JP5832063B2 - Well sealant composition containing cationic latex and method of use thereof - Google Patents

Description

(Field of Invention)
The present invention relates to maintenance of a well. More specifically, the present invention relates to maintenance of a well using a sealant composition containing a cationic latex and a method for using the well.

(Background of the invention)
Natural resources such as gas, oil, and water present in the underground layer or zone are usually recovered by drilling the well to the underground layer while circulating drilling fluid through the well. After finishing the drilling fluid circulation, a series of pipes, for example casings, are passed through the wells. Thereafter, the drilling fluid typically circulates down through the interior of the pipe and circulates up through an annulus located between the outside of the pipe and the well wall. Next, primary cementing is usually performed. This places the cement slurry in the annulus and hardens it into a firm mass (ie, a sheath). This attaches a series of pipes to the well wall and seals the annulus. Secondary cementing work can be continued.

  The fluid used to service the well can be lost to the underground layer while circulating this fluid through the well. These fluids have depleted zones, relatively low pressure zones, lost circulation zones with natural cracks, and fracture gradients with higher hydrostatic pressure for maintenance fluids. There is a possibility of entering the underground layer through permeable zones such as weak zones. As a result, the maintenance provided by such fluids becomes more difficult. Furthermore, the loss of such fluids increases the overall cost of the work, such as the increased equipment time required, the fluid being relatively expensive, and possibly the need for casing mounting.

  There are various ways to control drilling fluid circulation loss. Such methods include adding loss prevention materials to the drilling fluid itself and continuing the drilling process or infusion of fluid until fluid circulation is restored. Similarly, cementing slurry can be lost to the formation during injection for a variety of reasons, including exceeding the formation's tear gradient due to high hydrostatic pressure. A specific method of preventing fluid circulation loss is to inject a cement slurry, sodium silicate solution, or latex fluid containing cement into an aqueous or non-aqueous fluid and mix it with another suitable fluid. Forming a solid plug in the mud zone.

  If such a method succeeds in preventing drilling fluid from being lost, the operator can either casing the well or use a drill ahead process (see below). For example, an operator can temporarily cease excavation, casing a well, and resuming further excavation after the casing is cemented. As a result, the diameter of the previous well can be reduced from that point. Well casing is performed when excavation is resumed without casing the well and when the mud treatment is not strong enough to withstand the hydrostatic pressure of the drilling fluid. Alternatively, if the mud treatment provides sufficient reinforcement to the mud zone and, as a result, can withstand hydrostatic pressure even if drilling continues without casing the well, it is more economical at the well construction stage. It is more profitable at the production stage. This not only saves the cost of the casing, but also increases the diameter of the well when completed, and this wide diameter will increase the production rate of the fluid. The latter process is referred to in the art as the “drill ahead” process.

  Another oil field problem that occurs during the construction of wells or in mature oil wells is the production of undesirable water. Wells that collect hydrocarbons are usually made in hydrocarbon-containing formations, but these formations may contain parts that contain water or are adjacent to parts that contain water. There is a possibility. In general, the term "water-containing part" refers to any part of the underground that has the potential to produce water, and the water is sufficiently saturated to produce water with hydrocarbons. Possibly including hydrocarbon-containing moieties. The high mobility of water allows water to flow into the well through natural fissures and / or highly permeable muscles present in the formation. During oil well construction, drilling through the clear water zone can cause water to flow into the well through natural or induced cracks. The production of water together with hydrocarbons from underground wells is a major problem and cost for hydrocarbon production. If these wells have been used for many years, the ratio of water to recovered hydrocarbons may not be desirable considering the cost of producing water, separating it from the hydrocarbon, and treating it. This can be a significant economic loss.

  In order to increase the flow of hydrocarbons to the well, subterranean stimulation treatments have long been used in the field of hydrocarbon production. One such treatment method is hydraulic fracturing. According to this method, a special fluid is injected into the underground layer with sufficient pressure to create or enlarge at least one fracture in the layer, thereby reducing the amount of fluid flowing through this layer to the well. increase. However, if there is water in the formation, the water level will increase continuously and gradually, and it will be necessary to block this crack and introduce new cracks at different depths in the well. May reach. In any such case, a repair fluid containing a sealant composition (e.g., a cementitious composition) needs to be pumped into the crack and plugged to control the production of undesirable water from the crack. Such a method of controlling water production is often referred to as conformance control. Magnesium salt-based sealant systems, commonly referred to as sorrel cement, contain magnesium oxide and soluble salts such as magnesium chloride, magnesium sulfate, or primary or dibasic ammonium phosphate and should be suitable for such adaptive control applications. I know. Sorrel cements based on magnesium chloride and magnesium sulfate as soluble salts become unstable when exposed to water. This instability appears as cracking in a short time when exposed to water, and thereafter the structural bond as a sealant is lost.

