RU2632086C1 - Two-component cement compositions with delayed setting - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: way of cementing includes: providing a pozzolanic suspension containing pozzolane and water in an amount of 33 wt % to 200 wt % by weight of pozzolan; providing a calcareous suspension containing slaked lime and water in an amount of 33 wt % to 200 wt % by weight of lime; providing the possibility of separate storage of pozzolanic suspension and calcareous suspension for about one day or more; mixing the pozzolanic suspension and the calcareous suspension to form a cement composition. Mass ratio of pozzolans for lime is from 10:1 to 1:1; and the possibility of setting cement compositions. The invention also relates to a method of fluid displacement in the underground reservoir and cementing system. The invention is developed in dependent claims of the formula of the invention.

EFFECT: activation of cement compositions with delayed term of setting while maintaining an acceptable time and starts development of compressive strength.

20 cl, 15 tbl, 3 dwg

Description

[0001] Embodiments of the present invention relate to underground cementing operations and, in some embodiments, to delayed setting cement compositions and methods for using delayed setting cement compositions in underground formations.

[0002] Cement compositions can be used in various underground operations. For example, during the construction of an underground well, a string of pipes (for example, casing, liner, expandable pipe elements, etc.) can be lowered into the wellbore and cemented in place. The process of cementing a pipe string in place is commonly referred to as “primary cementing”. In the conventional primary cementing method, the cement composition can be pumped into the annulus between the walls of the wellbore and the outer surface of the pipe string located therein. The cementitious composition can set in an annular gap to form an annular casing of hardened, substantially impermeable cement (i.e., cementitious casing) that can support and hold the pipe string in place in the wellbore and can attach the outer surface of the pipe string to the subterranean formation . Among other things, the cement sheath surrounding the pipe string prevents fluids from moving into the annulus and protects the pipe string from corrosion. Cement compositions can also be used in repair cementing methods for sealing cracks or holes in pipe columns or cement shells, for sealing highly permeable zones or formation cracks, or for installing cement plugs or the like.

[0003] In underground cementing operations, many different cement compositions are used. In some cases, delayed setting cementitious compositions are used. Delayed setting cementitious compositions are characterized in that they remain in a liquid state suitable for pumping for at least one day (e.g., about 7 days, about 2 weeks, about 2 years or more) at room temperature (e.g. about 26.6 ° C (80 ° F)) under static storage. If necessary, delayed setting cementitious compositions should be capable of activation with the subsequent development of the required compressive strength. For example, a cement setting activator may be added to a delayed setting cement composition to initiate setting of the composition in a hardened mass. Among other things, delayed setting cement compositions may be suitable for use in such downhole applications in which it is necessary to obtain the cement composition in advance. This may allow storage of the cementitious composition prior to use. In addition, this may provide the possibility of obtaining a cement composition in a convenient place with subsequent transportation to the work site. Accordingly, capital costs can be reduced by reducing the need for bulk storage at the site and mixing equipment. This may be particularly suitable for offshore cementing operations where space on board for installing containers may be limited.

[0004] Despite the fact that cement compositions with delayed setting have been developed to date, there are problems with their successful application in underground cementing operations. For example, delayed setting cement compositions obtained using Portland cement may cause undesirable gelation problems that may limit their use and effectiveness in cementing operations. Other delayed setting compositions, for example, compositions containing hydrated lime and quartz, may be effective for some operations, but may be of limited use at lower temperatures because they cannot develop sufficient compressive strength when used in underground formations having lower static bottomhole temperatures. In addition, the problem may lie in the activation of some cement compositions with delayed setting while maintaining an acceptable thickening time and the development of compressive strength.

BRIEF DESCRIPTION OF GRAPHIC MATERIALS

[0001] These drawings illustrate some aspects of some embodiments of the method according to the present invention, and should not be used to limit or define the scope of the specified method.

[0002] In FIG. 1 shows a system for the production and delivery of a cement composition with delayed setting into the wellbore in accordance with some embodiments of the invention.

[0003] FIG. 2A depicts ground equipment that can be used to lay a cement composition with delayed setting in the wellbore in accordance with some embodiments of the invention.

[0004] FIG. 2B shows the laying of a cement composition with delayed setting in the annulus of a wellbore in accordance with some embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0005] Illustrative embodiments of the present invention relate to underground cementing operations, and more particularly, in some embodiments, to delayed setting cement compositions and methods for applying delayed setting cement compositions in underground formations.

[0006] Embodiments of delayed setting cement compositions may typically comprise water, pozzolan, and hydrated lime. Cement compositions may optionally further comprise a dispersant and / or cement setting retarder. Alternatively, embodiments of a delayed setting cement composition may include a delayed setting two-component cement composition containing separate composite suspensions, where one composite suspension contains pozzolan and the other composite suspension contains lime. Options for the implementation of two-component cement compositions with delayed setting are discussed in detail below. Advantageously, embodiments of delayed setting cement compositions may be able to remain in a liquid state suitable for pumping by a pump for an extended period of time. For example, delayed setting cement compositions can be maintained in a liquid state suitable for pumping for at least about 1 day or longer. Advantageously, delayed setting cementitious compositions can develop the required compressive strength after activation at relatively low temperatures. Although delayed setting cement compositions may be suitable for many underground cementing operations, they may be particularly suitable for use in underground formations having relatively low static bottomhole temperatures, for example, temperatures below about 93.3 ° C (200 ° F) or ranging from about 37.7 ° C (100 ° F) to about 93.3 ° C (200 ° F). In alternative embodiments, delayed setting cement compositions may be used in subterranean formations having static bottomhole temperatures of up to 232.2 ° C (450 ° F) or higher.

[0007] The water used in various embodiments may be from any source, provided that it does not contain an excess of compounds that can adversely affect other components of delayed setting cement compositions. For example, the cement composition may contain fresh water or salt water. Salt water, as a rule, may contain one or more salts dissolved in it, and may be saturated or unsaturated, depending on the specific application. Seawater or brines may be suitable for use in various embodiments. In addition, water may be present in an amount sufficient to provide a pumpable suspension. Water is present in delayed setting cement compositions in an amount in the range of about 33% to about 200% by weight of pozzolan. In some embodiments of the invention, water may be present in delayed setting cement compositions in an amount in the range of from about 35% to about 70% by weight of pozzolan. Those skilled in the art, having the advantage of the present description, can determine the appropriate amount of water for a selected application.

[0008] Embodiments of delayed setting cement compositions may include pozzolan. For use in various embodiments, any pozzolan is suitable. Illustrative embodiments containing pozzolan may contain fly ash, silica dust, metakaolin, natural pozzolan (e.g., pumice), or combinations thereof.

[0009] Embodiments of pozzolan may contain fly ash. Various types of fly ash may be suitable, including the fly ash classified by the American Petroleum Institute as Class C and Class F fly ash, API Specification for Materials and Testing for Well Cements, API Specification 10, fifth edition, July 1, 1990 Class C fly ash contains silicon dioxide and lime, so when mixed with water it can set and form a hardened mass. Class F fly ash, as a rule, does not contain enough lime to initiate the cementation reaction, therefore an additional source of calcium ions is required for a delayed setting cement composition containing fly ash class F. In some embodiments of the invention, the lime may be mixed with Class F fly ash in an amount in the range of about 0.1% to about 100% by weight of fly ash. In some cases, the lime may be slaked lime. Suitable examples of fly ash include, but are not limited to, cement additive POZMIX ^® A manufactured by Halliburton Energy Services, Inc., Houston, Texas.

[0010] Embodiments of pozzolan may contain metakaolin. Typically, metakaolin is a white pozzolan, which can be obtained by heating kaolin clay, for example, to temperatures in the range from about 600 ° C to about 800 ° C.

[0011] Embodiments of pozzolan may contain natural pozzolan. Natural pozzolans are usually found on the surface of the earth and set and harden in the presence of hydrated lime and water. Embodiments containing natural pozzolan may include pumice, diatomaceous earth, volcanic ash, opaline shale, tuff, and combinations thereof. Natural pozzolans can be shredded or unshredded. Typically, natural pozzolans can have any particle size distribution appropriate for the particular application. In some embodiments of the invention, natural pozzolans may have an average particle size in the range of from about 1 micron to about 200 microns. The average particle size corresponds to d50 values measured using particle size analyzers, such as analyzers manufactured by Malvern Instruments, Worcestershire, UK. In particular embodiments, natural pozzolans may have an average particle size in the range of from about 1 micron to about 200 microns, from about 5 microns to about 100 microns, or from about 10 microns to about 50 microns. In one particular embodiment, natural pozzolans may have an average particle size of less than about 15 microns. An example of a suitable industrial natural pozzolan is pumice made by Hess Pumice Products, Inc., Malad, Idaho, sold as a lightweight aggregate DS-325 that has a particle size of less than about 15 microns. It should be understood that too small a particle size can cause mixing problems, while too large a particle size can cause insufficiently effective suspension in the compositions and weaker reactivity due to the smaller surface area. Those skilled in the art, having the advantage of the present disclosure, may select the particle size of natural pozzolans suitable for use in the selected application.

