High-temperature and high-salinity reservoir depth profile control gel water shutoff agent and preparation method thereof

Abstract

The application discloses a high-temperature and high-salt oil reservoir deep profile control gel water shutoff agent and a preparation method thereof. The gel main agent is prepared from acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer and core-shell polymer with acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer as the core, and is crosslinked with a high-temperature resistant organic crosslinking agent. The acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is crosslinked with the high-temperature resistant organic crosslinking agent first to form the gel, when the gel gradually appears a small amount of degradation or hydration, the high-temperature resistant / anti-shearing core-shell structure polymer dispersion dispersed in the gel is gradually exposed, at the same time, the shell layer is broken to release the core polymer to be dissolved and absorb the gel degradation and hydration liquid, and the high-temperature resistant organic crosslinking agent is crosslinked again, and the crosslinking can be prolonged to more than 60 days at 120 DEG C and 41938.8 mg / L salinity.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-temperature and high-salt reservoir depth profile control gel water shutoff agent and its preparation method, belonging to the technical field of oil development. BACKGROUND

[0002] With the development of oilfield development, the complexity of oil storage space structure and the problem of reservoir heterogeneity are increasingly prominent. The range of water flooding is very limited, resulting in a large amount of water flowing into the high permeability zone, and ultimately the water forms an invalid channeling bypass, thereby significantly reducing the recovery rate and increasing the cost of oilfield development. Oil well water outflow can also destroy the structure of the reservoir, causing a large amount of sand to be carried out of the well; at the same time, oil well water outflow can accelerate the corrosion of downhole equipment, becoming a hidden danger of sudden accidents. Therefore, profile control and water shutoff are being more and more widely used as a reasonable and effective important measure. The effect of profile control and water shutoff can be reflected in: plugging high permeability layers in oil wells, activating low permeability layers to play a role, reducing water cut, and improving production rate. Changing the water drive route to avoid invalid channeling is a means that can effectively plug high permeability layers and improve water drive efficiency value and expand swept volume.

[0003] In the 1990s, Mack et al. first developed a polyacrylamide profile control and water shutoff technology using the adsorption and capture principle of chemical agents in pore throat media. Later, many experts and scholars conducted in-depth research on the basis of this and proposed deep profile control and water shutoff technology. Since the 21st century, foreign and domestic reports have focused on deep profile control and water shutoff, respectively, using microorganisms, precipitation, gel, and colloidal dispersion gel to implement deep profile control, and good results have been achieved.

[0004] Polymer gel plugging agents are commonly used to plug channeling channels and improve recovery. It is a substance with a network structure formed by high molecular weight polymers losing fluidity through the action of crosslinking agents. Polymer gels are widely used due to their high temperature and high salt resistance, and the preparation process is relatively simple, making them a popular topic among researchers. The most common polymer is polyacrylamide.

[0005] In recent years, research results on gel formed by crosslinking temperature-resistant and salt-resistant polyacrylamide as the main gel-forming agent with organic crosslinking agents have been disclosed. For example, CN113897189B uses non-ionic polyacrylamide and temperature-resistant and salt-resistant acrylamide / 2-acrylamide-2-methylpropanesulfonic acid sodium complex as the main gel-forming agent of the gel system, which shortens the gelation start-up time of the gel. However, this type of existing gel water shutoff agent breaks and hydrates under high salt and high salinity conditions within 30 days.

[0006] In order to prolong the gelation time of the deep profile control water plugging under the condition of 120 DEG C, more effectively maintain the gel strength without decline, and reduce the risk of opening the channeling channel and water outflow caused by the premature failure of profile control water plugging, the present application is proposed. SUMMARY

[0007] The present application aims to solve the technical deficiency of the existing gel type profile control water plugging agent, and provides a high-temperature and high-salt oil reservoir deep profile control water plugging gel system and its preparation method, which can prolong the gelation stability of the gel system to 60 days without gel breaking and hydration under the premise of ensuring the gel strength and stability of the gel system at the temperature of 120 DEG C and the salinity of 41938.8 mg / L, greatly prolongs the gelation stability of the gel system, and achieves the effect of deep profile control water plugging.

[0008] The technical scheme adopted by the present application is: a high-temperature and high-salt oil reservoir deep profile control water plugging agent, characterized by being composed of the following components in percentage of the mass of the gel: 0.8%-1.2% of a gelation main agent, 0.3%-0.6% of a high-temperature resistant organic crosslinking agent, and the rest being a simulated salt water solvent.

[0009] Further, the gelation main agent comprises acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer and core-shell polymer.

