Weighted elastomers, cement compositions comprising weighted elastomers, and methods of use.

(54) Title: WEIGHTED ELASTOMERS, CEMENT COMPOSITIONS INCLUDING WEIGHTED ELASTOMERS AND METHODS OF USE.

(54) Title: WEIGHTED ELASTOMERS, CEMENT COMPOSITIONS COMPRISING WEIGHTED ELASTOMERS, AND METHODS OF USE.

(57) Summary

Methods and compositions are provided that relate to weighted elastomers. Weighted elastomers can comprise an elastomer and a ballasting agent, attached to an outer surface of the elastomer. One embodiment includes a method of cementing which comprises providing a cement composition containing cement, water and a weighted elastomer. Furthermore, the cement composition can be introduced into an underground formation and allowed to set therein.

(57) Abstract

Methods and compositions are provided that relate to weighted elastomers. The weighted elastomers may comprise an elastomer and a weighting agent attached to an outer surface of the elastomer. An embodiment ineludes a method of cementing that comprises providing a cement composition containing cement, water, and a weighted elastomer. In addition, the cement composition may be introduced into a subterranean formation and allowed to set therein.

Yes'

Si MU niU. ·· R i:. Mexican Institute of Industrial Property

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PATENT TITLE NO. 345321

Owner (s): HALLIBURTON ENERGY SERVICES, INC.

Address: 10200 Bellaire Boulevard, Houston, Texas, 77072, USA

Name: WEIGHTED ELASTOMERS, CEMENT COMPOSITIONS INCLUDING WEIGHTED ELASTOMERS AND METHODS OF USE.

Classification: lnt.CI.8: C09K8 / 02; C09K8 / 52; C09K8 / 588

Inventor (s): CRAIG WAYNE RODDY; JEFFERY D. «ARCHER; RICKEY L. MORGAN;

DARRELL CHAD BRENNEIS

REQUEST

Number: International filing date:

MX / a / 2014/003775 7 June 22, 2011 «Divisional Patent Number: 321698

PRIORITY

Country: Date: Number:

US June 23, 2010 12 / 821,514

Validity: Twenty years

Expiration Date: June 22, 2031

The reference patent is granted based on articles 1, 2, section V, 6, section III, and 59 of the Industrial Property Law.

In accordance with article 23 of the Industrial Property Law, this patent has a validity of twenty years, non-extendable, counted from the date of filing of the international application and will be subject to the payment of the fee to keep the rights in force. .

Whoever signs the present title does so based on the provisions of articles (F factions III and 7 bis 2 of the Industrial Property Law (Official Gazette of the Federation (DOF) 08/27/1991. Amended on 02 / 08/1994, 10/25/1996. 12/26/1987, 05/17/1999, 01/26/2004, 06/16/2005, 01/25/2006, 05/06/2009, 06/01 / 2010, 18Ό6 / 2010, 08/280010. 27®1 / 2012 and 04/09/2012); articles 1 *. 3rd section V subsection a), 4th and 12th sections I and III of the Regulation of the Mexican Institute of Industrial Property (DOF 12/14/1990, amended on 07/01/2002. 15/07/2004, 07/28 2004 and 7 / 0Θ / 2007); Articles 1, 3. 4th, 5th section V maso a), 16 sections I and III and 30 of the Organic Statute of the Mexican Institute of Industrial Property (DOF 12/27/1999, amended on 10/10/2002, 07/29/2004, 08/04/2004 and 09/13/2007); 1, 3 and 5 subsection a) of the Agreement that delegates powers to the Deputy General Directors, Coordinator, Divisional Directors, Heads of Regional Offices, Divisional Deputy Directors, Departmental Coordinators and other subordinates of the Mexican Institute of Industrial Property. (DOF 12/15/1999, amended on 02/04/2000, 07/29/2004, 08/04/2004 and 09/13/2007).

Issue Date: January 25, 2017

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WEIGHTED ELASTOMERS, CEMENT COMPOSITIONS THAT

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UNDERSTAND WEIGHTED ELASTOMERS AND METHODS OF USE

FIELD OF THE INVENTION

The present invention relates to weighted elastomers and, more particularly, in certain embodiments, to weighted elastomers, cement compositions comprising the weighted elastomers, and methods for using the weighted elastomers in cementing operations.

BACKGROUND OF THE INVENTION

Cement compositions can be used in a variety of underground applications. For example, in underground well construction, a chain of pipes (eg casing, reinforced pipes, expandable tubulars, etc.) can be run in a borehole and cemented in place. The process for cementing the pipe chain in place is commonly referred to as primary cementing. In a typical primary cementing method, a cement composition can be pumped into a ring between the borehole walls and the outer surface of the string of pipes attached to the borehole. The cementitious composition can set in the annular space, thus forming a₂ IMPI »

MEXICAN INSTITUTE rw LA TTOFUDaO, substantially impervious, hardened cement ring casing (i.e., cement casing) that can support and position the pipe chain in the borehole and can join the outer surface of the pipe chain with the underground formation. Among other things, the cement wrap surrounding the pipe chain must function to prevent fluid migration in the ring, as well as protect the pipe chain from corrosion. Cement compositions can also be used in repair cementation methods, for example, to seal cracks or holes in pipe lines or cement envelopes, to seal areas or fractures in a fairly permeable formation, to place a plug of cement, and the like.

Elastomers are an additive that can be included in a cement composition. Among other reasons, elastomers can be included in a cement composition to improve the mechanical properties of the set cement composition. For example, elastomers can be included in a cement composition to improve the elasticity and ductility of the set cement composition, thereby potentially nullifying possible stresses that may be encountered by the cement composition in a borehole. In some cases, they can be used³ IMPIgg

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W LA mOHSTY elastomers that swell in contact with water and / or ^{, h}pOTJo61eov These swellable elastomers can help - to * manLeirCT 5T zonal isolation, for example, by increasing volume when in contact with oil and / or water to seal cracks in the cement shell and / or micro-ring between the shell shell. cement and pipe chain or formation that can be created.

