阅读说明：本技术 用于捕获反应物的胶囊设计 (Capsule design for capturing reactants ) 是由 伊丽莎白·Q·孔特雷拉斯 于 2018-12-21 设计创作，主要内容包括：一种使用气体控制添加剂在井眼中提供气体迁移控制的方法,该方法包括以下步骤：将气体控制添加剂与水泥混合以形成水泥浆料,其中气体控制添加剂包括半透膜和洗涤剂,使得半透膜形成围绕芯部的壳,使得洗涤剂在芯部中；将水泥浆料引入井眼中；以及使洗涤剂与抗性气体反应以产生辅助副产物,其中抗性气体从含烃地层迁移至井眼中,并渗透通过半透膜到达气体控制添加剂的芯部。(A method of providing gas migration control in a wellbore using a gas control additive, the method comprising the steps of: mixing a gas control additive with the cement to form a cement slurry, wherein the gas control additive comprises a semi-permeable membrane and a detergent, such that the semi-permeable membrane forms a shell around a core, such that the detergent is in the core; introducing a cementitious slurry into the wellbore; and reacting the detergent with a resistant gas to produce a secondary byproduct, wherein the resistant gas migrates from the hydrocarbon containing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.)

1. A method of providing gas migration control in a wellbore using a gas control additive, the method comprising the steps of:

mixing the gas control additive with cement to form a cement slurry, wherein the gas control additive comprises a semi-permeable membrane and a detergent such that the semi-permeable membrane forms a shell around a core such that the detergent is in the core;

introducing the cementitious slurry into the wellbore; and

reacting the detergent with a resistant gas to produce a secondary byproduct, wherein the resistant gas migrates from the hydrocarbon containing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

2. The method of claim 1, further comprising the steps of:

the cement slurry is allowed to set to form hardened cement.

3. The method of claim 1 or 2, wherein the semi-permeable membrane comprises a polymer selected from the group consisting of: polyamides, aromatic amides, polyesters, polyurethanes, polyureas, and combinations thereof.

4. The method of any one of claims 1 to 3, wherein the semi-permeable membrane attracts the resistant gas.

5. The method of any one of claims 1 to 4, wherein the detergent is selected from the group consisting of: liquid detergents, solid detergents, adsorbents, and combinations thereof.

6. The method of any one of claims 1 to 5, wherein the detergent is iron (III) oxide.

7. The method of any one of claims 1 to 5, wherein the detergent is calcium hydroxide.

8. The method of any one of claims 1 to 7, wherein the gas control additive is present in the cementitious slurry at a concentration of less than about 3% by weight of the cementitious slurry.

9. The method of any one of claims 1 to 8, wherein the resistant gas is selected from the group consisting of: hydrogen sulfide, mercaptans, carbon dioxide, natural gas, and combinations thereof.

10. The method of any one of claims 1 to 9, wherein the auxiliary byproduct is water.

11. The method of any one of claims 1 to 9, wherein the auxiliary byproduct is calcium carbonate.

12. The method of any one of claims 1 to 11, wherein the auxiliary byproduct permeates through the semi-permeable membrane from the core.

13. The process of any one of claims 1 to 12, wherein in the reacting step, a solid product is produced, wherein the semi-permeable membrane prevents the solid product from permeating through the semi-permeable membrane from the core of the gas control additive.

14. The method of claim 13, wherein the solid product forms a physical barrier in the micro-annulus to prevent migration of the resistant gas.

15. A method of providing gas migration control in a wellbore using a gas control additive, the method comprising the steps of:

mixing the gas control additive with cement to form a cement slurry, wherein the gas control additive is formed by:

mixing a first solvent, a first monomer, and a surfactant to produce a continuous phase;

mixing a second solvent, a second monomer, and a detergent to produce a dispersed phase;

mixing the continuous phase and the dispersed phase to form a mixture having an emulsion such that the dispersed phase is dispersed as droplets in the continuous phase, wherein an interface defines the droplets of the dispersed phase dispersed in the continuous phase;

forming a polymer at the interface of the droplets such that the polymer forms a semi-permeable membrane surrounding a core, wherein the core comprises a dispersed phase such that the semi-permeable membrane surrounding the core forms the gas control additive; and

allowing the gas control additive to settle from the mixture; and

separating the gas control additive from the mixture using a separation process;

introducing the cementitious slurry into the wellbore; and

reacting the detergent with a resistant gas to produce a secondary byproduct, wherein the resistant gas migrates from the hydrocarbon containing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

16. The method of claim 15, further comprising the steps of:

the cement slurry is allowed to set to form hardened cement.

17. The method of claim 15 or 16, wherein the dispersed phase comprises a buffer.

18. The method of any one of claims 15-17, wherein the buffer comprises phosphate.

19. The method of any one of claims 15 to 18, wherein the first solvent is selected from the group consisting of: oil, mineral oil, cyclohexane, chloroform, and combinations thereof.

20. The method of any one of claims 15-19, wherein the first monomer comprises a trifunctional acid chloride.

21. The method of claim 20, wherein the first monomer is selected from the group consisting of: 1,3, 5-benzenetricarboxylic acid chloride, sebacoyl chloride, and combinations thereof.

22. The method of any one of claims 15 to 21, wherein the surfactant is selected from the group consisting of: sorbitan esters, polysorbates, and combinations thereof.

23. The method of any one of claims 15 to 22, wherein the second solvent is selected from the group consisting of: water, ethanol, methanol, and combinations thereof.

