Rice hull modified modifying and flooding agent and preparation method thereof

Abstract

The invention discloses a rice hull modified profile control and flooding agent and a preparation method thereof, and belongs to the technical field of oilfield development. According to the method, rice hulls are used as raw materials to prepare the rice hull modified profile control and flooding agent, firstly, the rice hulls are ground and carbonized, then oleophylic groups with surface activity are'grafted 'on carbonized rice hull bodies, the carbonized rice hulls are modified, and the rice hull modified profile control and flooding agent is obtained. The rice hull modified profile control and displacement agent has a hydrophilic and oleophylic'amphiphilic 'structure, and the oil-water interfacial tension with in-situ crude oil can reach 10 <-3 > mN / m order of magnitude, so that the rice hull modified profile control and displacement agent not only has the effect of adjusting a profile, but also has the effect of washing oil, can overcome the viscous force of residual oil in a stratum and displace more residual oil, so that the oil displacement effect is improved. Therefore, the crude oil recovery rate is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of oilfield development, and in particular to a rice husk modified control and displacement agent and a preparation method thereof. Background Art

[0002] After years of water injection development, high permeability zones or large pores have already existed in the formations. As a technical means to further improve the recovery rate of oil reservoirs through water injection development, the water injection barrier is established by injecting water injection agents into the formation to block the high permeability areas, so that the subsequent injected water can flow around, expand the water injection sweep volume, and play a role in adjusting the water injection profile.

[0003] At present, the most widely used control and displacement agent is the granular control and displacement agent, which can be used alone or as a filler in combination with a polymer or polymer gel.

[0004] However, in the late stage of water-driven oil reservoir development, there is still a large amount of residual oil in the formation, and this part of crude oil is relatively viscous. The main function of granular type displacement agent is to block large pores and adjust the water injection profile, but it does not have the effect of washing oil. The viscosity of crude oil makes the effect of injected water in expanding the swept volume limited, and it is difficult for injected water to displace the residual oil. Summary of the invention

[0005] The present application provides a rice husk modified displacement agent and a preparation method thereof, which has the function of washing oil, can overcome the viscosity of the remaining oil in the formation, displace more remaining oil, and thus further improve the crude oil recovery rate. The technical solution is as follows:

[0006] In one aspect, a method for preparing a rice husk modified flooding agent is provided, the preparation method comprising:

[0007] Grinding and carbonizing raw rice husks with a moisture content of less than 15% to obtain carbonized rice husks;

[0008] Adding the carbonized rice husk and water into a stirring tank and stirring for a first period of time;

[0009] Adding a composite surfactant into the stirring tank and stirring for a second period of time to obtain a rice husk modified displacement agent;

[0010] The total mass fraction of the carbonized rice husk, the composite surfactant and water is 100, the mass fraction ratio of the carbonized rice husk to the composite surfactant is 9-24:1, and the rest is water;

[0011] The composite surfactant is composed of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate and alkyl alcohol amide, or the composite surfactant is composed of a silane coupling agent, fatty acid amide and cationic surfactant, or the composite surfactant is composed of the silane coupling agent and betaine surfactant.

[0012] In a possible implementation, grinding and carbonizing the original rice husks with a moisture content of less than 15% to obtain the carbonized rice husks includes:

[0013] The original rice husk with a moisture content of less than 15% is put into a ball mill for grinding at a speed of 200 to 600 rpm, and after grinding for 20 to 40 minutes, rice husk powder with a particle size of 80 to 150 meshes is obtained;

[0014] The rice husk powder is placed in a carbonization furnace for carbonization at a temperature of 280° C. to 350° C. After carbonization for 3 to 4 hours, the powder is sorted to obtain the carbonized rice husk.

[0015] In another possible implementation, if the composite surfactant is composed of the silane coupling agent, the fatty acid amide and the cationic surfactant, the composite surfactant is added to the stirring tank and stirred for a second time to obtain the rice husk modified displacement agent, comprising:

[0016] Adding the silane coupling agent into the stirring tank and stirring for a third period of time;

[0017] The fatty acid amide and the cationic surfactant are added to the stirring tank and stirred for a fourth time to obtain the rice husk modified driving agent; wherein the sum of the third time and the fourth time is the second time.

[0018] In another possible implementation, the mass ratio of at least one of the fatty alcohol polyoxyethylene ether, the fatty acid polyoxyethylene ester, the alkyl glycoside and the polysorbate to the alkyl alcohol amide is 0.1 to 0.3:1.