[0010] Further, the weight percentage of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer in the gelation main agent is 65%-80%, and the weight percentage of the core-shell polymer in the gelation main agent is 20%-35%.

[0011] Further, the molecular weight of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is 10-15 million, and the mole percentage of 2-acrylamido-2-methylpropanesulfonic acid sodium in the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is 45%.

[0012] Further, the core-shell polymer comprises a shell layer and a core, and the core is synthesized by acrylamide and 2-acrylamido-2-methylpropanesulfonic acid sodium, wherein the mole percentage of 2-acrylamido-2-methylpropanesulfonic acid sodium monomer is 45%-55%; the shell layer is composed of one of vinyl polyethylene glycol ether-1000 (VPEG-1000) or ethylene glycol monovinyl polyoxyethylene ether (EPEG-1000), and the weight percentage of the shell layer in the core-shell polymer is 4%-8%.

[0013] The preparation method of the core-shell polymer comprises the following steps:

[0014] S1: nucleation reaction:

[0015] Core layer emulsion: in a 2L reactor, 300-400 parts of water, 2-8 parts of non-ionic surfactant A, 2-8 parts of non-ionic surfactant B, 4-10 parts of anionic surfactant C, 60-120 parts of acrylamide, 240-300 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 0.01-0.05 parts of sodium formate, 0.05-0.1 parts of disodium ethylenediaminetetraacetate are added, the pH is adjusted to 6.3-6.5, and the mixture is stirred and mixed thoroughly to emulsify uniformly;

[0016] After 40 minutes of nitrogen replacement, 0.005-0.02 parts of benzoyl peroxide are added and stirred uniformly, then the reaction is initiated with 1g / L sodium bisulfite solution, the reaction temperature is controlled to rise at a speed of 30-40s / 0.5℃, the whole reaction temperature is controlled at 48-50℃, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25℃, the core emulsion is obtained, and nitrogen is kept blowing;

[0017] S2: shell reaction:

[0018] Shell water phase: in 200-300 parts of deionized water, 15-20 parts of one of VPEG-1000 or EPEG-1000 are added, and 1-5 parts of non-ionic surfactant D are added, and the mixture is stirred and mixed thoroughly to obtain the shell water phase;

[0019] The above core emulsion is kept at 25℃ under nitrogen, 0.01-0.02 parts of ammonium persulfate and 0.2 parts of azobisdimethylaminoformamidine dihydrochloride (V50) are added, and then the shell water phase is slowly added and stirred uniformly; the shell reaction is carried out by continuously dropping 1g / L sodium metabisulfite solution, and the reaction temperature is controlled to rise at a speed of 30-40s / 0.5℃, when the temperature reaches 80℃, the reaction is kept for 3 hours, and then the temperature is lowered to obtain the polymer;

[0020] S3: powder making:

[0021] The above polymer is obtained by spray drying to obtain a 50-100μm polymer powder, i.e. a fine powder-like core-shell polymer.

[0022] Further, the non-ionic surfactant A is one or more of SPAN40, SPAN65, SPAN80; the non-ionic surfactant B is one or more of AEO-3, AEO-7, AEO-9; the anionic surfactant C is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, triethanolamine dodecyl benzene sulfonate; and the non-ionic surfactant D is one or more of coconut monoethanolamine, coconut diethanolamine, myristic acid diethanolamine.

[0023] Further, the high-temperature-resistant organic crosslinking agent is an organic aluminum-zirconium crosslinking agent.

[0024] Further, the preparation steps of the high-temperature-resistant organic aluminum-zirconium crosslinking agent are as follows:

[0025] In a three-necked flask, 150-250 parts of deionized water is added, and after being heated to 60°C, 50-150 parts of polyhydric alcohol is slowly added while stirring;

[0026] During stirring, 10-20 parts of aluminum salt and 15-25 parts of zirconium salt are added to the solution of step 1) by weight fraction, and they are fully stirred to dissolve;

[0027] The temperature of the reactor is adjusted to 80°C, 15-25 parts of organic acid, 5-15 parts of gluconate, and 1-5 parts of crosslinking aid are added by weight fraction, and after complete dissolution by stirring, the complexation reaction is carried out at 80°C reflux for 4 hours, and then slowly cooled to room temperature to obtain the high-temperature-resistant organic aluminum-zirconium crosslinking agent.

[0028] Further, the zirconium salt is one or both of zirconium oxychloride and zirconium chloride; the aluminum salt is one or both of aluminum chloride and aluminum sulfate; the polyhydric alcohol is one or more of ethylene glycol, propylene glycol, and glycerol; the organic ligand is one or more of potassium gluconate and sodium gluconate; the organic acid is one or both of lactic acid and succinic acid; and the crosslinking aid is one or both of dimethyl diimine ester and N,N'-methylene bisacrylamide.