Bulking agents may also be included in the cement compositions to increase the density of the cement composition. A cement composition having an increased density may be suitable, for example, in deep wells where high pressure may be encountered. Examples of ballasting agents that can be used include, but are not limited to, hematite, hausmannite, barite, and sand.

A problem frequently encountered when both elastomers and ballasting agents are included in a cement composition is that elastomers and ballasting agents tend to segregate in different areas of the cement composition. For example, ballasting agents generally tend to sink, while elastomers tend to float, which can leave certain areas with little or no ballast and other areas with little or no elastomer. As a result, the cement composition can ⁴ IMPI ^ í

MEXICAN INSTITUTE does not have a uniform distribution of density when it is introduced in the formation, giving as a result -— in- ¹ a ....... potential for cement composition design specifications not being met. To avoid this unwanted segregation, great care must often be exercised in formulating cement compositions that comprise both elastomers and ballasting agents. This can result in added expense and complexity due, among other things, to a need for additional additives and monitoring.

SUMMARY OF THE INVENTION

The present invention relates to weighted elastomers and, more particularly, in certain embodiments, to weighted elastomers, cement compositions comprising the weighted elastomers, and methods for using the weighted elastomers in cementing operations.

According to a first aspect of the present invention, a weighted elastomer is provided. The weighted elastomer may comprise an elastomer and a ballasting agent attached to an outer surface of the elastomer. The weighted agent may comprise a material selected from the group consisting of pumice, pearlite,⁵ IMPIag

MEXICAN INSTITUTE

OF THE PROPERTY Qj ?? and a combination thereof. The elastomer 'poñyferaacr can have a specific gravity -dij. to the IHéliOb about 1.1.

In one embodiment, the weighted elastomer is present in an amount from about 0.1% to about 100% by dry weight of the cementitious components in the cement composition.

In one embodiment, the elastomer comprises an elastomer selected from the group consisting of polypropylene, polyethylene, styrenedivinylbenzene, polyisoprene, polybutadiene, polyisobutylene, polyurethane, a styrene-butadiene random copolymer, a styrene-butadiene block copolymer, acrylonitrilene, acrylonitrile block copolymer -styrene-butadiene, and any combination thereof.

In one embodiment, the elastomer comprises a styrene-butadiene block copolymer.

In one embodiment, the elastomer comprises a swellable elastomer, and wherein the ballasting agent does not fully coat the swellable elastomer.

In one embodiment, the swellable elastomer comprises a petroleum swellable elastomer selected from the group consisting of natural rubber, polyurethane rubber, nitrile rubber, hydrogenated nitrile rubber, β IMPIg rubber.

INSTITUTO MSXICANO Dt LA PROPERTY V »acrylate-butadiene, polyacrylate rubber, butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene rubber, isoprene rubber, chloroprene rubber, neoprene rubber, butadiene rubber, rubber made of styrene butadiene copolymer, sulfonated polyethylene, ethylene acrylate rubber, ethylene epichlorohydrin oxide, copolymer rubber, ethylene-propylene copolymer (cross-linked peroxide), ethylene-propylene copolymer (cross-linked sulfur), ethylene-propylene-diene terpolymer rubber, ethylene vinyl acetate copolymers, a fluorine rubber, a fluorine-silicone rubber, a silicone rubber, poly 2,2,1 bicyclo heptene (polynorbornane ), alkylstyrene, crosslinked substituted vinyl acrylate copolymer, and any combination thereof.

In one embodiment, the swellable elastomer comprises a water-swellable elastomer selected from the group consisting of polymethacrylate, polyacrylamide, an insoluble acrylic polymer, polyacrylate starch acid graft copolymer and salts thereof, a polyethylene oxide polymer, a polymer of the carboxymethylcellulose type, poly (acrylic acid) and salts thereof, poly (co-acrylamide acrylamide) and salts thereof, graft-polyethylene oxide of polyacrylic acid and salts thereof, poly (2-hydroxyethyl methacrylate),

<img file="MX345321B_D0004.tif" />

poly (2-hydroxypropyl methacrylate), cyclic acid anhydride graft copolymer with polyvinyl alcohol, isobutylenemaleic anhydride, vinyl acetate acrylate copolymer, polyacrylonitrile starch graft copolymer, and any combination thereof.

In one embodiment, the swellable elastomer is dual, oil / water swellable, and comprises a oil swellable material and a water swellable material.

In one embodiment, the ballasting agent comprises pearlite.

In one embodiment, the ballasting agent comprises pumice stone.

In accordance with another aspect of the present invention, a cement composition is provided. The cement composition can comprise cement, water, and a weighted elastomer. The weighted elastomer may comprise an elastomer and a ballasting agent attached to an outer surface of the elastomer. The weighted agent may comprise a material selected from the group consisting of pumice, pearlite, and a combination thereof.

In accordance with another aspect of the present invention, a method for cementing is provided. The method of cementing may comprise providing a cement composition comprising cement, water, and an elastomer.

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MEXICAN INSTITUTE

OF THE WEIGHTED TXOHETY. The weighted elastomer can comprise an elastomer and a ballasting agent attached to the outer surface of the elastomer. The weighted agent may comprise a material selected from the group consisting of pumice, pearlite, and a combination thereof. The method of cementing may further comprise allowing the cement composition to set.