[0019] In another possible implementation, the alkyl alcohol amide is an alkyl diethanol amide, wherein the alkyl group in the alkyl diethanol amide is a saturated hydrocarbon group or an unsaturated hydrocarbon group having 8 to 20 carbon atoms;

[0020] The number of ethylene oxide additions in the fatty alcohol polyoxyethylene ether is 6 to 8, and the fatty alcohol is a long-chain hydrocarbon group with 16 to 20 carbon atoms;

[0021] The fatty acid in the fatty acid polyoxyethylene ester is a long-chain hydrocarbon group with 16 to 20 carbon atoms;

[0022] The alkyl group in the alkyl glycoside is a monohydric alcohol or a polyhydric alcohol having 6 to 10 carbon atoms.

[0023] In another possible implementation, the mass ratio of the fatty acid amide, the cationic surfactant and the silane coupling agent is 1:0.3-0.5:0.1-0.3.

[0024] In another possible implementation, the silane coupling agent is an aminosilane coupling agent, a bisaminosilane coupling agent or a triaminosilane coupling agent;

[0025] The cationic surfactant is dodecyltrimethylammonium chloride or hexadecyltrimethylammonium chloride;

[0026] The fatty acid amide is fatty acid diethanolamide or fatty acid ethanolamide, and the fatty acid in the fatty acid amide is a long-chain fatty acid with 8 to 20 carbon atoms.

[0027] In another possible implementation, the mass ratio of the silane coupling agent to the betaine surfactant is 0.3-0.5:1.

[0028] In another possible implementation, the betaine surfactant is hydroxysulfonpropyl betaine, sulfonpropyl betaine, alkyl betaine, phosphate betaine or alkylamide betaine, and the number of carbon atoms in the hydrocarbon-substituted part of the betaine surfactant is 12 to 18.

[0029] On the other hand, a rice husk modified driving agent is provided, and the rice husk modified driving agent is prepared by any of the preparation methods described above.

[0030] The present application provides a method for preparing a rice husk modified displacement agent. The method uses rice husk as a raw material to prepare the rice husk modified displacement agent. The rice husk is first ground and carbonized, and then a surface-active lipophilic group is "grafted" onto the carbonized rice husk body to modify the carbonized rice husk to obtain a rice husk modified displacement agent. The rice husk modified displacement agent has a hydrophilic and lipophilic "amphipatic" structure, and the oil-water interfacial tension with the formation crude oil can reach 10 -3 The magnitude of mN / m indicates that the rice husk modified displacement agent has the function of adjusting the profile as well as washing oil, which can overcome the viscosity of the remaining oil in the formation and displace more remaining oil, thereby further improving the crude oil recovery rate.

[0031] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of a method for preparing a rice husk modified displacement agent provided in an embodiment of the present application;

[0033] Figure 2 This is a microscopic morphology of a carbonized rice husk type I provided in an embodiment of the present application;

[0034] Figure 3 This is a microscopic morphology of a hexadecyl diethanolamide rice husk modified displacement agent provided in an embodiment of the present application;

[0035] Figure 4 It is a schematic diagram of thermogravimetric curves of a carbonized rice husk type I and a hexadecyl diethanolamide rice husk modified control agent provided in the examples of the present application. DETAILED DESCRIPTION

[0036] In order to make the technical solutions and advantages of the present application clearer, the implementation methods of the present application are described in further detail below.

[0037] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0038] Figure 1 is a flow chart of a method for preparing a rice husk modified displacement agent provided in an embodiment of the present application, see Figure 1 , the method comprising:

[0039] Step 101: Grinding and carbonizing raw rice husks with a moisture content of less than 15% to obtain carbonized rice husks.

[0040] The raw rice husk with a moisture content of less than 15% is put into a ball mill for grinding at a speed of 200 to 600 rpm, and after grinding for 20 to 40 minutes, rice husk powder with a particle size of 80 to 150 meshes is obtained; the rice husk powder is put into a carbonization furnace for carbonization at a carbonization temperature of 280° C. to 350° C., and is sorted after carbonization for 3 to 4 hours to obtain carbonized rice husk.

[0041] The speed of the ball mill can be 200 rpm, 300 rpm, 400 rpm, 500 rpm or 600 rpm. The grinding time can be 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes. The particle size of the rice husk powder can be 80 mesh, 90 mesh, 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh or 150 mesh.

[0042] The carbonization temperature may be 280° C., 290° C., 300° C., 310° C., 320° C., 330° C., 340° C., or 350° C. The carbonization time may be 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or 4 hours.