[0012] Embodiments of delayed setting cement compositions may include slaked lime. In the context of the present invention, the term "slaked lime" is to be understood as calcium hydroxide. In some embodiments of the invention, slaked lime may be in the form of quicklime (calcium oxide), which is hydrated when mixed with water to form slaked lime. Slaked lime can be introduced into various embodiments, for example, to obtain a hydraulic composition with pozzolan. Thus, slaked lime is introduced in a mass ratio of pozzolan to slaked lime, comprising from about 10: 1 to about 1: 1, or in a ratio of from about 3: 1 to about 5: 1. Slaked lime can be incorporated into cementitious compositions with delayed setting in an amount, for example, in the range of from about 10% to about 100% by weight of pozzolan. In some embodiments, slaked lime may be present in an amount in the range between any and / or including values of about 10%, about 20%, about 40%, about 60%, about 80%, or about 100% by weight of pozzolan. In some embodiments, cementitious components present in a delayed setting cement composition may consist essentially of pozzolan and slaked lime. For example, cementitious components may contain mainly pozzolan and slaked lime without any additional cementitious components (e.g. Portland cement) that hydraulically set in the presence of water. Those skilled in the art, having the advantage of the present description, can determine the appropriate amount of slaked lime to be used for the selected application.

[0013] Embodiments of delayed setting cement compositions may include a cement setting retarder. For use in delayed setting cement compositions, numerous cement setting retarders can be used. For example, a cement set retarder may include phosphonic acids such as ethylene diamine tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid), etc .; lignosulfonates such as sodium lignosulfonate, calcium lignosulfonate, etc .; salts such as tin (II) sulfate, lead acetate, monobasic calcium phosphate, organic acids such as citric acid, tartaric acid, etc .; cellulose derivatives such as hydroxyethyl cellulose (HEC) and carboxymethyl hydroxyethyl cellulose (SMNES); synthetic co- or terpolymers containing sulfonate and carboxyl groups, such as sulfonate-functionalized copolymers of acrylamide and acrylic acid; borate compounds such as alkali metal borates, sodium metaborate, sodium tetraborate, potassium pentaborate; derivatives thereof or mixtures thereof. Examples of suitable cement setting retardants include, among others, phosphonic acid derivatives. One example of a suitable cement set retarder is the Micro Matrix ^® cement set retardant manufactured by Halliburton Energy Services, Inc. Typically, a cement setting retarder may be present in cement compositions with delayed setting in an amount sufficient to delay setting by the required time. In some embodiments, a cement setting retarder may be present in delayed setting cement compositions in an amount in the range of about 0.01% to about 10% by weight of pozzolan. In specific embodiments of the invention, the cement setting retarder may be present in an amount in the range between any and / or including values of about 0.01%, about 0.1%, about 1%, about 2%, about 4%, about 6%, about 8% or about 10% by weight of pozzolan. Those skilled in the art, having the advantage of the present specification, can determine the appropriate amount of cement setting retarder to be used for the selected application.

[0014] As mentioned above, embodiments of delayed setting cement compositions may optionally comprise a dispersant. Examples of suitable dispersants include, without limitation, dispersants based on sulfonated formaldehyde (e.g., sulfonated acetone condensed with formaldehyde), examples of which may include a dispersant Daxad ^® 19 manufactured by Geo Specialty Chemicals, Ambler, Pennsylvania. Other suitable dispersants may be a polycarboxylated ether dispersants, such as dispersants Liquiment ^® 5581F and Liquiment ^® 514L, manufactured by BASF Corporation, Houston, Texas; or Ethacryl ™ G dispersant manufactured by Coatex, Genay, France. A further example of a suitable commercially available dispersant is the CFR ™ -3 dispersant manufactured by Halliburton Energy Services, Inc. of Houston, Texas. Dispersant Liquiment ^® 514L may contain 36 mass. % polycarboxylated ether in water. Although various dispersants may be used in accordance with embodiments of the present invention, polycarboxylated ether dispersants may be particularly suitable for use in some embodiments. Not limited to theory, it is believed that polycarboxylated ether dispersants can synergistically interact with other components of a delayed cement composition. grasping. For example, it is believed that polycarboxylated ether dispersants may interact with some cement set retarders (e.g. phosphonic acid derivatives), resulting in a gel that suspends pozzolan and slaked lime in the composition for an extended period of time.

[0015] In some embodiments of the invention, the dispersant may be incorporated into delayed setting cement compositions in an amount in the range of from about 0.01% to about 5% by weight of pozzolan. In specific embodiments, the dispersant may be present in an amount in the range between any and / or including values of about 0.01%, about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4 % or about 5% by weight of pozzolan. Those skilled in the art having the advantage of the present disclosure may determine the appropriate amount of dispersant to be used for the selected application.

[0016] Some embodiments of delayed setting cement compositions may contain silica sources other than pozzolan, for example, crystalline silica and / or amorphous silica. Crystalline silicon dioxide is a powder that can be incorporated into various embodiments of delayed setting cement compositions, for example, to prevent a decrease in the compressive strength of cement. Amorphous silica is a powder that can be incorporated into various embodiments of delayed setting cement compositions as a lightweight filler and / or to increase the compressive strength of cement. Amorphous silicon dioxide is typically a by-product of the process of producing ferrosilicon, where amorphous silicon dioxide can be formed by oxidation and condensation of gaseous silicon dioxide, SiO, which is formed in the process as an intermediate. An example of a suitable source of amorphous silica is Silicalite ™ cement additive manufactured by Halliburton Energy Services, Inc., Houston, Texas. In embodiments containing additional sources of silicon dioxide, 9

an additional source of silica can be used as needed to improve compressive strength or setting time.

[0017] Other additives suitable for use in underground cementing operations may also be incorporated into delayed setting cement compositions. Examples of such additives include, but are not limited to: weighting agents, lightweight additives, blowing agents, additives to improve mechanical properties, materials to combat loss of circulation, additives to control filtration, additives to control water absorption, antifoam agents, foaming agents, thixotropic additives and their combinations. In various embodiments, one or more of these additives can be added to the delayed setting cement compositions after storage, but before the delayed setting cement composition is added to the subterranean formation. Those skilled in the art having the advantage of the present disclosure can easily determine the type and amount of additive suitable for a particular application and the desired result.

[0018] Those skilled in the art will appreciate that embodiments of delayed setting cement compositions typically should have a density suitable for a particular application. For example, cementitious compositions may have a density in the range of from about 0.4793 t / m ³ (4 pounds per gallon (“lb / gal.”)) To about 2.399 t / m ³ (20 pound / gal). In some embodiments, cementitious compositions may have a density in the range of from about 0.9586 t / m ³ (8 lb / gal) to about 2,037 t / m ³ (17 lb / gal). Embodiments of delayed setting cement compositions may be foamed or non-foamed, or may contain other means for reducing density, such as hollow microspheres, low density elastic granules, or other density reducing additives known in the art. In various embodiments of the invention, the density may be reduced after storage, but before being introduced into the subterranean formation. In various embodiments, weighting additives can be used to increase the density of delayed setting cement compositions. Examples of suitable weighting agents may include barite, hematite, hausmannite, calcium carbonate, siderite, ilmenite, or combinations thereof. In specific embodiments, the weighting additives may have a specific gravity of 3 or more. Those skilled in the art having the advantage of the present disclosure can determine the appropriate density for a particular application.

[0019] As mentioned above, delayed setting cement compositions can have delayed setting in that they remain in a liquid state suitable for pumping for at least one day (for example, about 1 day, about 2 weeks, about 2 years or more) at room temperature (for example, about 26.6 ° C (80 ° F)) under static storage. For example, delayed setting cement compositions may be maintained in a liquid state suitable for pumping for a period of time from about 1 day to about 7 days or more. In some embodiments, delayed setting cement compositions may be maintained in a liquid state suitable for pumping for at least about 1 day, about 7 days, about 10 days, about 20 days, about 30 days, about 40 days, about 50 days, about 60 days or more. It is believed that the liquid is in a liquid state suitable for pumping if the liquid has a consistency of less than 70 units of Verdun consistency ("Sun"), measured on a pressure consistency meter in accordance with the procedure for determining the thickening time of cement, established in API RP Practice 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005.

[0020] If necessary, applications for delayed setting cement compositions can be activated (for example, by mixing with a cement setting activator) and can set in a hardened mass. The term "cement setting activator" or "activator" as used herein refers to an additive that activates a cement composition with a delayed or too slow setting and can also accelerate the setting of a cement composition with a delayed, too slow or different setting. For example, embodiments of delayed setting cement compositions can be activated to produce a hardened mass over a period of time ranging from about 1 hour to about 12 hours. For example, embodiments of delayed setting cement compositions can set with the formation of a hardened mass over a period of time in the range between any and / or including values of about 1 day, about 2 days, about 4 days, about 6 days, about 8 days, about 10 days or about 12 days.