In accordance with another aspect of the present invention, there is provided a method which may comprise providing a fluid comprising a weighted elastomer. The weighted elastomer may comprise an elastomer and a ballasting agent attached to an outer surface of the elastomer. The weighted agent may comprise a material selected from the group consisting of pumice, pearlite, and a combination thereof. The method may further comprise introducing the fluid into an underground formation.

The features and advantages of the present invention will be readily apparent to those of skill in the art. While many changes can be made by those skilled in the art, these changes are within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some

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embodiments of the present invention, and not

MEXICAN INSTITUTE Df THE PROPERTY is due to limit or define the invention. ¹¹ '' '

Figure 1 is an illustration of a weighted elastomer in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to weighted elastomers and, more particularly, in certain embodiments, to weighted elastomers, cement compositions comprising weighted elastomers, and methods for using weighted elastomers in cementing operations. As used herein, the term "weighted elastomer" refers to an elastomer that has been weighted to have a specific gravity of at least about 1.1. One of the many potential advantages of the methods and compositions of the present invention may be that the inclusion of the weighted elastomer in the embodiments of the cement compositions can reduce the problems associated with segregation, especially when used in combination with ballasting agents. , since it may only be necessary to direct the additives with specific gravities greater than that of water.

One embodiment of the cement compositions of

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MEXICAN INSTITUTE OF MONEY · ' ^or The present invention comprises cement, water and a weighted STOIMoméf comprising an elastomer and an agent ρδΜόΜ2ΓόΓδ⁼ bonded to an outer surface of the elastomer. In certain embodiments, the cement compositions may further comprise a ballasting agent. Those of ordinary skill in the art will appreciate that embodiments of cementitious compositions in general must have a density suitable for a particular application. By way of example, embodiments of the cement compositions may have a density between about 0.5 kg / 1 to about 2.4 kg / 1 (4 pounds per gallon (Ib / gal) to about 20 Ib / gal). In certain embodiments, the cement compositions can have a density between about 1.0 kg / 1 to about 2.0 kg / 1 (8 Ib / gal to about 17 Ib / gal). In certain embodiments, the cement composition can have a heavyweight cement composition having a density of at least about 1.7 kg / l (about 14 Ib / gal). Those of ordinary skill in the art will, with the benefit of this description, recognize the appropriate density for a particular application.

Hydraulic cement is a component that may be included in the embodiments of the cement compositions of the present invention. Any of a variety

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of hydraulic cements suitable for

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ΙΝΤΠΤυΤΟ MWICANO ftlAHOFlEftAD underground cementing operations can be uteiliga'i? in accordance with the embodiments of the present invention. Suitable examples include hydraulic cements comprising: calcium, aluminum, silicon, oxygen and / or sulfur, which set and harden by reaction with water. These hydraulic cements include, but are not limited to, Portland cements, pozzolanic cements, plasters, cements with a high content of alumina, stone cements, silica cements and combinations thereof. In certain embodiments, the hydraulic cement can comprise a Portland cement. Portland cements that may be suitable for use in the embodiments of the present invention are classified as Class A, C, G, H cements according to the American Petroleum Institute, API Specification for Materials and Testing for Well Cements, API Specification 10, Fifth Ed., July 1, 1990. In addition, in some embodiments, hydraulic cements suitable for use in the present invention may include cements classified as ASTM Type I, II or III.

The water used in embodiments of the cement compositions of the present invention may include, for example, fresh water, salt water (for example, water containing one or more salts dissolved therein), brine (for example, salt water

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from underground formations), seawater, or combinations thereof. In general, the water can come from any source, as long as, for example, it does not contain an excess of compounds that may undesirably affect the other components in the cement composition. In some embodiments, the water may be included in an amount sufficient to form a pumpable slurry. In some embodiments, water may be included in the cement compositions of the present invention in an amount from about 40% to about 200% by dry weight of the cementitious components (bwoc). In some embodiments, the water may be included in an amount between about 40% to about 150% bwoc.

A weighted elastomer can be included in embodiments of the cement compositions of the present invention. The weighted elastomer may comprise, for example, an elastomer and a weighted agent bonded to an outer surface of the elastomer. As illustrated in FIG. 1, weighted elastomer 10 may comprise elastomer 20 and ballasting agent 30 bonded to an outer surface 40 of the elastomer, in embodiments of the present invention. Weighted elastomer is generally heavier ¹³ IMPI ^

MEXICAN INSTITUTE

OF THE FtOnEBAD Qn »_gg than elastomers that have been used up to 'WSl'ía, that the weighted elastomer has been weighed to a high gravity ¹¹specific of at least about 1.1. Of its many potential advantages, one of these advantages to using weighted elastomer is that the segregation problems associated with using elastomers can be reduced or even eliminated. For example, when using weighted elastomer in combination with a weighting agent, the problems associated with using a floating elastomer and sinking weighting agent should generally be avoided.

The weighted elastomer can be added to the cement compositions by dry blending with the cement prior to the addition of the water, by mixing with the water to be added to the cement, or by mixing with the cement composition consecutively with or after the addition of the water. In addition, the weighted elastomer can be included in the cement composition embodiments in an amount desired for a particular application. In some embodiments, the weighted elastomer may be present in an amount from about 0.1% to about 100% bwoc (eg, about 1%, about 5%, about 10%, about 20%, about

<img file="MX345321B_D0009.tif" />

30%, about 40%, about 50%, about 60%, about 70%, about 80%, about 90%, etc.) In certain embodiments, the weighted elastomer may be present in an amount from about 1% to about 30%. % bwoc and alternatively in an amount between about 5% to about 25% bwoc.