[0043] After the carbonization time is reached, the carbonized rice husk powder can be put into an airflow separator and separated by high-speed airflow to obtain carbonized rice husk. The carbonized rice husk is micro-nano particles, that is, the particle size of the carbonized rice husk can reach the micro-nano level.

[0044] Step 102: Add the carbonized rice husk and water into a mixing tank and mix for a first time period.

[0045] Add carbonized rice husk and water into a stirring tank and stir for a certain period of time, so that the carbonized rice husk is fully saturated with water and a large number of hydroxyl groups are adsorbed on the surface of the carbonized rice husk.

[0046] Among them, the first duration can be set and changed as needed. For example, the first duration is 10 to 30 minutes, specifically 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, and there is no specific limitation on this.

[0047] Step 103: Add the composite surfactant into the stirring tank and stir for a second period of time to obtain a rice husk modified displacement agent.

[0048] The total mass fraction of carbonized rice husk, composite surfactant and water is 100, wherein the mass fraction ratio of carbonized rice husk to composite surfactant is 9 to 24:1, and the rest is water. For example, the mass fraction ratio of carbonized rice husk to composite surfactant is 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1 or 24:1.

[0049] In the embodiments of the present application, the composite surfactant can be composed of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate and alkyl alcohol amide, or can be composed of a silane coupling agent, fatty acid amide and cationic surfactant, or can be composed of a silane coupling agent and a betaine surfactant.

[0050] If the composite surfactant is composed of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate and alkyl alcohol amide, step 103 can be replaced by: first adding alkyl alcohol amide to the stirring tank, and then adding at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate, stirring for a second time to obtain the rice husk modified control agent.

[0051] The mass ratio of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate to alkyl alcohol amide is 0.1-0.3:1.

[0052] In this implementation, the composite surfactant may be formed by compounding any one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate with alkyl alcohol amide. For example, the composite surfactant is compounded by fatty alcohol polyoxyethylene ether and alkyl alcohol amide, or the composite surfactant is compounded by fatty acid polyoxyethylene ester and alkyl alcohol amide, or the composite surfactant is compounded by alkyl glycoside and alkyl alcohol amide, or the composite surfactant is compounded by polysorbate and alkyl alcohol amide.

[0053] The composite surfactant can also be formed by compounding any two of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate with alkyl alcohol amide. For example, the composite surfactant is compounded by fatty alcohol polyoxyethylene ether and fatty acid polyoxyethylene ester with alkyl alcohol amide, or the composite surfactant is compounded by fatty alcohol polyoxyethylene ether and alkyl glycoside with alkyl alcohol amide, or the composite surfactant is compounded by fatty alcohol polyoxyethylene ether and alkyl glycoside with alkyl alcohol amide, or the composite surfactant is compounded by fatty alcohol polyoxyethylene ether and alkyl glycoside with alkyl alcohol amide, or the composite surfactant is compounded by fatty acid polyoxyethylene ester and alkyl glycoside with alkyl alcohol amide, or the composite surfactant is compounded by fatty acid polyoxyethylene ester and polysorbate with alkyl alcohol amide, or the composite surfactant is compounded by alkyl glycoside and polysorbate with alkyl alcohol amide. Among them, when any two of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate are compounded with alkyl alcohol amide, the mass ratio of any two reagents can be set and changed as needed, for example, the mass ratio of the two reagents is 1:1.

[0054] The composite surfactant can also be formed by compounding any three of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate with alkyl alcohol amide. For example, the composite surfactant is compounded by fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and alkyl glycoside with alkyl alcohol amide, or the composite surfactant is compounded by fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and polysorbate with alkyl alcohol amide, or the composite surfactant is compounded by fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate with alkyl alcohol amide. Among them, when any three of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate are compounded with alkyl alcohol amide, the mass ratio of any three reagents can be set and changed as needed, for example, the mass ratio of the three reagents is 1:1:1.

[0055] The composite surfactant can also be compounded by fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate with alkyl alcohol amide. When fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate are compounded with alkyl alcohol amide, the mass ratio of the four reagents can be set and changed as needed, for example, the mass ratio of the four reagents is 1:1:1:1.

[0056] In the embodiment of the present application, the alkyl alcohol amide may be an alkyl diethanol amide, wherein the alkyl group in the alkyl diethanol amide is a saturated hydrocarbon group or an unsaturated hydrocarbon group having a carbon number between 8 and 20 (8≤C≤20).

