Plugging agent composition, application and oil and gas reservoir plugging method

Abstract

The invention discloses a plugging agent composition, application and an oil and gas reservoir plugging method. The plugging agent composition contains polymer latex and a stabilizer, and the stabilizer has a cross-linkable group and / or a coupleable group; in the presence of cracks and / or leakage points, the crosslinkable groups and / or the coupleable groups in the stabilizer are crosslinked or coupled, so that the polymer latex is coagulated and cured. The plugging agent composition is an intelligent pressure-sensitive plugging material, can realize plugging along with leakage and is free of leakage and plugging, compared with an existing latex demulsification type plugging material, metal cations do not need to be used for demulsification, the plugging agent composition can go deep into cracks for plugging, cracks with different sizes from the nano-micron level to the millimeter level can be plugged, the plugging effect is excellent, and the plugging effect is good. And the use requirements in the oil and gas reservoir plugging field can be well met.

Description

Plugging agent composition and application thereof and oil and gas reservoir plugging method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese Patent Application No. 202211366131.2, filed on October 31, 2022, entitled “Plugling Agent Composition and Application and Oil and Gas Reservoir Plugging Method,” the contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to the field of well drilling and completion plugging, and in particular to a plugging agent composition and its application, and an oil and gas reservoir plugging method. Background Art

[0004] Drilling lost circulation is a phenomenon in which a large amount of drilling fluid leaks into the drilled formation during drilling construction. It is widely encountered in oil fields at home and abroad, causing great harm to oil and gas exploration, development and drilling operations, and threatening safe production.

[0005] Existing plugging materials can be divided into traditional plugging materials and intelligent plugging materials. Traditional plugging materials are mainly bridge plugging, and because it is difficult to grasp the leakage layer situation, most of them are blind plugging, which has great limitations in terms of use process and plugging effect. Among intelligent plugging materials, temperature-sensitive plugging materials and shear cross-linking plugging materials require temperature or shear stress preset according to the leakage situation, and it is difficult to effectively plug unknown leakage layers. In contrast, pressure-sensitive plugging materials do not require leakage layer preset and can identify and plug the leakage layer in real time during the flow process. Existing pressure-sensitive plugging materials mainly use salting-out method for demulsification, which requires adding salt to the latex as a demulsifier to cause the latex to solidify and then achieve plugging. However, the addition of salt will cause metal cation residues, which has a significant adverse effect on the performance of the rubber plugging material formed after demulsification. In addition, the curing time of the latex in the salting-out method is very short, which does not give the plugging material fluid the opportunity to penetrate into the cracks, resulting in a "door-sealed" type of plugging, and there are also certain restrictions on the plugging size.

[0006] Therefore, it is necessary to provide a new drilling plugging material.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems in the prior art of plugging agents that, due to the use of salt to promote latex solidification, residual metal cations have a significant adverse effect on the performance of the plugging material formed after the latex is solidified, the "door-sealing" type plugging causes limited plugging effect, and there is a limit on the size of the plugged cracks. A plugging agent composition and its application and an oil and gas reservoir plugging method are provided. The plugging agent composition contains a stabilizer that can have the dual functions of "stabilizing" or "demulsifying" the polymer latex according to the pressure change, so that the polymer latex starts demulsification, coagulation and solidification at the cracks and / or leak points, achieving plugging as the leak occurs and no plugging when there is no leak. There is no need to use salt as a demulsifier, thereby avoiding adverse effects on the performance of the plugging material formed after the polymer latex is solidified. The plugging agent composition is more suitable for the needs of drilling and completion plugging deep into the cracks, and can plug leaks in wells of different sizes.

[0009] To achieve the above objectives, the present invention provides, in a first aspect, a plugging agent composition, comprising a polymer latex and a stabilizer, wherein the stabilizer has a crosslinkable group and / or a coupling group; in the presence of cracks and / or leaks, the crosslinkable groups and / or coupling groups in the stabilizer undergo crosslinking or coupling, causing the polymer latex to coagulate and solidify.

[0010] The second aspect of the present invention provides use of the plugging agent composition described in the first aspect in plugging oil reservoirs.

[0011] A third aspect of the present invention provides a method for plugging leaks in oil and gas reservoirs, comprising: injecting the plugging agent composition described in the first aspect into an oil and gas reservoir formation, wherein the composition flows into cracks and / or leak points in the oil and gas reservoir formation during the injection process, and condenses and solidifies at the cracks and / or leak points to form a solidified product having a pressure resistance of not less than 5 MPa at 100°C.

[0012] Through the above technical solution, the present invention has the following beneficial effects:

[0013] (1) The plugging agent composition provided by the present invention is an intelligent pressure-sensitive plugging material, wherein the stabilizer has a cross-linkable group and / or a coupling group, which can maintain a fluid state in the absence of cracks and / or leaks. When encountering cracks and / or leaks, the plugging effect is activated under the pressure difference and filtration loss, thereby realizing intelligent plugging that plugs as leaks occur, and does not plug when there is no leak.

[0014] (2) The plugging agent composition provided by the present invention adopts a new demulsification mechanism, which contains a stabilizer with dual functions of "stabilization" and "demulsification". Under normal conditions (no cracks and / or leaks), the stabilizer can make the polymer latex in the composition maintain system stability and fluidity. However, under the pressure difference and filtration loss, the stabilizer fails, causing the polymer latex to become unstable and demulsified, thereby achieving coagulation, solidification and plugging, avoiding the effect of the prior art plugging agent using salt demulsification on the performance of the rubber plugging material formed after the latex is solidified. In addition, the crosslinkable group and / or coupling group of the stabilizer has a positive effect on the viscosity, mechanical strength and other aspects of the rubber plugging material formed after solidification, bringing better plugging effect. The solidified product of the plugging agent composition provided by the present invention can withstand a pressure of not less than 5MPa at 100°C.

[0015] (3) The plugging agent composition provided by the present invention can plug cracks or leaks of varying sizes, ranging from nanometers to millimeters (20nm-1mm), at 100°C, providing a plugging material with greater adaptability to plugging sizes in the field of well drilling and completion plugging. The plugging agent composition provided by the present invention, when containing a bridging material, can effectively plug cracks with a width of up to 2mm. Specifically, in a plugging performance test, the cured product can withstand a pressure of 12MPa at 120°C after plugging a crack with a width of 2mm. DETAILED DESCRIPTION

[0016] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0017] A first aspect of the present invention provides a plugging agent composition comprising a polymer latex and a stabilizer, wherein the stabilizer has a crosslinkable group and / or a coupling group; in the presence of cracks and / or leaks, the crosslinkable groups and / or coupling groups in the stabilizer undergo crosslinking or coupling, causing the polymer latex to coagulate and solidify.

[0018] According to the present invention, the components of the plugging agent composition have fluidity after mixing, wherein the stabilizer can respectively play a "stabilizing" or "demulsifying" role on the polymer latex under different circumstances. Specifically, the stabilizer can make the polymer latex stable in the absence of cracks and / or leaks, and can cause the polymer latex to coagulate and solidify in the presence of cracks and / or leaks. In the absence of cracks and / or leaks, the "stable existence" means that the latex particles in the polymer latex are uniformly dispersed in the liquid system of the polymer latex under the action of factors such as static electricity, van der Waals force and capillary force (the polymer latex in the "stable existence" state, even if the latex particles therein will precipitate due to gravity after being placed for a long time, will not produce agglomeration and caking, and can be restored to a uniformly dispersed state with a slight stirring), so that the polymer latex maintains a stable colloidal emulsion state and maintains good fluidity; in the case of cracks and / or leaks, due to the pressure difference at the crack and / or leak position, under the action of pressure difference and filtration loss, the stabilizer itself will undergo dehydration cross-linking (or coupling), and the cross-linked (or coupled) stabilizer gradually loses its stabilizing effect on the polymer latex, thereby causing the polymer latex to become unstable and undergo phase transition, that is, demulsification, coagulation and solidification. Compared with the plugging agents in the prior art that use salt to promote latex demulsification and solidification, the present invention adopts a completely different demulsification method. The stabilizer with dual functions in the composition can make the polymer latex stable or demulsify under different circumstances, thereby realizing intelligent plugging that plugs as leakage occurs and does not plug when there is no leakage. It also avoids the adverse effects of residual metal cations brought about by the salt demulsification method on the performance of the rubber plugging material formed after the latex is solidified, providing new ideas and methods for plugging in the drilling field and ensuring safe and efficient operations.