24. The method of any one of claims 15-23, wherein the second monomer comprises an amine group.

25. The method of claim 24, wherein the second monomer is selected from the group consisting of: ethylenediamine, m-phenylenediamine, p-phenylenediamine, hexamethylenediamine, 4' -methylenedianiline, and combinations thereof.

26. The method of any one of claims 15 to 25, wherein the detergent is selected from the group consisting of: iron (III) oxide, calcium hydroxide, and combinations thereof.

27. The method of any one of claims 15 to 26, wherein the resistant gas is selected from the group consisting of: hydrogen sulfide, mercaptans, carbon dioxide, natural gas, and combinations thereof.

28. The method of any one of claims 15 to 27, wherein the ancillary byproducts are selected from the group consisting of: water, calcium carbonate, calcium bicarbonate, and combinations thereof.

29. The method of any of claims 15 to 28, wherein the detergent is tethered in the core via site isolation by using a chelating agent selected from the group consisting of: polyethylene glycol, polystyrene, polyethyleneimine, polyvinyl alcohol, ethylene diamine tetraacetic acid, hydroxyethylethylene diamine triacetic acid, nitrilotriacetic acid, diethylene triamine pentaacetic acid, and combinations thereof.

30. A gas control additive for providing gas migration control in a wellbore, the gas control additive comprising:

a semi-permeable membrane comprising a polymer, the semi-permeable membrane forming a shell having a core such that the core comprises a detergent, the semi-permeable membrane being capable of allowing permeation of a resistant gas through the membrane into the core; and

the detergent being capable of reacting with the resistant gas permeating into the core to produce a secondary by-product,

wherein the polymer comprises a difunctional amino group-containing subunit derived from a first monomer and a trifunctional acid chloride-containing subunit derived from a second monomer.

31. The gas control additive of claim 30, further comprising:

a chelating agent that is water soluble and capable of binding the detergent in the core via site segregation and increasing the solubility of the detergent.

32. The gas control additive of claim 31 wherein the chelating agent is selected from the group consisting of: polyethylene glycol, polystyrene, polyethyleneimine, polyvinyl alcohol, ethylene diamine tetraacetic acid, hydroxyethylethylene diamine triacetic acid, nitrilotriacetic acid, diethylene triamine pentaacetic acid, and combinations thereof.

33. The gas control additive of any one of claims 30-32 wherein the detergent is selected from the group consisting of: iron (III) oxide, calcium hydroxide, and combinations thereof.

34. The gas control additive of any one of claims 30-33, wherein the first monomer is selected from the group consisting of: ethylenediamine, m-phenylenediamine, p-phenylenediamine, hexamethylenediamine, 4' -methylenedianiline, and combinations thereof.

35. The gas control additive of any one of claims 30-34, wherein the second monomer is selected from the group consisting of: 1,3, 5-benzenetricarboxylic acid chloride, sebacoyl chloride, and combinations thereof.

36. The gas control additive of any one of claims 30-35, wherein the resistant gas is selected from the group consisting of: hydrogen sulfide, mercaptans, carbon dioxide, natural gas, and combinations thereof.

37. The gas control additive of any one of claims 30-36 wherein the auxiliary byproduct is selected from the group consisting of: water, calcium carbonate, calcium bicarbonate, and combinations thereof.

Technical Field

Compositions and methods for use with cement are disclosed. In particular, compositions and methods for controlling a downhole environment during a cementing operation are disclosed.

Background

In many wellbores, cement may be used to form a layer between the casing and the formation. Gas channeling occurs when the hydrostatic pressure of the cement slurry is reduced as the cement slurry sets. If the pressure of the gas in the formation is greater than the hydrostatic pressure of the cement slurry, the gas in the formation will migrate from the formation through the slurry. As a result, permanent channels are formed in the cement. Due to these channels, communication with the surface may occur and interlayer isolation may be lost. Migration of gas from the formation through the cement increases the pressure behind the casing. The migration of gases can reduce the integrity of the cement sheath. The reduction in the integrity of the cement sheath can lead to long term gas breakthrough and sustained annular pressure. Pressure build-up between the casing string and the casing, known as the casing-casing annulus (CCA), can cause micro-annuli in the cement. As used herein, "micro-annulus" refers to a small gap that can be formed between a casing or liner and the surrounding cement sheath. The build up of annular pressure during the productive life of the well can threaten well production and well safety. The buildup of pressure can result in a dangerous blowout or a controlled pressure release of a few pounds per square inch at the wellhead that is less severe.

Early detection of CCA problems may reduce the risk of high severity blowouts and may avoid production losses. Remedial solutions to CCA problems (such as job changes and mechanical bleed units) may reduce CCA problems. Other methods aim to make the cement sheath resistant to the influx of formation gases. One method includes the addition of a film-forming latex additive to render the cement slurry resistant to the influx of formation gases. One problem with the use of latex additives is that the latex does not prevent the cement sheath from failing at temperatures above 82 ℃ or above 100 ℃.

Disclosure of Invention

Compositions and methods for cementitious slurries are disclosed. In particular, compositions and methods for controlling a downhole environment during a cementing operation are disclosed.