[0029] Further, the simulated brine salinity is 41938.8 mg / L, wherein the Ca2+ concentration is 9693.7 mg / L and the Mg2+ concentration is 1123.1 mg / L.

[0030] A preparation method of a high-temperature and high-salt reservoir depth profile control gel water shutoff agent, characterized in that: 0.65-0.80% of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer powder and 0.20-0.35% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L, a Ca2+ concentration of 9693.7 mg / L, and a Mg2+ concentration of 1123.1 mg / L, and fully stirred and dispersed for 60 minutes, and then 0.3-0.6% of an organic aluminum-zirconium crosslinking agent is added and continuously stirred for 60 minutes.

[0031] The high-temperature and high-salt oil reservoir depth profile control jell blocking water agent has the beneficial effects of the prior art as follows: the core-shell polymer and the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer are compounded in a high-temperature and salt-resistant manner, so that the jell forming time is significantly prolonged, and the jell strength and stability are more long-acting and persistent. The shell layer of the core-shell polymer adopts a vinyl polyethylene glycol ether-1000 (VPEG-1000) or ethylene glycol monovinyl polyoxyethylene ether-1000 (EPEG-1000) macromonomer, the unsaturated double bond in the molecular structure of which is directly connected with an oxygen atom to form a molecular structure of a group of C-O bonds, so that the electron cloud distribution of the C=C double bond is deviated to improve the charge environment, and the reaction activity of the double bond in the macromonomer is very high, and the polymerization reaction is more easily performed.

[0032] The acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is first crosslinked with the high-temperature-resistant organic aluminum zirconium crosslinking agent to form jell, and the core-shell polymer is completely retained due to the characteristics of temperature resistance, salt resistance and mechanical shear resistance, and is not involved in the crosslinking reaction in the early stage, and the hydrophilic groups on the surface of the shell layer of the core-shell polymer swell rapidly to form a dispersion after water absorption, and the double bond in the shell layer molecule of the core-shell polymer is a substitution structure, which further reduces the steric hindrance of the swing of the polyether side chain, the increase in the swing freedom of the hydrophilic polyether side chain improves the wrapping and adsorption of water, and the characteristics make the core-shell copolymer become a high-temperature-resistant and salt-resistant surface dispersion, which is wrapped in the jell formed above. After the action of the high-temperature and high-salt 120℃, 41938.8mg / L simulated brine for a period of time, the jell gradually degrades and hydrates, and the core-shell structure polymer dispersion in the jell gradually exposes and the hydrophilic shell layer is broken under the action of high temperature and high salt, and the released core polymer dissolves and absorbs the jell hydration liquid in the early stage, and then is secondarily crosslinked with the high-temperature-resistant organic crosslinking agent in the jell system. In this way, the jell strength and long-acting stability are ensured, and the effective time of the jell profile control and water blocking in the formation depth is prolonged to more than 60 days. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The jell forming strength grade evaluation (the jell forming strength gradually increases from A to L). DETAILED DESCRIPTION

[0034] The following examples of the present application simulate the brine with a salinity of 41938.8mg / L, and the water quality analysis results of the flowback fluid in the Xinjiang Jimsar block are simulated.

[0035] The following examples of the present application relate to the preparation method of the high-temperature-resistant organic aluminum zirconium crosslinking agent.

[0036] 1) In a three-necked flask, 160 parts of deionized water was added, and after being heated to 60°C, 75 parts of propylene glycol was slowly added while stirring, and stirred for 20 minutes;

[0037] 2) During stirring, 15 parts of aluminum sulfate and 18 parts of zirconium oxychloride were added to the solution of step 1), and they were fully dissolved by stirring,

[0038] 3) The temperature of the reactor was adjusted to 80°C, 21 parts of lactic acid and 12 parts of potassium gluconate were added, 3 parts of dimethyl imine ester was added, and after fully dissolving by stirring, the complexing reaction was carried out at 80°C reflux for 4 hours, and then slowly cooled to room temperature to obtain the high-temperature resistant organic aluminum zirconium crosslinking agent;

[0039] In the following examples and comparative examples, the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer powder is commercially available, and the molar percentage of 2-acrylamido-2-methylpropanesulfonic acid sodium is 45%.