  Anionic latex is used as an additive to improve the properties of the cement slurry. High alumina cement is commonly used for cementing wells containing acidic gases such as formation fluids containing carbon dioxide or hydrogen sulfide. These cements can also be used for cementing hot wells. The use of anionic latex to control fluid loss, decrease permeability or improve the mechanical properties of high alumina cements often results in cement slurries with poor fluid loss control and leaching of latex into the aqueous fluid around the cement A hardened cement composition was obtained. While the well has been in use for many years, the leaching of latex with water increases the permeability of the hardened cement, adversely affecting its mechanical properties by reducing its strength and elasticity.

  Accordingly, there is a need for improved well sealant compositions that are suitable for mud applications, particularly those involving drill-ahead operations. There is also a need for an improved magnesium salt sealant composition that is less prone to degradation in structure, especially in conformity control operations. There is a further need for improved sealant compositions, particularly high alumina based sealant compositions, that include latex that does not leach from the sealant composition. The present disclosure addresses these needs as well as other needs that will be apparent to those skilled in the art.

(Some brief summary of preferred embodiments)
The present invention relates to a well sealant composition comprising a cementitious material to be injected into a well and a cationic latex, and a method of using the same.
According to one aspect of the present invention, a well sealant composition comprising a cementitious material and a cationic latex is provided. This composition can be introduced into a well.
According to another aspect of the present invention, there is provided a method for maintaining a well in contact with an underground layer, comprising placing a well sealant composition comprising a cementitious material and a cationic latex in the well.

  The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art will appreciate that the disclosed concepts and specific embodiments can be readily utilized as a basis for improving the structure for carrying out the same purposes of the present invention or as a basis for designing other structures. I want. Moreover, those skilled in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

Detailed Description of Preferred Embodiments
This specification discloses a sealant composition comprising a cementitious material capable of exhibiting a pH in the range of about 3 to about 10 when mixed in an aqueous fluid, and a cationic latex. In one embodiment, the sealant composition comprises non-Portland cement and a cationic latex. In another embodiment, the sealant composition comprises a high alumina cement and a cationic latex. Alternatively, the sealant composition comprises magnesia (magnesium oxide), magnesium chloride, magnesium sulfate or a soluble phosphate of ammonium or alkali metal ions and a cationic latex. As used herein, “sealant composition” refers to drilling, finishing, refurbishing, repairing, or any method to recover material present in the underground layer through which the well has penetrated. Refers to the fluid used to prepare the well. Examples of sealant compositions include, but are not limited to, cement slurries, sludge pills, curable fluids, filling compositions for plug-and-abandon purposes, chemical packers, temporary plugs, A spacer fluid, a finishing fluid, or a repair fluid. All of these are well known in the art. Such sealant compositions can be used in well maintenance operations known to those skilled in the art.

In one embodiment, the sealant composition comprises a cationic latex. The cationic latex can include a latex-forming monomer and a positively charged monomer. Examples of latex forming monomers that can be used to produce cationic latex include, but are not limited to, vinyl aromatic monomers (eg, styrenic monomers), ethylene, butadiene, vinyl nitrile (eg, acrylonitrile), Examples include olefinically unsaturated esters of C _{1 to} C ₈ alcohols, or combinations thereof. In some embodiments, nonionic monomers that exhibit steric effects and contain long ethoxylates or hydrocarbon tails can also be used. Examples of positively charged monomers that can be used to produce cationic latex include, but are not limited to, those that already have a positive charge that cannot be neutralized at pH values above about 10. Alternatively, there may be mentioned positively charged monomers that can be neutralized at pH values above about 10. Examples of the former monomer type include, but are not limited to, monomers containing quaternary ammonium groups, such as trimethylaminopropylmethacrylamide bromide, or other onium species such as trialkylsulfonium or tetraalkylphosphonium structures Is mentioned. Examples of the latter monomer type include, but are not limited to, protonated tertiary amine-containing monomers such as dimethylaminomethacrylamide that becomes cationic upon protonation of the amine nitrogen when polymerized in acidic media. . Examples of commercially available cationic latexes include, but are not limited to, ROADCHEM 600 or UP-65K, which are cationic styrene-butadiene latexes sold by VSS Asphalt Technologies and Ultrapave, respectively.