Any of a variety of elastomers can be weighted to form the weighted elastomers in accordance with the embodiments of the present invention. In general, elastomers can be used in particulate form. As used herein, the term "particles" refers to solid state materials that have a well-defined physical configuration, as well as those with irregular geometries, including any particulate elastomers that have the physical configuration of platelets, scraps, fibers, flakes, ribbons, bars, strips, spheroids, hollow beads, toroids, granules, tablets or any other physical configuration. Examples of suitable elastomers include, but are not limited to, polypropylene, polyethylene, styrenedivinylbenzene, polyisoprene, polybutadiene, polyisobutylene, polyurethane, a random and block copolymer of styrene-butadiene, acrylonitrile-butadiene and

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acrylonitrile-styrene-butadiene.

In certain embodiments, the elastomer can be a swellable elastomer. As used herein, an elastomer is characterized as swellable when it increases in volume in contact with petroleum and / or swells in contact with aqueous fluids. By way of example, the elastomer may be a petroleum-swellable elastomer, which increases in volume in contact with any of a variety of petroleum, such as crude oil, diesel, kerosene, and the like, as well as petroleum-based fluids. and gaseous or liquid hydrocarbons located in underground formations. By way of a further example, the elastomer may be a water-swellable elastomer that increases in volume in contact with aqueous fluids, such as fresh water, salt water, and the like, as well as, water-based fluids and aqueous fluids located in underground formations. Among other things, the use of a swellable elastomer in the embodiments of the cement compositions can help maintain area insulation, for example, by swelling when it comes in contact with oily and / or aqueous fluids to seal cracks in the shell. cement and / or the micro-ring between the cement envelope and the pipe chain or formation that may be created.

Swellable elastomers suitable for use in general cement composition embodiments can swell to about 500% of their original size at the surface. Under downhole conditions, this swelling may be higher or lower depending on the conditions present. For example, swelling can be at least 10% under downhole conditions. In some embodiments, swelling can be up to about 200% under downhole conditions. However, as those of ordinary skill in the art will appreciate, with the benefit of this disclosure, the actual swelling when the swellable elastomer is included in a cement composition can vary, for example, based on the concentration of the swellable elastomer included in the composition of cement and the amount of oily and / or aqueous fluid present, among other factors.

Petroleum swellable elastomers to be used in the weighted elastomer embodiments include any of a variety of materials that swell on contact with petroleum. Some specific examples of suitable petroleum-swellable elastomers include, but are not limited to, natural rubber, polyurethane rubber, nitrile rubber, hydrogenated nitrile rubber, acrylate-butadiene rubber,₁₇ IMPIS

MEXICAN INSTITUTE&gt; 5 «

Say LA PROHEDAD CVa. INDUSTRIAL polyacrylate, butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene rubber, isoprene rubber, chloroprene rubber, neoprene rubber, butadiene rubber, styrene © butadiene copolymer rubber, sulfonated polyethylene, ethylene acrylate, ethylene epichlorohydrin oxide, copolymer rubber, ethylene-propylene copolymer (cross-linked peroxide), ethylene-propylene copolymer (cross-linked sulfur), Ethylene-propylene-diene terpolymer rubber, ethylene vinyl acetate copolymers, fluorine rubber, fluorine-silicone rubber, silicone rubber, poly 2,2,1 bicyclo heptene (polynorbornane), alkylstyrene, crosslinked substituted vinyl acrylate copolymer. Petroleum swellable elastomer blends can also be used. Other elastomers that behave in a similar way relative to petroleum may also be suitable . Those of ordinary skill in the art, with the benefit of this disclosure, will be able to select a suitable petroleum-swellable elastomer for use in the compositions of the present invention based on a variety of factors, including: they include the application in which the composition will be used and the desired swelling characteristics.

Water-swellable elastomers that must be

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IMPI pondeí ^ fo ^^ uyeiT that— a® iTtH'fihañ 'when specific to use in the elastomer modalities any of a variety of materials in contact with water. Some examples of water-swellable elastomers include, but are not limited to, super absorbent polymers (such as polymethacrylate and polyacrylamide) and non-soluble acrylic polymers (such as starch-polyacrylate acid graft copolymer and salts thereof), polymers of polyethylene oxide, polymers of the carboxymethyl-cellulose type, polyacrylic acid and salts thereof, poly (acrylic-coacrylamide) and salts thereof, graft-poly (ethylene oxide) of poly (acrylic acid) and salts thereof, poly (2-hydroxyethyl methacrylate), poly (2-hydroxypropyl methacrylate), graft copolymer of cyclic acid anhydride and polyvinyl alcohol, anhydride isobutylenemaleic, vinylacetate-acrylate copolymer and starch-polyacrylonitrile graft copolymers. Water-swellable elastomer blends will also be suitable. Other elastomers that behave in a similar way with respect to aqueous fluids will also be suitable. Those of ordinary skill in the art, with the benefit of this disclosure, will be able to select a suitable water-swellable elastomer for use in the compositions of the present invention based on a₁₉ IMPIS

IN JTTTVT · MUKANO

DI LA MI REDAD 1 &amp; 1NDUSTUAL variety of factors, including the application in which the composition will be used and the desired swelling characteristics.

The modalities of the swellable elastomers can be dual, oil / water swellable, as the elastomer can comprise a combination or blend of both oil swellable and water swellable materials. A particle is characterized as oil / water dual swell when it swells on contact with oil and also swells on contact with aqueous fluids. According to embodiments of the present invention, the petroleum swellable material and / or the water swellable material may comprise an elastomer. By way of example, the swellable elastomer may comprise an ethylenepropylene polymer (eg, ethylenepropylene copolymeric rubber or ethylene-propylene-diene terpolymeric rubber) and bentonite. By way of a further example, the swellable elastomer may comprise a butyl rubber and sodium bentonite.