[0021] In some embodiments, delayed setting cement compositions after activation can set and achieve the desired compressive strength. The compressive strength, as a rule, is the ability of a material or structure to withstand compressive forces applied in the axial direction. The compressive strength can be measured at a specific time after activation of the cement composition with a delayed setting, and the resulting composition is kept at a certain temperature and pressure. The compressive strength can be measured by destructive or non-destructive methods. In the destructive method, the strength of the samples of the composition for processing the near-barrel zone is physically tested at various points in time, destroying the samples in a compression testing machine. Compressive strength is calculated from the breaking load divided by the cross-sectional area that can withstand the specified load, and is recorded in units of pound-force per square inch (psi). Non-destructive methods may use the UCA ™ Ultrasonic Cement Analyzer from Fann Instrument Company, Houston, Texas. Compressive strength values can be determined in accordance with API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005.

[0022] For example, delayed setting cement compositions can develop 24-hour compressive strengths in the range of about 344.7378 kPa (50 psi) to about 34473.7864 kPa (5000 psi), alternatives from about 689.4757 kPa (100 psi) to about 31026.4078 kPa (4500 psi), or alternatively from about 344.7378 kPa (50 psi) to about 27579 , 0291 kPa (4000 psi). In some embodiments of the invention, delayed setting cementitious compositions can develop a 24-hour compressive strength of at least about 344.7378 kPa (50 psi), at least about 689.4757 kPa (100 psi) . inch), at least about 3447.3786 kPa (500 psi) or more. In some embodiments, the values of compressive strength can be determined using destructive or non-destructive methods at temperatures ranging from 37.7 ° C (100 ° F) to 93.3 ° C (200 ° F).

[0023] In some embodiments of the invention, delayed setting cement compositions may have the desired thickening time after activation. The thickening time usually refers to the time during which a liquid, such as a delayed setting cement composition, remains in a liquid state suitable for pumping. Numerous laboratory technologies can be used to measure thickening times. A pressure measuring consistometer, operated in accordance with the procedure described in API RP Practice 10B-2 above, can be used to determine if a liquid is in a liquid state suitable for pumping. The thickening time can be the time during which the fluid for processing the trunk zone reaches a value of 70 Vs, and can be recorded as the time until 70 Vs is reached. In some embodiments of the invention, the cementitious compositions may have a thickening time of more than about 1 hour, alternatively more than about 2 hours, alternatively more than about 5 hours at 20684.2718 kPa (3000 psi) and temperatures in the range of about 10 ° C ( 50 ° F) to about 204.4 ° C (400 ° F), alternatively in the range of about 26.6 ° C (80 ° F) to about 121.1 ° C (250 ° F) and alternatively at a temperature of about 60 ° C (140 ° F).

[0024] Embodiments may include the addition of a cement setting agent to delayed setting cement compositions. Examples of suitable cement setting agents include, but are not limited to: zeolites, amines, such as triethanolamine, diethanolamine; silicates such as sodium silicate; zinc formate; calcium acetate, hydroxides of the elements of group IA and group IIA, such as sodium hydroxide, magnesium hydroxide and calcium hydroxide; monovalent salts, such as sodium chloride; divalent salts such as calcium chloride; silicon nanodioxide (i.e., silicon dioxide having a particle size of less than or about 100 nanometers); polyphosphates; and their combinations. In some embodiments of the invention, a combination of a polyphosphate and a monovalent salt may be used for activation. The monovalent salt may be any salt that dissociates to form a monovalent cation, such as sodium and potassium salts. Specific examples of suitable monovalent salts include potassium sulfate and sodium sulfate. In combination with monovalent salts, various polyphosphates, including polymer metaphosphate salts, phosphate salts and combinations thereof, can be used to activate delayed setting cement compositions. Specific examples of the polymer metaphosphate salts that can be used include sodium hexametaphosphate, sodium trimetaphosphate, sodium tetramethaphosphate, sodium pentametaphosphate, sodium heptametaphosphate, sodium octametaphosphate, and combinations thereof. A specific example of a suitable cement setting agent comprises a combination of sodium sulfate and sodium hexametaphosphate. In specific embodiments, a cement setting agent may be provided that is added to the delayed setting cement composition in the form of a liquid additive, for example, a liquid additive containing a monovalent salt, polyphosphate and optionally a dispersant.

[0025] A cement setting activator should be added to various delayed setting cementitious embodiments in an amount sufficient to initiate setting setting delayed setting in a hardened mass. In some embodiments of the invention, the cement setting agent may be added to the cement composition in an amount in the range of from about 0.1% to about 20% by weight of pozzolan. In specific embodiments, the cement setting activator may be present in an amount in the range between any and / or including values of about 0.1%, about 1%, about 5%, about 10%, about 15%, or about 20% by weight of pozzolan. Those skilled in the art, having the advantage of the present disclosure, can determine the appropriate amount of cement setting activator to use for the selected application.

[0026] Embodiments of delayed setting cement compositions may include the use of two separate composite suspensions that are mixed to form a two-component delayed setting cement composition. Embodiments of a delayed setting two-component cement composition may include providing a pozzolanic suspension and a lime suspension, which are stored separately instead of adding cement setting retarders. In a two-component cementitious composition with delayed setting, two separate suspensions can be used, so that none of the suspensions can be hydrated and, therefore, set separately. Therefore, each individual suspension of a delayed setting two-component cement composition must be maintained in a delayed setting condition (i.e., kept in a liquid state suitable for pumping for at least about one day [for example, at least about 1 day , about 2 weeks, about 2 years or more] at room temperature under static storage). Embodiments of a two-component delayed setting cementitious composition may comprise two composite suspensions. One compound suspension contains pozzolan and water. Another composite suspension contains lime and water. In various embodiments of the invention, each suspension may be stored at a drilling site or other storage location prior to use. If necessary, the use of two composite suspensions can be mixed with each other before or during injection into the well. The mixed suspension may then thicken and set over a desired period of time.

[0027] Advantageously, the use of a two-component delayed setting cementitious composition may allow faster setting at lower temperatures (for example, at temperatures below 60 ° C (140 ° F)). In addition, since the reactive components of the delayed setting two-component cement composition are stored separately, additional additives or higher additive concentrations (e.g., additional silica sources, see above) can be added to the delayed setting cement composition without risk of premature setting or gelation.

[0028] Embodiments of delayed setting two-component cement compositions may typically comprise two composite suspensions, a pozzolanic suspension and a lime suspension. Both compound suspensions contain water. Optionally, any composite suspension may further comprise a dispersant and / or cement setting retarder. Advantageously, embodiments of delayed setting two-component cement compositions may be able to remain in a liquid state suitable for pumping by a pump for an extended period of time. For example, delayed setting two-component cementitious compositions can be maintained in a liquid state suitable for pumping for at least about 1 day or longer. Advantageously, delayed setting two-component cementitious compositions can develop the required compressive strength after activation (for example, by mixing two composite suspensions) at relatively low temperatures. Although delayed setting two-component cementitious compositions may be suitable for many underground cementing operations, they may be particularly suitable for use in underground formations having relatively low static downhole temperatures, for example, temperatures below about 93.3 ° C (200 ° F) or in the range of from about 37.7 ° C (100 ° F) to about 93.3 ° C (200 ° F). In alternative embodiments, delayed setting cement compositions may be used in subterranean formations having static bottomhole temperatures of up to 232.2 ° C (450 ° F) or higher.

[0029] Embodiments of a pozzolan suspension may include pozzolan. For use in various embodiments, any pozzolan is suitable. Illustrative embodiments containing pozzolan may include fly ash, silica dust, metakaolin, diatomaceous earth, natural pozzolan (e.g., pumice), or combinations thereof. In one embodiment of a delayed setting two-component cementitious composition, the pozzolan can be a non-hydraulic pozzolan, i.e. pozzolan, which does not interact when mixed with water to form a cementitious material in the absence of slaked lime. For example, some types of Class C fly ash may be unsuitable for use in one embodiment of a delayed setting two-component cement composition, since Class C fly ash may contain lime and therefore interact when mixed with water to form a cementitious material.

[0030] Embodiments of the pozzolanic suspension may contain fly ash. Various types of fly ash may be suitable, including the fly ash classified by the American Petroleum Institute as Class F fly ash, API Specification for Materials and Testing for Well Cements, API Specification 10, fifth edition, July 1, 1990. Fly ash Class C ablation contains silicon dioxide and lime; therefore, when mixed with water, it may set with the formation of a hardened mass and, therefore, may not be suitable for use in a pozzolanic suspension, since it may undesirably set during mixing with water. Class F fly ash, as a rule, does not contain enough lime to initiate the cementation reaction; therefore, when mixed with water, it remains in a liquid state suitable for pumping. Suitable examples of fly ash include, but are not limited to, cement additive POZMIX ^® A manufactured by Halliburton Energy Services, Inc., Houston, Texas.

[0031] Embodiments of the pozzolanic suspension may contain metakaolin. Typically, metakaolin is a white pozzolan, which can be obtained by heating kaolin clay, for example, to temperatures in the range from about 600 ° C to about 800 ° C.