[0057] The addition number of ethylene oxide in the fatty alcohol polyoxyethylene ether can be set and changed as needed, for example, the addition number of ethylene oxide is 6 to 8. And the fatty alcohol in the fatty alcohol polyoxyethylene ether is a long-chain hydrocarbon group with 16 to 20 carbon atoms (16≤C≤20).

[0058] The fatty acid in the fatty acid polyoxyethylene ester is a long-chain hydrocarbon group with 16 to 20 carbon atoms (16≤C≤20).

[0059] The alkyl group in the alkyl glycoside is a monohydric alcohol or a polyhydric alcohol having 6 to 10 carbon atoms (6≤C≤10).

[0060] In this implementation, the second duration may be 10 to 30 minutes, for example, the second duration is 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, and there is no specific limitation on this.

[0061] If the composite surfactant is composed of a silane coupling agent, a fatty acid amide and a cationic surfactant, step 103 can be replaced by: adding a silane coupling agent to the stirring tank and stirring for a third time; adding a fatty acid amide and a cationic surfactant to the stirring tank and stirring for a fourth time to obtain a rice husk modified driving agent. The sum of the third time and the fourth time is the second time.

[0062] The mass ratio of fatty acid amide, cationic surfactant and silane coupling agent is 1:0.3-0.5:0.1-0.3. For example, the mass ratio of fatty acid amide, cationic surfactant and silane coupling agent is 1:0.3:0.1, 1:0.4:0.1, 1:0.5:0.1, 1:0.3:0.2, 1:0.4:0.2, 1:0.5:0.2, 1:0.3:0.3, 1:0.4:0.3 or 1:0.5:0.3.

[0063] In the embodiments of the present application, the silane coupling agent is soluble in water and can be an aminosilane coupling agent, a bisaminosilane coupling agent, or a triaminosilane coupling agent, without specific limitation.

[0064] The cationic surfactant may be dodecyltrimethylammonium chloride or hexadecyltrimethylammonium chloride.

[0065] The fatty acid amide may be fatty acid diethanolamide or fatty acid ethanolamide, wherein the fatty acid in the fatty acid amide is a long-chain fatty acid having 8 to 20 carbon atoms, for example, the fatty acid in the fatty acid amide is caprylic acid, lauric acid, myristic acid, palmitic acid, oleic acid or coconut acid.

[0066] In this implementation, the third duration may be 10 to 30 minutes, the fourth duration may be 10 to 30 minutes, and correspondingly, the second duration may be 20 to 60 minutes. For example, the third duration is 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes. The fourth duration is 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes.

[0067] If the composite surfactant is composed of a silane coupling agent and a betaine surfactant, step 103 can be replaced by: adding a silane coupling agent to the stirring tank and stirring for a fifth time; adding a betaine surfactant to the stirring tank and stirring for a sixth time to obtain a rice husk modified displacement agent. The sum of the fifth time and the sixth time is the second time.

[0068] The mass ratio of the silane coupling agent to the betaine surfactant is 0.3 to 0.5: 1. For example, the mass ratio of the silane coupling agent to the betaine surfactant is 0.3: 1, 0.4: 1 or 0.5: 1.

[0069] In the embodiment of the present application, the silane coupling agent may be an aminosilane coupling agent, a bisaminosilane coupling agent or a triaminosilane coupling agent.

[0070] The betaine surfactant may be hydroxysulfopropyl betaine, sulfopropyl betaine, alkyl betaine, phosphate betaine or alkylamide betaine, and the number of carbon atoms of the hydrocarbon-substituted part in the betaine surfactant is 12 to 18 (12≤C≤18).

[0071] In this implementation, the fifth duration may be 10 to 30 minutes, and the sixth duration may be 10 to 30 minutes. For example, the fifth duration is 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, and the sixth duration is 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes.

[0072] It should be noted that if the composite surfactant is composed of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate and alkyl alcohol amide, the carbonized rice husk and alkyl alcohol amide mainly react through intermolecular dehydration reaction to obtain a rice husk modified flooding agent. If the composite surfactant is composed of a silane coupling agent, a fatty acid amide and a cationic surfactant, the carbonized rice husk reacts with the silane coupling agent, the fatty acid amide and the cationic surfactant to obtain a rice husk modified flooding agent. If the composite surfactant is composed of a silane coupling agent and a betaine surfactant, the carbonized rice husk reacts with the silane coupling agent and the betaine surfactant to obtain a rice husk modified flooding agent.

