A coupled modified high temperature resistant and salt resistant deep plugging and diverting agent and its preparation method and application

Abstract

The invention relates to the technical field of oil and gas production increase, and specifically to a coupling modified high temperature resistant and salt resistant deep plugging and diverting agent, and a preparation method and application thereof; the plugging and diverting agent comprises a coupling agent for synthesis modification, a coupling agent modified filler, a high temperature resistant and salt resistant monomer, a cross-linking agent, an initiator, and a promoter; the plugging and diverting agent of the invention has a special chemical structure in its molecular structure so that it has good mechanical properties and stability, and the coupling structure has good physical adsorption and chemical adsorption, so it has strong water absorption and expansion capacity, high elastic deformation performance, plugging strength and water retention performance; and the plugging and diverting agent has the advantages of simple preparation process, rich raw material source, low price, convenient construction, excellent performance, etc., and can be used for deep profile control and water plugging in high temperature and high mineralization oil reservoirs, and can meet the needs of deep profile control and water plugging in oil fields.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas production enhancement, and in particular to a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent, and a preparation method and application thereof. Background Art

[0002] In the process of crude oil extraction, with the extraction of crude oil, the formation energy decreases and the crude oil extraction volume decreases. In order to improve the crude oil recovery rate, the method of injecting water into the formation is generally used to improve the crude oil recovery rate. However, after long-term water injection development of the oil field, the physical properties of the reservoir have changed greatly, especially the formation of high permeability and large pore formations, which makes the average permeability of the flooded formation higher than the original permeability. The water flow only moves along the high permeability layer in the formation and rarely enters the medium and low permeability layer, that is, the fingering phenomenon occurs. At this time, the simple plugging of the near-well area can no longer overcome the bypass of the injected water, and the effect of reducing water and increasing oil is getting worse and worse. It is an inevitable trend to carry out deep profile adjustment of the reservoir. The so-called deep profile adjustment is to use a large dose of plugging agent to plug the high permeability zone deep inside the reservoir, forcing the liquid flow to turn, so that the injected water can reach the medium and low permeability areas that have not been affected before, improve the displacement effect, and increase the recovery rate.

[0003] Since the amount of plugging agent required for deep profile control is large, it is not only required to have good plugging performance, but also to have a wide supply, low price, easy pumping, and the injection process can work continuously for a long time. After long-term scientific research, a deep profile control system based on pre-crosslinked particles has been formed. Pre-crosslinked particles are a profile control and water plugging agent that can absorb water and swell. It is not like a cross-linked polymer gel plugging agent. Although it is also prepared by a cross-linking reaction between a polymer monomer and a cross-linking agent under the action of an initiator, it is a granular agent with a certain particle size prepared on the ground according to the needs of the pore characteristics of the target layer. Compared with cross-linked polymer gel treatment agents that freeze under formation conditions after injection of a cross-linked system, pre-cross-linked particles reduce the adverse effects of environmental factors such as formation temperature, salinity, formation shear, formation water dilution, and chromatographic separation effects on the treatment effect of oil and water wells; pre-cross-linked particles also have good selective entry capabilities for oil, water and permeability, thereby reducing the damage of pre-cross-linked particles to non-target layers (low permeability layers); according to the permeability and porosity of the target oil reservoir, the diameter size of the pre-cross-linked particles can be optimized and screened to produce temporary blockage on the surface of the low permeability layer with high oil saturation, protect the non-target layer, and allow the subsequently injected pre-cross-linked particles to only enter the large pores or cracks flushed out by the previously injected water, thereby playing a role in selective profile adjustment.

[0004] At present, pre-crosslinked particle plugging agents have been widely used in high permeability, "large pore" and medium and low temperature water well profile control, and have achieved good results. However, for ultra-high temperature and high mineralization reservoirs (temperature above 150°C, mineralization greater than 20×104mg / L), the existing pre-crosslinked particles will degrade to a certain extent above 120°C, and the plugging effect will deteriorate, which is manifested in the rapid drop in water injection pressure after profile control, poor injection effect and short effective period.