  Methods for preparing cationic latex are known to those skilled in the art. For example, a cationic latex can be prepared by conventional emulsion polymerization using an azo-based initiator such as 2,2′-azobis (isobutylamidine hydrochloride). Alternatively, the cationic latex can be made by copolymerization of a cationic or amine-containing comonomer with the latex. Methods for preparing cationic latex are disclosed in US Pat. Nos. 4,791,161; 4,560,736; 3,108,979; and 3,399,159, each of which is incorporated herein by reference in its entirety.

  In one embodiment, the sealant composition can further comprise any cementitious material other than Portland cement. In one embodiment, the sealant composition can further comprise a cementitious material wherein the pH of the resulting sealant composition when mixed in water is about 3 to about 10. Examples of suitable cementitious materials include, but are not limited to, high alumina cement, magnesia cement, gypsum cement, gypsum plaster, zinc oxychloride cement, aluminum oxychloride cement, zinc phosphate cement, silicic acid phosphate cement or these The combination of these is mentioned.

  In one embodiment, the hydraulic cement comprises a high alumina cement, a gypsum cement, a magnesia based cement, or a combination thereof. Alternatively, the sealant composition includes a high alumina cement. It contains calcium, aluminum and oxygen, which condenses and hardens by reaction with water. As used herein, high alumina cement refers to a cement comprising from about 35% to about 80% by weight calcium aluminate. Such cements can further contain small amounts of iron oxide and silica. Examples of suitable high alumina cementitious materials include, but are not limited to, SECAR 60, SECAR 51 and SECAR 71, which are high alumina hydraulic cements commercially available from Lafarge Aluminates, Cheasapeake, VA, and Halliburton. THERMALOCK cement, a high alumina cement commercially available from Energy Services. Cationic latex is not very effective when used in combination with Portland cement (eg, Class A, C, G and H cements). Therefore, the cementitious material preferably excludes such Portland cement.

  In one embodiment, the hydraulic cement includes magnesia-based cement, also known as sorrel cement. Sorrel cement is based on magnesia (magnesium oxide) and soluble salts such as soluble chlorides, sulfates or phosphates. Suitable salts include magnesium salts such as magnesium chloride or magnesium sulfate, or soluble phosphates such as primary or dibasic ammonium phosphate. Examples of magnesium oxide suitable for the manufacture of sorrel cement compositions include, but are not limited to, OXYMAG magnesia-based cement products that are finely ground magnesium oxide powder, and AQUAMAG water that is an aqueous magnesium hydroxide suspension. A magnesium oxide is mentioned. Both are commercially available from Premier Chemicals LLC, King of Prussia, PA (Pennsylvania). Soluble magnesium salts such as magnesium chloride and magnesium sulfate and soluble phosphates such as ammonium phosphate are widely available commercially. The discussion of various magnesia cements can be found in "Lea's Chemistry of Cement and Concrete" by Peter Hewlett: Fourth Edition, pages 813-820: 2003: Elsevier Publishing Can do.

  In some embodiments, a sealant composition comprising a cationic latex contains a sufficient amount of water to form a cementitious slurry that can be poured. The water may be fresh water or salt water. For example, it may be an unsaturated salt solution or a saturated salt solution such as brine or seawater. The water can be present in an amount of about 20 to about 180 weight percent of the cement, or about 28 to about 60 weight percent of the cement. The cement composition can have a density of about 4 pounds / gallon to about 23 pounds / gallon. In an alternative embodiment, the cement composition can have a density of about 12 pounds / gallon to about 17 pounds / gallon. In other alternative embodiments, the cement composition may be a low density cement composition having a density of about 6 pounds / gallon to about 14 pounds / gallon.

  In one embodiment, the sealant composition comprising a cationic latex further comprises hydraulic cement and a non-aqueous carrier fluid. This non-aqueous carrier fluid can thicken or solidify when mixed with an aqueous fluid in a well zone where fluid (eg, drilling fluid) is lost. In such embodiments, the sealant composition including the cationic latex includes a sufficient amount of non-aqueous fluid to form an injectable slurry. Such non-aqueous fluids are well known to those skilled in the art and include, but are not limited to, diesel oil, linear α-olefin, mineral oil, ester, or combinations thereof. Such sealant compositions containing non-aqueous fluids may require suspending aids, such as organophilic clays, to prevent sedimentation of cement particulate matter. The amount of non-aqueous solvent included in the composition may depend on the specific gravity of the non-aqueous fluid and the desired slurry density. Methods for determining the amount of non-aqueous fluid required to prepare a sealant composition comprising a cationic latex are known to those skilled in the art.