As described above, the weighted elastomer is an elastomer that has been weighted to have a specific gravity of at least about 1.1 (e.g., about 1.5, about 2, about 2.5, about 3, about 3.5, ²⁰ IMPI ^

MEXICAN INSTITUTE DE LA PROPIEDAD approximately 4, approximately 4.5, approximately'e'S ™ #). Alternatively, the elastomer may be weighted to "" have a specific gravity of at least about 2, at least about 3, or at least about 4. One of ordinary skill in the art will be able to recognize a suitable specific gravity of the weighted elastomer for a particular application.

An example of a suitable weighted elastomer may comprise an elastomer and a ballasting agent attached to an outer surface of the elastomer. By way of example, a plurality of particles of the ballasting agent may be attached to the outer surface of the elastomer. Ballasting agents are typically materials that weigh more than water and can be used to increase the density of a cement composition. By way of example, ballasting agents may have a specific gravity of at least 2 (eg, about 2, about 4, etc.) Examples of ballasting agents that may be used include, but are not limited to, pumice, pearlite, hematite, hausmannite, barite, sand (eg, silica flour), cement, and combinations thereof. In one embodiment, the pearlite includes unexpanded pearlite. Specific examples of suitable weighting agents include HI-DENSE® weighting agent, available from Halliburton ²¹ IMPI ητπτυτο MLXfCAHO Jj, FROM THE FROMSDAQ JgW »

Energy Services, Inc., and cement admixture ^ T &amp; SA-I ^^ CS ^ available from Halliburton Energy Services / —Ti rer · —Err mode, the abrasiveness of the ballasting agent may be a factor to consider when selecting a material for weight the elastomer. Weighting agents that are less abrasive may be desirable, in certain embodiments, to reduce or even avoid potential damage to elastomers during weighted elastomer manufacture. In one embodiment, pumice and / or pearlite can be selected to weight the elastomer relative to a more abrasive material, such as barite.

The amount of ballasting agent used in general weighted elastomer embodiments can depend on a number of factors, including the particular elastomer, the specific gravity desired for the elastomer, the particular ballasting agent, and the specific end use application. . In certain embodiments, the weighted elastomer may have a weight ratio of ballasting agent to elastomer between about 99: 1 to about 0.1: 1, and alternatively, a weight ratio of between about 3: 1 to about 1: 1.

The ballasting agent in general can have a particle size that is less than the particle size

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INSTITUTO MMCANO DE LA RROniDAD INDUSTRIAL elastomer. By way of example, the ballasting agent may have a particle size that is less than or equal to about 50% of the particle size of the elastomer. In certain embodiments, the ballasting agent may have a particle size that is less than or equal to about 10% of the particle size of the elastomer and, alternatively, less than or equal to about 5% of the particle size of the elastomer.

While the ballasting agent may be attached to the outer surface of the elastomer, the ballasting agent in general should not completely cover the elastomer in certain embodiments of the present invention. In other words, at least a portion of the elastomer surface must be left uncovered, in certain embodiments, after bonding of the ballasting agent. This may be convenient, for example, such that the elastomer (eg, a swellable elastomer) can come into contact with fluids after placement in a borehole. In certain embodiments, at least from about 1% to about 99% (eg, about 5%, about 10%, about 25%, about 50%, about 75%, etc.) of the surface of the elastomer portion of the weighted elastomer may be uncovered.

The ballasting agent can be attached to the elastomer using any

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M THE PROPERTY,,. . ,, „Industrial r * ®» _ suitable technique. By way of example, the ballasting agent can be attached to the outer surface of the elastomer with an adhesive. Any of a variety of adhesives that can adhere the ballasting agent to the outer surface of the elastomer may be suitable. Examples of suitable adhesives may include, but are not limited to, water-based acrylic paints, oil-based paints, and oil-based primers.

A variety of techniques can be used to bond the ballasting agent to the elastomer with an adhesive. For example, the first elastomer can be mixed with the adhesive to at least partially coat the elastomer with the adhesive. This mixture is then passed through a screen to remove the larger pieces of the elastomer. The ballasting agent can then be combined with this mixture in such a way that the adhesive binds the ballasting agent to the outer surface of the elastomer. In another embodiment, the ballasting agent (rather than the elastomer) can first be mixed with the adhesive to at least partially coat the ballasting agent with the adhesive. The elastomer can then be combined with this mixture in such a way that the adhesive binds the ballasting agent to the outer surface of the elastomer. After this, the mixture can be passed through a screen to remove larger pieces. Yes²⁴ IMPIOUS

MEXICAN INSTITUTE is desired, then additional weighting can be added to the mix. --------

While the embodiments may provide bonding of a ballasting agent to the elastomer, one or more additional ballasting agents may be included in the embodiments of the cement compositions herein. invention. It should be understood that this ballasting agent separates from, and may be the same or different from, the ballasting agent, which may be attached to the elastomer. As described above, ballasting agents are typically materials that weigh more than water and can be used to increase the density of a cement composition. By way of example, the ballasting agents may have a specific gravity of at least 2 (eg, about 2, about 4, etc.). Examples of the weighting agents that may be used include, but are not limited to, pumice, pearlite, hematite, hausmannite, barite, sand (eg, silica flour), cement, and combinations thereof. Specific examples of suitable weighting agents include HILENSE® weighting agent, available from Halliburton Energy Services, Inc., and SSA 1 cement additive.^MR, available from Halliburton Energy Services, Inc.