[0019] In the present invention, the pressure differential refers to the difference between the internal and external pressures of cracks and / or leaks in the wellbore wall. Specifically, it refers to the pressure difference between the working fluid pressure in the wellbore (internal pressure) and the pore pressure in the formation where the cracks and / or leaks are located (external pressure). For example, during drilling and completion operations, a positive pressure differential exists in a leaking formation, meaning that the working fluid pressure in the wellbore is greater than the formation pore pressure.

[0020] In the present invention, as the names imply, a crack refers to an elongated opening in a wellbore wall, and a leak point refers to a hole-like opening with a smaller aspect ratio than a crack. Both can be regular or irregular in shape. Both cracks and leak points can create a difference between the internal and external pressures. The use of cracks and / or leak points in the present invention is intended to illustrate that the plugging agent composition of the present invention can be used to plug wellbore wall openings of various shapes.

[0021] According to the present invention, the cured product formed by curing the polymer latex has an excellent sealing effect on cracks and / or leaks. Preferably, the cured product can withstand a pressure of not less than 5 MPa at 100°C, and preferably can withstand a pressure of 5-12 MPa at 100°C.

[0022] In the present invention, the plugging performance test adopts the American Fann permeability plugging instrument (PPA type).

[0023] According to the present invention, the concentration of metal cations in the composition is lower than 0.1 wt %, so that a cured product formed by curing the composition has better mechanical strength and corrosion resistance, thereby achieving a better blocking effect.

[0024] In the present invention, the metal cations include but are not limited to Na + , K + Mg 2+ , Ca 2+ 、Zn 2+ 、Cu 2+ At least one of .

[0025] According to the present invention, further, the composition does not contain a metal cation demulsifier, in particular does not contain a demulsifier having a divalent or higher valence metal cation. In the present invention, the metal cation demulsifier refers to an agent that can use the metal cation group it contains to break the charge balance and thus demulsify the polymer latex, including but not limited to Zn(OAc)2, Cu(OAc)2, CuSO4, CaCl2, MgSO4, NaCl, Na2SO3, Na2SO4, CH3COONa, KH2PO4, etc.

[0026] According to the present invention, in the composition, the weight ratio of the polymer latex: stabilizer is 1:(0.0001-0.2), preferably 1:(0.001-0.1), which helps the stabilizer to better "stabilize" or "demulsify" the polymer latex under different circumstances.

[0027] According to the present invention, in the composition, the stabilizer has a crosslinkable group and / or a coupling group, while the latex stabilizers of the prior art (for example, casein, gelatin, sulfate, etc.) do not have a crosslinkable group and / or a coupling group. The crosslinkable group and / or the coupling group are key factors that enable the stabilizer to possess the dual-effect functions of "stability" and "emulsification". Under normal conditions (there are no cracks and / or leaks), the stabilizer can be adsorbed or grafted on the latex particles of the polymer latex and form a hydration layer, which allows the polymer latex to be stably present through the combined action of electrostatic force, steric hindrance and the hydration layer; when pressure difference and filtration loss occur due to cracks and / or leaks, the latex particles dehydrate the layer, exposing the stabilizer, and the crosslinkable group and / or the coupling group undergo crosslinking (or coupling), with the crosslinking method being chemical crosslinking or physical crosslinking. The stabilizer after crosslinking loses its effectiveness, prompting the polymer latex to demulsify. By controlling the proportion of the crosslinkable group and / or the coupling group in the stabilizer, the crosslinking and demulsification process can be carried out in a gradual manner, so that the composition first coagulates and thickens, but does not immediately solidify (i.e., the plugging process is controlled to be two stages of thickening and solidification performed in sequence), thereby giving the composition (plugging material fluid) the opportunity to continue to penetrate the cracks and / or leak points, and further solidify in the process of entering the cracks and / or leak points, achieving deep plugging, rather than just plugging on the surface or shallow part, avoiding the "door-sealing" plugging caused by rapid solidification, and having better sealing performance, which is more suitable for the plugging needs of drilling and completion well leakage. Preferably, based on the total weight of the stabilizer, the content of the crosslinkable group and / or the coupling group in the stabilizer is 0.001-20% by weight, preferably 0.01-8% by weight.

[0028] According to the present invention, the cross-linkable group and / or coupling group also has a beneficial effect on the viscosity, mechanical strength and other aspects of the rubber plugging material formed after the composition is cured, which is conducive to obtaining a better plugging effect.

[0029] According to the present invention, the crosslinkable group and / or coupling group refer to the group that can be crosslinked or coupled reaction occurs under the specific conditions of the present invention to form a larger molecule, because crosslinking or coupling reaction can achieve the purpose of the present invention, so the present invention does not particularly distinguish between crosslinking or coupling reaction. In the present invention, the crosslinkable group and / or coupling group can be selected from at least one of unsaturated double bond or triple bond, epoxy group, sulfydryl, amino, urea group, acyloxy, monoalkoxyphenyl, benzyl, halogen and siloxy. According to a preferred embodiment of the present invention, the crosslinkable group and / or coupling group is siloxy. In an embodiment of the present invention, the content of siloxy is used as the content of crosslinkable group and / or coupling group.

[0030] In the present invention, the content of the crosslinkable group and / or the coupling group can be calculated by infrared spectroscopy combined with nuclear magnetic resonance spectrum. Specifically, the composition is first subjected to gel chromatography separation to separate the stabilizer, and the type of the crosslinkable group and / or the coupling group in the stabilizer is determined by infrared spectroscopy analysis. Then, the content of the crosslinkable group and / or the coupling group is determined by quantitative nuclear magnetic internal standard method. Specifically, the stabilizer obtained by the gel chromatography separation is sampled and weighed, and the weighed stabilizer sample and the internal standard are mixed into a solution (if the hydrogen spectrum is tested, The internal standard substance for quantitative analysis by hydrogen spectrum internal standard method is adopted; if the silicon spectrum is tested, the internal standard substance for quantitative analysis by silicon spectrum internal standard method is adopted), and the solution is subjected to nuclear magnetic resonance test (when the crosslinkable group and / or the coupling group is a siloxy group, silicon nuclear magnetic resonance is adopted), and the peak area of ​​the characteristic peak of the crosslinkable group and / or the coupling group in the stabilizer measured by nuclear magnetic resonance and the peak area of ​​the characteristic peak of the internal standard substance are calculated to obtain the amount of the crosslinkable group and / or the coupling group, and then divided by the amount of the weighed stabilizer sample to obtain the content of the crosslinkable group and / or the coupling group in the stabilizer. In addition, in the case of known raw materials, the content of the crosslinkable group and / or the coupling group can also be calculated according to the raw material input amount.

[0031] According to the present invention, the stabilizer is a polymer, which contains the cross-linkable group and / or the coupling group, and further contains At least one of the groups, preferably containing At least one of the groups; wherein M1, M2, M3, M4, M5 and M6 are each independently selected from H + 、Na + , K + or NH4 + .

[0032] According to the present invention, in the structural formula of the above group, Indicates the attachment position of the group to the polymer main chain or side chain.

[0033] According to the present invention, the weight average molecular weight of the stabilizer is 10,000-100,000 g / mol, preferably 20,000-50,000 g / mol.

[0034] In the present invention, the weight average molecular weight of the polymer is measured by gel chromatography.