Sealant compositions comprising a cationic latex can further include monovalent (eg, Na ⁺ ), divalent (eg, Ca ²⁺ , Mg ²⁺ ), and trivalent cation salts. In such embodiments, the composition can be saturated with the disclosed salt to ensure that the composition does not wash away or dissolve the salt zone in the underground. Alternatively, the sealant composition itself may require the use of a salt, as in the case of, for example, magnesium oxide-based sorrel cement. Cationic latex has a relatively high resistance to salt. Thus, the latex is stable in the presence of salts contained in sealant compositions including cationic latexes, and is stable in the presence of salts that may be encountered in wells. Will. Thus, there is no need to introduce additional stabilizing surfactants (eg, ethoxylated nonylphenol surfactants) into the composition. In one embodiment, the salt encountered in the well does not raise the pH of the composition. If required, the stabilizing surfactant can be used in a sealant composition comprising a cationic latex and can be distinguished from an ethylenically unsaturated surfactant incorporated into the latex polymer backbone. I want you to understand.

In one embodiment, the sealant composition comprising the cationic latex further comprises a surfactant. The surfactant can be any surfactant that stabilizes a sealant composition comprising a cationic latex. In some embodiments, the surfactant is anionic, cationic, or neutral. Alternatively, the surfactant can be a zwitterion (ie, including anionic and cationic charges). This is commonly called betaine. Zwitterionic surfactants containing sulfonate groups are called sultaines. In one embodiment, the surfactant is a betaine, such as co mosquitoes cocamidopropyl betaine. Alternatively, the surfactant is a sultaines such as co mosquitoes cocamidopropyl hydroxy sultaine. Examples of suitable surfactants include, but are not limited to, the zwitterionic surfactant HC-2 surface active suspending agent commercially available from Halliburton Energy Services, and Witco Corporation, Dublin, Ohio. ) REWOTERIC AM HC, a sultain commercially available from the state.

  Sealant compositions containing a cationic latex can further contain additives to improve or change its properties. Examples of suitable additives include fluid absorbent materials, hollow glass or ceramic beads, hematite, materials that increase density such as manganese oxide or barium sulfate, particulate materials, organophilic clays, superabsorbents for aqueous fluids, Examples include thickeners, suspension aids, dispersants, setting retarders, fluid loss agents, mechanical property modifiers such as fibers and elastomers, or combinations thereof.

The sealant composition comprising the cationic latex can be used for any purpose. In one embodiment, a sealant composition comprising a cationic latex is used to service a well that penetrates an underground formation. It should be understood that “underground” includes both areas below the exposed ground and areas below the ground covered by water, such as ocean or fresh water. Well maintenance includes, but is not limited to, placing a sealant composition containing cationic latex in the well for the following purposes: separating the underground layer from a portion of the well; Supporting the conduit in; sealing the void or crack in the conduit; blocking the void or crack in the cement sheath located in the annulus of the well; blocking the drilling; opening between the cement sheath and the conduit To prevent loss of aqueous or non-aqueous drilling fluid into a mud zone such as voids, vugular zones or fissures; plug wells for abandonment purposes; process fluid path Temporary plugs that change; as chemical packers used as a fluid prior to cement slurry during cementing operations; and seal the annulus between wells and extendable pipes or pipe strings A. For example, a sealant composition containing a cationic latex can thicken in the mud zone and thereby restore circulation. The thickened mixture is flexible, elastic and can condense into a tough material. This material can prevent further fluid loss if circulation is resumed. Sealant compositions comprising a cationic latex can withstand substantial pressure, such as the hydrostatic pressure of a drilling fluid or cement slurry, without being displaced or extruded. In one embodiment, the sealant composition comprising the cationic latex sets into a hard mass having a compressive strength of about 250 psi to about 15000 psi. As used herein, compressive strength is defined as the ability of a material to withstand an axially directed pushing force. The maximum strength of the material with respect to the axial force, the American Petroleum Institute (API) standard 10A, 23 edition, April 2002 (American Petroleum Institute (API) Specification 10A, 23 rd Edition, April 2002) is determined in accordance with. Beyond the limit of compressive strength, the material is irreversibly deformed and no longer provides structural support and / or zone separation.