[0005] Therefore, a coupled modified high-temperature resistant and salt-resistant deep plugging and diversion agent and its preparation method and application are proposed. The coupled modified high-temperature resistant and salt-resistant deep plugging and diversion agent can be used for deep profile control and water plugging in high-temperature and high-mineralization reservoirs, and solve the deep profile control and water plugging problems of high-temperature and high-mineralization reservoirs (temperature higher than 150°C, mineralization greater than 20×104mg / L). Summary of the invention

[0006] In view of the shortcomings of the prior art described above, the present invention uses a macromolecular coupling agent to modify the surface of the filler. On the one hand, the Si-O bond in the macromolecular coupling agent forms a hydrogen bond with the OH- on the surface of the filler. On the other hand, the carbon-carbon double bond at the end of the macromolecular coupling agent undergoes a free radical polymerization reaction with the polymer to form a strong chemical structure, so that a thicker double-layer coating structure is formed on the surface of the filler. This thicker double-layer flexible interface improves the interaction between the filler and the network polymer to a greater extent, further enhancing the stability and mechanical properties of the plugging agent. At the same time, the macromolecular coupling agent combines with the filler to form Si-O-Si and Si-O-Al bonds to improve the stability of the plugging agent at high temperatures; therefore, the deep plugging agent (coupled modified high temperature resistant and salt resistant deep plugging and diverting agent) prepared by this scheme has a temperature resistance of up to 180°C, and can be used for deep profile control and water plugging in high temperature and high mineralization (temperature above 150°C, mineralization greater than 20×104mg / L) reservoirs.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A coupled modified high temperature resistant and salt resistant deep plugging and diverting agent, comprising, by weight:

[0009] Coupling agent modified filler: 50-70 parts; high temperature and salt resistant monomer: 30-50 parts; cross-linking agent: 0.005-0.04 parts; initiator: 0.05-0.12 parts; accelerator: 0.008-0.08 parts; water: 30-60 parts.

[0010] In a preferred embodiment of this scheme, the coupling agent modified filler includes a filler and a macromolecular coupling agent;

[0011] The mass ratio of the filler to the macromolecular coupling agent is 90-99:1-10.

[0012] In a preferred embodiment of the present scheme, the filler is one or more of silicon dioxide, oil well cement, fly ash, sodium bentonite, calcium carbonate, modified starch, and carboxymethyl cellulose.

[0013] In a preferred embodiment of this solution, the filler includes silicon dioxide, sodium bentonite, and calcium carbonate;

[0014] The mass ratio of silicon dioxide, sodium bentonite and calcium carbonate is 4:(1-3):(3-6).

[0015] In a preferred embodiment of this scheme, the macromolecular coupling agent is prepared from the following raw materials:

[0016] 50-70 parts of butyl acrylate, 10-30 parts of sodium p-styrene sulfonate, 1-10 parts of methyl methacrylate, 10-30 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 3 parts of dibenzoyl peroxide, and 3 parts of dodecyl mercaptan.

[0017] In a preferred embodiment of the present scheme, the high temperature and salt resistant monomer is one or more of acrylamide, methacrylamide, acrylic acid, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate.

[0018] Further, in a preferred embodiment of the present scheme, the high temperature and salt resistant monomers include acrylamide, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate;

[0019] The mass ratio of acrylamide, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate is 7:(0.5~2.5):(0.5~2.5).

[0020] In a preferred embodiment of the present scheme, the cross-linking agent is one or more of N,N-methylenebisacrylamide, 1,6-hexanediol diacrylate and divinylbenzene.

[0021] In a preferred embodiment of the present scheme, the initiator is one or more of ammonium persulfate, potassium persulfate, tert-butyl hydroperoxide, benzoyl peroxide and azobisisobutyramidine hydrochloride.