In a first aspect, a method of providing gas migration control in a wellbore using a gas control additive is provided. The method includes the step of mixing a gas control additive with cement to form a cement slurry. The gas control additive includes a semi-permeable membrane and a detergent. The semi-permeable membrane forms a shell around the core so that the detergent is in the core. The method includes the step of introducing a cementitious slurry into the wellbore. The method includes the step of reacting the detergent with a resistant gas to produce an auxiliary byproduct. The resistant gas migrates from the hydrocarbon containing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

In certain aspects, the method further comprises the step of setting the cement slurry to form a hardened cement. In certain aspects, the semipermeable membrane comprises a polymer, which may include polyamides, aromatic amides, polyesters, polyurethanes, and polyureas. In certain aspects, the semi-permeable membrane attracts a resistant gas. In certain aspects, the detergents may include liquid detergents, solid detergents, and adsorbents. In certain aspects, the detergent is iron (III) oxide. In certain aspects, the detergent is calcium hydroxide. In certain aspects, the gas control additive is present in the cementitious slurry at a concentration of less than about 3% by weight of the cementitious slurry. In certain aspects, the resistant gas may include hydrogen sulfide, mercaptans, carbon dioxide, and natural gas. In certain aspects, the co-product is water. In certain aspects, the secondary byproduct is calcium carbonate. In certain aspects, the secondary byproduct permeates from the core through the semi-permeable membrane. In certain aspects, in the reacting step, a solid product is produced. The semi-permeable membrane prevents the solid product from permeating through the semi-permeable membrane from the core of the gas control additive. In certain aspects, the solid product forms a physical barrier in the micro-annulus to prevent migration of the resistant gas.

In a second aspect, a method of providing gas migration control in a wellbore using a gas control additive is provided. The method includes the step of mixing a gas control additive with cement to form a cement slurry. Forming a gas control additive by: the first solvent, the first monomer, and the surfactant are mixed to produce a continuous phase. Forming a gas control additive by: mixing the second solvent, the second monomer, and the detergent to produce the dispersed phase. Forming a gas control additive by: the continuous phase and the dispersed phase are mixed to form a mixture having an emulsion such that the dispersed phase is dispersed as droplets in the continuous phase. The interface defines droplets of a dispersed phase dispersed in a continuous phase. Forming a gas control additive by: the polymer is formed at the interface of the droplets so that the polymer forms a semi-permeable membrane surrounding the core. The core includes a dispersed phase such that the semi-permeable membrane surrounding the core forms the gas control additive. Forming a gas control additive by: allowing the gas control additive to settle out of the mixture. Forming a gas control additive by: the gas control additive is separated from the mixture using a separation process. The method includes the step of introducing a cementitious slurry into the wellbore. The method includes the step of reacting the detergent with a resistant gas to produce an auxiliary byproduct. The resistant gas migrates from the hydrocarbon containing formation into the wellbore and permeates through the semi-permeable membrane to the core of the gas control additive.

In certain aspects, the method further comprises the step of setting the cement slurry to form a hardened cement. In certain aspects, the dispersed phase comprises a buffer. In certain aspects, the buffer comprises phosphate. In certain aspects, the first solvent may comprise oil, mineral oil, cyclohexane, and chloroform. In certain aspects, the first monomer comprises a trifunctional acid chloride. In certain aspects, the first monomer may include 1,3, 5-benzenetricarboxylic acid chloride and sebacoyl chloride. In certain aspects, the surfactant may include sorbitan esters and polysorbates. In certain aspects, the second solvent may include water, ethanol, and methanol. In certain aspects, the second monomer comprises an amine group. In certain aspects, the second monomer can include ethylenediamine, m-phenylenediamine, p-phenylenediamine, hexamethylenediamine, and 4, 4' -Methylenedianiline (MDA). In certain aspects, the detergent may include iron (III) oxide and calcium hydroxide. In certain aspects, the resistant gas may include hydrogen sulfide, mercaptans, carbon dioxide, and natural gas. In certain aspects, the ancillary byproducts may include water, calcium carbonate, and calcium bicarbonate. In certain aspects, the detergent is tethered in the core via site isolation using chelating agents including polyethylene glycol, polystyrene, polyethyleneimine, polyvinyl alcohol, ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid (NTA), and diethylenetriaminepentaacetic acid (DTPA).

In a third aspect, a gas control additive for providing gas migration control in a wellbore is provided. The gas control additive comprises a semi-permeable membrane. The semipermeable membrane comprises a polymer. The semi-permeable membrane forms a shell having a core such that the core comprises the detergent. The semi-permeable membrane is capable of allowing the permeation of a resistant gas through the membrane into the core. The gas control additive comprises a detergent. The detergent is capable of reacting with the resistant gas permeating into the core to produce a secondary by-product. The polymer includes a difunctional amino group-containing subunit derived from a first monomer and a trifunctional acid chloride-containing subunit derived from a second monomer.

In certain aspects, the gas control additive further comprises a chelating agent. The chelant is water soluble and is capable of binding the detergent in the core via site segregation and increasing the solubility of the detergent. In certain aspects, the chelating agent can include polyethylene glycol, polystyrene, polyethyleneimine, polyvinyl alcohol, EDTA, HEDTA, NTA, and DTPA. In certain aspects, the detergent may include iron (III) oxide and calcium hydroxide. In certain aspects, the first monomer can include ethylenediamine, m-phenylenediamine, p-phenylenediamine, hexamethylenediamine, and MDA. In certain aspects, the second monomer may include 1,3, 5-benzenetricarboxylic acid chloride and sebacoyl chloride. In certain aspects, the resistant gas may include hydrogen sulfide, mercaptans, carbon dioxide, and natural gas. In certain aspects, the ancillary byproducts may include water, calcium carbonate, and calcium bicarbonate.