  A sealant composition comprising a cationic latex can form a sealant composition and can provide a relatively sticky mass within the mud zone. The sealant composition containing the cationic latex can further form a non-flowing complete mass within the mud zone. This mass fills the zone and prevents the loss of subsequently injected drilling fluid. This allows further excavation. It should be understood that it may be desirable to promote the thickening reaction to quickly fill the voids. In another embodiment, it may be desirable to extend or retard thickening to penetrate deeper into the voids. The active polymer content of the latex emulsion can range from about 0.2% to about 30% by weight of the cement composition. Alternatively, it can be about 3% to about 15% by weight of the cement composition.

  In one embodiment, the sealant composition comprising the cationic latex is entered into the well as a single stream and is activated in downhole conditions to form a barrier that substantially seals the mud zone. In another embodiment, a sealant composition comprising a cationic latex can be placed downhole as a combination of two streams. In such processes, the sealant-based components can be injected as an aqueous or non-aqueous fluid or a combination thereof. In one embodiment, the cationic latex is in an aqueous stream. The cementitious material can be introduced into the well as a non-aqueous fluid and mixed with an aqueous fluid containing a cationic latex. Thus, for example, if the cementitious material comprises a single cementitious material such as gypsum or high aluminate cement (e.g. calcium aluminate), such material is suspended in a non-aqueous fluid and the drill tube or casing is It can be injected downward and the annulus can be brought into contact with an aqueous stream comprising a cationic latex injected downward. Alternatively, a non-aqueous stream containing cementitious material can be injected down the annulus and an aqueous stream containing latex can be injected down the drill tube or casing. On the other hand, if two components are required to set the cementitious material, for example in the case of sorrel cement, a non-aqueous suspension of one component, for example magnesium oxide, down the drilling pipe or annulus It can be injected as a liquid. An aqueous stream comprising a cationic latex and a second component of the cementitious composition, such as magnesium chloride, magnesium sulfate, or a soluble salt such as primary or secondary ammonium phosphate, is used to circulate an annulus or drilling pipe or casing. It can be injected downward. In one embodiment, a sealant composition comprising a magnesia-based cement and a latex that has become cationic because it was prepared at an acidic pH is prepared using a two-stream process. In this method, the cement as a non-aqueous suspension is contacted with a second aqueous cationic latex stream that is mixed downhole.

Methods for introducing compositions into wells to seal underground zones are described in US Pat. Nos. 5,913,364; 6,167,967; and 6,258,757. Each of which is incorporated herein by reference in its entirety.
In one embodiment, a sealant composition comprising a cationic latex can be used in well finishing operations such as first and second cementing operations. The composition can be placed in an annulus of the well and set to separate the underground from different parts of the well. In this way, the sealant composition comprising the cationic latex forms a barrier that prevents fluid in the underground layer from moving to other underground layers. Within the annulus, the fluid further serves to support a well conduit, such as a casing.

  In one embodiment, the well in which the sealant composition comprising the cationic latex is disposed belongs to a multiple well form. It should be understood that a multi-well configuration includes at least two primary wells connected by one or more auxiliary wells. In a second cementing, often referred to as squeeze cementing, the well sealant composition containing the cationic latex can be strategically placed in the well for the following purposes: voids in the conduit or Blocking cracks, plugging voids or cracks in a hardened sealant (e.g. cement sheath) in the annulus, plugging a relatively small opening known as a microannulus between the hardened sealant and the conduit And so on. In this way, the composition serves as a sealant composition. Various approaches that can be employed to use sealant compositions in wells are described in US Pat. Nos. 5,346,012 and 5,588,488. These are incorporated herein by reference in their entirety.

  In other embodiments, the additive is also injected into the well with a sealant composition comprising a cationic latex. For example, fluid absorbent materials, particulate materials, organophilic clay, resins, aqueous superabsorbents, thickeners, suspending agents, dispersants, fluid loss agents, mechanical property modifiers such as fibers and elastomers, Alternatively, a combination of these can be injected into the stream with the disclosed composition.

  In one embodiment, a sealant composition comprising a high alumina cement and a cationic latex has superior fluid loss control of the cement slurry when compared to the same composition except that it does not contain a cationic latex, and leaching. Reduced. In another embodiment, a sealant composition comprising magnesia-based cement and cationic latex has increased structural integrity when compared to the same composition except that it does not contain a cationic latex.