[0035] According to the present invention, preferably, the stabilizer has a structural unit A represented by formula (1), a structural unit B represented by formula (2) or formula (3), and a structural unit C represented by formula (4) or formula (5);

[0036] Wherein, in formula (1), R1, R2, R3, and R4 are each independently selected from -H, -CH3, -COOM 1 、-SO3M 2 、-CH2COOM 3 、 -CH2SO3M 4 、 or -CONHC(CH3)2CH2SO3M 8 , and R1, R2, R3, and R4 are not selected from -H or -CH3 at the same time; wherein, M 1 、M 2 、M 3 、M 4 、M 5 、M 6 、M 7 and M 8 Each independently selected from H + , K + 、Na + or NH4 + ;

[0037] In formula (2), R5, R6, and R7 are each independently selected from -H or C1-C 18 alkyl; R8 is selected from C1-C3 alkylene; R9 is selected from C1-C3 alkylene;

[0038] In formula (3), R 10 、R 11 、R 12 、R 13 、R 14 are each independently selected from -H or C1-C4 alkyl; R 15 is selected from C1-C4 alkylene; Q is selected from H + , K + 、Na + or NH4 + ;

[0039] In formula (4), R 16 、R 17 、R 18 Each independently selected from -H or C1-C 18 Alkyl; R 19 Selected from chemical bonds, C1-C 18 Alkylene or -COOCH2CH2CH2-; R 20 Selected from C1-C2 alkyl, -CH2OCH3 or -CH2CH2OCH3;

[0040] In formula (5), R 21 、R 22 、R 23 Each independently selected from -H or C1-C18 Alkyl; R 24 Selected from C1-C 18 Alkylene; R 25 An alkylene group selected from C1-C3; R 26 an alkyl group selected from C1-C2;

[0041] The molar ratio of structural unit A:structural unit B:structural unit C is (1-2000):100:(0.01-400), preferably (50-1500):100:(0.05-100), and more preferably (200-1200):100:(0.1-30).

[0042] According to a particularly preferred embodiment of the present invention, the stabilizer is a copolymer-I having a structural unit A represented by the above formula (1), a structural unit B represented by the above formula (2), and a structural unit C represented by the above formula (4) or formula (5);

[0043] Wherein, in formula (1), R1, R2, R3, and R4 are each independently selected from -H, -CH3, -COOM 1 、-SO3M 2 、-CH2COOM 3 、-CH2SO3M 4 、 or -CONHC(CH3)2CH2SO3M 8 , and R1, R2, R3, and R4 are not selected from -H or -CH3 at the same time; wherein, M 1 、M 2 、M 3 、M 4 、M 5 、M 6 、M 7 and M 8 Each independently selected from H + , K + 、Na + or NH4 + ;

[0044] In formula (2), R5, R6, and R7 are each independently selected from -H or a C1-C2 alkyl group; R8 is selected from a C1-C3 alkylene group; and R9 is selected from a C1-C2 alkylene group.

[0045] In formula (4), R 16 、R 17 、R 18 are each independently selected from -H or C1-C2 alkyl; R 19 Selected from a chemical bond or -COOCH2CH2CH2-; R 20Selected from C1-C2 alkyl, -CH2OCH3 or -CH2CH2OCH3;

[0046] In formula (5), R 21 、R 22 、R 23 are each independently selected from -H or C1-C2 alkyl; R 24 An alkylene group selected from C1-C2; R 25 An alkylene group selected from C1-C3; R 26 an alkyl group selected from C1-C2;

[0047] In the copolymer-I, the molar ratio of structural unit A:structural unit B:structural unit C is (1-2000):100:(0.01-400), preferably (50-1500):100:(0.05-100), and more preferably (200-1200):100:(0.1-30).

[0048] According to the present invention, the preparation method of the copolymer-I comprises: in the presence of an initiator and a chain transfer agent, polymerizing an unsaturated polyether monomer, an unsaturated acid or its salt or its anhydride and a silane coupling agent to obtain the copolymer-I.

[0049] According to one embodiment of the present invention, in the preparation method of the copolymer-I, the feeding amount of each raw material satisfies the following relationship: the molar ratio of unsaturated acid or its salt or its anhydride: unsaturated polyether monomer: silane coupling agent is (1-2000):100:(0.01-400); the molar ratio of initiator: (unsaturated acid or its salt or its anhydride + unsaturated polyether monomer) is (0.01-5):100, wherein, when the initiator is a redox initiation system, it is measured as an oxidant; the molar ratio of chain transfer agent: (unsaturated acid or its salt or its anhydride + unsaturated polyether monomer) is (0.01-10):100.

[0050] According to the present invention, in the preparation method of the copolymer-I, the unsaturated polyether monomer can be selected from at least one of methyl allyl alcohol polyoxyethylene ether, methyl allyl alcohol polyoxypropylene ether, isopentenol polyoxyethylene ether and isobutylenol polyoxyethylene ether, preferably isopentenol polyoxyethylene ether.

[0051] According to the present invention, in the preparation method of the copolymer-1, the unsaturated acid or its salt or its anhydride refers to an unsaturated acid, or a sodium salt, potassium salt, ammonium salt of an unsaturated acid, or an anhydride of an unsaturated acid. Preferably, the unsaturated acid can be selected from at least one of acrylic acid, methacrylic acid, vinyl sulfonic acid, vinyl phosphoric acid, maleic acid, itaconic acid, fumaric acid, 2-acrylamide-2-methylpropanesulfonic acid, styrenesulfonic acid and propenylsulfonic acid, preferably acrylic acid and / or itaconic acid.

[0052] According to the present invention, in the preparation method of the copolymer-I, the silane coupling agent can be selected from at least one of vinyltriacetoxysilane, vinyltriethoxysilane (A-151), vinyltrimethoxysilane (A-171), vinyltri(β-methoxyethoxy)silane (A-172), γ-aminopropyltriethoxysilane (KH-550), γ-glycidoxypropyltrimethoxysilane (KH-560), vinyloctadecyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane (KH-570), preferably γ-methacryloxypropyltrimethoxysilane.

[0053] According to the present invention, the initiator is preferably a redox initiator containing an oxidizing agent and a reducing agent.

[0054] According to the present invention, in the preparation method of the copolymer-I, the initiator, the oxidant can be selected from at least one of hydrogen peroxide, peracetic acid, ammonium persulfate, sodium persulfate and potassium persulfate, preferably hydrogen peroxide. The concentration of the hydrogen peroxide is preferably 25-30% by weight.

[0055] According to the present invention, in the preparation method of the copolymer-I, in the initiator, the reducing agent can be selected from at least one of ascorbic acid, sodium formaldehyde sulfoxylate and sodium dithionite, preferably ascorbic acid.

[0056] According to the present invention, in the preparation method of the copolymer-I, the chain transfer agent can be selected from mercaptoacetic acid and / or 3-mercaptopropionic acid, preferably 3-mercaptopropionic acid.

[0057] According to the present invention, in the method for preparing copolymer-I, the unsaturated polyether monomer, unsaturated acid or its salt or its anhydride, oxidizing agent, reducing agent, and chain transfer agent are preferably fed in the form of aqueous solutions. Preferably, in the aqueous solution containing the unsaturated polyether monomer, the concentration of the unsaturated polyether monomer is 20-90% by weight; in the aqueous solution containing the unsaturated acid or its salt or its anhydride, the concentration of the unsaturated acid or its salt or its anhydride is 20-80% by weight; in the aqueous solution containing the oxidizing agent, the concentration of the oxidizing agent is 9-40% by weight; and in the aqueous solution containing the reducing agent and chain transfer agent, the concentration of the reducing agent is 2-10% by weight, and the concentration of the chain transfer agent is 2-6% by weight.

[0058] According to a preferred embodiment of the present invention, the preparation method of the copolymer-I comprises:

[0059] (1) heating the aqueous solution containing the unsaturated polyether monomer to 50-70° C., maintaining the temperature for 0.2-1 h, and adding the aqueous solution containing the oxidant;

[0060] (2) then simultaneously adding the aqueous solution containing an unsaturated acid or its salt or its anhydride, a silane coupling agent, and the aqueous solution containing a reducing agent and a chain transfer agent; wherein the addition time of the aqueous solution containing an unsaturated acid or its salt or its anhydride and the silane coupling agent is 2-4 hours, and the addition time of the aqueous solution containing a reducing agent and a chain transfer agent is 2.5-4.5 hours;

[0061] (3) After all the raw materials in step (2) are added, the mixture is kept warm for 0.5-1 hour to obtain the copolymer-I.

