CA2642930A1

CA2642930A1 - Subterranean treatment fluids comprising substantially hydrated cement particulates

Info

Publication number: CA2642930A1
Application number: CA 2642930
Authority: CA
Inventors: Craig W. Roddy
Original assignee: Individual
Current assignee: Halliburton Energy Services Inc
Priority date: 2006-03-24
Filing date: 2007-03-21
Publication date: 2007-10-04
Also published as: WO2007110591A1; GB0817239D0; GB2451007A; AR060058A1; AU2007231193A1; NO20083987L; RU2008142119A; MX2008011817A

Abstract

Fracturing fluids comprising a base fluid and substantially hydrated cement particulates. Methods of fracturing a subterranean formation comprising fracturing the subterranean formation so as to create or enhance one or more fractures in the subterranean formation; introducing a fracturing fluid comprising a base fluid and substantially hydrated cement particulates into the one or more fractures; and depositing at least a portion of the substantially hydrated cement particulates in the one or more fractures in the subterranean formation. Methods of gravel packing comprising providing a gravel packing fluid comprising a base fluid and substantially hydrated cement particulates, introducing the gravel packing fluid into a subterranean formation, and depositing at least a portion of the substantially hydrated cement particulates in the subterranean formation so as to form a gravel pack. Gravel packing fluids that comprise a base fluid, and gravel comprising substantially hydrated cement particulates.

Description

SUBTERRANEAN TREATMENT g'I.,UIIDS COMEPRISIlwTG SUBSTANTIALLY
KYDRATEI) CEMENT PARTICULATES

BACKGROUND
The present invention relates to substantially hydrated cement particulates.
More particularly, the present invention relates to subterranean treatinent fluids comprising substantially hydrated cement particulates and associated methods of use in subterranean applications.
Hydraulic fracturing is a process cominonly used to increase the flow of desirable fluids, such as oil and gas, from a portion of a subterranean formation.
Hydraulic fracturing operations generally involve introducing a fracturing fluid into a subterranean formation at or above a pressure sufficient to create or enhance one or more fractures in the fonnation.
Enhancing a fracture includes enlarging a pre-existing fracture in the fonnation. The fracturing fluid inay comprise particulates, often referred to as "proppant"
that are deposited in the fractures. The proppant fimctions to prevent the fractures from fully closing upon the release of pressure, fonning conductive channels through which fluids may flow to (or froin) the well bore.
Another process that involves the use of particulates is gravel packing. A
"gravel pack" is a tenn cominonly used to refer to a voh.une of particulate materials (such as sand) placed into a well bore to at least partially reduce the migration of unconsolidated fonnation particulates into the well bore. Gravel packing operations coininonly involve placing a gravel pack screen in the well bore neighboring a desired portion of the subterranean fonnation, and packing the surrounding annulus between the screen and the subterranean fonnation with particulate materials that are sized to prevent and inhibit the passage of fonnation solids through the gravel pack with produced fluids. In some instances, a screenless gravel packing operation may be perfonned.
Conventional particulates included as proppant and/or gravel in subterranean trea.tinent fluids include, but are not liinited to: sand; bauxite; ceramic materials; glass lnaterials; polymer materials; Teflon"" inaterials; nut shell pieces; seed shell pieces; fruit pit pieces; wood; composite particulates; cured resinous particulates coinprising nut shell pieces, seed shell pieces, inorganic fillers, and/or fruit pit pieces; and coinbinations thereof.
Conventionally, composite particulates that may be used comprise a binder and a filler material wherein suitable filler inaterials include silica, alumina, fumed carbon, carbon black, graphite, mica, titanium dioxide, meta-silicate, calcium silicate, kaolin, talc, zirconia, boron, fly ash, hollow glass microspheres, solid glass, and coinbinations thereof Sand is a common particulate utilized in subterranean treatrnent fluids as either proppant or gravel, but there may be issues related to supply and cost associated with using sand.
To modify one or more properties of a subterranean treatnlent fluid, various admixtures may be incl-Lided in the subterranean treatment fluid. As used herein, the term "admixture" refers to materials, other than the base fluid used for inalcing the subterranean treaftnent fl_uid, which may be added to the subterranean treatinent fluid before or during its mixing. Admixtures oftentimes are provided in the fonn of liquids or soluble solids (e.g., powders). Atternpts have been inade to counteract the problems that may be associated with the delivery of adinixtures in solid and liquid fonn. For instance, an adniix-ture provided in powdered form may become dry compacted, or the adinixture, in another instance, may be coated onto a carrier particle. However, iinprovelnents are needed for the delivery of adinixtures into subterranean treatinent fluids.