[0022] In a preferred embodiment of the present scheme, the accelerator is one or more of ferrous persulfate, sodium sulfite, sodium bisulfite, ascorbic acid, and sodium thiosulfate.

[0023] The method for preparing the above-mentioned coupled modified high temperature resistant and salt resistant deep plugging and diverting agent comprises the following steps:

[0024] S1. Preparation of macromolecular coupling agent

[0025] Add 50-70 parts of butyl acrylate, 10-30 parts of sodium p-styrene sulfonate, 1 part of dibenzoyl peroxide and 1 part of dodecyl mercaptan to the reaction kettle, heat to 78-81°C, and react for 0.5-2h;

[0026] Then slowly drop 10 to 30 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1 to 10 parts of methyl methacrylate, 2 parts of dibenzoyl peroxide and 2 parts of dodecyl sulfide, and the dropwise addition time is controlled within 2 hours;

[0027] After the addition is completed, keep warm for 1 hour to obtain a colorless or light yellow transparent liquid, which is the macromolecular coupling agent;

[0028] S2. Preparation of coupling agent modified filler

[0029] Add 90-99 parts of filler into the mixing stirring kettle, and simultaneously add 1-10 parts of the macromolecular coupling agent synthesized in step S1, stir and heat to 80° C., and continue stirring for 0.5-2 hours to obtain a coupling agent modified filler;

[0030] S3. Preparation of mixed solution

[0031] Add 30 to 50 parts of high temperature and salt resistant monomers and 30 to 60 parts of water into a reaction kettle, stir evenly, add 0.05 to 0.15 parts of a cross-linking agent, and then add 50 to 70 parts of the coupling agent modified filler synthesized in step S2, stir for 10 to 50 minutes, and obtain a mixed solution;

[0032] S4. Preparation of rubber particles

[0033] The mixed solution formed in step S3 is transferred to a polymerization reactor, and then 0.1 to 0.3 parts of an initiator and 0.08 to 0.16 parts of an accelerator are added, allowed to react, and then extruded and granulated to obtain rubber particles;

[0034] S5. Preparation of coupled modified high temperature resistant and salt resistant deep plugging and diverting agent

[0035] The rubber particles obtained in step S4 are dried, crushed and sieved to obtain a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent.

[0036] In a preferred embodiment of the present scheme, the average diameter of the glue particles is 10 mm.

[0037] In a preferred embodiment of the present scheme, the method for preparing the above-mentioned coupled modified high temperature resistant and salt resistant deep plugging and diverting agent specifically comprises the following steps:

[0038] S1. Preparation of macromolecular coupling agent

[0039] Add 50-70 parts of butyl acrylate, 10-30 parts of sodium p-styrene sulfonate, 1 part of dibenzoyl peroxide and 1 part of dodecyl mercaptan to a reaction kettle, heat to 78-81°C, and react for 1 hour; then slowly drop 10-30 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1-10 parts of methyl methacrylate, 2 parts of dibenzoyl peroxide and 2 parts of dodecyl mercaptan, and the drop time is controlled within 2 hours; after the drop addition is completed, keep warm for 1 hour to obtain a colorless or light yellow transparent liquid, which is the macromolecular coupling agent;

[0040] S2. Preparation of coupling agent modified filler

[0041] Add 90-99 parts of filler into the mixing stirring kettle, and simultaneously add 1-10 parts of the macromolecular coupling agent synthesized in step S1, stir thoroughly and raise the temperature to 80° C., and continue stirring for 1 hour to obtain a coupling agent modified filler;

[0042] S3. Preparation of mixed solution

[0043] Add 30 to 50 parts of high temperature and salt resistant monomers and 30 to 60 parts of water into a reaction kettle, stir evenly, add 0.05 to 0.15 parts of a cross-linking agent, and then add 50 to 70 parts of the coupling agent modified filler synthesized in step S2, stir for 30 minutes, and obtain a mixed solution;