[0073] The present application provides a method for preparing a rice husk modified displacement agent. The method uses rice husk as a raw material to prepare the rice husk modified displacement agent. The rice husk is first ground and carbonized, and then a surface-active lipophilic group is "grafted" onto the carbonized rice husk body to modify the carbonized rice husk to obtain a rice husk modified displacement agent. The rice husk modified displacement agent has a hydrophilic and lipophilic "amphipatic" structure, and the oil-water interfacial tension with the formation crude oil can reach 10 -3 The magnitude of mN / m indicates that the rice husk modified displacement agent has the function of adjusting the profile as well as washing oil, which can overcome the viscosity of the remaining oil in the formation and displace more remaining oil, thereby further improving the crude oil recovery rate.

[0074] The preparation process is simple and has low energy consumption, which is in line with the concept of energy conservation, emission reduction and green development. Moreover, rice husks are reused as agricultural waste at low cost, which solves the environmental problems caused by incineration and contributes to the construction of green mines. In addition, the displacement agent prepared in this application is not limited by the temperature and mineralization of the reservoir formation, and is suitable for the profile control, water plugging and oil displacement of the residual oil in the reservoir in the later stage of water injection development, as well as the profile control, water plugging and oil displacement of high-temperature and high-salt reservoirs. The displacement agent has good dispersibility in water and can be directly pumped into the formation through a profile control pump after being diluted 2 to 10 times on site. The preparation and injection process is simple, and it can also be prepared and injected immediately, which is convenient to use.

[0075] The technical solution of the present application will be described in detail below through specific embodiments.

[0076] Among them, the original rice husk was purchased from the market;

[0077] Hexadecyl diethanolamide, industrial-grade reagent, effective content greater than 90%;

[0078] Nonadecanediethanolamide, industrial-grade reagent, effective content greater than 90%;

[0079] Polysorbate 20, industrial-grade reagent, effective content greater than 90%;

[0080] Alkyl polyglycoside (APG0810), industrial grade reagent, effective content greater than 90%;

[0081] Cocoamide, industrial-grade reagent, effective content greater than 90%;

[0082] Octyldecanoic acid diethanolamide, industrial-grade reagent, effective content greater than 90%;

[0083] Polyoxyethylene oleate (A115), industrial-grade reagent, effective content greater than 90%;

[0084] Aminosilane coupling agent (WA-320), industrial-grade reagent, effective content greater than 90%;

[0085] Bisaminosilane coupling agent (KH-602), industrial-grade reagent, effective content greater than 90%;

[0086] Triaminopropyltriethoxysilane, industrial grade reagent, effective content greater than 90%;

[0087] Dodecyltrimethylammonium chloride, industrial grade reagent, effective content greater than 95%;

[0088] Hexadecyltrimethylammonium chloride, industrial grade reagent, effective content greater than 95%;

[0089] Lauramidopropyl betaine, industrial-grade reagent, effective content greater than 90%;

[0090] Dodecyl dimethyl hydroxypropyl betaine phosphate, industrial grade reagent, effective content greater than 90%.

[0091] The on-site water is the reinjection water after the treatment of the produced fluid from the Zao II oil layer in the WG block. The average temperature of the Zao II oil layer in the WG block is 104°C, the viscosity of the underground crude oil is 55mPa.s, and the total mineralization of the formation water is 27000mg / L.

[0092] Firstly, two types of carbonized rice husk with different particle sizes were prepared, namely carbonized rice husk type I and type II.

[0093] The preparation process of carbonized rice husk type I is as follows: grind the original rice husk with a moisture content of less than 15% in a ball mill at a speed of 200 rpm for 25 minutes, put the ground rice husk powder into a carbonization furnace for high-temperature carbonization for 3 hours at a carbonization temperature of 280°C, and perform high-speed airflow sorting after carbonization to obtain carbonized rice husk micro-nano particles type I.

[0094] The particle size of carbonized rice husk type I was measured by laser particle size analyzer. The median particle size D 50 5.5μm, D 90 14.8μm. Figure 2 , Figure 2 This is the microstructure of carbonized rice husk type I.

[0095] The preparation process of carbonized rice husk type II is as follows: grind the original rice husk with a moisture content of less than 15% in a ball mill at a speed of 600 rpm for 20 minutes, put the ground rice husk powder into a carbonization furnace for high-temperature carbonization for 4 hours at a carbonization temperature of 350°C, and perform high-speed airflow sorting after carbonization to obtain carbonized rice husk micro-nano particles type II.

[0096] The particle size of carbonized rice husk type II was measured by laser particle size analyzer. The median particle size D 50 1.2μm, D 90 is 5.0μm.