[0040] Example 1: Preparation of core-shell polymer:

[0041] Example 1: Preparation of core-shell polymer: S1: nucleation reaction:

[0042] Core layer emulsion: In a 2L reactor, 350 parts of water, 5 parts of SPAN80, 4 parts of AEO-7, 7 parts of dodecylbenzenesulfonic acid triethanolamine salt, 96 parts of acrylamide, 254 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium, 0.03 parts of sodium formate, and 0.08 parts of ethylenediaminetetraacetic acid disodium, were added, and the pH was adjusted to 6.3-6.5, and the mixture was fully stirred to emulsify uniformly;

[0043] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide was added and stirred uniformly, then the reaction was initiated with 1g / L sodium bisulfite solution, and the reaction temperature was controlled at 48-50°C by controlling the dropping speed to make the temperature rise at a speed of 30-40s / 0.5°C, and the polymerization reaction was carried out for 4.5 hours, and then cooled to 25°C, and the core emulsion was obtained and kept under nitrogen;

[0044] S2: shell coating reaction:

[0045] Shell water phase: 250 parts of deionized water, 19 parts of VPEG-1000, and 2.5 parts of coconut oil diethanolamine were added, and the mixture was fully stirred to obtain the shell water phase;

[0046] The above core layer emulsion is kept at 25°C under nitrogen, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, and then the shell layer aqueous phase is slowly added, and fully stirred to be uniform; the shell coating reaction is carried out by continuously dropping 1 g / L sodium bisulfite solution, the reaction temperature is controlled at 30-40 s / 0.5°C, when the temperature reaches 80°C, it is kept for 3 hours, after the reaction is completed, the temperature is lowered, and the polymer is obtained;

[0047] S3: powdering:

[0048] The above polymer is obtained by spray drying to obtain 50-100 μm polymer powder, i.e. core-shell polymer fine powder;

[0049] A preparation method of a high-temperature and high-salt oil reservoir depth profile control jell agent: according to mass percentage, 0.65% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.35% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L, fully stirred, dispersed and dissolved for 60 minutes, 0.5% of organic aluminum zirconium crosslinking agent is added and continuously stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the gel strength and hydration condition are observed and tracked for 60 days. Example 2:

[0050] S1: nucleation reaction:

[0051] Core layer emulsion: in a 2L reactor, 350 parts of water, SPAN80 6 parts, AEO-7 3 parts, dodecylbenzenesulfonic acid triethanolamine salt 7 parts, acrylamide 83 parts, 2-acrylamido-2-methylpropane sulfonic acid sodium 268 parts, sodium formate 0.03 parts, and ethylenediaminetetraacetic acid disodium 0.08 parts are added, the pH is adjusted to 6.3-6.5, and the mixture is fully stirred and emulsified;

[0052] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide are added and stirred uniformly, then 1 g / L sodium bisulfite solution is used to initiate the reaction, the reaction temperature rising speed is controlled at 30-40 s / 0.5°C by controlling the dropping speed, the whole reaction temperature is controlled at 48-50°C, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25°C, the core emulsion is obtained, and nitrogen is kept blowing;

[0053] S2: shell coating reaction:

[0054] Shell layer aqueous phase: 250 parts of deionized water, 18 parts of VPEG-1000, and 2.5 parts of cocodimethyl ethanolamine are added, fully stirred and uniformly prepared into a shell layer aqueous phase;

[0055] The above core layer emulsion is kept at 25℃ under nitrogen condition, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, then the shell layer aqueous phase is slowly added, and fully stirred to be uniform; the coating reaction is carried out by continuously dropping 1g / L sodium bisulfite solution, the reaction temperature rising speed is controlled to be 30-40s / 0.5℃, when the temperature reaches 80℃, the reaction is kept for 3 hours, after the reaction is finished, the temperature is lowered, and the polymer is obtained;

[0056] S3: powdering:

[0057] The above polymer is obtained by spray drying to obtain 50-100μm polymer powder, i.e. core-shell polymer fine powder;

[0058] A preparation method of a high-temperature and high-salt oil reservoir depth profile control jell agent: according to mass percentage, 0.72% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.28% of core-shell polymer fine powder are added into simulated brine with a salinity of 41938.8mg / L, fully stirred, dispersed and dissolved for 60 minutes, 0.5% of organic aluminum zirconium crosslinking agent is added and continuously stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120℃ oven, and the gel strength and hydration condition are observed and tracked for 60 days. Example 3:

[0059] S1: nucleation reaction:

[0060] Core layer emulsion: in a 2L reactor, 350 parts of water, SPAN80 5 parts, AEO-7 4 parts, sodium dodecyl sulfate 7 parts, acrylamide 71 parts, 2-acrylamido-2-methylpropane sulfonic acid sodium 281 parts, sodium formate 0.03 parts, and disodium ethylenediaminetetraacetate 0.08 parts are added, the pH is adjusted to 6.3-6.5, and the mixture is fully stirred and emulsified;