Drawings

These and other features, aspects, and advantages of the scope of the present disclosure will become better understood with regard to the following description, claims, and accompanying drawings. It is to be noted, however, that the appended drawings illustrate only several embodiments and are therefore not to be considered limiting of its scope, for the scope of the disclosure may admit to other equally effective embodiments.

Fig. 1 provides a photomicrograph image of the gas control additive, which is developed using a scanning electron microscope.

Fig. 2 provides a schematic representation of a gas migration control method using a detergent.

Fig. 3 provides a schematic representation of a gas migration control method using a gas scrubbing additive, wherein the scrubbing agent is iron (III) oxide.

Fig. 4 provides a schematic representation of a gas migration control method using a gas scrubbing additive, wherein the scrubbing agent is calcium hydroxide.

In the drawings, similar components or features, or both, may have similar reference numerals.

Detailed Description

While the scope of the compositions and methods will be described with several embodiments, it will be understood that one of ordinary skill in the relevant art will appreciate that many examples, variations, and modifications of the devices and methods described herein are within the scope and spirit of the embodiments.

Thus, the described embodiments are set forth without any loss of generality to, and without imposing limitations upon, such embodiments. Those skilled in the art will appreciate that the scope of the present disclosure includes all possible combinations and uses of the specific features described in the specification.

Compositions and methods relate to gas control additives that control gas migration through cement and pressure build-up in a wellbore. The gas control additive comprises a detergent encapsulated by a semi-permeable membrane. The gas control additive may be mixed with the cement slurry during the cementing operation such that the resistant gas encounters the gas control additive as the resistant gas migrates through the cement. The resistant gas permeates through the semi-permeable membrane and reacts with the detergent. The reaction between the detergent and the resistant gas does not degrade the semi-permeable membrane. The reaction between the detergent and the resistant gas may produce auxiliary by-products which are able to permeate the membrane and return to the cement. Byproducts from the reaction between the detergent and the resistant gas may remain in the semi-permeable membrane. Due to the semi-permeability of the semi-permeable membrane, passive permeation of the resistant gas into the core of the gas control additive may occur, which may subsequently render the resistant gas inactive.

Advantageously, the described compositions and methods can remove or convert a resistant gas to an auxiliary byproduct, wherein the auxiliary byproduct has reduced permeability and is less corrosive than the resistant gas. Advantageously, the semi-permeable membrane in the gas control additive composition and method can minimize leaching, chemical contamination, and can provide thermal shielding of the detergent. The gas control additive can withstand the high temperatures of the downhole environment and protect the detergent from the high temperatures. Advantageously, the gas control additive may provide an immediate solution for gas migration control. Advantageously, the gas control additive can mitigate cement degradation.

As used throughout, "gas control additive" refers to one or more particles of a particular combination of semipermeable membrane and detergent. Reference to a single gas control additive includes a plurality of particles. Reference to a plurality of gas control additives refers to different compositions of semi-permeable membranes or detergents.

As used throughout, "resistant gas" refers to one or more gases that may have a negative impact on the hardened cement, casing, or other aspects of the wellbore. The resistant gas may include acid gases such as hydrogen sulfide, mercaptans, carbon dioxide, natural gas, and combinations thereof.

As used throughout, "scavenger" or "gas scrubber" refers to a compound that can remove or deactivate a gas.

As used throughout, "auxiliary byproduct" refers to a byproduct from a reaction that neutralizes the resistant gas, which may have a positive effect on the cement in the wellbore. The ancillary byproducts may be present as solids, liquids, or gases. As an example, the auxiliary byproduct may be water present as water vapor or liquid water, where the water may positively affect the cement by providing hydration of the hardened cement. Other examples of ancillary byproducts may include compounds with bicarbonate or carbonate salts, including cyclic carbonates, and solid sulfur. As an example, the secondary by-product may be calcium carbonate. Calcium carbonate is a cementitious material that is capable of physically forming a barrier to gases, which is advantageous if the cementitious slurry is of the self-healing type.

As used throughout, "shell" refers to an outer shell that completely surrounds a core.

As used throughout, the term "semipermeable" refers to the ability of certain components to pass through. The ability of a component to pass through a semi-permeable membrane depends on the size and charge of the component.

As used throughout, "shear rate" refers to the mixing speed when forming the emulsion-based gas control additive.

As used throughout, "cementitious environment" refers generally to any stage of the cement process and includes cement slurries and hardened cement.

As used throughout, "immiscible" means that a homogeneous mixture is not formed when two or more solvents are added together. Immiscible solvents may form an emulsion. Non-limiting examples of immiscible solvents include oil and water, and cyclohexane and water.

As used throughout, "wellbore" refers to a hole drilled into a subterranean formation of the earth, where the subterranean formation may contain hydrocarbons. The wellbore may be at a depth and diameter from the earth's surface and may be embedded in the subterranean formation vertically, horizontally parallel to the surface, or at any angle between vertical and parallel.

As used throughout, "aromatic amide" refers to aromatic polyamides. Terms such as "aromatic amide", "polyaramid", "aromatic amide polymer" and "aromatic polyamide" are used interchangeably. Commercial examples of aromatic amides include(available from Wilmington, Del.))、(available from Teijin Araid USA, Inc, of Koniels, Georgia),(available from Teijin Aramid USA, Inc. of Koniels, Georgia) andpara-aromatic amides such as (available from Kolon Industries, Inc., Gwachon, Korea) and(available from Wilmington, Del.)) And(available from Teijinamidad USA, Inc, of Koniels, Georgia) or the like. Para-aromatic amides are aromatic amides in which the polymer chain is attached para to the acyl subunit or functional group. A meta-aromatic amide is one in which the polymer chains are linked through the meta position of the acyl subunit or functional group.