[0097] The rice husk modified flooding agent is prepared using carbonized rice husk type I and type II respectively.

[0098] Example 1 Preparation of hexadecyl diethanolamide rice husk modified flooding agent

[0099] Add 90 parts of on-site water and 9 parts of carbonized rice husk type I into a stirring tank and stir for 30 minutes, then add 0.9 parts of hexadecyl diethanolamide, 0.05 parts of polysorbate-20 and 0.05 parts of alkyl glycoside (APG0810) in sequence and stir for 30 minutes to obtain hexadecyl diethanolamide rice husk modified flooding agent.

[0100] According to "SY / T 5370-2018 Surface and Interfacial Tension Determination Method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) hexadecyl diethanolamide rice husk modified displacement agent solution is 0.0052mN / m.

[0101] The core flooding simulation experiment was used to evaluate the effect of improving crude oil recovery of hexadecyl diethanolamide rice husk modified displacement agent. The core parameters were: water-measured core permeability 302mD, porosity 35.8%, saturated oil 55.2%. When the water content of water flooding reached 98%, the recovery rate was 42.1%; after injecting the hexadecyl diethanolamide rice husk modified displacement agent prepared in Example 1, the final recovery rate was 62.5%. Compared with water flooding, the recovery rate was increased by 20.4%.

[0102] Also, see Figure 3 , Figure 3 The microstructure of the modified flooding agent of hexadecyl diethanolamide rice husk is shown in Figure 3 It can be seen that compared with Figure 2 , Figure 3 The surface of the medium carbonized rice husk type I is covered with a layer of composite surfactant, indicating that the hexadecyl diethanolamide rice husk modified displacement agent is indeed prepared by the above method.

[0103] See also Figure 4 , Figure 4The thermogravimetric curves of carbonized rice husk type I and hexadecyl diethanolamide rice husk modified flooding agent are shown in Figure 1. Compared with the thermogravimetric curve of carbonized rice husk type I, the hexadecyl diethanolamide rice husk modified flooding agent has a large mass loss between 400 and 500 ° C, and this mass loss is mainly caused by the composite surfactant on the surface of carbonized rice husk type I. This also shows that the hexadecyl diethanolamide rice husk modified flooding agent was prepared by the above method.

[0104] Example 2 Preparation of Nonadecanediethanolamide Rice Husk Modified Displacement Agent

[0105] Add 75 parts of on-site water and 24 parts of carbonized rice husk type II into a stirring tank and stir for 30 minutes. Then add 0.77 parts of nonadecanediethanolamide and 0.23 parts of polyoxyethylene oleate in sequence and stir for 30 minutes to obtain nonadecanediethanolamide rice husk modified flooding agent.

[0106] According to "SY / T 5370-2018 Surface and Interfacial Tension Determination Method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) nonadecanediethanolamide rice husk modified displacement agent solution is 0.0089mN / m.

[0107] The core flooding simulation experiment was used to evaluate the effect of improving crude oil recovery of nonadecanediethanolamide rice husk modified displacement agent. The core parameters were: water-measured core permeability 215mD, porosity 31.2%, saturated oil 54.8%. When the water content of water flooding reached 98%, the recovery rate was 45.6%; after the nonadecanediethanolamide rice husk modified displacement agent prepared in Example 2 was injected, the final recovery rate was 64.9%. Compared with water flooding, the recovery rate was increased by 19.3%.

[0108] Example 3 Preparation of aminosilane coupling agent rice husk modified flooding agent

[0109] Add 85 parts of on-site water and 13.5 parts of carbonized rice husk type II into a stirring tank, stir for 10 minutes, add 0.1 parts of aminosilane coupling agent (WA-320), stir for 15 minutes. Finally, add 1 part of cocamide and 0.4 parts of dodecyltrimethylammonium chloride, stir for 30 minutes to obtain aminosilane coupling agent rice husk modified displacement agent.

[0110] According to "SY / T 5370-2018 Surface and Interfacial Tension Determination Method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) aminosilane coupling agent rice husk modified flooding agent is 0.0095mN / m.

[0111] The core flooding simulation experiment was used to evaluate the effect of aminosilane coupling agent rice husk modified displacement agent on improving crude oil recovery. The core parameters were: water-measured core permeability 102mD, porosity 26.9%, saturated oil 56.3%. When the water content of water flooding reached 98%, the recovery rate was 48.5%; after injecting the aminosilane coupling agent rice husk modified displacement agent prepared in Example 3, the final recovery rate was 68.2%. Compared with water flooding, the recovery rate was increased by 19.7%.