  Although the invention has been described universally, the following examples are given as specific embodiments of the invention and are intended to demonstrate their implementation and advantages. It should be understood that these examples are given for illustrative purposes and are not intended to limit the scope of the claims in any way.

(Example 1)
The mechanical properties and leaching of high aluminate cement slurries with the addition of the cationic styrene-butadiene latex JG-6082 obtained from Dow Reichhold Corporation were compared with those of the high aluminate cement slurries without this. A cement slurry was prepared containing DRM-AIR 3000L with THERMALOCK cement, 39% water, 0.4% citric acid, and 0.01 gal / sk added. D-AIR 3000L antifoaming agent is an antifoaming agent, and THERMALOCK cement is a high alumina cement. Both are commercially available from Halliburton Energy Services. The slurry had a final density of 15ppg. All percentages shown are relative to the weight of the cement. Two additional slurries containing 0.5 gal / sk or 1.0 gal / sk cationic latex (indicated), 0.06 gal / sk HC-2, 34% water, and 0.05 gal / sk DAIR 3000L antifoam. Prepared. HC-2 surfactant suspending agent is a zwitterionic surfactant commercially available from Halliburton Energy Services. The slurry containing the cationic latex had a final density of 14.9ppg. All slurries were cured for 72 hours at about 87.8 ° C. (190 ° F.) under a pressure of 3000 psi. Mechanical properties, i.e., Young's modulus and Poisson's ratio, are measured in accordance with ASTM D 3148-02 (Standard Test Method for Elastic Moduli of Intact Rock Core Specimens in Uniaxial Compression). ). On the other hand, latex leachability was determined by placing the set cement in water at about 26.7 ° C (80 ° F) for 18 hours and observing whether the water was cloudy (indicating latex leaching into the solution). Asked. Compressive strength, the American Petroleum Institute (API) standard 10A, 23 edition, April 2002 (American Petroleum Institute (API) Specification 10A, 23 rd Edition, April 2002) was measured as described in. Tensile strength was measured with dogbone briquettes according to the method described in Test CRD-C260-01 in the US Army Corps of Engineers' Handbook for Concrete and Cement. The results of these experiments are shown in Table 1. These results demonstrate that the leachability of slurry formulations containing cationic latex has been reduced.

(Example 2)
Different latexes were compared for their ability to improve permeability, leachability, material strength and fluid loss. The basic slurry formulation is shown in Table 2.

これらの結果は、カチオン性ラテックスの添加が流体ロスを改善し、浸透性を下げ、機械的強さを改善し、水にさらされたときの凝結組成物の浸出性を低下させることを実証している。 Latex 2000 or cationic latex was added to the base slurry formulation. Latex 2000 cement additive is a conventional anionic styrene-butadiene latex commercially available from Halliburton Energy Services. The cationic latex used in Examples 1-4 is a cationic styrene butadiene latex commercially available from Dow Reichhold Inc. as JG-6082. The slurry had a final density of 14.0 ppg and was cured at about 87.8 ° C. (190 ° F.) for 72 hours. The mechanical properties and leachability of the coagulated slurry were determined by the method described in Example 1, and are shown in Table 3. Fluid loss, the American Petroleum Institute (API) standard 10A, 23 edition, April 2002 (American Petroleum Institute (API) Specification 10A, 23 rd Edition, April 2002) was measured as described in. The permeability of cement was ^measured using a cement permeation meter according to the method described in the American Petroleum Institute (API) Specification 10A, 23rd Edition, April 2002. Measured using.

These results demonstrate that the addition of cationic latex improves fluid loss, lowers permeability, improves mechanical strength, and reduces the leachability of the coagulated composition when exposed to water. ing.

これらの結果は、カチオン性ラテックスの添加により、弾性が改善され脆さが低下した組成物が得られたことを実証している。 (Example 3)
Composition 2 of Example 2 was cured at about 121 ° C. (250 ° F.) for 10 days and the mechanical properties and permeability of the composition were determined. The results are shown in Table 4.

These results demonstrate that the addition of a cationic latex resulted in a composition with improved elasticity and reduced brittleness.