[0044] S4. Preparation of rubber particles

[0045] The mixed solution formed in step S3 is transferred to a polymerization reactor, and then 0.1-0.3 parts of an initiator and 0.08-0.16 parts of an accelerator are added, and the mixture is allowed to react for 2 hours; the composite is then extruded by hydraulic means, and cut and granulated during the extrusion process to obtain rubber particles;

[0046] S5. Preparation of coupled modified high temperature resistant and salt resistant deep plugging and diverting agent

[0047] The rubber particles obtained in step S4 are dried at 105° C. for 5 hours, and the dried particles are crushed and sieved to obtain coupled modified high temperature resistant and salt resistant deep plugging and diverting agents of different particle sizes.

[0048] The above-mentioned coupled modified high-temperature resistant and salt-resistant deep plugging and diverting agent, or the coupled modified high-temperature resistant and salt-resistant deep plugging and diverting agent prepared by the above-mentioned preparation method is used in the field of oil production.

[0049] Beneficial effects of the present invention:

[0050] (1) The coupling-modified high-temperature-resistant and salt-resistant deep plugging and diverting agent disclosed in the present invention adopts a bulk polymerization method to synthesize a macromolecular coupling agent whose organic group is a long-chain Si-O bond. The high boiling point of the macromolecular coupling agent and the high bond energy brought by the Si-O bond can effectively improve the high-temperature resistance of the plugging and diverting agent, and the maximum adaptable temperature can reach 180°C;

[0051] (2) The coupling modified high temperature resistant and salt resistant deep plugging and diverting agent disclosed in the present invention, the methoxy functional group in the macromolecular coupling agent reacts with the hydroxyl group on the surface of the filler, so that the macromolecular coupling agent is grafted and coated on the surface of the filler, so that the filler is more evenly dispersed, and the strength and elasticity of the plugging and diverting agent are well improved. Therefore, the plugging and diverting agent has the characteristics of good toughness after expansion, arbitrary deformation, not easy to break and fracture, high chemical stability, and high compressive strength;

[0052] (3) The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent disclosed in the present invention contains a large number of water absorbing groups, which can form hydrogen bonds with water, so that it has the characteristics of unchanged volume when encountering oil and swelling and softening when encountering water;

[0053] (4) The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent disclosed in the present invention contains a large number of salt resistant groups -SO 3— , thus improving the salt resistance of the polymer, so the plugging and diverting agent has good salt resistance and is suitable for plugging formation water with a mineralization of up to 25×104gm / L;

[0054] (5) The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent disclosed in the present invention has an applicable temperature of 20 to 180°C, a mineralization degree of 0 to 20×104 gm / L, good compatibility with formation water, no biological toxicity, and good stability. It will not be destroyed for more than 300 days in a 180°C system. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The present invention is a process flow chart for preparing the coupled modified high temperature resistant and salt resistant deep plugging and diverting agent. DETAILED DESCRIPTION

[0056] In order to solve the technical problems existing in the above-mentioned prior art, the general idea of ​​the technical solution provided in the embodiments of the present application is as follows:

[0057] Example 1

[0058] A method for preparing a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent comprises the following steps:

[0059] Step 1: add 700kg butyl acrylate, 100kg sodium p-styrene sulfonate, 10kg dibenzoyl peroxide and 10kg dodecyl mercaptan to a reaction kettle with a heating device, heat to 78-81°C, and react for 1h; then drop 100kg γ-(methacryloyloxy)propyltrimethoxysilane and 100kg methyl methacrylate into the reaction kettle, as well as 20kg dibenzoyl peroxide and 20kg dodecyl mercaptan, and control the drop time to be 2h; after the drop addition is completed, keep warm for 1h to obtain a colorless to light yellow transparent liquid, which is the macromolecular coupling agent.

[0060] Step 2: Add 900 kg of filler into a mixing stirring kettle, then add 100 kg of macromolecular coupling agent, stir thoroughly and heat to 80° C., continue stirring for 1 hour, stop stirring, and obtain a coupling agent-modified filler.