The ballasting agent may be added to the

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₂₅ IMPI (Νίτττυτο muucano Di LA rUOntOAD INDUSTRIAL modalities of cement composition by dry mixing with the cement before adding the water, by mixing with the water to be added to the cement, or by mixing with the cement composition consecutively or after the addition of the water When used, the ballasting agent may be included in the cement composition in an amount sufficient to, for example, provide the desired density. By way of example, the ballasting agent may be included in an amount between about 0.1% to about 150% bwoc, alternatively, in an amount between about 10% to about 70% bwoc, and alternatively, in an amount between about about 15%. 50% bwoc.

Other additives suitable for use in underground cementing operations may also be added to the embodiments of the cement compositions, in accordance with the embodiments of the present invention. Examples of these additives include, but are not limited to, retrogression resistant additives, set accelerators, set retarders, ballasting agents, light weight additives, gas generation additives, additives to improve mechanical properties, loss materials. circulation, additives for control of

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filtration, dispersants, additives for

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of fluids, antifoaming agents, agents - thixotropic additives, and combinations thereof. Specific examples of these and other additives include crystalline silica, amorphous silica, fumed silica, salts, fibers, hydratable clays, calcined shale, vitrified shale, microspheres, fly ash, slag, diatomite, metakaolin, rice husk ash, natural pozzolana, zeolite, cement kiln dust, lime, resin, latex, combinations thereof, and the like. One of ordinary skill in the art, with the benefit of this description, will be able to easily determine the type and amount of additive useful for a particular application and the desired result.

In accordance with embodiments of the present invention, a method of the present invention may comprise providing a cement composition comprising: cement, water, and a weighted elastomer, and allowing the cement composition to set. As will be appreciated, the cement composition can be allowed to set in any suitable location where it may be convenient for the cement composition to set into a hardened mass. By way of example, the cement composition can be allowed to set in a variety of locations, both above and below ground.

Additionally, the cement compositions of the present invention can be used in a variety of underground applications where cement compositions can be used, including but not limited to primary cementing, repair cementing, and drilling operations. An example of a method of the present invention may comprise introducing a cement composition comprising: cement, water, and a weighted elastomer into an underground formation, and allowing the cement composition to set in the underground formation. As desired by one of ordinary skill in the art, for the benefit of this description, embodiments of the cement compositions of the present invention useful in this method may comprise any of the additives mentioned above, as well as any of a variety of other additives suitable for use in an underground application. The placement of the cement composition in the underground formation is intended to encompass the placement of the cement composition in a borehole and / or the placement of the cement composition in the rock surrounding the borehole with the borehole penetrating the underground formation. In illustrative embodiments of a primary cementation, a composition may be introduced

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MEXICAN INSTITUTE DI LA MONEDAD INDUSTRIAL of cement in a space between an underground formation and a conduit (for example, casing, expandable casing, reinforced pipes, etc.) located in the underground formation. The cement composition can be allowed to set to form a hardened mass in the space between the underground formation and the conduit. In general, in most cases, the hardened mass must be attached to the canal in the formation. The method may further comprise, for example, introducing the conduit into the underground formation. In addition, in illustrative repair luting embodiments, a cement composition may be used, for example, in pressure luting operations (eg, to seal voids and / or holes in the formation, cement shell and / or a pipe) or in the placement of cement plugs.

While the foregoing discussion is directed to the use of a weighted elastomer in cementation methods, those of ordinary skill in the art will appreciate that the present art also encompasses the use of weighted elastomers in a variety of different underground treatments, including include; drilling fluids, completion fluids, stimulation fluids, separating fluids, as well as cleaning fluids. According to one embodiment, an elastomer

<img file="MX345321B_D0014.tif" />

₂₉ IMPI ' ^{, Π}ητ7? Λ5ί.^{κ: ΑΝΟ} Weighted may be included in a separating fluid. For example, a separating fluid may be placed between fluids contained or to be pumped into a borehole. Examples of fluids among which stripper fluids will be used include cementitious compositions and drilling fluids, between different drilling fluids during drilling the fluid shift out, and between drilling fluids and completion brines. Among other things, stripper fluids can be used to improve drilling fluid and remove filter cake from borehole walls, to improve displacement efficiency, and to physically separate chemically incompatible fluids. For example, a hydraulic cement composition and a drilling fluid can be separated by a separating fluid when the cement composition is placed in the borehole. In accordance with embodiments of the present invention, the separating fluid can prevent, or at least partially reduce, the intermixing of the cement composition and the drilling fluid and can facilitate removal of the filter cake and the gelled drilling fluid. borehole walls during displacement of the drilling fluid through the cementitious composition. According to another embodiment, the weighted elastomer may be included

<img file="MX345321B_D0015.tif" />

in a drilling fluid.

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INSTITUTO MMCAN Oí LA PftOHtSAD INDUSTRIAL

By way of example, one method may comprise using a bit to enlarge a borehole, and circulating a drilling fluid comprising a weighted elastomer after the bit removes debris.

To facilitate a better understanding of the present technique, the following examples of some specific embodiments are provided. In no way should the following examples be read to limit or define the scope of the invention.

EXAMPLE 1

Illustrative weighted elastomers were prepared according to a first procedure as follows. One hundred grams of an elastomer (WELLLIFE® 665 elastomer, available from Halliburton Energy Services, Inc.) was mixed with 120 cubic centimeters of a water-based adhesive (paint) until all of the elastomer was fully and evenly coated. The sample was then passed through a 16 mesh screen to remove larger pieces. Then, a sufficient amount of a weighing agent (HI-DENSE® weighting agent, available from Halliburton Energy Services, Inc.) was mixed with the sample to completely and evenly coat the sample. After this, if IMPI

MEXICAN INJNTVTO »5 ^» DE LA «OMÍDAD The sample was passed through a sieve to remove excess weighting agent from the sample. The portion of the sample collected on the mesh was then dried in a vacuum overnight at 80 ° C (175 ° F). After drying, the sample was cooled to room temperature, and the specific gravity was measured using an Ultrapycnometer 1000 by Quantachrome Instruments. A portion of the dried sample was then washed with water on an 80 mesh screen to remove any weighing agent that did not sufficiently adhere to the sample. The sample was then dried again in a vacuum overnight at 80 ° C (175 ° F).