[0112] Example 4 Preparation of bisaminosilane coupling agent rice husk modified flooding agent

[0113] Add 68.5 parts of on-site water and 30 parts of carbonized rice husk type I into the stirring tank, stir for 30 minutes, add 0.3 parts of bisaminosilane coupling agent (KH-602), stir for 20 minutes. Finally, add 1 part of octyl decanoic acid diethanolamide and 0.2 parts of hexadecyl trimethyl ammonium chloride, stir for 30 minutes to obtain γ-aminopropyl trimethoxysilane rice husk modified displacement agent.

[0114] According to "SY / T 5370-2018 Surface and interfacial tension determination method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) bis-aminosilane coupling agent rice husk modified displacement agent is 0.0089mN / m.

[0115] The core flooding simulation experiment was used to evaluate the effect of improving crude oil recovery of the bisaminosilane coupling agent rice husk modified displacement agent. The core parameters were: water-measured core permeability 58mD, porosity 28.9%, saturated oil 57.8%. When the water content of water flooding reached 98%, the recovery rate was 51.2%; after the bisaminosilane coupling agent rice husk modified displacement agent prepared in Example 4 was injected, the final recovery rate was 71.3%. Compared with water flooding, the recovery rate was increased by 20.1%.

[0116] Example 5 Preparation of betaine I rice husk modified flooding agent

[0117] In a stirring tank, 67.7 parts of on-site water and 31 parts of carbonized rice husk type II were added by mass and stirred for 15 minutes, and then 0.3 parts of triaminopropyl triethoxysilane were added and stirred for 15 minutes, and then 1 part of lauroylamidopropyl betaine was added and stirred for 20 minutes to obtain betaine I rice husk modified flooding agent.

[0118] According to "SY / T 5370-2018 Surface and Interfacial Tension Determination Method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) betaine I rice husk modified flooding agent is 0.0075mN / m.

[0119] The core flooding simulation experiment was used to evaluate the effect of betaine I rice husk modified displacement agent on improving crude oil recovery. The core parameters were: water-measured core permeability 101mD, porosity 30.2%, saturated oil 50.8%. When the water content of water flooding reached 98%, the recovery rate was 60.1%; after the betaine I rice husk modified displacement agent prepared in Example 5 was injected, the final recovery rate was 77.5%. Compared with water flooding, the recovery rate was increased by 17.4%.

[0120] Example 6 Preparation of betaine II rice husk modified flooding agent

[0121] In a stirring tank, 78.5 parts of on-site water and 20 parts of carbonized rice husk type II were added by mass and stirred for 15 minutes, and then 0.5 parts of aminosilane coupling agent (WA-320) were added and stirred for 15 minutes, and then 1 part of dodecyl dimethyl hydroxypropyl phosphate betaine was added and stirred for 20 minutes to obtain betaine II rice husk modified flooding agent.

[0122] According to "SY / T 5370-2018 Surface and interfacial tension determination method", the oil-water interfacial tension value of 0.5% (calculated according to surfactant concentration) betaine II rice husk modified flooding agent is 0.0066mN / m.

[0123] The core flooding simulation experiment was used to evaluate the effect of betaine II rice husk modified displacement agent on improving crude oil recovery. The core parameters were: water-measured core permeability 45mD, porosity 26.2%, saturated oil 58.8%. When the water content was 98% in water flooding, the recovery rate was 46.8%; after the betaine II rice husk modified displacement agent prepared in Example 6 was injected, the final recovery rate was 68.0%. Compared with water flooding, the recovery rate was increased by 21.2%.

[0124] Comparative Example 1

[0125] The 9% carbonized rice husk type I solution was prepared using on-site water. The oil-water interfacial tension was measured to be 89mN / m, which does not have the effect of washing oil. The results of the core flooding simulation experiment showed that the carbonized rice husk type I solution was injected after water flooding to 98% water content, and the recovery rate was only increased by 9.5% compared with water flooding.

[0126] Comparative Example 2

[0127] The 24% carbonized rice husk type II solution was prepared using on-site water. The oil-water interfacial tension was measured to be 77mN / m, which does not have the effect of washing oil. The results of the core flooding simulation experiment showed that the carbonized rice husk II solution was injected after water flooding to 98% water content, and the recovery rate was only increased by 10.2% compared with water flooding.

