightweight settable compositions
after foaming with a foaming additive and a gas. Six different base
lightweight settable compositions, designated Samples 1-6, were
prepared having a density of 12.5 lbs/gal using the indicated
amounts of water, pumice, lime, shale, and/or zeolite, or
metakaolin. The amounts of these components are indicated in the
tables below with percent by weight of blend ("% bwob") indicating
the percent of the component by weight of the blend of pumice,
shale, and/or zeolite. Every sample was then foamed by using a
foaming additive (ZONESEALANT.TM. 2000 agent, available from
Halliburton Energy Services, Inc) in an amount of 2% by weight of
the water to provide the foam density listed in the table below.
The pumice used for the tests was DS 200 lightweight aggregate
available from Hess Pumice Products, Malad City, Id. The lime used
for the tests was Texas lime from Cleburne, Tex. The shale and
zeolite used for the tests were supplied by Magnablend, Inc.,
Waxahachie, Tex. The metakaolin used for the tests was METAMAX.RTM.
pozzolanic cement additive, available from BASF. Every foamed
sample is a foamed version of a previous sample and corresponds to
another sample previously listed above. The foamed samples are
presented in Table 4.
[0060] After preparation, the samples were allowed to cure for
twenty-four hours in a 2'' by 4'' metal cylinder that was placed in
a water bath at 140.degree. F. to form set cylinders. Immediately
after removal from the water bath, destructive compressive
strengths were determined using a mechanical press in accordance
with API RP 10B-2. The results of this test are set forth
below.
TABLE-US-00004 TABLE 4 Components 24 Hr Foam Water Lime Shale
Zeolite Comp. Foamed Density (% Pumice (% (% (% Metakaolin Strength
Sample (lb/gal) bwob) (% bwob) bwob) bwob) bwob) (% bwob) (psi) 26
9.36 78.65 100 5 -- -- -- 72 27 9.9 82.24 100 10 -- -- -- 113 28
9.89 81.38 50 2.5 50 -- -- 73 29 9.88 94.97 50 5 50 -- -- 20 30
9.48 84.37 50 15 25 25 -- 238 31 9.54 93.57 50 15 -- -- 50 193
[0061] 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.
[0062] 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 but equivalent 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 in the claims below. Also,
the terms in the claims 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 and spirit of the present
invention. If there is any conflict in the usages of a word or term
in this specification and one or more patent(s) or other documents
that may be incorporated herein by reference, the definitions that
are consistent with this specification should be adopted.
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