The gas control additive consists of a detergent encapsulated by a semi-permeable membrane. The specific gravity of the gas control additive may be between 1.0 and 1.5, or between 1.2 and 1.4. The gas control additive is capsule based.

The detergent may be any scavenger capable of reacting with the resistant gas to neutralize the resistant gas. The detergent may include a liquid detergent, a solid detergent, and an adsorbent. The detergent may comprise a commercially available gas detergent. The liquid detergent may include sodium hydroxide (NaOH), sodium carbonate (Na)₂CO₃) Hydrogen, hydrogenMagnesium oxide (Mg (OH)₂) Calcium hydroxide (Ca (OH)₂) And combinations thereof. Sodium hydroxide is also known as caustic soda. Sodium carbonate is also known as soda ash. Aqueous calcium hydroxide is also known as lime water. Solid detergents may include activated alumina, metals, metal oxides, alkali metal bases, dry adsorbents, titanium dioxide, and combinations thereof. The metals may include iron (Fe (II) or Fe (III)), lead (Pb (II)), copper (Cu (II)), mercury (Hg (II)), and arsenic (As (III)). The metal oxide may include zinc oxide (ZnO), iron oxide, and combinations thereof. The iron oxide may Include Iron (II) oxide (FeO), iron (III) oxide (Fe)₂O₃) Iron (II, III) oxide (Fe)₃O₄Or FeO. Fe₂O₃) And combinations thereof. Iron (II, III) oxide is also known as magnetite. Other metal compounds include lead acetate (e.g., Pb (CH)₃COO)₂、Pb(CH₃COO)₄And Pb₃(OH)₄(CH₃COO)₂) Zinc carbonate (e.g., ZnCO)₃And Zn₅(OH)₆(CO₃)₂) Copper carbonate (CuCO)₃) And combinations thereof. The alkali metal base may include sodium hydroxide and calcium hydroxide. The adsorbent may comprise any compound having a reaction mechanism that resists adsorption of a gas to the surface of the compound.

In at least one embodiment, iron (III) may be reacted with hydrogen sulfide to produce solid iron (III) sulfide (Fe)₂S₃). Iron (II) can be reacted with hydrogen sulfide to produce solid iron (II) sulfide (FeS). Magnetite can be reacted with hydrogen sulfide to produce iron (III) sulfide, iron (II) sulfide or iron (II) disulfide (FeS)₂). Zinc carbonate can react with hydrogen sulfide to produce solid zinc sulfide (ZnS). Copper carbonate can react with hydrogen sulfide to produce solid copper (II) sulfide (CuS). Calcium hydroxide can react with carbon dioxide to produce solid calcium carbonate (CaCO)₃)。

The semipermeable membrane may be a semipermeable polymer. The polymer may be formed by a polycondensation reaction. The polymer may be a crosslinked polymer. Examples of polymers that can form the semipermeable membrane include polyamides and aromatic amides. The polycondensation reaction can form other polymers suitable for use in semipermeable membranes, such as polyesters, polyurethanes, and polyureas. Without being bound by any theory, it is believed that the amine groups, polyamides and aromatic amides can attract resistant gases, such as hydrogen sulfide. Advantageously, the aromatic amide has high temperature resistance and impact strength. The semipermeable membrane forms a shell. The semi-permeable membrane may be resistant to temperatures up to 400 c. The semipermeable membrane may be designed such that the detergent cannot permeate through the semipermeable membrane. The semi-permeable membrane may act as a barrier so that the detergent cannot interact with other reactants in the cement slurry. The semi-permeable membrane maintains the integrity of the detergent and prevents degradation of the detergent in the presence of the cementitious slurry until needed. The semi-permeable membrane does not degrade. The semi-permeable membrane prevents the detergent from reacting with the cement hydrate. The semi-permeable membrane provides a controlled release rate of the secondary product. The degree of crosslinking of the aromatic amide polymer may determine the permeability of the semipermeable membrane. The release rate can be controlled by adjusting the permeability of the semipermeable membrane.

The gas control additive may be formed by interfacial polymerization. In the interfacial polymerization process, two immiscible fluids (e.g., a continuous phase and a dispersed phase) are blended together until the dispersed phase is dispersed as droplets in the continuous phase, thereby forming an emulsion. Each phase comprises a monomer and a polymer may be formed at the interface between the dispersed droplet and the continuous phase, thereby forming a shell around the droplets of the dispersed phase such that the dispersed phase is captured within the shell. The shell formed by interfacial polymerization is a semi-permeable membrane. Each phase may include a cross-linking agent as a monomer.

The continuous phase may include a solvent, monomers, and surfactants. The solvent for the continuous phase may be any solvent that is immiscible with water. Suitable non-polar solvents for use as the continuous solvent include oils, mineral oils, cyclohexane, chloroform, and combinations thereof. The monomer for the continuous phase may be any acid chloride monomer. The monomer for the continuous phase may be any monomer comprising a trifunctional acid chloride or a difunctional acid chloride. Examples of monomers for the continuous phase include 1,3, 5-benzenetricarboxylic acid chloride and sebacoyl chloride. The monomers used in the continuous phase may be used as crosslinking agents. The surfactant may include sorbitan esters, polyethoxylated sorbitan esters, and combinations thereof. More than one monomer for the continuous phase may be used to control the permeability of the semi-permeable membrane.