[0061] Step 3: add 300 kg of high temperature and salt resistant monomer and 600 kg of water to a stirred reactor, stir evenly, add 1.5 kg of cross-linking agent, and then add 700 kg of coupling agent modified filler, stir for 30 minutes to form a mixed solution.

[0062] Step 4: Transfer the mixed solution to a polymerization reactor, add 1 kg of initiator and 0.6 kg of accelerator, and let it react for 2 hours. Hydraulically extrude the composite, and cut and granulate it during the extrusion process to obtain rubber particles of about 10 mm.

[0063] Step five, drying the rubber particles in a drying room at 105°C for 5 hours to obtain dried particles, and crushing and sieving the dried particles to obtain coupled modified high temperature resistant and salt resistant deep plugging and diverting agents of different particle sizes.

[0064] In this solution, the filler is a mixture of silicon dioxide, sodium bentonite and calcium carbonate in a ratio of 4:3:3.

[0065] In this scheme, the high temperature and salt resistant monomer is a mixture of acrylamide, sodium p-styrene sulfonate and 2-acrylamido-2-methylpropane sulfonic acid in a ratio of 7:2.5:0.5.

[0066] In this embodiment, the cross-linking agent is N,N-methylenebisacrylamide.

[0067] In this embodiment, the initiator is ammonium persulfate.

[0068] In this scheme, the accelerator is sodium bisulfite.

[0069] The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent obtained in this example has a mineralization of 20×10 4In the simulated formation water, the expansion multiple is 7 times, the sample has good toughness, and the compressive strength after expansion is 4.57MPa. Under the condition of 150℃, the sample is intact after aging for 120 days without degradation.

[0070] Example 2

[0071] A method for preparing a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent comprises the following steps:

[0072] Step 1: add 500kg butyl acrylate, 200kg sodium p-styrene sulfonate, 10kg dibenzoyl peroxide and 10kg dodecyl mercaptan to a reaction kettle with a heating device, heat to 78-81°C, and react for 1h; then drop 200kg γ-(methacryloyloxy)propyltrimethoxysilane, 100kg methyl methacrylate into the reaction kettle, 20kg dibenzoyl peroxide and 20kg dodecyl mercaptan, and control the drop time to 2h; after the drop addition is completed, keep warm for 1h to obtain a colorless to light yellow transparent liquid, which is the macromolecular coupling agent.

[0073] Step 2: Add 950 kg of filler into the mixing stirring kettle, then add 50 kg of macromolecular coupling agent, stir thoroughly and heat to 80° C., continue stirring for 1 hour, stop stirring, and obtain coupling agent modified filler.

[0074] Step 3: add 300 kg of high temperature and salt resistant monomer and 600 kg of water to a stirred reactor, stir evenly, add 1.5 kg of cross-linking agent, and then add 700 kg of coupling agent modified filler, stir for 30 minutes to form a mixed solution.

[0075] Step 4: Transfer the mixed solution to a polymerization reactor, add 1 kg of initiator and 0.6 kg of accelerator, and let it react for 2 hours. Hydraulically extrude the composite, and cut and granulate it during the extrusion process to obtain rubber particles of about 10 mm.

[0076] Step five, drying the rubber particles in a drying room at 105°C for 5 hours to obtain dried particles, and crushing and sieving the dried particles to obtain coupled modified high temperature resistant and salt resistant deep plugging and diverting agents of different particle sizes.

[0077] In this solution, the filler is a mixture of silicon dioxide, sodium bentonite and calcium carbonate in a ratio of 4:2:4.

[0078] In this solution, the high temperature and salt resistant monomer is a mixture of acrylamide, sodium p-styrene sulfonate and 2-acrylamido-2-methylpropane sulfonic acid in a ratio of 7:1:2.

[0079] In this embodiment, the cross-linking agent is N,N-methylenebisacrylamide.

[0080] In this embodiment, the initiator is ammonium persulfate.

[0081] In this solution, the accelerator is sodium bisulfite.