[0061] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide are added and stirred uniformly, then the reaction is initiated by continuously dropping 1g / L sodium bisulfite solution, the reaction temperature rising speed is controlled to be 30-40s / 0.5℃, the whole reaction temperature is controlled to be 48-50℃, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25℃, the core emulsion is obtained, and nitrogen is kept blowing;

[0062] S2: coating reaction:

[0063] Shell layer aqueous phase: 17 parts of VPEG-1000 are added to 250 parts of deionized water, then 2.5 parts of coconut oil diethanolamine are added, and the shell layer aqueous phase is fully stirred and prepared;

[0064] The above core layer emulsion is kept at 25°C under nitrogen atmosphere, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, and then the shell layer aqueous phase is slowly added, and stirred uniformly; the shell coating reaction is carried out by continuously dropping 1 g / L sodium bisulfite solution, and the reaction temperature is controlled at 25-30 s / 0.5°C, when the temperature reaches 80°C, it starts to keep warm for 3 hours, after the reaction is completed, the temperature is lowered, and the polymer is obtained;

[0065] S3: powdering:

[0066] The above polymer is obtained by spray drying to obtain 50-100 μm polymer powder, i.e. core-shell polymer fine powder;

[0067] A preparation method of a high-temperature and high-salt oil reservoir depth profile control gel water shutoff agent: according to mass percentage, 0.80% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.20% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L and stirred, dispersed and dissolved for 60 minutes, 0.5% of organic aluminum zirconium crosslinking agent is added and continues to stir for 60 minutes; then the system solution is poured into an ampoule bottle, which is placed in a 120°C oven, and the gel strength and hydration condition are observed and tracked for 60 days. Example 4:

[0068] S1: nucleation reaction:

[0069] Core layer emulsion: in a 2L reactor, 350 parts of water, SPAN80 5 parts, AEO-7 4 parts, sodium dodecyl sulfate 7 parts, acrylamide 95 parts, 2-acrylamido-2-methylpropane sulfonic acid sodium 252 parts, sodium formate 0.03 parts, and disodium ethylenediaminetetraacetate 0.08 parts are added, the pH is adjusted to 6.3-6.5, and the mixture is stirred and mixed uniformly;

[0070] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide are added and stirred uniformly, then 1 g / L sodium bisulfite solution is used to initiate the reaction, the reaction temperature rising speed is controlled at 30-40 s / 0.5°C by controlling the dropping speed, the whole reaction temperature is controlled at 48-50°C, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25°C, the core emulsion is obtained, and nitrogen is kept blowing;

[0071] S2: shell coating reaction:

[0072] Shell layer aqueous phase: according to mass fraction, 22 parts of EPEG-1000 are added to 250 parts of deionized water, and 2.5 parts of cocodimethyl ethanolamine are added, and the shell layer aqueous phase is prepared by stirring uniformly;

[0073] The above core layer emulsion is kept at 25°C under nitrogen, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, and then the shell layer aqueous phase is slowly added, and fully stirred to be uniform; the shell coating reaction is carried out by continuously dropping 1 g / L sodium bisulfite solution, the reaction temperature is controlled at 30-40 s / 0.5°C, when the temperature reaches 80°C, it is kept for 3 hours, after the reaction is completed, the temperature is lowered, and the polymer is obtained;

[0074] S3: powdering:

[0075] The above polymer is obtained by spray drying to obtain 50-100 μm polymer powder, i.e. core-shell polymer fine powder;

[0076] A preparation method of a high-temperature and high-salt oil reservoir depth profile control jell agent: according to mass percentage, 0.65% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.35% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L, fully stirred, dispersed and dissolved for 60 minutes, 0.5% of organic aluminum zirconium crosslinking agent is added and continuously stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the gel strength and hydration condition are observed and tracked for 60 days. Example 5:

[0077] S1: nucleation reaction:

[0078] Core layer emulsion: in a 2L reactor, 350 parts of water, SPAN80 5 parts, AEO-7 4 parts, sodium dodecyl sulfate 7 parts, acrylamide 82 parts, 2-acrylamido-2-methylpropane sulfonic acid sodium 266 parts, sodium formate 0.03 parts, and disodium ethylenediaminetetraacetate 0.08 parts are added, the pH is adjusted to 6.3-6.5, and the mixture is fully stirred and emulsified;

[0079] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide are added and stirred uniformly, then 1 g / L of sodium bisulfite solution is used to initiate the reaction, the reaction temperature rising speed is controlled at 30-40 s / 0.5°C by controlling the dropping speed, the whole reaction temperature is controlled at 48-50°C, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25°C, the core emulsion is obtained, and nitrogen is kept blowing;