The dispersed phase may include solvent, monomer and detergent. Solvents for the dispersed phase may include water, ethanol, methanol, and combinations thereof. The monomer for the dispersed phase may be any water-soluble diamine. The monomer for the dispersed phase may be any monomer comprising a difunctional amino group. Examples of monomers for the dispersed phase include ethylenediamine, m-phenylenediamine, p-phenylenediamine, hexamethylenediamine, polyethyleneimine, MDA, and combinations thereof. More than one monomer for the dispersed phase may be used to control the permeability of the semi-permeable membrane. The detergent may be heterogeneous or solubilised. The detergent may be blended into the dispersed phase. In at least one embodiment, the detergent may be blended into the dispersed phase to form an emulsion. In at least one embodiment, a chelating agent may be added to the dispersed phase to improve the water solubility of the detergent. Examples of chelating agents include EDTA, HEDTA, NTA, DTPA and combinations thereof. Examples of chelating agents also include polyethylene glycol, polyvinyl alcohol, and combinations thereof. Chelating agents in the form of salts may be added to the dispersed phase, such as iron (III) ethylenediaminetetraacetate monosodium salt (Na [ Fe (III) EDTA)]). In at least one embodiment, a buffer may be added to the dispersed phase. The buffering agent may enhance the scrubbing ability of the gas control additive. Examples of buffers include phosphate buffers, such as trisodium phosphate (Na)₃PO₄). As will be appreciated by those skilled in the art, phosphoric acid is one having multiple acid dissociation constants (K)_a) The polybasic acid of (2). pK of phosphoric acid_aValues of 2.15, 6.86 and 12.32. Approximately three pKs can be prepared_aA phosphate buffer at the pH of any one of the values. When trisodium phosphate is used as buffer, the pH of the dispersed phase can be set to about 12.3.

The continuous phase solvent and the dispersed phase solvent may be selected such that the two fluids are immiscible with each other.

The monomers for the continuous phase and the monomers for the dispersed phase may be selected together in view of the properties of the polymer forming the semipermeable membrane. The monomers used for the continuous phase and the monomers used for the dispersed phase may be selected to produce polyamides, aromatic amides, polyesters, polyurethanes, polyureas, and combinations thereof. The amount of monomer added to the continuous phase can control the permeability of the semipermeable membrane.

The continuous and dispersed phases are blended together until the dispersed phase is dispersed as droplets in the continuous phase, thereby forming an emulsion. Depending on the volume of the phases, a water-in-oil (w/o) emulsion or an oil-in-water (o/w) emulsion may be formed. Thus, depending on the volume of each phase, the continuous phase may be the dispersed phase and, conversely, the dispersed phase may also be the continuous phase. The droplets may have different shapes including spherical, rod-shaped and fiber-shaped. The size of the droplets of the dispersed phase may be between 100 nanometers (nm) and 50 micrometers (μm), or between 100nm and 1 μm, or between 1 μm and 10 μm, or between 10 μm and 50 μm.

Referring to fig. 1, a photomicrograph image shows the polydispersity of the capsules of the gas control additive. Some evidence of film-forming behavior is also shown, which can also be used to mitigate gas channeling. Figure 1 includes capsules of gas control additives having an average diameter of about 142 nm. The micrograph images were developed using a Scanning Electron Microscope (SEM), including sputter coating the sample with palladium and gold, and imaging with a Zeiss cross beam 540 SEM (Carl Zeiss AG, germany, kohenn). The size and shape of droplets of the dispersed phase in the continuous phase can be controlled by shear rate, use of laminar flow, solvent in the dispersed phase, density of the solvent in the dispersed phase, blending rate of the solvent in the continuous phase and the solvent in the dispersed phase, and viscosity of the dispersed phase. In at least one embodiment, the fibers may be formed using laminar flow. The size of the droplets can be optimized to impart low rheological properties to the cement slurry.

A polymer is formed at the interface of the dispersed droplets and the continuous phase, thereby creating capsules of the gas control additive. Polymerization takes place at room temperature. The mixture is stirred to improve the homogeneity of the polymer. In at least one embodiment, the mixture may be stirred for a period of time from about 24 hours to about 72 hours. In at least one embodiment, the gas control additive may settle to the bottom of the reactor. In the next step, the gas control additive is separated from the remaining liquid. The separation method used to separate the gas control additive may be any method that is capable of separating the liquid and leaving the dry capsules as a free flowing powder. The separation method may include decantation, filtration, centrifugation, rotary evaporation, vacuum drying, oven drying, and combinations thereof. In at least one embodiment, the separation process leaves liquid at the core, thereby producing a liquid redox scrubbing gas control additive. In at least one embodiment, the separation process dries the gas control additive, thereby removing liquid from the core. In at least one embodiment, the dry capsules may be washed to remove any continuous phase residue and then dried.

In at least one embodiment, the continuous phase containing the solvent and the surfactant can be mixed with the dispersed phase containing the solvent and the monomer such that the dispersed phase is dispersed as droplets in the continuous phase, thereby forming an emulsion. The monomers for the continuous phase may then be added to the emulsion, causing polymer to form at the interface of the droplets due to the reaction of the monomers in the dispersed phase and the monomers in the continuous phase.

Other agents that may be added to the continuous and dispersed phases include emulsifiers. In at least one embodiment, the emulsifier added to the continuous phase is sorbitan trioleate. In at least one embodiment, the emulsifier added to the dispersed phase is a polyethoxylated sorbitan ester.