The present invention relates to substantially hydrated cement particulates.
More particularly, the present invention relates to subterranean treatinent fluids comprising substantially hydrated cement particulates and associated methods of use in subterranean applications.

An embodiment of the present invention provides a fracturing fluid that comprises a base fluid, and substantially hydrated ceinent particulates.
Anotlier embodiinent of the present invention provides a gravel packing fluid that comprises a base flliid, and gravel comprising substantially hydrated cement particulates.
An embodiment of the present invention provides a method of fracturing a subterranean forination that comprises fracturing the subterranean fonnation so as to create or enhance one or more fractures in the subterranean fonnation; introducing a fracturing fluid coinprising a base fluid and substantially hydrated ceinent particulates into the one or more fractures; and depositing at least a portion of the substantially hydrated cenient particulates in the one or more fractures in the subterranean fonnation.

Another einbodiment of the present invention provides a method of gravel packing that comprises providing a gravel packing fluid coinprising a base fluid and substantially hydrated cement particulates, introducing the gravel packing fluid into a subterranean formation, and depositing at least a portion of the substantially hydrated cement particLilates in the subterranean formation so as to form, a gravel pack.
The features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of the exainple embodiinents, which follows.
DESCRIPTION OF PREFERRED FM-BODI1.VIENTS

The present invention relates to substantially hydrated cement particulates.
More particularly, the present invention relates to subterranean treatinent fluids colnprising substantially hydrated cement particulates and associated methods of use in subterranean applications. While the substantially hydrated cement particulates of the present invention are useful in a variety of applications, they may be particularly useful when included in fractLiring fluids as proppant or in gravel paclcing fluids as gravel.
The subterranean treatment fluids of the present invention generally colnprise a base fluid and substantially hydrated cement particulates. In some embodiments, the substantially hydrated cement particulates may colnprise an admixture. The substantially hydrated cement particulates may be included in the subterranean treatment fluid as proppant, gravel, lost circulati on inaterials, carriers for admixtures, or combinations thereof.
The base fluids utilized in the subterranean treatment fluids of the present invention can be any fhiid suitable for use as a base fluid in fracturing or gravel packing operations.
Suitable base fluids include, but are not limited to, water, aqueous gels, viscoelastic surfactant gels, oil gels, gases, liquefied gases, liquefied hyrdocarbons, einulsions, and coinbinations thereof Suitable aqueous gels are generally comprised of water and one or more gelling or viscosifying agents. Optionally, the aqueous gel further may comprise a crosslinking agent for crosslinking the gelling agent and further increasing the viscosity of the fluid. Suitable viscoelastic surfactant gels may coinprise a viscoelastic surfactant and water. Suitable emulsions can be colnprised of two immiscible liquids such as an aqueous liquid or gelled liquid and a hydrocarbon. Suitable water used in the base fluids can be fresh water, salt water (e.g.,, water containing one or lnore salts dissolved therein), brine (e.g., saturated salt water), seawater, or any other aqueous liquid that does not adversely affect other coinponents in the subterranean treatment fluid. The base fluid may also be foained or unfoained as desired for a particular application and may include, for exainple, air, carbon dioxide, and/or nitrogen.
The subterranean treatinent fluids of the present invention further coinprise substantially hydrated cement particulates. The substantially hydrated cement particulates may be forined in any suitable manner. In certain einbodiments of the present invention, the substantially hydrated cement particulates present in the subterranean treatment fluids of the present invention are formed by providing a settable co?nposition coinprising a hydraulic cementitious material and water; allowing the settable coinposition to set into a substantially hydrated mass; and comminuting the substantially hydrated mass into smaller particles so as to form the substantially hydrated cement particulates used in the methods of the present invention. In another einbodiment, the settable coinposition further may coznprise an admixture. By including an admixture in the settable composition, the substantially hydrated cement particulates fonned using this settable cornposition should comprise the admixture.
In another embodiment, after colnminution of the substantially hydrated mass into the substantially hydrated celnent particulates, the substantially hydrated cement particulates may be coated with at least one admixture. This permits the coinbination of adtnixtures that may not be coinpatible when used in solution. An example method for producing the substantially hydrated cement particulates andlor intermixing the admixtures therein is described in U.S.
Patent No. 6,648,962, the disclosLU-e of which is incorporated herein by reference.
Comminution of the substantially hydrated mass to fonn the substantially hydrated cement particulates may be accomplished by any of a variety of suitable metllods. For exalnple, corruninution may be achieved by subjecting the substantially hydrated mass to colnpressive or grinding forces, such as by using a jaw crusher, a roller crusher (e.g., opposed steel rollers), a ball mill, a disk inill, or a grinder. After cornininution, the substantially hydrated cement particulates inay be highly granulate with a high surface area, thereby providing a high loading surface.
The size of the substantially hydrated cement particulates may vary based upon the desired application. In certain embodiments, the substantially hydrated cement particulates may have an average diameter in the range of from about 5 micrometers to about 2.5 milliineters. However, it should be understood that, in other embodiinents, the substantially hydrated ceinent particulates may have an average diaineter of greater than about 2.5 millimeters or of less than about 5inicrometers as desired. One of ordinary skill in the art with the benefit of this disclosure will know the appropriate size, of particulates for a particular application.