[0082] The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent obtained in this example has a mineralization of 20×10 4 In the simulated formation water, the expansion multiple is 9 times, the sample has good toughness, and the compressive strength after expansion is 3.64MPa. Under the condition of 150℃, the sample is intact after aging for 90 days without degradation.

[0083] Example 3

[0084] A method for preparing a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent comprises the following steps:

[0085] Step 1: add 500kg butyl acrylate, 100kg sodium p-styrene sulfonate, 10kg dibenzoyl peroxide and 10kg dodecyl mercaptan to a reaction kettle with a heating device, heat to 78-81°C, and react for 1h; then drop 300kg γ-(methacryloyloxy)propyltrimethoxysilane, 100kg methyl methacrylate into the reaction kettle, 20kg dibenzoyl peroxide and 20kg dodecyl mercaptan, and control the drop time to 2h; after the drop addition is completed, keep warm for 1h to obtain a colorless to light yellow transparent liquid, which is the macromolecular coupling agent.

[0086] Step 2: Add 990 kg of filler into the mixing stirring kettle, then add 10 kg of macromolecular coupling agent, stir thoroughly and heat to 80° C., continue stirring for 1 hour, stop stirring, and obtain coupling agent modified filler.

[0087] Step 3: add 300 kg of high temperature and salt resistant monomer and 600 kg of water to a stirred reactor, stir evenly, add 1.5 kg of cross-linking agent, and then add 700 kg of coupling agent modified filler, stir for 30 minutes to form a mixed solution.

[0088] Step 4: Transfer the mixed solution to a polymerization reactor, add 1 kg of initiator and 0.6 kg of accelerator, and let it react for 2 hours. Hydraulically extrude the composite, and cut and granulate it during the extrusion process to obtain rubber particles of about 10 mm.

[0089] Step five, drying the rubber particles in a drying room at 105°C for 5 hours to obtain dried particles, and crushing and sieving the dried particles to obtain coupled modified high temperature resistant and salt resistant deep plugging and diverting agents of different particle sizes.

[0090] In this solution, the filler is a mixture of silicon dioxide, sodium bentonite and calcium carbonate in a ratio of 4:1:5.

[0091] In this solution, the high temperature and salt resistant monomer is a mixture of acrylamide, sodium p-styrene sulfonate and 2-acrylamido-2-methylpropane sulfonic acid in a ratio of 7:1.5:1.5.

[0092] In this embodiment, the cross-linking agent is N,N-methylenebisacrylamide.

[0093] In this embodiment, the initiator is ammonium persulfate.

[0094] In this solution, the accelerator is sodium bisulfite.

[0095] The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent obtained in this example has a mineralization of 20×10 4 In the simulated formation water, the expansion ratio is 12 times, the sample has good toughness, and the compressive strength after expansion is 2.83MPa. Under the condition of 150℃, the sample is intact after aging for 90 days without degradation.

[0096] Example 4

[0097] A method for preparing a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent, reference Figure 1 Therefore, the following steps are included:

[0098] Step 1: add 500kg butyl acrylate, 200kg sodium p-styrene sulfonate, 10kg dibenzoyl peroxide and 10kg dodecyl mercaptan to a reaction kettle with a heating device, heat to 78-81°C, and react for 1h; then drop 200kg γ-(methacryloyloxy)propyltrimethoxysilane, 100kg methyl methacrylate into the reaction kettle, 20kg dibenzoyl peroxide and 20kg dodecyl mercaptan, and control the drop time to 2h; after the drop addition is completed, keep warm for 1h to obtain a colorless to light yellow transparent liquid, which is the macromolecular coupling agent.

[0099] Step 2: Add 950 kg of filler into the mixing stirring kettle, then add 50 kg of macromolecular coupling agent, stir thoroughly and heat to 80° C., continue stirring for 1 hour, stop stirring, and obtain coupling agent modified filler.