これらの結果は、前記ラテックスを添加しない以外は同一の組成物と比較した場合、カチオン性ラテックスを含むマグネシア系セメント組成物については、構造の完全性が失われるまでに大幅な遅れがあることを実証している。 (Example 4)
A cement composition having the following common slurry design was prepared: MgCl ₂ 690 g, MgO 690 g, H ₂ 0 300 g. The indicated amount of JG-6082 was added to the base slurry. JG-6082 is a cationic latex commercially available from Dow Reichhold Inc. as a 50% aqueous emulsion. Samples were poured into plastic containers with lids and cured in an oven at 60 ° C. (140 ° F.) for 72 hours. The cured sample was removed from the plastic container and kept in water. The time elapsed until a visible crack occurred in the solid sample was recorded. Table 5 shows the time when structural integrity was lost as revealed by the appearance of cracks.

These results show that there is a significant delay before the structural integrity is lost for magnesia-based cement compositions containing cationic latex when compared to the same composition except that the latex is not added. It has been demonstrated.

  While the preferred embodiment of the invention has been illustrated and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described herein are merely representative and are not limiting. Many changes and modifications may be made to the invention disclosed herein and are within the scope of the invention. Where a range or limit of numbers is specified, such specific range or limit may be a repetitive range or limit of a similar size within the specified range or limit (e.g., about 1 to about It should be understood that up to 10 includes 2, 3, 4, etc .; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). Use of the term “optionally” with respect to any element in a claim means that the element in question is required or not required. Both options are meant to be within the scope of the claims. The use of broader terms such as `` comprises '', `` includes '', `` having '', such as `` consisting of '', `` consisting essentially of '', `` comprised substantially of '', etc. It should be understood that it supports narrower terms.

  Accordingly, the scope of protection is not limited by the above description, but only by the appended claims. This scope includes all equivalents of the claimed subject matter. All claims are incorporated herein as embodiments of the invention. Accordingly, the claims are a further description and are an addition to the preferred embodiments of the present invention. The discussion of a reference herein, particularly any reference whose publication date may be after the priority date of the present application, is not an admission that it is prior art to the present invention. The disclosures of all patents, patent applications, and publications cited herein provide representative, procedural or other details that supplement those described herein. To the extent that this is done, it is incorporated herein by reference.

Claims (39)