Generally, the hydraulic ceinentitious material used to form the substantially hydrated cement particulates may be any hydraulic ceinentitious material that is suitable for use in cementing operations. A variety of hydraulic ceinentitious materials are suitable for use, including those colnprised of calciuin, aluminuin, silicon, oxygen, and/or sulfur, which set and harden by reaction with water. Such hydraulic cementitious materials include, but are not limited to, Portland ceinents, pozzolanic celnents, gypsum ceinents, soil cements, calciurn phosphate cements, high-alumina content cements, silica ceinents, high-alkalinity cements, slag cements, ceinent lciln dust, or mixtures thereof. "Cement kiln dust," as that terin is used herein, refers to a partially calcined kiln feed which is typically relnoved from the gas stream and collected in a dust collector during the inanufacture of cement. The chemical analysis of cement kiln dust from various celnent manufactures varies depending on a number of factors, including the particular kiln feed, the efficiencies of the cement production operation, and the associated dust collection systeins. Cenzent kiln dust generally may comprise a variety of oxides, such as Si02, A1203, Fe203, CaO, MgO, SO3, Na20, and K20.
Vitrified shale also may be used to fonn the substantially hydrated cement particulates. Among other things, in some embodilnents, vitrified shale inay be included in the settable coinpositions used to fonrn the substantially hydrated cement particulates. Such vitrified shale may react with lime present in, or added to, the settable coinposition to fonn a suitable cementing material, for exanple, calcium silicate hydrate. A variety of vitrified shales are suitable, including those comprising silicon, aluminum, calcitiun, and/or magnesium. Suitable exanples of vitrified shale include, but are not limited to, PRESSUR-SEAL`g' FINE LCM material and PRESSUR-SEAL' COARSE LCM inaterial, which are comniercially available froin TXI Energy Services, Inc., Houston, Texas.
The water utilized to fonn the substantially liydrated cement particulates can be fresh water, salt water (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated salt water), or seawater. Generally, the water can be from any source, provided that it does not adversely affect other coinponents in the settable composition.
The water may be present in an ainount sufficient to forin a puinpable slurry. In certain exeinplary elnbodiments, the water is present in the settable compositions of the present invention in an amount in the range of from about 30% to about 180% by weight of the hydraulic cementitious material. In certain einbodirnents, the water may be added to the hydraulic ceinentitious material, a.d.mixture(s), or both. In another ernbodiment, the water may be incorporated in an aqueous dispersion, emulsion, or solution containing the admixture(s).
In certain embodiments of the present invention, the substantially hydrated cement particulates ftirther may coinprise a zeolite. Zeolites generally are porous ahunino-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 tenn "zeolite" refers to all natural and synthetic fonns of zeolite.
In certain embodilnents of the present invention, the substantially hydrated cement particulates further inay coinprise an admixture. Among other things, this provides for the delivery of admixture(s) into a subterranean treatment fluid, for exalnple, when the substantially hydrated cement particulates coinprising an adinixture are added to a settable composition. The adznixture(s) may be provided as soluble solids (e.g., powders) or liquids.
Any admixture commonly used in fracturing or gravel packing flLUds may be included in the settable compositions. A wide variety of adinixtures may be included in the subterranean treatinent fluid, including, but not limited to, fluid loss control additives, surfactants, salts, defoa.mers, fonnation conditioning agents, expanding additives, flow enhancing additives, acids, corrosion inhibitors, breakers, crosslinking agents, viscoelastic surfactants, friction reducers, gelling agents, biocides, algicides, coinbinations thereof, and the like. One skilled in the art with the benefit of this disclosure will know the type of admixture to include for a particular application.
In certain einbodilnents of the present invention, after coinminution of the substantially hydrated mass into the substantially hydrated ceinent particulates, the substantially hydrated cement particulates may be coated with at least one admixture. The coating of the adinixture(s) onto the substantially hydrated ceinent particulates may be applied using any suitable coating method.
The ainount of admixture or admixtures to include in the settable coinpositions, coat onto the substantially hydrated cement particulates, or both, should depend, iwer alia, on the desired ainount of the admixture(s) to incorporate into the subterranean treatinent fluid. The desired ainount of the admixture(s) to incorporate into the subterranean treatment fluid may depend, inter alia, on the type of admixture(s) employed. Generally, the adrnixture(s) may be included in the settable coinposition in an adinixture(s)-to-hydraulic cementitious material weight ratio in the range of from about 5:95 to about 95:5. One of ordinary skill in the art with the benefit of this disclosure will know the appropriate a.inount of the adinixti.ire(s) to include in the settable composition for a particular application.
Ainong other things, the methods of the present invention may provide for the accurate measurement of the amount of the adinixture(s) added to subterranean treatinent fluids as well as avoiding time-consuming labor, energy costs, and processing complexity that may be associated with conventional methods for the delivery of admixtLU-es into subterranean treatinent fluids. An accurate measurement of the amount of adinixture(s) in the subterranean treatment fluid may be obtained whether the admixture(s) is added to a settable composition, coated onto the substantially hydrated ceinent particulates, or both. For example, the alnount of the ad.inixture(s) introduced into the subterranean treatinent fluid inay be obtained by measuring the bulk weight of the substantially hydrated cement particulates and the relative amount of admixtures.
Typically, the substantially hydrated cement particulates may be included in a subterranean treatment fluid of the present invention in an amount sufficient for a particular application. In some embodiments, the substantially hydrated cement particulates are present in an ainount up to about 30 pounds per gallon (ppg). In some embodiments, the substantially hydrated cement particulates are present in an amount up to about 23. ppg. In some embodiments, the substantially hydrated ceinent particulates are present in an amount up to about 12 ppg. One of ordinary skill in the art, with the benefit of this disclosure, will recognize the appropriate substantially hydrated cement particulates concentration of the subterranean treatinent fluids for a chosen application.
Furtllerinore, additional additives may be added to the subterranean treatment fluids of the present invention as deein.ed appropriate by one skilled in the art.
Examples of such additives include, but are not limited to, fluid loss control additives, lost circulation materials, surfactants, salts, fonnation conditioning agents, defoainers, acids, corrosion inhibitors, breakers, biocides, algicides, crosslinlcing agents, gelling agents, viscoelastic surfactants, friction reducers, expanding additives, flow enhancing additives, coinbinations thereof, and the lilce.