[0100] Step 3: add 400 kg of high temperature and salt resistant monomer and 500 kg of water into a stirred reactor, stir evenly, add 1.0 kg of cross-linking agent, and then add 600 kg of coupling agent modified filler, stir for 30 minutes to form a mixed solution.

[0101] Step 4: Transfer the mixed solution to a polymerization reactor, add 1.5 kg of initiator and 0.6 kg of accelerator, and let it react for 2 hours. Hydraulically extrude the composite, and cut and granulate it during the extrusion process to obtain rubber particles of about 10 mm.

[0102] Step five, drying the rubber particles in a drying room at 105°C for 5 hours to obtain dried particles, and crushing and sieving the dried particles to obtain coupled modified high temperature resistant and salt resistant deep plugging and diverting agents of different particle sizes.

[0103] In this solution, the filler is a mixture of silicon dioxide, sodium bentonite and calcium carbonate in a ratio of 4:2:4.

[0104] In this solution, the high temperature and salt resistant monomer is a mixture of acrylamide, sodium p-styrene sulfonate and 2-acrylamido-2-methylpropane sulfonic acid in a ratio of 7:0.5:2.5.

[0105] In this embodiment, the cross-linking agent is N,N-methylenebisacrylamide ammonium.

[0106] In this embodiment, the initiator is ammonium persulfate.

[0107] In this solution, the accelerator is sodium bisulfite.

[0108] The coupled modified high temperature resistant and salt resistant deep plugging and diverting agent obtained in this example has a mineralization of 20×10 4 In gm / L simulated formation water, the expansion multiple is 10 times, the sample has good toughness, and the compressive strength after expansion is 3.47MPa. Under 150℃ condition, the sample is intact after aging for 150 days without degradation.

[0109] Example 5

[0110] On-site implementation:

[0111] Well TXXX was completed in July 2011, with a depth of 4972.28m (inclined depth) / 4558.90m (vertical depth). It was put into production with self-flowing in the early stage, and there was no waterless oil production period. In August 2010, it switched to pumping production. After high water content, two rounds of water plugging were implemented, and the cumulative oil production increased by 299t. The water plugging effect was not ideal, and it has been producing with high water content (water content 95.6%). The cumulative liquid production of this well is 132.8×10 4 t, cumulative oil production 21.9×10 4 t. The formation temperature in the middle of the oil layer is 148.94℃, and the water density in the oil well is 1.1145g / cm 3 , mineralization 24.3×10 4mg / L. The reservoir type is medium-porosity, medium-permeability, unsaturated lithologic reservoir. The reservoir porosity is distributed between 10.1% and 24.2%, with an average of 21.2%, and the permeability is distributed between 17.6 and 512×10 -3 μm 2 The average value is 186×10 -3 μm 2 Two chemical plugging operations were carried out in the early stage, and the water reduction effect was not obvious, indicating that the strength and dosage of the plugging agent needed to be increased. Therefore, a high-temperature and salt-resistant deep plugging diverter with strong oil-water selectivity, good injection performance and greater strength and a medium-quality oil composite were used for deep plugging.

[0112] From March 3 to March 6, 2022, a water plugging test was carried out in the TXXXH well, and a total of 1602m of water plugging agent was injected. 3 Among them, the coupled modified high temperature resistant and salt resistant deep plugging and diverting agent (Example 1) + polymer 1364m 3 , high strength gel 238m 3 , displacing polymer 175m 3 The construction pressure dropped first and then increased, with the highest construction pressure of 19.23MPa and the maximum construction displacement of 5.3 cubic meters per hour. Production was directly sought after plugging. The initial oil pressure was 0.71MPa, with a daily liquid output of 19.1t and a daily oil output of 9.2t, and a water content of 51.8%. After 180 days of continuous production, the water content dropped from 95.6% to 51.8%, and the cumulative oil production increased by 1,247t.