[0062] According to another particularly preferred embodiment of the present invention, the stabilizer is a copolymer-II having a structural unit A represented by the above formula (1), a structural unit B represented by the above formula (3), and a structural unit C represented by the above formula (4) or formula (5);

[0063] Wherein, in formula (1), R1, R2, R3, and R4 are each independently selected from -H, -CH3, -COOM 1 、-SO3M 2 、-CH2COOM 3 、-CH2SO3M 4 、 or -CONHC(CH3)2CH2SO3M 8 , and R1, R2, R3, and R4 are not selected from -H or -CH3 at the same time; wherein, M 1 、M 2 、M 3 、M 4 、M 5 、M 6 、M 7 and M 8 Each independently selected from H + , K + 、Na + or NH4 + ;

[0064] In formula (3), R 10 、R 11 、R 12 、R 13 、R 14 are each independently selected from -H or C1-C2 alkyl; R 15 is selected from C1-C2 alkylene; Q is selected from H + , K + 、Na + or NH4 + ;

[0065] In formula (4), R 16 、R17 、R 18 are each independently selected from -H or C1-C2 alkyl; R 19 Selected from a chemical bond or -COOCH2CH2CH2-; R 20 Selected from C1-C2 alkyl, -CH2OCH3 or -CH2CH2OCH3;

[0066] In formula (5), R 21 、R 22 、R 23 are each independently selected from -H or C1-C2 alkyl; R 24 An alkylene group selected from C1-C2; R 25 An alkylene group selected from C1-C3; R 26 an alkyl group selected from C1-C2;

[0067] In the copolymer-II, the molar ratio of structural unit A:structural unit B:structural unit C is (1-2000):100:(1-100), preferably (50-1500):100:(5-50), and more preferably (200-800):100:(10-30).

[0068] According to the present invention, the preparation method of the copolymer-II comprises: polymerizing 2-acrylamido-2-methylpropanesulfonic acid, an unsaturated acid or its salt or anhydride and a silane coupling agent in the presence of an initiator to obtain the copolymer-II.

[0069] According to the present invention, in the preparation method of the copolymer-II, the feeding amount of each raw material satisfies the following relationship: the molar ratio of the unsaturated acid or its salt or its anhydride: 2-acrylamido-2-methylpropanesulfonic acid: silane coupling agent is (1-2000):100:(0.01-400); the molar ratio of the initiator: (unsaturated acid or its salt or its anhydride + 2-acrylamido-2-methylpropanesulfonic acid) is (0.01-10):100.

[0070] According to the present invention, in the preparation method of the copolymer-II, the definitions of the unsaturated acid or its salt or its anhydride, and the silane coupling agent are the same as those of the unsaturated acid or its salt or its anhydride, and the silane coupling agent in the preparation method of the copolymer-I.

[0071] According to the present invention, in the method for preparing copolymer II, the initiator can be selected from at least one of a peroxide initiator, an azo initiator, and a redox initiator, preferably at least one of a persulfate initiator, a persulfate-sulfite system initiator, and a hydrogen peroxide-ascorbic acid system initiator. The initiator is preferably added in the form of a solution, preferably, the concentration of the initiator in the initiator-containing solution is 5-20% by weight.

[0072] According to a preferred embodiment of the present invention, the preparation method of the copolymer-II comprises:

[0073] 2-Acrylamido-2-methylpropanesulfonic acid and water are mixed in a weight ratio of 1:(2-6) to obtain an aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid; the pH value of the aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid is adjusted to 9-12, the temperature is raised to 30-70° C., and then the unsaturated acid or its salt or anhydride, the initiator solution and the silane coupling agent are added, and the temperature is raised to 50-120° C. for reaction for 2-6 hours to obtain the copolymer-II.

[0074] According to the present invention, in the composition, the polymer latex can be selected from at least one of nitrile butadiene latex, styrene butadiene latex, styrene acrylic latex, butyl latex, pure acrylic latex, chloroprene latex, natural rubber latex, fluororubber latex, polybutadiene latex, EPDM latex, silicone rubber latex and polyacrylate latex, preferably nitrile butadiene latex and / or styrene acrylic latex.

[0075] According to the present invention, the polymer latex contains latex particles with a particle size (i.e., particle size) of 20-300 nm and / or latex particles with a particle size of 300 nm-2 mm. In the present invention, the polymer latex further includes a matrix latex and / or a latex prepolymer, wherein the matrix latex refers to an emulsion formed by dispersing polymer particles in water, preferably, the particle size of the latex particles in the matrix latex is 20-300 nm; the latex prepolymer refers to an emulsion containing larger latex particles formed by aggregation of latex particles in the matrix latex, preferably, the particle size of the latex particles in the latex prepolymer is 300 nm-2 mm.

[0076] According to the present invention, the particle size of the latex particles is measured by a laser particle size analyzer (Malvern, model Mastersizer 3000).

[0077] In the present invention, the particle size range of the latex particles mentioned above means that the minimum and maximum particle sizes of all the latex particles contained in the polymer latex both fall within the range. For example, a latex particle size of 20-300 nm means that the minimum and maximum particle sizes of all the latex particles contained in the polymer latex both fall within the range of 20-300 nm. For example, the minimum particle size of all the latex particles contained in the polymer latex is 20 nm, and the maximum particle size is 300 nm. For another example, the minimum particle size of all the latex particles contained in the polymer latex is 20 nm, and the maximum particle size is 50 nm. For another example, the minimum particle size of all the latex particles contained in the polymer latex is 100 nm, and the maximum particle size is 150 nm. For another example, the minimum particle size of all the latex particles contained in the polymer latex is 200 nm, and the maximum particle size is 300 nm. All of the above situations fall within the latex particle size range of the present invention.

[0078] According to the present invention, when all the polymer latex in the composition is made of matrix latex, it can have an excellent blocking effect on nano-micron-scale cracks and / or leaks.

[0079] According to the present invention, when a portion of the polymer latex in the composition is a latex prepolymer, the large-sized latex particles contained in the latex prepolymer can act like "seed crystals" and "bridges," promoting better cohesion and solidification of the latex particles in the base latex to form a solid rubber plugging material with viscous force, thereby achieving a plugging effect on larger nano-micron-scale cracks and / or leaks. Furthermore, when all of the polymer latex in the composition is a latex prepolymer, a plugging effect on large-sized cracks and / or leaks (approaching or reaching the millimeter level) can be achieved.

[0080] In the present invention, the latex prepolymer can be obtained by conventional methods, for example, by reacting an agglomerating agent with a base latex. In a preferred embodiment of the present invention, the preparation method of the latex prepolymer comprises: adding an agglomerating agent to a base latex and thoroughly mixing them, adjusting the pH of the system to 9-10 with sodium hydroxide, and then reacting under stirring to obtain the latex prepolymer; wherein the weight ratio of the agglomerating agent to the base latex is (0.5-3):100; and the reaction conditions include: a temperature of 30-50°C and a reaction time of 0.5-2 hours.

[0081] In the present invention, the agglomerating agent is defined in a wide range and can be prepared by conventional methods or commercially available, including but not limited to ethanol, polyurethane emulsion, polyethyleneimine, polyetheramine, etc. In a preferred embodiment of the present invention, an agglomerating agent prepared by the following method can be used:

[0082] In the presence of an initiator, an emulsifier and water, an olefin monomer is reacted with an α,β-unsaturated carboxylic acid to obtain an agglomerating agent;

[0083] Among them, preferably, the olefin monomer is butyl acrylate; the α,β-unsaturated carboxylic acid is methacrylic acid; the initiator is sodium persulfate, and the emulsifier is sodium dodecylbenzenesulfonate;

[0084] Preferably, the mass ratio of α,β-unsaturated carboxylic acid to olefin monomer is (0.03-0.45):1, preferably (0.1-0.25):1;

[0085] Preferably, the reaction conditions include: temperature of 50-90° C. and time of 4-9 h.

[0086] According to the present invention, in the polymer latex, the types of polymers contained in the base latex and the latex prepolymer can be the same (for example, the base latex is styrene acrylic latex, and the latex prepolymer is a styrene acrylic latex prepolymer), or different (for example, the base latex is styrene acrylic latex, but the latex prepolymer is an EPDM latex prepolymer), preferably the same.

[0087] According to the present invention, the composition further comprises a surfactant. Preferably, the surfactant is selected from anionic surfactants and / or nonionic surfactants.