Gas control additives may be used to provide gas migration control. The gas control additive is mixed with the cement slurry at any time prior to introducing the cement slurry into the formation. In at least one embodiment, the gas control additive may be mixed with the cement slurry according to API RP10-B standards. The gas control additive may be mixed with the cement slurry as a free flowing dry powder, as a liquid filled capsule, or as part of a liquid emulsion. The gas control additive may be used with any type of cementitious slurry. In at least one embodiment, the cement in the cementitious slurry is hydrophilic. In at least one embodiment, the cementitious slurry comprises grade G portland cement. In at least one embodiment, the detergent is present in the cement slurry at a concentration between about 0.05% by weight of the cement and about 0.5% by weight of the cement. In at least one embodiment, the polymer of the semi-permeable membrane is present in the cement slurry at a concentration of up to about 3% by weight of the cement. In at least one embodiment, two or more gas control additives may be added to the cement slurry such that two or more different detergents are brought into the cement slurry. The gas control additive may be mixed in the cement slurry such that the gas control additive is distributed throughout the cement slurry. The cement slurry may be introduced into the formation according to any method for cementing in a wellbore or formation.

The cement slurry sets into hardened cement such that the gas control additive is embedded in the hardened cement. In some embodiments, the hardened cement including the gas control additive exhibits an unconfined compressive strength in a range of about 2,500psi to about 3,500psi at about 350 ° f for about 120 hours. In other embodiments, the hardened cement including the gas control additive exhibits an unconfined compressive strength in the range of about 2,800psi to about 3,500psi at about 350 ° f for about 120 hours. In still other embodiments, the hardened cement including the gas control additive exhibits an unconfined compressive strength in the range of about 3,000psi to about 3,400psi at about 350 ° f for about 120 hours. By way of comparison, the clarified cement exhibits an unconfined compressive strength in the following range under similar conditions: from about 3,000psi to about 4,000psi, or from about 3,400psi to about 3,700psi, or from about 3,500psi to about 3,600 psi. Also by way of comparison, the hardened cement containing latex exhibits an unconfined compressive strength in similar conditions in the following range: from about 1,500psi to about 2,500psi, alternatively from about 1,800psi to about 2,300psi, alternatively from about 1,900psi to about 2,200 psi. In some embodiments, the hardened cement including the aromatic amide capsules exhibits a limited compressive strength at room temperature in the range of about 5,000psi to about 14,000 psi. In other embodiments, the hardened cement including the aromatic amide capsules exhibits a limited compressive strength at room temperature in a range of from about 9,000psi to about 12,000 psi.

The resistant gas may migrate from the formation through the cement slurry and the hardened cement. The gas may encounter the gas control additive as the resistant gas migrates through the cement slurry or hardened cement. Due to the amine group, the resistant gas can be attracted by the polyamide or aromatic amide-based semipermeable membrane. In some embodiments, the resistant gas does not react with the semi-permeable membrane. The resistant gas may permeate through the semi-permeable membrane.

In the semi-permeable membrane, the resistant gas reacts with the detergent. In at least one embodiment, the resistant gas and the detergent react to produce an auxiliary byproduct and a secondary byproduct. The auxiliary by-products can permeate through the semi-permeable membrane into the cement slurry or hardened cement. In at least one embodiment, the secondary by-products are less corrosive than the resistant gas. In at least one embodiment, the auxiliary byproduct may be water, and the water may permeate through the semi-permeable membrane to the cement slurry or hardened cement, and may hydrate the cement. The volume of the gas control additive may change by less than 1 volume percent during the useful life of the gas control additive.

In other embodiments, the ancillary byproducts may include compounds having bicarbonate or carbonate salts (including cyclic carbonates) and solid sulfur. In at least one embodiment, the secondary byproduct may be a solid product including calcium bicarbonate or calcium carbonate. The calcium bicarbonate and calcium carbonate may be present in solid form such that the semi-permeable membrane prevents the solid product from permeating through the semi-permeable membrane from the core of the gas control additive. Furthermore, due to the cementitious nature of bicarbonate and carbonate-based compounds, the solid product may form a self-sealing physical barrier (if any) in the micro-annulus to prevent gas migration.

The gas control additive may continue to provide gas migration control until the detergent is exhausted or becomes unreactive. The semi-permeable membrane of inert gas control additives may provide reinforcement properties to the hardened cement when the detergent becomes unreactive. That is, the integrity of the polymeric shell is maintained regardless of the state of the detergent within the shell.

The gas migration control method and composition is free of detergents that permeate through the semi-permeable membrane from the core to the hardened cement. In at least one embodiment, the detergent is bound in the core of the gas control additive via site isolation using a linear polymer. The detergent may be bound to, within, or on the semi-permeable membrane. In at least one embodiment, the detergent may be site segregated using linear polymers such as polyethylene glycol (PEG), polystyrene, polyethyleneimine, polyvinyl alcohol, and combinations thereof. These linear polymers are generally water soluble. The side chains of these linear polymers can be designed to pin-point the detergent via chelation. Non-limiting examples of tethered detergents include salts, promoters, and metal catalysts. Examples of chelating agents include EDTA, HEDTA, NTA, DTPA and combinations thereof. Examples of chelating agents also include polyethylene glycol, polyvinyl alcohol, and combinations thereof. Chelating agents in the form of salts may be added to the dispersed phase, such as iron (III) ethylenediaminetetraacetate monosodium salt (Na [ Fe (III) EDTA ]). In other embodiments, these linear polymers may be broken such that the broken molecules may pass through a semi-permeable membrane. For example, linear polymers having carboxylic acid groups can be broken such that the broken molecules having carboxylic acid groups can be used as cement retarders. In some embodiments, the tackifier may be used for site isolation of the detergent.