In one einbodiment, the present invention provides a inethod of using a fracturing fluid in a subterranean formation colnprising: fracturing the subterranean forma.tion so as to create or enhance one or more fractures in the subterranean fon.nation;
introducing a fracturing fluid comprising a base fluid and substantially hydrated cement particulates into the one or more fractures; and depositing at least a portion of the substantially hydrated ceinent particulates in the one or more fractures in the subterranean fonnation. The substantially hydrated ceinent particulates deposited in the one or more fractures should prop the fractures so as to prevent thein from fully closing. In some embodi.inents, hydrocarbons ina.y be produced froln the subterranean formation through the one or more fractures.
In one elnbodiment, the present invention provides a method of gravel packing coinprising: providing a gravel packing fluid comprising a base fluid and substantially hydrated cement particulates; introducing the gravel packing fluid into a subterranean formation; and depositing at least a portion of the substantially hydrated cement particulates in the subterranean formation so as to form a gravel pack. In soine embodiment the gravel packing fluid may be introduced into an annulus between a screen and the subterranean formation. In some embodiments, hydrocarbons may be produced from the subterranean formation through the gravel pack.
Therefore, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those which are inherent therein.
While nuinerous changes inay be made by those skilled in the art, such changes are encompassed within the spirit of this invention as defined by the appended claims.