[0032] Embodiments of the pozzolan suspension may contain natural pozzolan. Natural pozzolans are usually found on the surface of the earth and set and harden in the presence of hydrated lime and water. Embodiments containing natural pozzolan may include pumice, diatomaceous earth, volcanic ash, opaline shale, tuff, and combinations thereof. Natural pozzolans can be shredded or unshredded. Typically, natural pozzolans can have any particle size distribution appropriate for the particular application. In some embodiments of the invention, natural pozzolans may have an average particle size in the range of from about 1 micron to about 200 microns. The average particle size corresponds to d50 values measured using particle size analyzers, such as analyzers manufactured by Malvern Instruments, Worcestershire, UK. In particular embodiments, natural pozzolans may have an average particle size in the range of from about 1 micron to about 200 microns, from about 5 microns to about 100 microns, or from about 10 microns to about 50 microns. In one particular embodiment, natural pozzolans may have an average particle size of less than about 15 microns. An example of a suitable industrial natural pozzolan is pumice made by Hess Pumice Products, Inc., Malad, Idaho, sold as a lightweight aggregate DS-325 that has a particle size of less than about 15 microns. It should be understood that too small a particle size can cause mixing problems, while too large a particle size can cause insufficiently effective suspension in the compositions and weaker reactivity due to the smaller surface area. Those skilled in the art, having the advantage of the present disclosure, may select the particle size of natural pozzolans suitable for use in the selected application.

[0033] Embodiments of the pozzolanic suspension comprise water. The water used in various embodiments of the pozzolanic suspension may be from any source, provided that it does not contain an excess of compounds that can adversely affect other components of the pozzolanic suspension. For example, a pozzolanic suspension may contain fresh water or salt water. Salt water, as a rule, may contain one or more salts dissolved in it, and may be saturated or unsaturated, depending on the specific application. Seawater or brines may be suitable for use in various embodiments. In addition, water may be present in an amount sufficient to provide a pumpable suspension. In some embodiments of the invention, water is individually present in the pozzolanic suspension in an amount in the range of from about 33% to about 200% by weight of pozzolan. In some embodiments of the invention, water may be present in the pozzolanic composition in an amount in the range of from about 35% to about 85% by weight of pozzolan. Those skilled in the art, having the advantage of the present description, can determine the appropriate amount of water for a selected application. Embodiments of a pozzolanic suspension may contain additives suitable for use in underground cementing operations. Any additives may be added to the pozzolan suspension, including additional sources of silica. Examples of additives include, but are not limited to: weighting agents, lightweight additives, gas-forming additives, additives to improve mechanical properties, materials to combat loss of circulation, additives to control filtration, additives to control water absorption, antifoam agents, foaming agents, thixotropic additives, dispersants, cement setting activators / accelerators, cement setting inhibitors, and combinations thereof. In various embodiments of a pozzolanic suspension, one or more of these additives may be added to the pozzolanic suspension before or after storage. In addition, one or more of these additives may be added to the pozzolanic suspension before or after mixing the pozzolanic suspension with the lime suspension. Those skilled in the art having the advantage of the present disclosure can easily determine the type and amount of additive suitable for a particular application and the desired result.

[0034] Embodiments of the lime suspension comprise slaked lime. In the context of the present invention, the term "slaked lime" is to be understood as calcium hydroxide. In some embodiments of the invention, slaked lime may be in the form of quicklime (calcium oxide), which is hydrated when mixed with water to form slaked lime. Slaked lime can be introduced into various versions of the implementation of the lime suspension to obtain a hydraulic composition with pozzolan. For example, slaked lime can be added in a mass ratio of pozzolan to slaked lime of about 10: 1 to about 1: 1, or in a ratio of about 3: 1 to about 5: 1 relative to the combined mixture of both compound suspensions. If present, the lime suspension may contain hydrated lime in an amount of about 10% to about 100% by weight of pozzolan present in the pozzolan suspension. In some embodiments, slaked lime may be present in the lime suspension in an amount in the range between any and / or including values of about 10%, about 20%, about 40%, about 60%, about 80%, or about 100% by weight of pozzolan in pozzolanic suspension. In some embodiments of the invention, the cementitious components present in the delayed setting two-component cementitious composition may consist essentially of pozzolan and slaked lime. For example, cementitious components can mainly contain pozzolan (e.g. pumice) and slaked lime without any additional cementitious components (e.g. Portland cement) that hydraulically set in the presence of water. Those skilled in the art, having the advantage of the present description, can determine the appropriate amount of slaked lime to be used for the selected application.

[0035] Embodiments of the lime slurry comprise water. The water used in various embodiments of the lime suspension may be from any source, provided that it does not contain an excess of compounds that can adversely affect other components of the lime suspension. For example, a lime slurry may contain fresh water or salt water. Salt water, as a rule, may contain one or more salts dissolved in it, and may be saturated or unsaturated, depending on the specific application. Seawater or brines may be suitable for use in various embodiments. In addition, water may be present in an amount sufficient to provide a pumpable suspension. Water is individually present in the lime suspension in an amount in the range of from about 33% to about 200% by weight of lime. In some embodiments of the invention, water may be present in the lime composition in an amount in the range of from about 35% to about 70% by weight of lime. Those skilled in the art, having the advantage of the present description, can determine the appropriate amount of water for a selected application.

[0036] Embodiments of the lime slurry may contain additives suitable for use in underground cementing operations. Any additives may be added to the lime suspension, including additional sources of silica. Examples of such additives include, but are not limited to: weighting agents, lightweight additives, gas-forming additives, additives to improve mechanical properties, materials to combat loss of circulation, additives to control filtration, additives to control water absorption, antifoam agents, foaming agents, thixotropic additives, dispersants , cement setting activators / accelerators, cement setting retarders and combinations thereof. In various embodiments of the lime suspension, one or more of these additives may be added to the lime suspension before or after storage. In addition, one or more of these additives may be added to the lime suspension before or after mixing the lime suspension with the pozzolanic suspension. Those skilled in the art having the advantage of the present disclosure can easily determine the type and amount of additive suitable for a particular application and the desired result.

[0037] Embodiments of delayed setting bicomponent cement compositions may include a cement setting retarder, as described above. Any cement setting retarder described above in embodiments of delayed setting cement compositions may also be suitable for embodiments of two-component delayed setting cement compositions. Cement setting retardants may be added to one or both of the composite suspensions, or may be added to the combined suspension. Among other reasons, cement setting retarders can be added to increase the thickening time. In some embodiments of the invention, the cement set retarder may be present in composite suspensions (each individually or both) or in a combined suspension of two-component delayed setting cement compositions in an amount in the range of about 0.01% to about 10% by weight of pozzolan. In specific embodiments, the cement setting retarder may be present in an amount in the range between any and / or including values of about 0.01%, about 0.1%, about 1%, about 2%, about 4%, about 6%, about 8 % or about 10% by weight of pozzolan for pozzolanic suspension or by weight of lime for lime suspension. Those skilled in the art, having the advantage of the present disclosure, can determine the appropriate amount of cement setting retarder to be used for the selected application.

[0038] As mentioned above, embodiments of delayed setting bicomponent cement compositions may optionally comprise a dispersant, as described above. Any dispersant described in embodiments of delayed setting cement compositions may also be suitable for embodiments of delayed setting two-component cement compositions. In some embodiments, the dispersant may be added to one or both of the composite slurries or to the combined suspension of two-component cementitious compositions with delayed setting in an amount in the range of about 0.01% to about 5% by weight of pozzolan or slaked lime. In specific embodiments, the dispersant may be present in an amount in the range between any and / or including values of about 0.01%, about 0.1%, about 0.5%, about 1%, about 2%, about 3%, about 4 % or about 5% by weight of pozzolan or slaked lime. Those skilled in the art having the advantage of the present disclosure may determine the appropriate amount of dispersant to be used for the selected application.

[0039] Embodiments may include the addition of a cement setting activator to a delayed setting two-component cement composition, as described above. Among other reasons, a cement setting agent may be introduced to reduce setting time. Any cement setting activator described in embodiments of delayed setting cement compositions may also be suitable for embodiments of delayed setting two-component cement compositions. Any cement setting activator can be added to any one or both of the composite suspensions, as well as to the combination suspension in an amount sufficient to accelerate the setting of the combined two-component composition with delayed setting (when added to only one compound suspension, setting time is reduced only when mixing the composite suspensions ) In various embodiments of the invention, the cement setting agent can be added to composite suspensions (each individually or both) or to a combined suspension of a two-component cement composition with delayed setting in an amount in the range of about 0.1% to about 20% by weight of pozzolan . In specific embodiments, the cement setting agent may be present in composite suspensions (each individually or both) or in a combination suspension of a two-component cement composition with delayed setting in an amount in the range between any and / or including values of about 0.1%, about 1 %, about 5%, about 10%, about 15%, or about 20% by weight of pozzolan. Those skilled in the art, having the advantage of the present disclosure, can determine the appropriate amount of cement setting activator to use for the selected application.