[0128] It can be seen from Examples 1 to 6 and Comparative Examples 1 to 2 that after the carbonized rice husk is modified, its oil-water interfacial tension is greatly reduced and can reach 10 -3mN / m order of magnitude, proving that the rice husk modified displacement agent prepared by the method provided by the present application has an oil washing effect. Moreover, the recovery rate after water flooding is also greatly improved. Therefore, the rice husk modified displacement agent prepared by the method provided by the present application has both the effects of profile control and oil washing.

[0129] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a rice husk modified flooding agent, characterized in that: The preparation method comprises: Grinding and carbonizing raw rice husks with a moisture content of less than 15% to obtain carbonized rice husks; Adding the carbonized rice husk and water into a stirring tank and stirring for a first period of time; Adding a composite surfactant into the stirring tank and stirring for a second period of time to obtain a rice husk modified displacement agent; The total mass fraction of the carbonized rice husk, the composite surfactant and water is 100, the mass fraction ratio of the carbonized rice husk to the composite surfactant is 9-24:1, and the rest is water; The composite surfactant is composed of at least one of fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkyl glycoside and polysorbate and alkyl alcohol amide, or the composite surfactant is composed of a silane coupling agent, fatty acid amide and cationic surfactant, or the composite surfactant is composed of the silane coupling agent and betaine surfactant.

2. The preparation method according to claim 1, characterized in that: The method of grinding and carbonizing the original rice husk with a moisture content of less than 15% to obtain the carbonized rice husk comprises: The original rice husk with a moisture content of less than 15% is put into a ball mill for grinding at a speed of 200 to 600 rpm, and after grinding for 20 to 40 minutes, rice husk powder with a particle size of 80 to 150 meshes is obtained; The rice husk powder is placed in a carbonization furnace for carbonization at a temperature of 280° C. to 350° C. After carbonization for 3 to 4 hours, the powder is sorted to obtain the carbonized rice husk.

3. The preparation method according to claim 1, characterized in that: If the composite surfactant is composed of the silane coupling agent, the fatty acid amide and the cationic surfactant, the composite surfactant is added to the stirring tank and stirred for a second time to obtain the rice husk modified displacement agent, comprising: Adding the silane coupling agent into the stirring tank and stirring for a third period of time; The fatty acid amide and the cationic surfactant are added to the stirring tank and stirred for a fourth time to obtain the rice husk modified driving agent; wherein the sum of the third time and the fourth time is the second time.

4. The preparation method according to claim 1, characterized in that: The mass ratio of at least one of the fatty alcohol polyoxyethylene ether, the fatty acid polyoxyethylene ester, the alkyl glycoside and the polysorbate to the alkyl alcohol amide is 0.1 to 0.3:

1.

5. The preparation method according to claim 1, characterized in that: The alkyl alcohol amide is an alkyl diethanol amide, wherein the alkyl group in the alkyl diethanol amide is a saturated hydrocarbon group or an unsaturated hydrocarbon group having 8 to 20 carbon atoms; The number of ethylene oxide additions in the fatty alcohol polyoxyethylene ether is 6 to 8, and the fatty alcohol is a long-chain hydrocarbon group with 16 to 20 carbon atoms; The fatty acid in the fatty acid polyoxyethylene ester is a long-chain hydrocarbon group with 16 to 20 carbon atoms; The alkyl group in the alkyl glycoside is a monohydric alcohol or a polyhydric alcohol having 6 to 10 carbon atoms.

6. The preparation method according to claim 1, characterized in that: The mass ratio of the fatty acid amide, the cationic surfactant and the silane coupling agent is 1:0.3-0.5:0.1-0.

3.

7. The preparation method according to claim 1, characterized in that: The silane coupling agent is an aminosilane coupling agent, a bisaminosilane coupling agent or a triaminosilane coupling agent; The cationic surfactant is dodecyltrimethylammonium chloride or hexadecyltrimethylammonium chloride; The fatty acid amide is fatty acid diethanolamide or fatty acid ethanolamide, and the fatty acid in the fatty acid amide is a long-chain fatty acid with 8 to 20 carbon atoms.

8. The preparation method according to claim 1, characterized in that: The mass ratio of the silane coupling agent to the betaine surfactant is 0.3-0.5:

1.

9. The preparation method according to claim 1, characterized in that: The betaine surfactant is hydroxysulfonpropyl betaine, sulfonpropyl betaine, alkyl betaine, phosphate betaine or alkylamide betaine, and the carbon number of the hydrocarbon-substituted part in the betaine surfactant is 12-18.

10. A rice husk modified flooding agent, characterized in that: The rice husk modified driving agent is prepared by the preparation method according to any one of claims 1 to 9.

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