Fig. 2 shows a schematic representation of a gas migration control method and a gas control additive 200. As shown in fig. 1, the gas control additive 200 has a spherical shape in which the shell includes a semi-permeable membrane 210. The gas in the box represents the resistant gas 220. The polyamide or aromatic amide-based material of the semi-permeable membrane 210 attracts the resistive gas 220. The resistant gas 220 permeates into the semi-permeable membrane 210. The resistant gas 220 reacts with a detergent 230 labeled SA. The solid line represents a linear polymer 240, wherein the linear polymer is capable of sequestering detergent 230 sites via side chains 242.

In at least one embodiment, the detergent is activated alumina, the semi-permeable membrane is composed of a polyamide polymer, and the hydrogen sulfide permeates through the semi-permeable membrane to react with the activated alumina.

In at least one embodiment, fig. 3 illustrates a gas migration control method using a gas scrubbing additive. The metal oxide based detergent 330 is encapsulated by the semi-permeable membrane 310. Semipermeable membrane 310 is a polyamide or an aromatic amide. As shown in FIG. 3, the detergent 330 is iron (III) oxide (Fe)₂O₃). Iron (III) oxide can be in solid form or in hydrated form (Fe)₂O₃·nH₂O) is present. The detergent 330 may be iron (II, III) oxide (Fe) called magnetite₃O₄Or FeO. Fe₂O₃) Which is a combination of iron (II) oxide and iron (III) oxide. The semi-permeable membrane 310 is designed such that solid or hydrated iron (III) oxide cannot permeate through the semi-permeable membrane 310. The resistant gas 320 is hydrogen sulfide (H)₂S). The semi-permeable membrane 310 may attract hydrogen sulfide. As the hydrogen sulfide permeates through the semi-permeable membrane 310, the hydrogen sulfide reacts with the iron (III) oxide to produce water and iron (III) sulfide (Fe)₂S₃). The hydrogen sulfide may react with the iron (II) oxide to produce water and iron (II) sulfide (FeS). The hydrogen sulfide can react with magnetite to produce iron (III) sulfide, iron (II) sulfide or iron (II) disulfide (FeS)₂). The secondary byproduct 360 is the produced water. The water produced may be present in gaseous or liquid form. The secondary byproduct 332 is iron (III) sulfide. The secondary byproduct 332 may also be iron (II) sulfide, iron (II) disulfide, or solid sulfur. The iron (III) sulfide may be present in solid form. Iron (III) sulfide remains in the semi-permeable membrane 310 and the produced water permeates out of the semi-permeable membrane 310.

In at least one embodiment, fig. 4 illustrates a method of gas migration control using a gas scrubbing additive. The metal hydroxide based detergent 430 may be encapsulated by a semi-permeable membrane 410. The semi-permeable membrane 410 is of polyamide or aromatic amide type. As shown in FIG. 4, the detergent 430 is calcium hydroxide (Ca (OH)₂). The calcium hydroxide may be in solid form or in hydrated form (Ca (OH)₂·nH₂O) is present. The semi-permeable membrane 410 is designed such that solid or hydrated calcium hydroxide cannot permeate through the semi-permeable membrane 410. In other embodiments, the metal hydroxide based detergent 430 may be present in an aqueous form, such as lime water, where the detergent 430 is also calcium hydroxide. The semi-permeable membrane 410 may be designed such that aqueous calcium hydroxide can permeate into the semi-permeable membrane 410. The resistant gas 420 is carbon dioxide (CO)₂). The semi-permeable membrane 410 may attract carbon dioxide. When carbon dioxide permeates through the semi-permeable membraneAt 410, the carbon dioxide reacts with the calcium hydroxide to produce water and calcium carbonate (CaCO)₃). The carbon dioxide can react with calcium hydroxide to produce bicarbonate, such as calcium bicarbonate (Ca (HCO)₃)₂). One auxiliary byproduct 460 is the water produced. The water produced may be present in gaseous or liquid form. Other ancillary by-products 432 of the reaction are calcium carbonate or calcium bicarbonate. The calcium carbonate is present in solid form. The calcium carbonate remains in the semi-permeable membrane 410 and the produced water permeates out of the semi-permeable membrane 410. Furthermore, calcium carbonate is a cementitious material capable of physically forming a barrier to gases, which is advantageous in case the cement paste is of the self-healing type.

The interfacial polymerization process described herein provides capsules that allow for reaction between detergent and resistant gases without causing the semi-permeable membrane to break down. This is superior to methods of encapsulating solids by spray drying and pan coating methods that deposit a chemical coating on the surface of the encapsulant, where the chemical coating dissolves or disintegrates to release the encapsulant.

Cement ductility refers to a measure of the reliability of cement, wherein the integrity of the cement is enhanced by making it more ductile and ductile. Advantageously, the semi-permeable membrane of the gas control additive improves the ductility of the cement.

In at least one embodiment, the gas control additive is free of molecular sieves. In at least one embodiment, the cementitious slurry with gas control additive is latex-free.

In at least one embodiment, the gas control additive may be included in certain drilling fluids as well as other completion fluids that may come into contact with the resistant gas during drilling.