[0040] Those skilled in the art will recognize that embodiments of delayed setting two-component cement compositions typically should have a density suitable for a particular application. For example, combined bicomponent cement compositions may have a density in the range of about 0.4793 t / m ³ (4 pounds per gallon (“lb / gal.”)) To about 2.379 t / m ³ (20 pound / gal). In some embodiments, the combined bicomponent cement compositions may have a density in the range of about 0.9586 t / m ³ (8 lb / gal) to about 2,037 t / m ³ (17 lb / gal). Embodiments of delayed setting bicomponent cement compositions may be foamed or non-foamed, or may contain other density reducing agents, such as hollow microspheres, low density elastic granules, or other density reducing additives known in the art. In various embodiments of the invention, the density may be reduced after storage, but before being introduced into the subterranean formation. In various embodiments, weighting additives can be used to increase the density of delayed setting two-component cementitious compositions. Examples of suitable weighting agents may include barite, hematite, hausmannite, calcium carbonate, siderite, ilmenite, or combinations thereof. In specific embodiments, the weighting additives may have a specific gravity of 3 or more. Those skilled in the art having the advantage of the present disclosure can determine the appropriate density for a particular application.

[0041] As mentioned above, composite suspensions of two-component delayed setting cement compositions can have delayed setting in that they remain in a liquid state suitable for pumping for at least one day (for example, about 1 day, about 2 weeks, about 2 years or more) at room temperature (for example, about 26.6 ° C (80 ° F)) under static storage. For example, composite suspensions of two-component cementitious compositions with delayed setting may be maintained in a liquid state suitable for pumping over a period of time from about 1 day to about 7 days or more. In some embodiments, composite suspensions of two-component delayed setting cement compositions can be maintained in a liquid state suitable for pumping for at least about 1 day, about 7 days, about 10 days, about 20 days, about 30 days, about 40 days, about 50 days, about 60 days or more. It is believed that the liquid is in a liquid state suitable for pumping if the liquid has a consistency of less than 70 units of Verdun consistency ("Sun"), measured on a pressure consistency meter in accordance with the procedure for determining the thickening time of cement, established in API RP Practice 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005.

[0042] If necessary, embodiments of delayed setting two-component cementitious compositions can be activated (eg, by mixing pozzolanic and calcareous suspensions) and can be set into a hardened mass. For example, embodiments of delayed setting bicomponent cement compositions can be activated to produce a hardened mass over a period of time ranging from about 1 hour to about 12 hours. For example, embodiments of delayed setting bicomponent cement compositions can set to form a set mass over a period of time in the range between any and / or including values of about 1 day, about 2 days, about 4 days, about 6 days, about 8 days, about 10 days or about 12 days.

[0043] In some embodiments, delayed setting two-component cementitious compositions after activation can set and achieve the desired compressive strength. The compressive strength, as a rule, is the ability of a material or structure to withstand compressive forces applied in the axial direction. The compressive strength can be measured at a specific time after activation of the two-component cementitious composition with a delayed setting, and the resulting composition is kept at a certain temperature and pressure. The compressive strength can be measured by destructive or non-destructive methods. In the destructive method, the strength of the samples of the composition for processing the near-barrel zone is physically tested at various points in time, destroying the samples in a compression testing machine. Compressive strength is calculated from the breaking load divided by the cross-sectional area that can withstand the specified load, and is recorded in units of pound-force per square inch (psi). Non-destructive methods may use the UCA ™ Ultrasonic Cement Analyzer from Fann Instrument Company, Houston, Texas. Compressive strength values can be determined in accordance with API RP 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005.

[0044] For example, delayed setting two-component cementitious compositions can develop 24-hour compressive strength in the range of about 344.7378 kPa (50 psi) to about 34473.7864 kPa (5000 psi), in alternatives, from about 689.4757 kPa (100 psi) to about 31026.4078 kPa (4500 psi), or alternatively from about 3447.378 kPa (500 psi) to about 27579.0291 kPa (4000 psi). In some embodiments, delayed setting two-component cementitious compositions can develop a 24-hour compressive strength of at least about 344.7378 kPa (50 psi), at least about 689.4757 kPa (100 psi) square inch), at least about 3447.3786 kPa (500 psi) or more. In some embodiments, the values of compressive strength can be determined using destructive or non-destructive methods at temperatures ranging from 37.7 ° C (100 ° F) to 93.3 ° C (200 ° F).

[0045] In some embodiments of the invention, the delayed setting two-component cement compositions may have the desired thickening time after activation. The thickening time usually refers to the time during which a liquid, such as a delayed setting cement composition, remains in a liquid state suitable for pumping. Numerous laboratory technologies can be used to measure thickening times. A pressure measuring consistometer, operated in accordance with the procedure described in API RP Practice 10B-2 above, can be used to determine if a liquid is in a liquid state suitable for pumping. The thickening time can be the time during which the fluid for processing the trunk zone reaches a value of 70 Vs, and can be recorded as the time until 70 Vs is reached. In some embodiments of the invention, delayed setting two component cementitious compositions can have a thickening time of more than about 1 hour, alternatively more than about 2 hours, alternatively more than about 5 hours, in the range of about 1000 psi. inch to about 20,000 psi inches and temperatures in the range of about 10 ° C (50 ° F) to about 204.4 ° C (400 ° F), alternatively in the range of about 26.6 ° C (80 ° F) to about 121.1 ° C (250 ° F) and alternatively at a temperature of about 60 ° C (140 ° F).

[0046] Embodiments of two-component delayed setting cement compositions can be used to displace previously pumped fluids (ie, embodiments of a two-component delayed setting cement composition can be used as a displacing fluid). A pozzolanic suspension of a two-component delayed setting cement composition containing pozzolan and water may have the same composition as conventional displacement fluids. Due to this similarity, in various embodiments of the invention, the pozzolanic suspension can be used as a displacing fluid. A pozzolanic suspension can be used to displace drilling fluid, to separate cement from a drilling fluid, to displace another composition for treating a near-trunk zone, to separate drilling fluid from a composition for treating a near-barrel zone and / or to separate cement from a composition for treating a near-barrel zone. Advantageously, the use of a pozzolanic slurry as a displacing fluid can provide conditioning to the subterranean formation through a portion of the same composition that can ultimately be used as an annular seal. Therefore, the risk of incompatibility between the sealant and the displacing fluid can be reduced.

[0047] In embodiments of the invention in which a pozzolanic composite slurry of a delayed setting two-component cement composition can be used as a displacement fluid, the density of the pozzolanic slurry can be adjusted by adding water and / or a thickener. Water and thickeners may be added in an amount to achieve the desired density to obtain a suitable rheological hierarchy for a given application. An example of a suitable thickener is the suspending agent SA-1015 ™ manufactured by Halliburton Energy Services, Houston, Texas. In addition, weighting agents can be added to control density if it is necessary to maintain a suitable rheological hierarchy. Those skilled in the art, having the advantage of the present description, can determine the appropriate density and density control method required for the selected application.

[0048] Further, in embodiments of the invention in which a pozzolanic suspension can be used as a displacing liquid, the displacing liquid can be foamed with a blowing agent and / or gas. The displacing fluid may be foamed, for example, to provide a reduced density of the displacing fluid. The gas used to foam the composition may be any gas suitable for foaming, including, but not limited to: air, nitrogen, or combinations thereof. Typically, the gas should be present in an amount sufficient to produce the desired amount or quality of foam. Foaming additives can be incorporated into various embodiments, for example, to facilitate foaming and / or stabilization of the resulting foam formed using them. Examples of suitable blowing agents include, but are not limited to: mixtures of the ammonium salt of a simple alkyl ether sulfate, surface-active cocoamidopropyl betaine, surface-active cocoamidopropyl dimethyl amine oxide, sodium chloride and water; mixtures of a surface-active ammonium salt of a simple alkyl ether sulfate, a surface-active cocoamidopropylhydroxysultaine, a surface-active cocoamidopropyl dimethyl amine oxide, sodium chloride and water; hydrolyzed keratin; mixtures of a surface active ethoxylated alcohol ether sulfate, a surface active alkyl or alkenamidopropyl betaine and a surface active alkyl or alkene dimethyl amine oxide; aqueous solutions of surface active alpha olefin sulfonate and surface active betaine; and their combinations. An example of a suitable blowing agent is ZONESEALANT ™ 2000 manufactured by Halliburton Energy Services, Houston, Texas.

[0049] It should be understood that any additive, component, or embodiment described herein can be further used or combined with embodiments of a two-component delayed setting cement composition. For example, all previously described additives, such as weighting agents, lightweight additives, gas-forming additives, additives to improve mechanical properties, materials to combat loss of circulation, additives to regulate filtration, additives to regulate water absorption, antifoam agents, foaming agents, thixotropic additives, dispersants, cement setting retarders, cement setting activators / accelerators, additional sources of silicon dioxide and the like, and their combinations can be used with options for implementing tstsolanovoy slurry of lime slurry and the combined slurry bicomponent cement compositions with delayed grasp the same manner as previously described. Therefore, an embodiment of a two-component delayed setting cement composition includes each additive, component, or other embodiment that can be used in combination; including the use of cement setting activators and cement setting retarders. For example, a delayed setting two-component cement composition may include a cement setting agent to reduce setting time and improve early strength, additionally or alternatively, a delayed setting two-component cement composition may include a cement setting retarder to increase thickening time. Any additive, component, or embodiment described herein may be added to one or both of the composite suspensions or to the combined suspension of two-component delayed setting cement compositions. In addition, any additive, component, or embodiment described herein that is used with a pozzolanic suspension, lime suspension, or combination suspension can also be used with delayed setting two-component cementitious compositions that contain a displacement fluid.