After drying, the sample was cooled to room temperature, and the specific gravity was again measured. The difference between the specific gravity after sieving and drying and the specific gravity after washing and drying was recorded. From this change in specific gravity, the adherence of the ballasting agent to the elastomer can be analyzed. The above procedure was repeated using an oil-based paint as the adhesive.

Additional weighted elastomers were prepared according to a second procedure. Two hundred grams of a weighting agent (HI-DENSE® weighting agent, available from Halliburton Energy Services, Inc.) was mixed with 100 grams of an oil-based adhesive (primer) until

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MEXICAN INSTITUTE * DE LA MIOREDAD all of the ballasting agent was coated ^ ES ^ al ^ y * uniformly. One hundred grams of a WELLLIFE® 665 TaHiTivo elastomer, available from Halliburton Energy Services, Inc.) was then mixed with the sample until a homogeneous mixture was obtained. After this, the sample was passed through a 16 mesh screen to remove larger pieces. Additional weighing agent was added to the sieved sample and mixed until the sample was evenly coated with the weighing agent. The sample was then passed through an 80 mesh screen to remove excess weighting agent from the sample. The sample collected on the sieve was then dried in a vacuum overnight at 80 ° C (175 ° F). After drying, the sample was cooled to room temperature, and the specific gravity was again measured using an Ultrapycnometer 1000 by Quantachrome Instruments. A portion of the dried sample was then washed with water on an 80 mesh screen to remove any of the weighing agent that had not sufficiently adhered to the sample. The sample was then dried again in a vacuum overnight at 80 ° C (175 ° F). After drying, the sample was cooled to room temperature, and the specific gravity was again measured. The difference between the specific gravity after sieving and drying and the gravity³³ IMPI rrsTrruro Mexican specified after washing and drying. As the specific gravity changes, it is possible to adhere to the ballasting agent with the elastomer.

The results of gravity measurements

<img file="MX345321B_D0016.tif" />

Specific to the three different adhesives are provided in the table below.

TABLE 1

<td>Adhesive</td><td>Preparation</td><td>Specific gravity after sieving and drying (g / cc)</td><td>Specific gravity after washing and drying (g / cc)</td><td>Specific gravity change</td>

<td>Water-based acrylic paint</td><td>Process #1</td><td> 1.8914</td><td> 1.8175</td><td> 0.0739</td>

<td>Oil-based paint</td><td>Process #1</td><td> 1.8835</td><td> 1.8650</td><td> 0.0185</td>

<td>Oil Based Primer</td><td>Process #2</td><td> 2.1889</td><td> 2.1740</td><td> 0.0149</td>

Based on the results shown in Table 1, a weighted elastomer can be prepared by attaching a ballasting agent to the outer surface of the elastomer. From this table, it can also be seen that a second preparation procedure using the oil-based primer resulted in a weighted elastomer with a

<img file="MX345321B_D0017.tif" />

higher specific severity than for the first

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INSTITUTO MtXICANO DI LA PROPIEDAD INt? UST »ÍAL preparation procedure.

EXAMPLE 2

The following series of tests was conducted to evaluate the mechanical properties of cement compositions comprising a weighted elastomer. As will be set forth below, the test results demonstrate that the inclusion of a weighted elastomer in the cement composition results in a set cement having properties suitable for particular luting applications.

The sample cement composition No. 1 (comparative) comprised Lehigh Class A cement and 35% bwoc of SSA-1 cement additive^MR. SSA-1 Cement Additive^MR is silica flour available from Halliburton Energy Services, Inc. This sample composition did not include the weighted elastomer. This sample had a density of 2,071 kg / 1 (17.28 pounds / gal).

Sample cement composition No. 2 comprised Lehigh Class A cement, 35% SSA1 cement additive bwoc^MR, 0.5% bwoc of CFR-3 cement friction reducer^mr, 2% bwoc of bentonite, 8% bwoc of a weighted elastomer, and (17.3 liters (4.56 gallons) of water per 43 kg (94-pounds) of as IMPI ^

INSTITUTO MSXICANO • ε LA MtOPltDAD INDUSTRIAL jftr sack of cement. The CFR-3 cement friction reducer »_________, ·। . j jj, m ...

is available from Halliburton Energy Services, Inc. The weighted elastomer included in this sample composition was a weighted elastomer prepared according to the second procedure of Example 1 using the oil-based primer as an adhesive. This sample had a density of 2,051 kg / 1 (17.12 Ib / gal).

Sample cement composition No. 3 comprised Lehigh Class A cement, 35% SSA1 cement additive bwoc^MR, 0.5% bwoc of CFR-3 cement friction reducer^mr, 2% bwoc of bentonite, 16% bwoc of a weighted elastomer, and 16.8 liters (4.54 gallons) of water per 43 kg (94 pounds) of cement bag. The weighted elastomer included in this sample composition was a weighted elastomer prepared according to the second procedure of Example 1 using the oil-based primer as an adhesive. This sample had a density of 2,051 kg / 1 (17.12 Ib / gal).