[0088] In the present invention, the anionic surfactant is selected from at least one of polyacrylamide, alkylbenzene sulfonate, alkylphenol polyoxyethylene ether ammonium sulfate, fatty acid sulfoalkyl ester, alkyl sulfonate salt, alkyl sulfonate, polysiloxane, α-olefin sulfonate and alkylolamide, preferably alkylphenol polyoxyethylene ether ammonium sulfate.

[0089] In the present invention, the nonionic surfactant is selected from at least one of alkylphenol polyoxyethylene ether, polyol monofatty acid ester, alkylamine oxide and N-alkylpyrrolidone, preferably alkylphenol polyoxyethylene ether.

[0090] According to the present invention, in the composition, the weight ratio of the polymer latex to the surfactant is 1:(0.0001-0.2), preferably 1:(0.001-0.1).

[0091] According to the present invention, the composition may also contain a bridging material, thereby enabling the sealing of larger cracks. When containing a bridging material, the sealant composition can effectively seal cracks up to 2 mm in width. In leak plugging performance tests (using a PAA permeability plugging instrument), a 2 mm crack was tested, demonstrating a post-sealing pressure resistance of 12 MPa at 120°C.

[0092] According to the present invention, preferably, the bridging material may be selected from at least one of walnut shells, elastic particles and fiber materials.

[0093] According to the present invention, preferably, the particle size of the walnut shell (ie, particle size) is 150-450 μm; and the particle size of the elastic particles is 450-850 μm.

[0094] In the present invention, the particle size of the bridging material is measured by sieving.

[0095] In the present invention, the particle size range of the walnut shells and the particle size range of the elastic particles mentioned above refer to the minimum and maximum particle sizes of all particles of the walnut shells or elastic particles falling within the range. For example, a walnut shell particle size of 150-450 μm means that the minimum and maximum particle sizes of all particles of the walnut shells fall within the range of 150-450 μm. For example, the minimum particle size of all particles of the walnut shells is 150 μm and the maximum particle size is 450 μm; for another example, the minimum particle size of all particles of the walnut shells is 150 μm and the maximum particle size is 200 μm; for another example, the minimum particle size of all particles of the walnut shells is 250 μm and the maximum particle size is 300 μm; for another example, the minimum particle size of all particles of the walnut shells is 350 μm and the maximum particle size is 450 μm. All of the above situations fall within the walnut shell particle size range of the present invention.

[0096] According to the present invention, preferably, the fiber length of the fiber material is 5-40 mm. In the present invention, the fiber length can be measured by optical microscopy.

[0097] In the present invention, preferably, the elastic particles can be selected from elastic graphite and / or elastic rubber; the fiber material can be selected from at least one of natural fiber, carbon fiber, ceramic fiber, steel fiber, polyester fiber, polyamide fiber and polypropylene fiber.

[0098] According to the present invention, in the composition, the weight ratio of the polymer latex to the bridging material is 1:(0.001-1), preferably 1:(0.01-0.2).

[0099] The plugging agent composition provided by the present invention can be obtained by mixing the above components.

[0100] In the present invention, the components of the plugging agent composition and, optionally, water are mixed to form a plugging agent suspension, which is used in the form of a suspension for plugging operations. When the plugging agent composition and water are combined to form a plugging agent suspension, the amount of water used to prepare the plugging agent suspension is preferably such that the solids content of the plugging agent suspension is 0.1-85% by weight.

[0101] According to a preferred embodiment of the present invention, the method for preparing the plugging agent suspension comprises:

[0102] In the case where the polymer latex contains both a base latex and a latex prepolymer, water is first mixed with the base latex and the surfactant in the plugging agent composition to obtain a first mixed product; then the first mixed product is second mixed with the stabilizer in the plugging agent composition to obtain a second mixed product; finally, the second mixed product is third mixed with the latex prepolymer in the plugging agent composition to obtain the plugging agent suspension;

[0103] In the case where the polymer latex is entirely base latex, water is first mixed with the base latex and surfactant in the plugging agent composition to obtain a first mixed product; then the first mixed product is secondly mixed with the stabilizer in the plugging agent composition to obtain the plugging agent suspension;

[0104] In the case where the polymer latex is entirely latex prepolymer, optional water is first mixed with the latex prepolymer and surfactant in the plugging agent composition to obtain a first mixed product; then the first mixed product is second mixed with the stabilizer in the plugging agent composition to obtain the plugging agent suspension.

[0105] The second aspect of the present invention provides use of the plugging agent composition described in the first aspect in plugging oil and gas reservoirs.

[0106] The plugging agent composition provided by the present invention has the intelligent plugging effect of plugging as leakage occurs and not plugging if there is no leakage. It can penetrate deep into cracks and / or leaking points to perform plugging, which solves the shortcomings of "door-sealing" plugging in terms of plugging effect. It adopts a demulsification method different from the salting-out method, so that the performance of the solidified product is not affected by metal cations. It has the advantages of good sealing, high strength and corrosion resistance. It can be applied to high-permeability leakage and nano-micron to millimeter-scale crack leakage formations, pressure-sensitive fracture-hole high-pressure gas reservoirs, gas storage leakage, etc., to achieve pore leakage plugging or crack sealing and gas blocking, and can achieve plugging as leakage occurs for induced and random multi-point leakage that reappears in the blocked formation.

[0107] A third aspect of the present invention provides a method for plugging leaks in oil and gas reservoirs, comprising: injecting the plugging agent composition described in the first aspect into an oil and gas reservoir formation, wherein the composition flows into cracks and / or leak points in the oil and gas reservoir formation during the injection process, and condenses and solidifies at the cracks and / or leak points to form a solidified product having a pressure resistance of not less than 5 MPa at 100°C.

[0108] According to the present invention, preferably, the temperature of the oil and gas reservoir formation is 30-120°C.

[0109] According to the present invention, preferably, the width of the crack is 20 nm-2 mm; the size of the leakage point is 20 nm-300 nm.

[0110] In the present invention, the width of a crack refers to the maximum cross-sectional dimension of the crack, and the size of a leak point refers to the maximum cross-sectional dimension of the leak point.

[0111] The oil and gas reservoir plugging method provided by the present invention adopts the plugging agent composition described in the present invention as the plugging material, can realize self-driven plugging, and is particularly suitable for plugging in scenarios where the leakage location is uncertain. It is adaptable to a variety of operating environments from normal temperature and pressure to high temperature and high pressure, and can plug cracks and / or leaks of different sizes from nanometers to millimeters. It has excellent plugging effect and only condenses and solidifies at the cracks and / or leaks. The plugging agent composition that has not reached the cracks and / or leaks to play a plugging role can remain in a fluid state and be recovered. Compared with existing plugging methods, it has advantages in terms of plugging effect, applicable scenarios and construction cost.

[0112] The present invention is described in detail below by way of examples. In the following examples and comparative examples, where specific conditions are not specified, the experiments were conducted under conventional conditions or those recommended by the manufacturer. All reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0113] Agglomerating agent-1: 40 parts by weight of butyl acrylate, 0.02 parts by weight of sodium persulfate, and 2 parts by weight of sodium dodecylbenzenesulfonate were added to a reactor, stirred, and heated to 70°C; then, a solution consisting of 80 parts by weight of butyl acrylate, 30 parts by weight of methacrylic acid, 0.06 parts by weight of sodium persulfate, and distilled water was added dropwise to the reactor and stirred for 6 hours to obtain agglomerating agent-1.

[0114] Agglomerating agent-2: polyetheramine D-400, commercially available.

[0115] Base latex-1: commercially available carboxylated nitrile latex, with a solid content of 45% by weight, wherein the particle size of the latex particles measured by Malvern laser particle size analyzer (Mastersizer 3000) is 70-200 nm.

[0116] Latex Prepolymer-1: 3 parts by weight of the aforementioned agglomerating agent-1 were added to 100 parts by weight of the aforementioned base latex-1 under rapid stirring at 300 rpm. The pH of the system was adjusted to 9 with sodium hydroxide. After the addition was complete, the mixture was stirred at 300 rpm and heated to 50° C. with stirring. The reaction was carried out for 2 hours to obtain a latex prepolymer of carboxylated butadiene nitrile latex. The particle size of the latex particles in the carboxylated butadiene nitrile latex prepolymer was measured by a Malvern laser particle size analyzer (Mastersizer 3000) to be 430-580 nm.