[0080] S2: shell coating reaction:

[0081] Shell layer aqueous phase: 21 parts of EPEG-1000 are added to 250 parts of deionized water, and 2.5 parts of cocodimethyl ethanolamine are added, fully stirred and uniformly prepared to obtain the shell layer aqueous phase;

[0082] The above core layer emulsion is kept at 25°C under nitrogen, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, and then the shell layer aqueous phase is slowly added, and fully stirred to be uniform; the shell coating reaction is carried out by continuously dropping 1 g / L sodium bisulfite solution, the reaction temperature is controlled at 30-40 s / 0.5°C, when the temperature reaches 80°C, it is kept for 3 hours, after the reaction is completed, the temperature is lowered, and the polymer is obtained;

[0083] S3: powdering:

[0084] The above polymer is obtained by spray drying to obtain 50-100 μm polymer powder, i.e. core-shell polymer fine powder;

[0085] A preparation method of a high-temperature and high-salt oil reservoir depth profile control jell agent: according to mass percentage, 0.72% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.28% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L, fully stirred, dispersed and dissolved for 60 minutes, 0.5% of organic aluminum zirconium crosslinking agent is added and continuously stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the gel strength and hydration condition are observed and tracked for 60 days. Example 6:

[0086] S1: nucleation reaction:

[0087] Core layer emulsion: in a 2L reactor, 350 parts of water, SPAN80 5 parts, AEO-7 4 parts, sodium dodecyl sulfate 7 parts, acrylamide 71 parts, 2-acrylamido-2-methylpropane sulfonic acid sodium 279 parts, sodium formate 0.03 parts, and disodium ethylenediaminetetraacetate 0.08 parts are added, the pH is adjusted to 6.3-6.5, and the mixture is fully stirred and emulsified;

[0088] After 40 minutes of nitrogen replacement, 0.01 parts of benzoyl peroxide are added and stirred uniformly, then 1 g / L of sodium bisulfite solution is used to initiate the reaction, the reaction temperature rising speed is controlled at 30-40 s / 0.5°C by controlling the dropping speed, the whole reaction temperature is controlled at 48-50°C, and the polymerization reaction is 4.5 hours, after which the temperature is lowered to 25°C, the core emulsion is obtained, and nitrogen is kept blowing;

[0089] S2: shell coating reaction:

[0090] Shell layer aqueous phase: 250 parts of deionized water, 20 parts of EPEG-1000, and 2.5 parts of cocodimethyl ethanolamine are added, fully stirred and uniformly prepared to obtain the shell layer aqueous phase;

[0091] The above core layer emulsion is kept at 25°C under nitrogen, 0.015 parts of ammonium persulfate and azo V500.2 parts are added, and then the shell layer aqueous phase is slowly added and stirred uniformly; a 1 g / L sodium pyrosulfite solution is continuously added dropwise for coating reaction, the reaction is controlled at a temperature rising speed of 30-40 s / 0.5°C, when the temperature reaches 80°C, the reaction is kept for 3 hours, after the reaction is completed, the temperature is lowered, and the polymer is obtained;

[0092] S3: powdering:

[0093] The above polymer is obtained by spray drying to obtain a 50-100 μm polymer powder, i.e. a core-shell polymer fine powder;

[0094] A preparation method of a high-temperature high-salt oil reservoir depth profile control jellifying water shutoff agent: according to mass percentage, 0.80% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder and 0.20% of core-shell polymer fine powder are added to simulated brine with a salinity of 41938.8 mg / L, stirred and dispersed and dissolved for 60 minutes, 0.5% of an organic aluminum zirconium crosslinking agent is added and stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the jellifying strength and hydration condition are observed and tracked for 60 days.

[0095] According to mass percentage, 1.0% of acrylamide / 2-acrylamido-2-methylpropane sulfonic acid sodium copolymer powder is added to simulated brine with a salinity of 41938.8 mg / L, stirred and dispersed and dissolved for 60 minutes, 0.5% of an organic aluminum zirconium crosslinking agent is added and stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the jellifying strength and hydration condition are observed and tracked for 60 days.

[0096] Comparative Example 2: The core-shell polymer is prepared according to Example 1.

[0097] According to mass percentage, 1.0% of core-shell polymer fine powder is added to simulated brine with a salinity of 41938.8 mg / L, stirred and dispersed and dissolved for 60 minutes, 0.5% of an organic aluminum zirconium crosslinking agent is added and stirred for 60 minutes; then the system solution is poured into an ampoule, which is placed in a 120°C oven, and the jellifying strength and hydration condition are observed and tracked for 60 days.