Claims

1. A fracturing or gravel packing fluid comprising:
a base fluid; and substantially hydrated cement particulates.

2. The fluid of claim 1 wherein the base fluid is selected from the group consisting of water, an aqueous gel, a viscoelastic surfactant gel, an oil gel, a gas, a liquefied gas, a liquified hydrocarbon, an emulsion, and combinations thereof.

3. The fluid of claim 1 wherein the substantially hydrated cement particulates comprise an admixture.

4. The fluid of claim 3 wherein the admixture comprises at least one material selected from the group consisting of a fluid loss control additive, a surfactant, a salt, a defoamer, a formation conditioning agent, an expanding additive, a flow enhancing additive, an acid, a corrosion inhibitor, a crosslinking agent, a breaker, a viscoelastic surfactant, a friction reducer, a gelling agent, a biocide, an algicide, and combinations thereof.

5. The fluid of claim 3 wherein the substantially hydrated cement particulates are coated with at least one additional admixture.

6. The fluid of claim 1 wherein the substantially hydrated cement particulates comprise at least material selected from the group consisting of Portland cement, a pozzolanic cement, a gypsum cement, a soil cement, a calcium phosphate cement, a high-alumina content cement, a silica cement, a high-alkalinity cement, a slag cement, cement kiln dust, a zeolite, vitrified shale, and mixtures thereof.

7. The fluid of claim 1 wherein the substantially hydrated cement particulates are coated with at least one admixture.

8. The fluid of claim 1 wherein the substantially hydrated cement particulates have an average particle diameter in the range of from about 5 micrometers to about 2.5 millimeters.

9. The fluid of claim 1 wherein the substantially hydrated cement particulates are present in the fracturing fluid in an amount up to about 30 pounds per gallon of the fracturing fluid.

10. The fluid of claim 1 wherein the fluid further comprises an additive selected from the group consisting of a fluid loss control additive, a lost circulation material, a surfactant, a salt, a formation conditioning agent, a defoamer, an acid, a corrosion inhibitor, a breaker, a biocide, an algicide, crosslinking agent, gelling agent, viscoelastic surfactant, friction reducer, an expanding additive, a flow enhancing additive, and combinations thereof.

11. The fluid of claim 1 wherein the fluid is foamed.

12. A method of fracturing a subterranean formation comprising:
fracturing the subterranean formation so as to create or enhance one or more fractures in the subterranean formation;
introducing a fracturing fluid comprising a base fluid and substantially hydrated cement particulates into the one or more fractures; and depositing at least a portion of the substantially hydrated cement particulates into the one or more fractures in the subterranean formation.