  A well sealant composition comprising a cementitious material and a cationic latex comprising a latex-forming monomer and a cationic monomer, the composition having a pH of 3 to 10 and the cementitious material comprising: The well sealant composition comprising non-Portland cement.   2. The composition of claim 1, wherein the cationic latex comprises a latex-forming monomer and a cationic monomer.   3. The composition of claim 2, wherein the latex forming monomer is a vinyl aromatic monomer, ethylene, butadiene, vinyl nitrile, or a combination thereof.   2. The composition of claim 1, wherein the cementitious material comprises alumina cement, magnesia cement, gypsum cement, zinc oxychloride cement, aluminum oxychloride cement, zinc phosphate cement, silicic acid phosphate cement, or combinations thereof.   2. The composition of claim 1, wherein the cementitious material comprises gypsum cement.   The composition of claim 1, wherein the sealant composition comprises an alumina cement having 35 wt% to 80 wt% calcium aluminate.   The composition of claim 1, wherein the sealant composition comprises magnesia-based cement further comprising magnesium oxide and a salt.   8. The composition of claim 7, wherein the salt is magnesium chloride, magnesium sulfate, ammonium soluble phosphate, alkali metal soluble phosphate, or a combination thereof.   The composition of claim 1, wherein the cationic latex has an active polymer content in an amount from 0.2% to 30% by weight of the cement composition.   2. The composition of claim 1, wherein the latex forming monomer is styrene, butadiene, or a combination thereof.   2. The composition of claim 1, wherein the cationic monomer comprises a quaternary ammonium group, an onium species, a sulfonium group, a phosphonium group, a tertiary amine, or a combination thereof.   2. The composition of claim 1, wherein the cationic latex comprises trimethylaminopropyl methacrylamide, a trialkylsulfonium compound, a tetraalkylphosphonium compound, or a combination thereof.   2. The composition of claim 1, wherein the sealant composition further comprises a salt of a monovalent cation, a salt of a divalent cation, a salt of a trivalent cation, or a combination thereof.   2. The composition of claim 1, wherein the sealant composition further comprises an anionic, cationic, neutral, or zwitterionic surfactant or a combination thereof.   2. The composition of claim 1, wherein the sealant composition further comprises a zwitterionic surfactant having a sulfonate group.   16. The composition of claim 15, wherein the zwitterionic surfactant comprises cocamidopropyl betaine, cocamidopropyl hydroxysultain, or a combination thereof.   2. The composition of claim 1, wherein the cementitious material comprises alumina cement and the cationic latex comprises a styrene-butadiene copolymer.   18. The composition of claim 17, further comprising a zwitterionic surfactant.   2. The composition according to claim 1, wherein the cementitious material includes magnesia-based cement, and the cationic latex includes a styrene-butadiene copolymer.   20. The composition of claim 19, wherein the magnesia-based cement includes magnesium oxide and magnesium chloride.   A method of providing a well in contact with an underground layer, comprising placing a sealant composition comprising a cementitious material and a cationic latex in the well, the cementitious material comprising non-Portland cement, The cationic latex includes a latex-forming monomer and a cationic monomer, and the cationic monomer is selected from the group consisting of a quaternary ammonium group, an onium group, a sulfonium group, a phosphonium group, a protonated tertiary amine, or a combination thereof. The method of claim 1, wherein the sealant composition has a pH of 3-10.   24. The method of claim 21, wherein the latex forming monomer is a vinyl aromatic monomer, ethylene, butadiene, vinyl nitrile, or a combination thereof.   24. The method of claim 21, wherein the cementitious material comprises alumina cement, magnesia based cement, gypsum cement, zinc oxychloride cement, aluminum oxychloride cement, zinc phosphate cement, silicic acid phosphate cement, or combinations thereof.   24. The method of claim 21, wherein the cementitious material comprises gypsum cement.   23. The method of claim 21, wherein the sealant composition comprises an alumina cement having 35 wt% to 80 wt% calcium aluminate.   24. The method of claim 21, wherein the sealant composition comprises a magnesia based cement further comprising magnesium oxide and a salt.   27. The method of claim 26, wherein the salt is magnesium chloride, magnesium sulfate, ammonium soluble phosphate, alkali metal soluble phosphate, or a combination thereof.   24. The method of claim 21, wherein the cationic latex has an active polymer content in an amount from 0.2% to 30% by weight of the cement composition.   The method of claim 21, wherein the latex-forming monomer is styrene, butadiene, or a combination thereof.   24. The method of claim 21, wherein the cationic monomer comprises a quaternary ammonium group, an onium group, a sulfonium group, a phosphonium group, a protonated tertiary amine, or a combination thereof.   24. The method of claim 21, wherein the cationic monomer comprises trimethylaminopropyl methacrylamide, a trialkylsulfonium compound, a tetraalkylphosphonium compound, or a combination thereof.   24. The method of claim 21, wherein the sealant composition further comprises a salt of a monovalent cation, a salt of a divalent cation, a salt of a trivalent cation, or a combination thereof.   24. The method of claim 21, wherein the sealant composition further comprises an anionic, cationic, neutral, or zwitterionic surfactant or a combination thereof.   24. The method of claim 21, wherein the sealant composition further comprises a zwitterionic surfactant having a sulfonate group or a carboxylate group.   35. The method of claim 34, wherein the zwitterionic surfactant comprises cocamidopropyl betaine, cocamidopropyl hydroxysultain, or a combination thereof.   24. The method of claim 21, wherein the maintenance of the well comprises disposing the sealant composition in the well for the following purposes: separating the underground layer from a portion of the well; Supporting a conduit in a well; closing a void or crack in the conduit; closing a void or crack in a cement sheath disposed in an annulus of the well; blocking a borehole; sealing the cement sheath and the Blocking the opening between the conduit; Preventing loss of aqueous or non-aqueous drilling fluid into the mud zone, such as voids, purse zones or fissures; Blocking wells for abandoned mine; Processing fluid Acting as a temporary plug that changes the course of the soil; Acting as a chemical packer; Acting as a spacer fluid before cement slurry in cementing operations; Wells and extendable pie Sealing the annulus between the pipe or pipe string; or a combination thereof.   24. The method of claim 21, wherein the well maintenance includes adaptive control or sludge treatment.   23. The method of claim 21, wherein the maintenance of the well includes a drill ahead process following a mud treatment.   24. The method of claim 21, wherein the sealant composition is disposed in a well using a two-stream process, wherein the aqueous stream comprises at least one component of the sealant composition, and the non-aqueous stream is The method comprising at least one other component of the sealant composition, wherein the two streams are contacted downhole to form the sealant composition in the well in situ.