[0098] Example 1: 0.65% of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer powder, 0.35% of core-shell polymer fine powder, 0.5% of high-temperature-resistant organic zirconium (commercially available) were added into simulated brine with a salinity of 41938.8 mg / L, and stirred and dispersed and dissolved for 60 minutes, and then 0.5% of phenolic resin was added and stirred for 60 minutes. Then the system solution was poured into an ampoule, which was placed in an oven at 120°C, and the gel strength and hydration condition were observed and tracked for 60 days.

[0099] Comparative Example 4: The core-shell polymer was prepared as in Example 4.

[0100] Example 1: 0.65% of acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer powder, 0.35% of core-shell polymer fine powder, 0.5% of high-temperature-resistant organic zirconium (commercially available) were added into simulated brine with a salinity of 41938.8 mg / L, and stirred and dispersed and dissolved for 60 minutes, and then 0.5% of phenolic resin was added and stirred for 60 minutes. Then the system solution was poured into an ampoule, which was placed in an oven at 120°C, and the gel strength and hydration condition were observed and tracked for 60 days.

[0101] The following is a comparison table of the performance of the gel systems of the examples and comparative examples:

[0102] From the above table, it can be seen that, compared to the long-term gel strength of more than 60 days and high water plugging rate of Examples 1-6, although Comparative Example 1 has fast gelation time and large initial gelation crosslinking strength, the gel strength at 30 days is only D (the gel strength results A-D are weak and not ideal), and gel breaking and hydration occur at 45-60 days;

[0103] Comparative Example 2 has long initial gelation time, and the gel strength at 2 days is not high;

[0104] Comparative Example 3 is similar to Example 2, but the difference is that the crosslinking agent used is a single high-temperature-resistant organic zirconium crosslinking agent, while in the examples, it is a composite high-temperature-resistant organic aluminum-zirconium crosslinking agent. The aluminum ions and zirconium ions in it respectively undergo double crosslinking reactions with the amide groups and carboxyl groups in the polymer molecules, which greatly improves the gel strength of the crosslinking acid system compared to the crosslinking system formed by a single zirconium ion crosslinking agent. The gel strength at 45 days decreases to E, and hydration occurs at 60 days (23.6%);

[0105] Comparative Example 4 is similar to Comparative Example 3, but the crosslinking agent used is phenolic resin. The gel strength at 45 days is D, and the hydration rate at 60 days is 26.3%, which has a large gap in application effect compared to the high-temperature-resistant organic aluminum-zirconium crosslinking agent used in the examples.

[0106] The test results show that the gel type profile control and water plugging agent provided by the application can provide longer and continuous gel strength and stability under high temperature and high salt conditions, and meets the needs of profile control and water plugging on the construction site.