13. The method of claim 12 wherein the base fluid is selected from the group consisting of water, an aqueous gel, a viscoelastic surfactant gel, an oil gel, a gas, a liquefied gas, a liquified hydrocarbon, an emulsion, and combinations thereof.

14. The method of claim 12 wherein the substantially hydrated cement particulates comprise an admixture.

15. The method of claim 14 wherein the admixture comprises at least one material selected from the group consisting of a fluid loss control additive, a surfactant, a salt, a defoamer, a formation conditioning agent, an expanding additive, a flow enhancing additive, an acid, a corrosion inhibitor, a crosslinking agent, a breaker, a viscoelastic surfactant, a friction reducer, a gelling agent, a biocide, an algicide, and combinations thereof.

16. The method of claim 14 wherein the substantially hydrated cement particulates are coated with at least one additional admixture.

17. The method of claim 12 wherein the substantially hydrated cement particulates comprise at least material selected from the group consisting of Portland cement, a pozzolanic cement, a gypsum cement, a soil cement, a calcium phosphate cement, a high-alumina content cement, a silica cement, a high-alkalinity cement, a slag cement, cement kiln dust, a zeolite, vitrified shale, and mixtures thereof.

18. The method of claim 12 wherein the substantially hydrated cement particulates are coated with at least one admixture.

19. The method of claim 12 further comprising the steps of:
providing a settable composition comprising a hydraulic cementitious material and water;
allowing the settable composition to set into a substantially hydrated mass; and comminuting the substantially hydrated mass into smaller particles so as to form the substantially hydrated cement particulates.

20. The method of claim 19 wherein the settable composition further comprises an admixture so that the substantially hydrated cement particulate comprises an admixture.

21. The method of claim 12 wherein the substantially hydrated cement particulates have an average particle diameter in the range of from about 5 micrometers to about 2.5 millimeters.

22. The method of claim 12 wherein the substantially hydrated cement particulates are present in the fracturing fluid in an amount up to about 30 pounds per gallon of the fracturing fluid.

23. The method of claim 12 wherein the fracturing fluid is foamed.

24. A method of gravel packing comprising:

providing a gravel packing fluid comprising a base fluid and substantially hydrated cement particulates;
introducing the gravel packing fluid into a subterranean formation; and depositing at least a portion of the substantially hydrated cement particulates into the subterranean formation so as to form a gravel pack.

25. The method of claim 24 wherein the base fluid is selected from the group consisting of water, an aqueous gel, a viscoelastic surfactant gel, an oil gel, a gas, a liquefied gas, a liquified hydrocarbon, an emulsion, and combinations thereof.

26. The method of claim 24 wherein the substantially hydrated cement particulates comprise at least material selected from the group consisting of Portland cement, a pozzolanic cement, a gypsum cement, a soil cement, a calcium phosphate cement, a high-alumina content cement, a silica cement, a high-alkalinity cement, a slag cement, cement kiln dust, a zeolite, vitrified shale, and mixtures thereof.

27. The method of claim 24 wherein the substantially hydrated cement particulates are coated with at least one admixture.

28. The method of claim 24 further comprising the steps of:
providing a settable composition comprising a hydraulic cementitious material and water;
allowing the settable composition to set into a substantially hydrated mass;
and comminuting the substantially hydrated mass into smaller particles so as to form the substantially hydrated cement particulates.

29. The method of claim 24 wherein the substantially hydrated cement particulates have an average particle diameter in the range of from about 5 micrometers to about 2.5 millimeters.

30. The method of claim 24 wherein the substantially hydrated cement particulates are present in the gravel packing fluid in an amount up to about 30 pounds per gallon of the gravel packing fluid.

31. The method of claim 24 wherein the gravel packing fluid is foamed.

32. The method of claim 24 wherein the gravel packing fluid is introduced into an annulus between a screen and the subterranean formation.