[0050] Those skilled in the art will understand that embodiments of delayed setting cement compositions, including two-component delayed setting cement compositions, can be used in numerous underground operations, including primary and repair cementing. In some embodiments of the invention, a delayed setting cement composition may be provided (in embodiments of a delayed setting two-component cement compositions, it may be a combination delayed setting two-component cement composition) that contains water, pozzolan, slaked lime, a cement setting retarder and optionally dispersant. Delayed setting cementitious composition can be introduced into the subterranean formation and left to set. In the context of this document, the introduction of a delayed setting cement composition into a subterranean formation includes introducing into any part of the subterranean formation, including, without limitation, into a wellbore drilled in the subterranean formation, into the bottomhole zone surrounding the wellbore, and both. Embodiments of the invention may further include delayed setting cement composition activation. Activation of a delayed setting cement composition may include, for example, adding a cement setting accelerator to a delayed setting cement composition, or mixing two composite suspensions of a delayed setting two-component cement composition.

[0051] In some embodiments of the invention, a delayed setting cement composition may be provided that comprises water, pozzolan, slaked lime, a cement setting retarder, and optionally a dispersant. Delayed setting cementitious composition may be stored, for example, in a container or other suitable reservoir. In alternative embodiments of the invention, a two-component delayed setting cement composition can be provided that contains a first part containing a composite slurry of pozzolan and water and a second part containing a composite slurry of slaked lime and water. The first and second parts can be stored separately and can be mixed before or during injection into the well. Delayed setting cementitious compositions may be left in storage for a desired period of time. For example, delayed setting cement compositions may be stored for a period of about 1 day, about 2 weeks, about 2 years or more. For example, delayed setting cement compositions can be stored for a period of about 1 day, about 2 days, about 5 days, about 7 days, about 10 days, about 20 days, about 30 days, about 40 days, about 50 days, about 60 days or up to about 2 years. In some embodiments, the delayed setting cement composition may be stored for a period of time in the range of about 1 day to about 2 years or more. Then, the delayed setting cement composition can be activated, for example, by mixing two composite suspensions with each other, introduced into the subterranean formation and left to set.

[0052] In primary cementing embodiments, for example, delayed setting cement compositions may be introduced into the annular space between the pipe located in the wellbore and the walls of the wellbore (and / or larger diameter pipes in the wellbore), where the well passes through an underground formation. Delayed setting cementitious composition may be left to set in the annular space to form an annular casing of hardened cement. Delayed setting cementitious composition may form a barrier that prevents fluid migration in the wellbore. Delayed setting cementitious composition may also, for example, support the pipe in the wellbore.

[0053] In embodiments of repair cementing, a delayed setting cement composition may be used, for example, in cementing operations or when installing cement plugs. For example, a delayed setting composition may be introduced into the wellbore to plug holes (e.g., voids or cracks) in the formation, in gravel packing, in the pipe, in the cement sheath and / or between the cement sheath and the pipe (for example, in an annular micro-gap) .

[0054] One embodiment includes a cementing method, comprising: providing a pozzolanic suspension containing pozzolan and water; providing a lime slurry containing slaked lime and water; providing the possibility of separate storage of pozzolanic suspension and lime suspension for about one day or more; mixing a pozzolanic suspension and a lime suspension to obtain a cement composition; and allowing the setting of the cement composition.

[0055] One embodiment includes a method of displacing fluid in a subterranean formation, comprising: providing a pozzolanic suspension containing pozzolan and water; providing a lime slurry containing slaked lime and water; introducing at least a portion of the pozzolanic suspension into the wellbore that passes through the subterranean formation so that the pozzolanic suspension displaces at least one fluid from the wellbore; activation of the delayed setting cement composition by mixing at least a portion of the pozzolanic suspension and at least a portion of the lime suspension to form a cement composition; the introduction of a cement composition into an underground formation; and enabling the setting of the cement composition in the subterranean formation.

[0056] One embodiment of the invention includes a cementing system comprising: a pozzolan suspension containing pozzolan and water; lime slurry containing slaked lime and water for combination with a pozzolanic slurry to form a cement composition.

[0057] Referring to FIG. 1, the following describes the preparation of a delayed setting cement composition in accordance with illustrative embodiments of the invention. In FIG. 1 shows a system 2 for producing a delayed setting cement composition and delivering it to a wellbore in accordance with certain embodiments of the invention. As shown, the delayed setting cement composition can be mixed in mixing equipment 4, such as, for example, a jet mixer, recirculation mixer or batch mixer, and then pumped into the wellbore using pumping equipment 6. In some embodiments of the invention, the mixing equipment 4 and pumping equipment 6 can be located on one or more cement trucks, as is clear to specialists in this field of technology. In some embodiments of the invention, a jet mixer may be used, for example, to continuously mix lime / setting material with water as it is pumped into the wellbore. In two-component delayed setting embodiments, mixing equipment (e.g., a jet mixer, a recirculation mixer and / or a batch mixer) can be used to mix the suspension of the delayed setting two-component cementitious composition.

[0058] An exemplary technology for applying a delayed setting cement composition to a subterranean formation is described below with reference to FIG. 2A and 2B. In FIG. 2A shows ground equipment 10 that can be used to lay a delayed setting cement composition in accordance with some embodiments of the invention. It should be noted that although in FIG. 2A shows a general ground operation, it will be understood by those skilled in the art that the principles described herein are equally applicable to underwater operations in which floating or offshore platforms and rigs can be used without departing from the scope of the present description. As shown in FIG. 2A, surface equipment 10 may include a cementing unit 12, which may contain one or more cement trucks. Cementing unit 12 may include mixing equipment 4 and pumping equipment 6 (for example, Fig. 1), as is clear to specialists in this field of technology. Cementing unit 12 may pump the cementitious composition 14 with a delayed setting through the feed pipe 16 and into the cementing head 18, which delivers the cementitious composition 14 with a delayed setting in the well.

[0059] Referring to FIG. 2B, delayed setting cement composition 14 may be incorporated into subterranean formation 20 in accordance with illustrative embodiments of the invention. As shown, the wellbore 22 may be drilled in the subterranean formation 20. Although the wellbore 22 is shown as being directed generally vertically into the subterranean formation 20, the principles described herein also apply to wellbores directed through the subterranean formation 20 at an angle. such as horizontal and deviated wellbores. As shown, the wellbore 22 comprises walls 24. In the illustrated embodiment, a conductor string 26 is inserted into the wellbore 22. The conductor string 26 may be cemented to the walls 24 of the wellbore 22 by a cement sheath 28. In the illustrated embodiment, in the wellbore 22 one or more additional pipes (eg, intermediate string, production string, liner, etc.), shown herein as column 30, may also be located. As shown oh, the annular space 32 of the wellbore is formed between the column 30 and the walls 24 of the wellbore 22 and / or the conductor string 26. One or more centralizers 34 may be connected to the string 30, for example, to center the string 30 in the wellbore 22 before and during cementing operations.

[0060] Continuing to refer to FIG. 2B, delayed setting cementitious composition 14 can be pumped into the interior of column 30. Delayed setting cementitious composition 14 can be provided downstream of column 30 through column shoe 32 in the bottom of column 30 and upward around column 30 into the annulus 32 boreholes. Delayed setting cement composition 14 may be left to set in the annulus 32 of the wellbore, for example, to form a cement sheath that supports and holds the column 30 in place in the wellbore 22. Although not shown, other techniques may also be used to introduce delayed setting cement composition 14. For example, a reverse circulation technology can be used that involves introducing a cementitious composition 14 with delayed setting into the subterranean formation 20 through the annular space 32 of the wellbore rather than through the string 30.

[0061] Once introduced, delayed setting cement composition 14 may displace other fluids 36, such as drilling fluids and / or displacement fluids, which may be present in the interior of the string 30 and / or in the annulus 32 of the wellbore. At least a portion of the displaced fluids 36 may exit the annulus 32 of the wellbore through a drain pipe 38 and may be placed, for example, in one or more drain tanks 40 (e.g., a mud reservoir), as shown in FIG. 2A. Referring again to FIG. 2B, the lower plug 44 may be inserted into the wellbore 22 before the delayed setting cement composition 14, for example, to separate the delayed setting cement composition 14 from the fluids 36 that may be inside the column 30 before cementing. After the bottom plug 44 has reached the column suspension sleeve 46, the membrane or other suitable device must be torn so that the delayed setting cement composition 14 passes through the bottom plug 44. In FIG. 2B, the bottom plug 44 is shown on a sleeve 46 for suspending a column. In the illustrated embodiment, the upper plug 48 may be inserted into the wellbore 22 after the delayed setting cement composition 14. The upper plug 48 may separate the delayed setting cementitious composition 14 from the displacement fluid 50, as well as pushing the delayed setting cementitious composition 14 through the lower plug 44.