After the sample compositions were prepared, tests were performed to determine the compressive strength, Young's modulus, and Poisson's ratio associated with each composition. Compressive strength tests were performed at room temperature in accordance with API Specification 10. Young's modulus and Poisson's ratio were determined

<img file="MX345321B_D0018.tif" />

statically by means of a test

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MEXICAN INSTITUTE

Ot THE RtONlOAD iNoumiAt of compression using a loading element. Young's modulus (or modulus of elasticity) for each sample composition was obtained by taking a ratio of a simple tensile stress applied to each sample to a resultant strain parallel to the stress in that composition. The Poisson's ratio for each sample was determined by calculating a ratio of the transverse strain to a corresponding axial strain that results from the axial stress distribution uniformly below a proportional limit for each sample. Young's modulus and Poisson's ratio were determined using ASTM D318402 and ASTM D2464-95a. The values ​​determined for each sample composition are provided in the following table.

TABLE 2

<td>Sample cement composition</td><td>Weighted elastomer (% bwoc)</td><td>Confinement pressure (psi)</td><td>Compressive strength / psi in 4 days (MPa)</td><td>Module Young</td><td>Poisson's ratio</td>

<td>No. 1</td><td> 0</td><td> 0</td><td> 118.73 (17,221)</td><td>3.34 E + 06</td><td> 0.208</td>

<td>No. 2</td><td> 8</td><td> 0</td><td> 80.14 (11,623)</td><td>2.63 E + 06</td><td> 0.217</td>

<td>No. 3</td><td> 16</td><td> 0</td><td> 58.24 (8,447</td><td>2.30 E + 06</td><td> 0.199</td>

<img file="MX345321B_D0019.tif" />

Additional tests were performed

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MEXICAN INSTITUTE, O £ THE PROPERTY on ^ Dvsswat different samples of each of the coutpi ^ oieiuiiiüü · dff cement sample to determine the Brazilian tensile strength. Brazilian tensile strength was determined at room temperature according to ASTM D3967496-96. The density of the set cement was also determined. The values ​​determined for each sample composition are provided in the following table.

TABLE 3

<td>Sample cement composition</td><td>Sample</td><td>Weighted elastorner (% bwoc)</td><td>Brazilian tensile strength / psi (MPa)</td><td>Density / Kg / 1 (Ib / gal)</td>

<td>No. 1</td><td>TO</td><td> 0</td><td> 10.02 (1,454)</td><td> 2.110 (17.61)</td>

<td>No. 1</td><td>B</td><td> 0</td><td> 9.170 (1,330)</td><td> 2.115 (17.65)</td>

<td>No. 1</td><td>C</td><td> 0</td><td> 9.542 (1,384)</td><td> 2.123 (17.72)</td>

<td>No. 1</td><td>D</td><td> 0</td><td> 9.846 (1,428)</td><td> 2.135 (17.82)</td>

<td>No. 2</td><td>TO</td><td> 8</td><td> 2.90 (421)</td><td> 2.072 (17.29)</td>

<td>No. 2</td><td>B</td><td> 8</td><td> 3.68 (534)</td><td> 2.077 (17.33)</td>

<td>No. 2</td><td>C</td><td> 8</td><td> 3.60 (522)</td><td> 2.073 (17.30)</td>

<td>No. 2</td><td>D</td><td> 8</td><td> 3.81 (553)</td><td> 2.073 (17.30)</td>

<td>No. 3</td><td>B</td><td> 16</td><td> 3.27 (474)</td><td> 2.055 (17.15)</td>

<img file="MX345321B_D0020.tif" />

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<td>Sample cement composition</td><td>Sample</td><td>Weighted elastomer (% bwoc)</td><td>Brazilian tensile strength / psi (MPa)</td><td>Density / Kg / 1 (Ib / gal)</td>

<td>No. 3</td><td>C</td><td> 16</td><td> 4.34 (629)</td><td> 2.047 (17.08)</td>

<td>No. 3</td><td>D</td><td> 16</td><td> 2.65 (385)</td><td> 2.045 (17.07)</td>

The average Brazilian tensile strengths and densities for the samples tested for each of the four sample cement compositions are provided in the following table.

TABLE 4

<td>Sample cement composition</td><td>Weighted elastomer (% bwoc)</td><td>Brazilian tensile strength / psi (MPa)</td><td>Density variation</td>

<td>No. 1</td><td> 0</td><td> 9.65 (1,399)</td><td> 1.2%</td>

<td>No. 2</td><td> 8</td><td> 3.50 (508)</td><td> 0.2%</td>

<td>No. 3</td><td> 16</td><td> 3.57 (518)</td><td> 0.5%</td>

Based on the results of these tests, a cement composition comprising a weighted elastomer may have suitable properties for particular applications.

Therefore, the present invention is well adapted to achieve the aforementioned purposes and advantages, as well as those that are inherent therein. The

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ΙΝΓΠΤυΤΟ MEXICANO particular modalities described above itszw * i-sow illustrative, since the present invention is -puo ^ te modifTecrg ^ and practiced in different ways although equivalents evident to those skilled in the art who have the benefit of the teachings herein. Although individual modalities are discussed, the invention covers all combinations and all those modalities. Furthermore, there are not intended to be limitations to the details of construction or design shown herein, other than as described in the following claims. Therefore, it is apparent that the particular illustrative embodiments described above can be altered or modified and all such variations are considered to be within the scope and spirit of the present invention. While the compositions and methods are described in terms of comprising, containing, or including various components or steps, the compositions and methods can also consist essentially of or consisting of the various components and steps. Wherever a numerical variance with a lower bound and an upper bound is described, any number and any included variance that falls within the variance are specifically described. In particular, each variation of values ​​(in the form between approximately a to approximately b, or, equivalently,

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MEXICAN INSTITUTE F2 * DE LA CURRENCIES C&gt; INDUSTRIAL from approximately a to b, or, equivalently, from approximately b) described herein should be understood to establish any number and variation covered within the broad scope of values.

Also, terms in the claims have their clear, normal meaning unless explicitly and clearly defined otherwise by the patent holder.