Claims

1. A high-temperature high-salinity reservoir depth profile control gel water shutoff agent, characterized in that, The composition is calculated by the mass percentage of the frozen gel as follows: 0.8%-1.2% of gelling main agent, 0.3%-0.6% of high-temperature resistant organic crosslinking agent, and the rest is simulated salt water solvent; the gelling main agent comprises acrylamide / 2-acrylamide-2-methylpropanesulfonic acid sodium copolymer and core-shell polymer; the core-shell polymer comprises a shell layer and an inner core, and the inner core is synthesized by acrylamide and 2-acrylamide-2-methylpropanesulfonic acid sodium, wherein the mole percentage of 2-acrylamide-2-methylpropanesulfonic acid sodium monomer is 45%-55%; the shell layer is one of vinyl polyethylene glycol ether-1000 or ethylene glycol monovinyl polyoxyethylene ether EPEG-1000, and the weight percentage of the shell layer in the core-shell polymer is 4%-8%; The preparation method of the core-shell polymer comprises the following steps: S1: nucleation reaction: Core layer emulsion: in a reactor, 300-400 parts of water, 2-8 parts of non-ionic surfactant A, 2-8 parts of non-ionic surfactant B, 4-10 parts of anionic surfactant C, 60-120 parts of acrylamide, 240-300 parts of 2-acrylamide-2-methylpropanesulfonic acid sodium, 0.01-0.05 parts of sodium formate, and 0.05-0.1 parts of ethylenediaminetetraacetic acid disodium are added, the pH is adjusted to 6.3-6.5, and stirring and mixing are performed to uniformly emulsify; after nitrogen replacement for 40 minutes, 0.005-0.02 parts of benzoyl peroxide is added and uniformly stirred, then a 1g / L sodium bisulfite solution is used to initiate the reaction, the temperature rising speed is controlled to be 30-40s / 0.5℃ by controlling the dropping speed, the whole reaction temperature is controlled to be 48-50℃, the polymerization reaction is performed for 4.5 hours, and after the reaction is completed, the temperature is lowered to 25℃, a core emulsion is obtained, and nitrogen blowing is maintained; S2: shell coating reaction: Shell layer aqueous phase: in 200-300 parts of deionized water, 15-20 parts of VPEG-1000 or EPEG-1000 is added, and 1-5 parts of non-ionic surfactant D is further added, and the shell layer aqueous phase is prepared by fully stirring and uniformly mixing; The above core layer emulsion is maintained at 25℃ under nitrogen blowing conditions, 0.01-0.02 parts of ammonium persulfate and 0.2 parts of azobis diisobutyl amidine dihydrochloride V50 are added, and then the shell layer aqueous phase is slowly added and uniformly stirred; a 1g / L sodium metabisulfite solution is continuously added dropwise to perform the shell coating reaction, the temperature rising speed is controlled to be 30-40s / 0.5℃, when the temperature reaches 80℃, 3 hours of heat preservation is started, after the reaction is completed, the temperature is lowered, and a polymer is obtained; S3: powder preparation: The above polymer is obtained by spray drying to obtain a 50-100μm polymer powder, that is, a fine powder core-shell polymer; the high-temperature resistant organic crosslinking agent is an organic aluminum zirconium crosslinking agent; The preparation steps of the high-temperature resistant organic aluminum zirconium crosslinking agent are as follows: In a three-necked flask, 150-250 parts of deionized water is added, and after being heated to 60℃, 50-150 parts of polyhydric alcohol is slowly added while stirring, and stirring is performed for 20 minutes; During stirring, 10-20 parts of aluminum salt and 15-25 parts of zirconium salt are added to the solution of step 1) by weight, and they are fully dissolved by stirring; The temperature of the reactor is adjusted to 80℃, 15-25 parts of organic acid and 5-15 parts of gluconate are added by weight, 1-5 parts of crosslinking aid is added, after fully dissolved by stirring, the complexing reaction is carried out at 80℃ reflux for 4 hours, and then slowly cooled to room temperature to obtain the high-temperature resistant organic aluminum zirconium crosslinking agent.

2. The high-temperature high-salinity reservoir depth profile control gel water shutoff agent according to claim 1, characterized in that: The weight percentage of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer in the gel-forming main agent is 65%-80%; the weight percentage of the core-shell polymer in the gel-forming main agent is 20%-35%.

3. The high-temperature high-salinity reservoir depth profile control gel water shutoff agent according to claim 2, characterized in that: The molecular weight of the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is 10-15 million, and the mole percentage of 2-acrylamido-2-methylpropanesulfonic acid sodium in the acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer is 45%.

4. The high-temperature high-salinity reservoir depth profile control gel water shutoff agent according to claim 1, characterized in that: The non-ionic surfactant A is one or more of SPAN40, SPAN65, and SPAN80; the non-ionic surfactant B is one or more of AEO-3, AEO-7, and AEO-9; the anionic surfactant C is one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and triethanolamine dodecyl benzene sulfonate; and the non-ionic surfactant D is one or more of coconut monoethanolamine, coconut diethanolamine, and myristic acid diethanolamine.

5. The high-temperature high-salinity reservoir depth profile control gel water shutoff agent according to claim 1, characterized in that: The zirconium salt is one or both of zirconium oxychloride and zirconium chloride; the aluminum salt is one or both of aluminum chloride and aluminum sulfate; the polyhydric alcohol is one or more of ethylene glycol, propylene glycol, and glycerol; the organic ligand is one or more of potassium gluconate and sodium gluconate; the organic acid is one or both of lactic acid and succinic acid; and the crosslinking aid is one or both of dimethyl diimine ester and N,N'-methylene bisacrylamide. 6.The high-temperature and high-salinity reservoir depth profile control gel water shutoff agent according to claim 1, characterized in that, The simulated brine has a salinity of 41938.8 mg / L, wherein Ca 2+ has a concentration of 9693.7 mg / L, Mg 2+ has a concentration of 1123.1 mg / L.

7. The method for preparing the high-temperature and high-salinity reservoir depth profile control gel water shutoff agent according to any one of claims 1-6, characterized in that: The acrylamide / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer powder, and the fine powder of the core-shell polymer are added to a simulated brine having a salinity of 41938.8 mg / L, Ca 2+ a concentration of 9693.7 mg / L, Mg 2+ a concentration of 1123.1 mg / L, and are dispersed with thorough agitation for 60 minutes. An organoaluminum zirconium crosslinking agent is added, and agitation is continued for 60 minutes.

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