[0062] The exemplary delayed setting cement compositions described herein may directly or indirectly affect one or more components or parts of equipment associated with the receipt, delivery, return, recycling, reuse, and / or disposal of the described delayed setting cement compositions grasping. For example, the delayed setting cementitious compositions described herein can directly or indirectly affect one or more mixers, associated mixing equipment, drilling fluid reservoirs, storage facilities or units, composition separators, heat exchangers, sensors, meters, pumps, compressors, etc. .P. equipment used to obtain, store, monitor, regulate and / or restore the former properties of illustrative cementitious compositions with delayed setting. The delayed setting cement compositions described above can also directly or indirectly affect any transport or delivery equipment used to transport delayed setting cement compositions to the drilling site or delivering them to the well, such as, for example, any transportation containers, pipes, pipelines, trucks , pipe systems and / or pipes used for the composite movement of cement compositions with delayed setting from one place to another, any pumps, compressors and whether the engines (e.g. on topsides or in the well) used to drive delayed setting cement compositions, any valves or similar connections used to control the pressure or flow rate of delayed setting cement compositions, and any sensors (i.e. ., pressure and temperature), measuring instruments and / or combinations thereof, etc. The delayed setting cement compositions described can also directly or indirectly affect various downhole equipment and tools that can be brought into contact with the delayed setting cement compositions, such as, but not limited to, the wellbore casing, the wellbore liner, the casing completions, insertion columns, drill string, flexible pipes, wire rope, cable wire, drill pipe, weighted drill pipes, hydraulic downhole motors spruce, downhole motors and / or pumps, cementing pumps, ground motors and / or pumps, centralizers, turbolizers, scrapers, float-type devices (e.g. shoes, couplings, valves, etc.), logging tools and related telemetry equipment, drive mechanisms (e.g. electromechanical devices, hydromechanical devices, etc.), sliding couplings, service couplings, plugs, networks, filters, flow regulators (e.g. inflow regulators, autonomous inflow regulators, flow regulators etc.), connectors (e.g. electro-hydraulic wet joint, dry joint, inductive coupler, etc.), control lines (e.g. electrical, fiber optic, hydraulic, etc.), inspection lines, drill heads and sub-bit extenders, sensors or distributed sensors, downhole heat exchangers, valves and associated actuating devices, gaskets, packers, cement plugs, bridge plugs and other downhole isolation devices or components and the like.

EXAMPLES

[0063] To facilitate understanding of the present embodiments of the invention, the following examples of certain aspects of certain embodiments of the invention are provided. These examples should in no way be taken as limiting or defining the full scope of the embodiments of the invention.

Example 1

[0064] A two-component delayed setting cementitious composition was prepared containing the following composite suspensions:

[0065] Suspension A was prepared in a Waring ^® mixer by first adding water to the mixer, then Liquiment ^® 5581F dispersant. The dispersant was left to disperse completely, then pumice, silica (Silicalite ™ cement additive) and weighting agent (MicroMax ^® FF weighting agent) were added. After all components were added, suspension A was stirred at a speed of 6000 rpm. within 40 seconds until complete homogenization of the sample. Suspension B was obtained in the same way as suspension A. The calculated density of suspension A was 1.597 t / m ³ (13.33 pounds per gallon (lb / gal)), and suspension B was 1.528 t / m ³ (12.75 lb / gal).

[0066] Immediately after preparation (designated 0 day) and periodically thereafter, the rheological properties of the samples were determined using a Fann Model 35A viscometer and a No. 2 spring with a Fann yield strength adapter (FYSA), in accordance with the procedure described in API RP Practice 10B-2, Recommended Practice for Testing Well Cements. If necessary, a dispersant was added to maintain appropriate viscosity values. % bwoP refers to "percent by weight of pumice," and% bwoHL refers to "percent by weight of slaked lime."

[0067] For combination settable slurry 129.4 g of suspension B was added to 500.0 g of the slurry A. The addition performed by the addition of the slurry A in the Waring ^® mixer set at 4000 rpm. / Min., And slowly pouring the slurry B to give suspension AB with the following final composition of the suspension:

[0068] The calculated density of the AB suspension was 1.585 t / m3 (13.23 lb / gal). Part of the AB suspension was activated with 10% bwoP CaCl2, mixing 200.0 g of AB suspension with 21.92 g of a 43% CaCl2 solution. The resulting sample is presented in table 5 as activated. Immediately after preparation, sample rheology was measured using a Fann Model 35A viscometer and a No. 2 spring with a Fann yield strength adapter (FYSA), in accordance with the procedure described in API RP Practice 10B-2, Recommended Practice for Testing Well Cements.

[0069] After mixing the two composite suspensions to activate the delayed setting cement composition, the combined suspension was cured in a 2 ”by 4” plastic cylinder, which was mounted in a water bath at a temperature of about 32.2 ° C (90 ° F) up to about 65.5 ° C (150 ° F) to give hardened cylinders. Then, the compressive strength (CS) with failure was measured using a mechanical press in accordance with API RP Practice 10B-2, Recommended Practice for Testing Well Cements. The test results are presented in Table 6 below. The compressive strength data presented is the average of the two cylinders of each sample. Compression strength measurements were performed after 24 hours.

[0070] For comparison, a delayed setting slurry was obtained which was not a two-component composition by mixing 350 g of water, 500 g of pumice, 100 g of slaked lime, 20 g of Micromax ^® weighting agent, 6.25 g of Micro Matrix ^® cement setting retarder and 3 5 g of the dispersant Liquiment ^® 5581F. The resulting suspension (NC1) was held for 35 days prior to use, activated with a 10% bwoP CaCl ₂ solution, and cured in a water bath for the same time as AB suspension.

* Suspension remained uncured and fluid

** The suspension turned into a gel and was not fluid

[0071] As Example 1 shows, the AB suspension is more active at lower temperatures than NC1. Not limited to theory, this effect may be due to the absence of cement setting retarders in the AB slurry and / or the addition of silicon dioxide.

Example 2

[0072] In the previous examples, pozzolanic and calcareous slurries were mixed to obtain slaked lime content of 20.0% bwoP. The following example shows that it may be advantageous to mix the two components in different ratios to obtain suspensions with a different lime content. In this example, 258.8 g of suspension B was mixed with 500.0 g of suspension A to give a lime content of 40% bwoP:

[0073] After mixing, the resulting sample was cured in a water bath at 32.2 ° C (90 ° F) for 24 hours, then the compressive strength at fracture was determined, which was 1034.2135 kPa (150 psi). The strength of the obtained sample was about 33% higher than the strength of the sample containing only 20% lime (1034.2135 kPa (105 psi)).

Example 3

[0074] Received a two-component cement composition with a delayed setting, containing the following composite suspensions:

[0075] C. The slurry was prepared in the mixer Waring ^®, adding water to the mixer first, followed by dispersing Liquiment ^® 5581F. Dispersant left until fully dispersed, then add pumice and weighting (weighting MicroMax ^® FF). After all components were added, suspension C was stirred at a speed of 6000 rpm. within 40 seconds until complete homogenization of the sample. Suspension D was obtained in the same way as suspension C. The calculated density of suspension C was 1.587 t / m ³ (13.24 pounds per gallon (lb / gal)), and suspension B was 1.528 t / m ³ (12.75 lbs. / gal).

[0076] Immediately after preparation (designated 0 day) and periodically thereafter, rheological properties of the samples were determined using a Fann Model 35A viscometer and a No. 2 spring with a Fann yield strength adapter (FYSA), in accordance with the procedure described in API RP Practice 10B-2, Recommended Practice for Testing Well Cements. If necessary, a dispersant was added to maintain appropriate viscosity values.

[0077] For combination settable slurry 129.4 g of the slurry D was added to 500.0 g of the slurry S. The addition performed by the addition of a suspension of C. Waring ^® mixer set at 4000 rpm. / Min., And slowly pouring the slurry D to give CD suspensions with the following final suspension composition:

[0078] The calculated density of the CD suspension was 1.573 t / m3 (13.13 lb / gal). A portion of the CD suspension was activated with 10% bwoP CaCl2, mixing 200.0 g of the CD suspension with 21.51 g of a 43% CaCl2 solution. The resulting sample is presented in table 11 as activated. Immediately after preparation, sample rheology was measured using a Fann Model 35A viscometer and a No. 2 spring with a Fann yield strength adapter (FYSA), in accordance with the procedure described in API RP Practice 10B-2, Recommended Practice for Testing Well Cements.