[0117] Base latex-2: commercially available styrene acrylic latex, with a solid content of 45% by weight, wherein the particle size of the latex particles measured by Malvern laser particle size analyzer (Mastersizer 3000) is 80-220 nm.

[0118] Latex Prepolymer-2: 3 parts by weight of the aforementioned agglomerating agent-2 were added to 30 parts by weight of the aforementioned base latex-2 under stirring at 300 rpm. The mixture was heated to 40°C with stirring for 30 minutes and allowed to stand for 2 hours. Deionized water was then slowly added dropwise with stirring at 150 rpm to reduce the solids content of the emulsion to 35% by weight. OP-10 emulsifier, representing 1% of the total weight of the solid phase, was added and stirred at 300 rpm for 1 hour to obtain a styrene-acrylic latex prepolymer. The particle size of the latex particles in the styrene-acrylic latex prepolymer was measured to be 315-460 nm using a Malvern Mastersizer 3000 laser particle size analyzer.

[0119] Preparation Example 1

[0120] 100 kg of prenol polyoxyethylene ether (TPEG-2400) and 150 kg of deionized water were added to a reactor, stirred and heated to 70°C, and the temperature was maintained for 1 hour; 1.5 kg of hydrogen peroxide (30% by weight) was added to 15 kg of deionized water, stirred and added to the reactor; 7.5 kg of ascorbic acid and 1 kg of 3-mercaptopropionic acid were added to 17 kg of deionized water to prepare a mixed aqueous solution of a reducing agent and a chain transfer agent; 40 kg of acrylic acid (AA) was added to 40 kg of water; An acrylic acid aqueous solution was prepared by adding 1 kg of deionized water; the above-mentioned mixed aqueous solution of the reducing agent and chain transfer agent, 1 kg of silane coupling agent (KH-570), and the above-mentioned acrylic acid aqueous solution were simultaneously added dropwise to a round-bottom flask. The acrylic acid aqueous solution and KH-570 were added dropwise over 4 hours, and the mixed aqueous solution of the reducing agent and chain transfer agent was added dropwise over 4.5 hours under the control of a peristaltic pump; after the addition of all the materials was completed, the mixture was stirred at this temperature for 0.5 hours, and then cooled to room temperature to obtain a stabilizer sample 1 (solid content 40 wt%);

[0121] The weight average molecular weight of stabilizer sample 1 was measured by gel chromatography and was 35000 g / mol;

[0122] In stabilizer sample 1, structural unit A Structural unit B Structural unit C The molar ratio is 800:100:10; based on the total weight of stabilizer sample 1, the content of siloxy group (i.e., cross-linked group) calculated according to the raw material feeding amount is 0.37 weight%.

[0123] Preparation Example 2

[0124] 100 kg of isopentanol polyoxyethylene ether (TPEG-2400) and 150 kg of deionized water were added to the reactor, stirred and heated to 70°C, and the temperature was maintained for 1 hour; 1.5 kg of hydrogen peroxide (30% by weight) was added to 15 kg of deionized water, stirred and added to the reactor; 75 kg of ascorbic acid and 10 kg of 3-mercaptopropionic acid were added to 17 kg of deionized water to prepare a mixed aqueous solution of a reducing agent and a chain transfer agent; 1083 kg of itaconic acid (IA) was added to 200 0kg deionized water to prepare an itaconic acid aqueous solution; the above-mentioned reducing agent and chain transfer agent mixed aqueous solution, 40kg silane coupling agent (KH-570), and the above-mentioned itaconic acid aqueous solution were simultaneously added dropwise to a round-bottom flask, and the itaconic acid aqueous solution and KH-570 were added dropwise in 4 hours by a peristaltic pump, and the reducing agent and chain transfer agent mixed aqueous solution were added dropwise in 4.5 hours; after all the materials were added dropwise, the mixture was kept warm and stirred for 0.5 hours, and then cooled to room temperature to obtain a stabilizer sample 2 (solid content 37wt%);

[0125] The weight average molecular weight of stabilizer sample 2 was measured by gel chromatography and was 32000 g / mol;

[0126] In stabilizer sample 2, structural unit A Structural unit B Structural unit C The molar ratio is 2000:100:400; based on the total weight of stabilizer sample 2, the content of siloxy group (i.e., cross-linked group) calculated according to the raw material feeding amount is 1.54 weight%.

[0127] Preparation Example 3

[0128] 100 kg of prenol polyoxyethylene ether (TPEG-2400) and 150 kg of deionized water were added to a reactor, stirred and heated to 70°C, and the temperature was maintained for 1 hour; 0.3 kg of hydrogen peroxide (30% by weight) was added to 15 kg of deionized water, stirred and added to the reactor; 1.5 kg of ascorbic acid and 0.2 kg of 3-mercaptopropionic acid were added to 17 kg of deionized water to prepare a mixed aqueous solution of a reducing agent and a chain transfer agent; 9 kg of vinyl sulfonic acid was added to 40 kg of deionized water to prepare a mixture of a reducing agent and a chain transfer agent; to form a vinyl sulfonic acid aqueous solution; the above-mentioned mixed aqueous solution of the reducing agent and the chain transfer agent, 0.2 kg of vinyl octadecyltrimethoxysilane, and the above-mentioned vinyl sulfonic acid aqueous solution were simultaneously added dropwise to a round-bottom flask, and the vinyl sulfonic acid aqueous solution and vinyl octadecyltrimethoxysilane were added dropwise in 4 hours by a peristaltic pump, and the mixed aqueous solution of the reducing agent and the chain transfer agent was added dropwise in 4.5 hours; after all the materials were added dropwise, the mixture was kept warm and stirred for 0.5 hours, and then cooled to room temperature to obtain a stabilizer sample 3 (solid content 33wt%);

[0129] The weight average molecular weight of stabilizer sample 3 was measured by gel chromatography and was 38000 g / mol;

[0130] In stabilizer sample 3, structural unit A Structural unit B Structural unit C The molar ratio is 200:100:1; based on the total weight of stabilizer sample 3, the content of siloxy group (i.e., cross-linked group) calculated according to the raw material feeding amount is 0.04 weight%.

[0131] Preparation Example 4

[0132] 100 kg of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was added to 200 kg of deionized water and stirred until dissolved, and the pH value of the resulting aqueous solution of 2-acrylamido-2-methylpropanesulfonic acid was adjusted to 10; the temperature was raised to 65° C., 37 kg of itaconic acid was added, and the mixture was stirred evenly. At the same time, 17 kg of a 10% mass concentration of azobisisobutylamidine hydrochloride initiator solution and 15 kg of γ-glycidyloxypropyltrimethoxysilane (KH-560) were respectively added dropwise; while the addition was being added dropwise, the temperature was slowly raised to 75° C. After the addition was complete, the reaction was continued for 4 hours, and then the temperature was cooled to room temperature to prepare stabilizer sample 4 (solid content 39 wt%);

[0133] The weight average molecular weight of stabilizer sample 4 was measured by gel chromatography and was 27000 g / mol;

[0134] In stabilizer sample 4, structural unit A Structural unit B Structural unit C The molar ratio is 59:100:13; based on the total weight of stabilizer sample 4, the content of siloxy group (i.e., cross-linked group) calculated according to the raw material feeding amount is 5.56 weight%.