[0113] The above only expresses the preferred implementation of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with the preferred embodiment, it is not used to limit the present invention. For ordinary technicians in this field, they can also make some modifications and improvements to the technical contents disclosed above without departing from the technical solution of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A coupled modified high temperature resistant and salt resistant deep plugging and diverting agent, characterized in that: By weight, it includes: Coupling agent modified filler: 50~70 parts; high temperature and salt resistant monomer: 30~50 parts; cross-linking agent: 0.005~0.04 parts; initiator: 0.05~0.12 parts; accelerator: 0.008~0.08 parts; water: 30~60 parts; The coupling agent modified filler comprises a filler and a macromolecular coupling agent; the mass ratio of the filler to the macromolecular coupling agent is 90-99:1-10 The filler comprises silicon dioxide, sodium bentonite and calcium carbonate; the mass ratio of silicon dioxide, sodium bentonite and calcium carbonate is 4:(1-3):(3-6); The macromolecular coupling agent is prepared from the following raw materials: 50-70 parts of butyl acrylate, 10-30 parts of sodium p-styrene sulfonate, 1-10 parts of methyl methacrylate, 10-30 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 3 parts of dibenzoyl peroxide, and 3 parts of dodecyl mercaptan; The high temperature and salt resistance monomer is one or more of acrylamide, methacrylamide, acrylic acid, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate.

2. A coupled modified high temperature resistant and salt resistant deep plugging and diverting agent according to claim 1, characterized in that: The high temperature and salt resistance monomers include acrylamide, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate; The mass ratio of acrylamide, sodium p-styrene sulfonate and sodium 2-acrylamido-2-methylpropane sulfonate is 7:(0.5~2.5):(0.5~2.5).

3. A coupled modified high temperature resistant and salt resistant deep plugging and diverting agent according to claim 1, characterized in that: The accelerator is one or more of ferrous persulfate, sodium sulfite, sodium bisulfite, ascorbic acid and sodium thiosulfate.

4. A method for preparing the coupled modified high temperature resistant and salt resistant deep plugging and diverting agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Preparation of macromolecular coupling agent Add 50-70 parts of butyl acrylate, 10-30 parts of sodium p-styrene sulfonate, 1 part of dibenzoyl peroxide and 1 part of dodecyl mercaptan to the reactor, heat to 78-81°C, and react for 0.5-2h; Then slowly drop 10-30 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1-10 parts of methyl methacrylate, 2 parts of dibenzoyl peroxide and 2 parts of dodecyl sulfide, and the dropping time is controlled within 2 hours; After the addition is completed, keep warm for 1 hour to obtain a colorless or light yellow transparent liquid, which is the macromolecular coupling agent; S2. Preparation of coupling agent modified filler Add 90-99 parts of filler into the mixing stirring kettle, and simultaneously add 1-10 parts of the macromolecular coupling agent synthesized in step S1, stir and heat to 80° C., and continue stirring for 0.5-2 hours to obtain a coupling agent modified filler; S3. Preparation of mixed solution Add 30-50 parts of high temperature and salt resistant monomers and 30-60 parts of water into a reaction kettle, stir evenly, add 0.05-0.15 parts of a cross-linking agent, and then add 50-70 parts of the coupling agent modified filler synthesized in step S2, stir for 10-50 minutes, and obtain a mixed solution; S4. Preparation of rubber particles The mixed solution formed in step S3 is transferred to a polymerization reactor, and then 0.1-0.3 parts of an initiator and 0.08-0.16 parts of an accelerator are added, allowed to react, and then extruded and granulated to obtain rubber particles; S5. Preparation of coupled modified high temperature resistant and salt resistant deep plugging and diverting agent The rubber particles obtained in step S4 are dried, crushed and sieved to obtain a coupled modified high temperature resistant and salt resistant deep plugging and diverting agent.

5. Use of the coupled modified high temperature resistant and salt resistant deep plugging control and diversion agent according to any one of claims 1 to 3, or the coupled modified high temperature resistant and salt resistant deep plugging control and diversion agent prepared by the preparation method according to claim 4 in the field of oil production.

Images