[0079] After mixing the two composite suspensions to activate the delayed setting cement composition, the combined suspension was cured in a 2 ”by 4” plastic cylinder, which was mounted in a water bath at a temperature of 87.7 ° C (190 ° F), s obtaining hardened cylinders. Then, the compressive strength (CS) with failure was measured using a mechanical press in accordance with API RP Practice 10B-2, Recommended Practice for Testing Well Cements. The test results are presented in table 12 below. The compressive strength data presented is the average of the two cylinders of each sample. Samples and control samples were cured at a pressure of 1 atmosphere, at a temperature of from about 32.2 ° C (90 ° F) to about 65.5 ° C (150 ° F); compressive strength measurements were performed after 24 or 48 hours.

[0080] For comparison, a delayed setting slurry was obtained which was not a two-component composition by mixing 350 g of water, 500 g of pumice, 100 g of slaked lime, 20 g of Micromax ^® weighting agent, 6.25 g of Micro Matrix ^® cement setting retarder and 3 5 g of the dispersant Liquiment ^® 5581F. The resulting suspension (NC1) was held for 35 days prior to use, activated with a 10% bwoP CaCl ₂ solution, and cured in a water bath for the same time as AB suspension.

* Suspension remained uncured and fluid

** The suspension turned into a gel and was not fluid

Example 4

[0081] Received a two-component cement composition with a delayed setting, containing the following composite suspensions:

[0082] Suspension E was prepared in a Waring ^® mixer by first adding water to the mixer, then Liquiment ^® 5581F dispersant. The dispersant was left to disperse completely, then pumice was added. After adding all the components, suspension E was stirred at a speed of 6000 rpm. within 40 seconds until complete homogenization of the sample. Suspension F was obtained in the same way as suspension E. The calculated density of suspension E was 1.606 t / m ³ (13.4 pounds per gallon (lb / gal)), and suspension F was 1.486 t / m ³ (12.4 lb / gal). Then suspension E and suspension F were stored for 48 hours. After 48 hours, none of the suspensions contained

free water. However, the suspension F slightly turned into a gel, and mixing was required to ensure its fluidity.

[0083] After 48 hours, 778.7 g of the slurry E was added to 175.4 g of the slurry F. Appendix E performed by adding a suspension of a Waring ^® mixer set at 4000 rpm. / Min., And slowly pouring the slurry F to give suspensions EF . After mixing, the gel was formed, and was added 1.0 g of a dispersant (dispersant Liquiment ^® 5581F), the mixture became fluid.

[0084] The calculated density of the finished suspension was 1,582 t / m ³ (13.2 lb / gal). 15.0 g of CaCl ₂ powder (2.5% bwoP + HL) was added to the prepared suspension, and then the prepared suspension was placed in a consistometer. Thickening time was measured after 5:38 hours at 60 ° C (140 ° F) and 20684.2718 kPa (3000 psi). The thickening time was measured using a high temperature and high pressure consistometer in accordance with the cement thickening time determination procedure specified in API RP Practice 10B-2, Recommended Practice for Testing Well Cements, First Edition, July 2005.

[0085] It should be understood that the compositions and methods are described herein in the context of "content", "containment" or "inclusion" of the various components or steps, and the compositions and methods may also "consist essentially of" or "consist of" various components and stages. Moreover, the singular forms used in the claims mean one or more elements.

[0086] For brevity, only certain ranges are fully disclosed herein. However, ranges from any lower limit can be combined with any upper limit to describe a range not described in full, just as ranges from any lower limit can be combined with any other lower limit to describe a range not described in full. in the same way, ranges from any upper limit can be combined with any other upper limit to describe a range not fully described. In addition, in all cases where a numerical range with a lower limit and an upper limit is described, any number and any included range falling within the specified range are specifically described. In particular, each range of values (in the form of “from about a to about b” or, equivalently, “from about a to b” or, equivalently, “from about a-b”) described herein should be understood as describing each number and range included in a wider range of values, even if they are not explicitly stated. Thus, each point or individual value can act as its own lower or upper limit, combined with any other point or individual value, or with any other lower or upper limit, to describe a range that is not fully described.

[0087] Therefore, embodiments of the present invention are well adapted to achieve the described and intrinsic results and advantages. The specific embodiments of the invention disclosed above are only illustrative, and can be modified and implemented in various, but equivalent ways, obvious to experts in this field, who have the opportunity to familiarize themselves with the present description. Although only individual embodiments of the invention were discussed, the present description covers all combinations of all embodiments of the invention. In addition, the design or project details described herein are not limited except as described in the claims below. Also, the terms in the claims are used in their simple, ordinary meaning, unless otherwise expressly indicated by the applicant. Thus, it should be understood that the particular illustrative embodiments described above can be changed or modified, while all such changes are within the scope and essence of these embodiments of the invention. If there is a conflict in the use of a word or term in the present description and one or more patent (s) or other documents that may be incorporated into this description by reference, the definitions corresponding to the present description should be adopted.

Claims (35)

 1. The method of cementing, including: providing pozzolanic suspension containing pozzolan and water in an amount of from 33 wt. % up to 200 wt. % by weight of pozzolan; providing a lime suspension containing slaked lime and water in an amount of from 33 wt. % up to 200 wt. % by weight of lime; providing the possibility of separate storage of pozzolanic suspension and lime suspension for about one day or more; mixing the pozzolanic suspension and the lime suspension to obtain a cement composition, the mass ratio of pozzolan to slaked lime being from 10: 1 to 1: 1; and providing the possibility of setting the cement composition. 2. The method according to p. 1, characterized in that the cement composition is injected into the wellbore, passing through an underground layer, and left to set. 3. The method according to p. 1 or 2, characterized in that the pozzolan is selected from the group consisting of fly ash, silica dust, metakaolin, pumice and any combination thereof. 4. The method according to p. 1, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition further comprises a dispersant. 5. The method according to p. 4, characterized in that the dispersant contains at least one dispersant selected from the group consisting of a dispersant based on sulfonated formaldehyde, a polycarboxylated ether dispersant, and any combination thereof. 6. The method according to p. 1, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition further comprises a cement retarder. 7. The method according to claim 6, characterized in that the cement setting retarder is selected from the group consisting of phosphonic acid, a phosphonic acid derivative, lignosulfonate, salt, organic acid, carboxymethylated hydroxyethyl cellulose, synthetic co or terpolymer containing sulfonate and carboxyl groups, borate compounds and any combination thereof. 8. The method according to p. 1, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition further comprises a cement setting activator; moreover, the cement setting agent contains at least one cement setting agent selected from the group consisting of amine, silicate, zinc formate, calcium acetate, hydroxide of an element of group IA; hydroxide of an element of group IIA, a monovalent salt, a divalent salt, silicon nanodioxide, polyphosphate, and any combination thereof. 9. The method according to claim 1, further comprising storing at least one of the pozzolanic suspension or lime suspension for a period of about 7 days or more until the mixing stage. 10. The method according to p. 1, further comprising pumping the cement composition through the feed pipe and into the annulus of the wellbore passing through the subterranean formation. 11. A method of displacing fluid in a subterranean formation, comprising: providing pozzolanic suspension containing pozzolan and water in an amount of from 33 wt. % up to 200 wt. % by weight of pozzolan; providing a lime suspension containing slaked lime and water in an amount of from 33 wt. % up to 200 wt. % by weight of lime; introducing at least a portion of the pozzolanic suspension into the wellbore passing through the subterranean formation so that the pozzolanic suspension displaces at least one fluid from the wellbore; activation of the delayed setting cement composition by mixing at least a portion of the pozzolanic slurry and at least a portion of the lime slurry to form a cementitious composition, wherein the mass ratio of pozzolan to slaked lime is from 10: 1 to 1: 1; the introduction of a cement composition into an underground formation; and providing the possibility of setting the cement composition in the subterranean formation. 12. The method according to p. 11, wherein the pozzolan is selected from the group consisting of fly ash, silica dust, metakaolin, pumice and any combination thereof. 13. The method according to p. 11 or 12, characterized in that the portion of the pozzolanic suspension that displaces at least one fluid from the wellbore is foamed until at least one fluid is displaced from the wellbore. 14. The method according to p. 11, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition further comprises a dispersant. 15. The method according to p. 11, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition further comprises a cement retarder. 16. The method according to p. 11, characterized in that at least one of the pozzolanic suspension, lime suspension or cement composition contains a cement setting activator. 17. The method according to p. 11, further comprising storing at least one of the pozzolanic suspension or lime suspension for a period of time about 7 days until the mixing stage. 18. The method according to p. 11, further comprising pumping the cement composition through the feed pipe and into the annulus of the wellbore passing through the subterranean formation. 19. A cementing system comprising: pozzolanic suspension containing pozzolan and water in an amount of from 33 wt. % up to 200 wt. % by weight of pozzolan; lime suspension for combination with pozzolanic suspension to obtain a cement composition, and the lime suspension contains hydrated lime and water in an amount of from 33 wt. % up to 200 wt. % by weight of lime, moreover, the mass ratio of pozzolan to slaked lime is from 10: 1 to 1: 1. 20. The system of claim 19, further comprising mixing equipment for mixing the pozzolanic suspension with the lime suspension to form a cement composition, and pumping equipment for delivering the cement composition to the wellbore.

Images