[0135] Preparation Example 5

[0136] 60 g of N-methylpyrrolidone and 50 g of prenol polyoxyethylene ether (TPEG-2400) were weighed, dissolved and mixed, and then placed in a three-necked flask in a constant temperature water bath, stirred at a speed of 200 rpm, and heated to 70° C.; 0.7 g of azobisisobutyronitrile was weighed and dissolved in 20 g of N-methylpyrrolidone, and mixed uniformly to prepare solution A; 12 g of 4-vinylphenylboric acid, 22 g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and 1 g of vinyltriacetoxysilane were weighed and dissolved in 55 g of N-methylpyrrolidone, and mixed uniformly to prepare solution B; the above solutions A and B were uniformly added dropwise to the three-necked flask via a peristaltic pump for 2 hours; after the addition was completed, the mixture was kept at 60° C. for 2 hours, and 60 g of water was uniformly added dropwise over 2 hours. After the reaction was completed, the pH of the polymer was adjusted to 9 and then cooled to room temperature to prepare stabilizer sample 5 (solid content 38 wt%);

[0137] The weight average molecular weight of polymer stabilizer 5 was measured by gel chromatography and was 60,000 g / mol;

[0138] In stabilizer sample 5, the structural unit Structural unit Structural unit The molar ratio is 389:600:21; based on the total weight of stabilizer sample 5, the content of siloxy group (i.e., cross-linked group) is calculated to be 1.17 wt % according to the raw material feeding amount.

[0139] Comparative Preparation Example 1

[0140] According to the method of Preparation Example 1, except that the silane coupling agent KH-570 was not added, the other conditions were the same as Preparation Example 1, and stabilizer sample 6 (solid content of 40wt%) was prepared.

[0141] Example 1

[0142] Plugging agent composition-1: 20 kg base latex-1, 2 kg stabilizer sample 1, 10 kg latex prepolymer-1 and 2 kg surfactant OP-10.

[0143] According to the proportions of the components in the above-mentioned plugging agent composition-1, base latex-1, surfactant OP-10 and water (the weight ratio of base latex-1: water is 1:0.4) were added to the reactor and stirred for 30 minutes; then stabilizer sample 1 was added and stirred for 15 minutes; then latex prepolymer-1 was added and stirred for 15 minutes to prepare a plugging agent suspension (denoted as S1).

[0144] Example 2

[0145] Plugging agent composition-2: 20 kg base latex-1, 2 kg stabilizer sample 2, 10 kg latex prepolymer-1 and 2 kg surfactant OP-10.

[0146] The plugging agent composition-2 and water were used to prepare a plugging agent suspension (denoted as S2) using the same method and parameters as in Example 1.

[0147] Example 3

[0148] Plugging agent composition-3: 20 kg base latex-1, 2 kg stabilizer sample 3, 10 kg latex prepolymer-1 and 2 kg surfactant OP-10.

[0149] The plugging agent composition-3 and water were used to prepare a plugging agent suspension (denoted as S3) using the same method and parameters as in Example 1.

[0150] Example 4

[0151] Plugging agent composition-4: 20 kg base latex-1, 2 kg stabilizer sample 4, 10 kg latex prepolymer-1 and 2 kg surfactant OP-10.

[0152] The plugging agent composition-4 and water were used to prepare a plugging agent suspension (denoted as S4) using the same method and parameters as in Example 1.

[0153] Example 5

[0154] Plugging agent composition-5: 20 kg base latex-1, 2 kg stabilizer sample 5, 10 kg latex prepolymer-1 and 2 kg surfactant OP-10.

[0155] The plugging agent composition-5 and water were used to prepare a plugging agent suspension (denoted as S5) using the same method and parameters as in Example 1.

[0156] Example 6

[0157] Plugging agent composition-6: 20 kg base latex-2, 2 kg stabilizer sample 1, 10 kg latex prepolymer-2 and 2 kg surfactant OP-10.

[0158] The plugging agent composition-6 and water were used to prepare a plugging agent suspension (denoted as S6) using the same method and parameters as in Example 1.

[0159] Example 7

[0160] Plugging agent composition-7: 20 kg base latex-1, 6 kg stabilizer sample 1, 10 kg latex prepolymer-1 and 6 kg surfactant OP-10.

[0161] The plugging agent composition-7 and water were used to prepare a plugging agent suspension (denoted as S7) using the same method and parameters as in Example 1.

[0162] Example 8

[0163] Sealing agent composition-8: 20 kg base latex-1, 6 kg purified stabilizer sample 1 (6 kg stabilizer sample 1 was purified by dialysis, and the purified liquid was freeze-dried to obtain 2.33 kg solid, and then the solid was dissolved in water to obtain 6 kg purified stabilizer sample 1), 10 kg latex prepolymer-1 and 6 kg surfactant OP-10.

[0164] The plugging agent composition-8 and water were used to prepare a plugging agent suspension (denoted as S8) using the same method and parameters as in Example 1.

[0165] Example 9

[0166] Plugging agent composition-9: 20 kg base latex-1, 2 kg stabilizer sample 1 and 2 kg surfactant OP-10.

[0167] According to the proportions of the components in the above-mentioned plugging agent composition-9, base latex-1, surfactant OP-10 and water (the weight ratio of base latex-1: water is 1:0.4) were added to the reactor and stirred for 30 minutes; then stabilizer sample 1 was added and stirred for 15 minutes to prepare a plugging agent suspension (denoted as S9).

[0168] Example 10

[0169] Plugging agent composition-10: 10 kg of latex prepolymer-1, 2 kg of stabilizer sample 1, and 2 kg of surfactant OP-10.

[0170] According to the proportions of the components in the above-mentioned plugging agent composition-10, latex prepolymer-1, surfactant OP-10 and water (the weight ratio of latex prepolymer-1:water is 1:0.4) were added to the reactor and stirred for 30 minutes; then, stabilizer sample 1 was added and stirred for 15 minutes to prepare a plugging agent suspension (denoted as S10).

[0171] Comparative Example 1

[0172] The method of Example 1 was followed, except that the stabilizer sample 1 was omitted from the components of the plugging agent composition-1. Other conditions were the same as those of Example 1, to prepare a plugging agent suspension (denoted as D1).

[0173] Comparative Example 2

[0174] A plugging agent suspension (denoted as D2) was prepared according to the method of Example 1, except that the stabilizer sample 1 in the components of the plugging agent composition-1 was replaced with an equal weight of silane coupling agent KH-570. Other conditions were the same as those of Example 1.

[0175] Comparative Example 3

[0176] A plugging agent suspension (denoted as D3) was prepared according to the method of Example 1, except that the stabilizer sample 1 in the components of the plugging agent composition-1 was replaced by an equal weight of the stabilizer 6 prepared in the comparative preparation example 1. Other conditions were the same as those of Example 1.

[0177] Test Case

[0178] 1. Stability and temperature resistance test

[0179] The plugging agent suspensions S1-S10 and D1-D3 prepared in Examples 1-10 and Comparative Examples 1-3 were aged using a high-pressure hydrothermal autoclave at an aging temperature of 120° C. for 16 h. The results are shown in Table 1.

[0180] Table 1

[0181] As shown in Table 1, the plugging agent suspensions S1-S10 can remain stable after aging at 120°C for 16 hours without thickening or gelling. This indicates that the stabilizer samples of the present invention can stabilize the polymer latex in the absence of cracks and / or leaks and have good high-temperature resistance.

[0182] 2. 10μm width crack sealing test

[0183] The plugging performance of the plugging agent was evaluated using the American Fann permeability plugging instrument (PPA model). The instrument is equipped with different specifications of filtration media, such as sand discs, ordinary filter paper or cracked stainless steel discs. The different specifications of filtration media can simulate cracks of different sizes from 10 microns to several millimeters. The maximum test temperature and maximum test pressure of the instrument are 260 ° C and 34.5 MPa, respectively.

[0184] Test method: A sand tray with a 10μm crack width was selected. 300ml of the plugging agent suspensions S1-S10 and D1-D3 prepared in Examples 1-10 and Comparative Examples 1-3, respectively, was added to the permeability plugging instrument. The test temperature of the permeability plugging instrument was then adjusted to 100°C. Pressurization was initiated, starting at 0.5MPa and increasing in increments of 0.5MPa until reaching 12MPa. At each pressure level, the pressure was maintained at a constant level of dripping or no leakage for 30 minutes, then increased by 0.5MPa. The plugging results of the sand trays S1-S10 and D1-D3 for 10μm cracks are shown in Table 2.

[0185] Table 2

[0186] As shown in Table 2, the plugging agent suspension prepared from the plugging agent composition provided by the present invention has excellent plugging performance for smaller micron-sized cracks (e.g., cracks with a width of 10 μm), with leakage no greater than 105 mL. The cured product can withstand a pressure of up to 12 MPa at 100°C. D1 and D2 are unusable as plugging agents. D3 has poor plugging performance and exhibits high leakage.

[0187] 3. 250μm width crack sealing test

[0188] According to the method of Test Example 2, the plugging performance of S1-S10 and D1-D3 was tested using the American Fann permeability plugging instrument (PPA type). The difference was that a sand disc with a crack width of 250 μm was used. The other steps and conditions were the same as those of Test Example 2. The results are shown in Table 3.

[0189] Table 3

[0190] As shown in Table 3, the plugging agent suspension prepared from the plugging agent composition provided by the present invention exhibited excellent plugging performance for cracks with a width of 250 μm, with a leakage loss of no more than 180 mL, and the cured product exhibited a pressure resistance of no less than 10 MPa at 100°C. Similar to the situation in Test Example 2, D1 and D2 were unusable as plugging agents. D3 exhibited poor plugging performance and exhibited significant leakage.

[0191] Test Example 4: 2mm width crack sealing test

[0192] Preparation of plugging slurry: 1 kg of walnut shell (particle size 270-350 μm), 1 kg of elastic rubber (particle size 780-850 μm) and 500 g of polypropylene fiber (fiber length 30-40 mm) were added to 20 kg of the plugging agent suspensions S1-S10 and D1-D3 prepared in Examples 1-10 and Comparative Examples 1-3, respectively, and stirred for 15 minutes to prepare the plugging slurry.

[0193] The plugging performance of the plugging slurry was tested using a Fann permeability plugging instrument (PPA) according to the method of Test Example 2, except that a sand disc with a 2 mm wide crack was used and the test temperature was 120°C. All other steps and conditions were the same as those of Test Example 2. The results are shown in Table 4.

[0194] Table 4

[0195] Table 4 shows that the plugging agent suspension prepared from the plugging agent composition provided by the present invention, combined with bridging materials (walnut shells, elastic rubber, and polypropylene fibers), can effectively plug cracks as wide as 2 mm. The cured product can withstand a pressure of 12 MPa at 120°C, and the leakage rate is no more than 100 mL. D1 and D2 gelled at 120°C and were unable to effectively plug 2 mm cracks, even when combined with bridging materials. D3 had poor plugging effect and a large leakage rate.

[0196] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A plugging agent composition comprising a polymer latex and a stabilizer, wherein: The stabilizer has a crosslinkable group and / or a coupling group; in the presence of cracks and / or leaks, the crosslinkable group and / or coupling group in the stabilizer undergoes crosslinking or coupling, causing the polymer latex to coagulate and solidify.

2. The composition according to claim 1, wherein The solidified product formed by the solidification can withstand a pressure of not less than 5 MPa at 100° C., preferably 5-12 MPa.

3. The composition according to claim 1 or 2, wherein The concentration of metal cations in the composition is less than 0.1% by weight; Preferably, the composition does not contain metal cation demulsifiers.

4. The composition according to any one of claims 1 to 3, wherein The weight ratio of the polymer latex to the stabilizer is 1:(0.0001-0.2), preferably 1:(0.001-0.1).

5. The composition according to any one of claims 1 to 4, wherein The content of the crosslinkable groups and / or coupling groups in the stabilizer is 0.001-20 wt %, preferably 0.01-8 wt %, based on the total weight of the stabilizer.

6. The composition according to claim 5, wherein The crosslinkable group and / or coupling group is a siloxy group.

7. The composition according to claim 5 or 6, wherein The stabilizer also contains At least one of the groups; wherein M1, M2, M3, M4, M5 and M6 are each independently selected from H + 、Na + , K + or NH4 + ; Preferably, the weight average molecular weight of the stabilizer is 10,000-100,000 g / mol, more preferably 20,000-50,000 g / mol.

8. The composition according to claim 5 or 6, wherein The stabilizer has a structural unit A represented by formula (1), a structural unit B represented by formula (2) or formula (3), and a structural unit C represented by formula (4) or formula (5); Wherein, in formula (1), R1, R2, R3, and R4 are each independently selected from -H, -CH3, -COOM 1 、-SO3M 2 、-CH2COOM 3 、-CH2SO3M 4 、 or -CONHC(CH3)2CH2SO3M 8 , and R1, R2, R3, and R4 are not selected from -H or -CH3 at the same time; wherein, M 1 、M 2 、M 3 、M 4 、M 5 、M 6 、M 7 and M 8 Each independently selected from H + , K + 、Na + or NH4 + ; In formula (2), R5, R6, and R7 are each independently selected from -H or C1-C 18 alkyl; R8 is selected from C1-C3 alkylene; R9 is selected from C1-C3 alkylene; In formula (3), R 10 、R 11 、R 12 、R 13 、R 14 are each independently selected from -H or C1-C4 alkyl; R 15 is selected from C1-C4 alkylene; Q is selected from H + , K + 、Na + or NH4 + ; In formula (4), R 16 、R 17 、R 18 Each independently selected from -H or C1-C 18 Alkyl; R 19 Selected from chemical bonds, C1-C 18 Alkylene or -COOCH2CH2CH2-; R 20 Selected from C1-C2 alkyl, -CH2OCH3 or -CH2CH2OCH3; In formula (5), R 21 、R 22 、R 23 Each independently selected from -H or C1-C 18 Alkyl; R 24 Selected from C1-C 18 Alkylene; R 25 An alkylene group selected from C1-C3; R 26 an alkyl group selected from C1-C2; The molar ratio of structural unit A:structural unit B:structural unit C is (1-2000):100:(0.01-400).

9. The composition according to any one of claims 1 to 8, wherein The polymer latex is selected from at least one of nitrile butadiene latex, styrene butadiene latex, styrene acrylic latex, butyl latex, pure acrylic latex, chloroprene latex, natural rubber latex, fluororubber latex, polybutadiene latex, EPDM latex, silicone rubber latex and polyacrylate latex, preferably nitrile butadiene latex and / or styrene acrylic latex.

10. The composition according to any one of claims 1 to 9, wherein The polymer latex contains latex particles with a particle size of 20-300 nm and / or latex particles with a particle size of 300 nm-2 mm.

11. The composition according to any one of claims 1 to 10, wherein The composition further comprises a surfactant; Preferably, the surfactant is selected from anionic surfactants and / or nonionic surfactants; Preferably, the anionic surfactant is selected from at least one of polyacrylamide, alkylbenzene sulfonate, alkylphenol polyoxyethylene ether ammonium sulfate, fatty acid sulfoalkyl ester, alkyl sulfonate salt, alkyl sulfonate, polysiloxane, α-olefin sulfonate and alkylolamide, and more preferably alkylphenol polyoxyethylene ether ammonium sulfate; Preferably, the nonionic surfactant is selected from at least one of alkylphenol polyoxyethylene ether, polyol monofatty acid ester, alkylamine oxide and N-alkylpyrrolidone, and more preferably alkylphenol polyoxyethylene ether.

12. The composition according to claim 11, wherein The weight ratio of the polymer latex to the surfactant is 1:(0.0001-0.2), preferably 1:(0.001-0.1).

13. The composition according to any one of claims 1 to 12, wherein The composition further comprises a bridging material; Preferably, the bridging material is selected from at least one of walnut shells, elastic particles and fiber materials; Preferably, the particle size of the walnut shell is 150-450 μm; the particle size of the elastic particles is 450-850 μm; and the fiber length of the fiber material is 5-40 mm. Preferably, the weight ratio of the polymer latex to the bridging material is 1:(0.001-1), more preferably 1:(0.01-0.2).

14. Use of the plugging agent composition according to any one of claims 1 to 13 in plugging leaks in oil and gas reservoirs.

15. A method for plugging leaks in an oil and gas reservoir, comprising: The plugging agent composition according to any one of claims 1 to 13 is injected into an oil and gas reservoir formation. During the injection process, the composition flows into the cracks and / or leak points of the oil and gas reservoir formation, and condenses and solidifies at the cracks and / or leak points to form a solidified product having a pressure resistance of not less than 5 MPa at 100°C.

16. The method according to claim 15, wherein The temperature of the oil and gas reservoir formation is 30-120°C; Preferably, the width of the crack is 20nm-2mm; the size of the leakage point is 20nm-300nm.