Temperature-sensitive magnetic dual-response intelligent nano chemical oil displacement agent and preparation method thereof

Abstract

The invention relates to the technical field of oilfield exploitation, in particular to a temperature-sensitive magnetic dual-response intelligent nano chemical oil displacement agent and a preparation method thereof. The invention discloses a temperature-sensitive magnetic dual-response intelligent nano chemical oil-displacing agent and a preparation method thereof, and on the basis of synthesizing a magnetic response intelligent nano chemical oil-displacing agent, the surface of the magnetic response intelligent nano chemical oil-displacing agent is coated with a temperature-sensitive polymer to form the temperature-sensitive magnetic dual-response intelligent nano chemical oil-displacing agent. The intelligent nano oil-displacing agent prepared by the invention is mild in preparation condition, simple in technical route and easy to realize large-scale production, has unique oil-displacing characteristics, can adapt to special conditions of different oil reservoir environments, plays a role in directionally improving the crude oil recovery rate, and has a relatively good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield exploitation, and in particular to a temperature-sensitive and magnetic dual-response intelligent nano-chemical oil-displacing agent and a preparation method thereof. Background Art

[0002] At present, most of my country's old oil fields are facing the dilemma of high water content, rapid drop in water injection pressure, insufficient energy, and rapid decline in production. Due to the difficulty in improving the flow ratio and reservoir heterogeneity in secondary oil recovery, crude oil is bound by capillary force or bypass, resulting in low sweep efficiency, so that the crude oil remaining in the pore cannot be displaced. Tertiary oil recovery technology solves the main problems such as low sweep efficiency and difficulty in changing rock formation wettability, and can effectively improve the displacement effect, thereby increasing crude oil recovery. As the main means of tertiary oil recovery, chemical flooding has gradually matured after decades of development. However, as domestic oil fields gradually transform from conventional oil reservoirs to low permeability oil reservoirs, tertiary oil recovery also faces technical barriers such as high energy consumption, high cost, and low recovery degree. It is urgent to explore new oil recovery technologies to meet field application needs.

[0003] In this context, smart nanoparticle flooding technology came into being. Nanoparticles have become the focus of the current oil and gas industry due to their large specific surface energy, strong adsorption, and strong hydrophobic and lipophilic properties. Smart nanochemical flooding agents can respond to temperature, magnetic fields, etc., significantly reduce the oil-water interfacial tension, and increase the contact angle between oil and rock formations, making it easier for crude oil to peel off from the rock formation and improve crude oil recovery. Summary of the invention

[0004] The purpose of the present invention is to provide a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent and a preparation method thereof. After the prepared intelligent nanochemical oil-displacing agent is injected into the formation, the flow direction, range and contact time of the nanofluid can be controlled by adding a magnetic field. At the same time, it can adapt to the characteristics of high-temperature and low-temperature oil reservoirs, realize intelligent operation, and thus achieve efficient displacement and improve recovery.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0006] In a first aspect, the present invention provides a method for preparing a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent, comprising the following steps:

[0007] The surfactant, nano-silica, magnetic nanoparticles, alkaline solution and polymer are mixed to synthesize a magnetically responsive intelligent nano-chemical oil displacement agent;

[0008] A thermosensitive polymer is coated on the surface of a magnetically responsive intelligent nanochemical oil-displacing agent to prepare a dual magnetically responsive thermosensitive composite intelligent nanochemical oil-displacing agent.

[0009] Among them, the thermosensitive material is polymerized and coated on the surface of the magnetically responsive intelligent nanochemical oil-displacing agent to prepare a dual magnetically responsive thermosensitive composite intelligent nanochemical oil-displacing agent with different surface hydrophilic / hydrophobic properties.

[0010] Furthermore,

[0011] The surfactant is an anionic surfactant dodecyl phosphate monoester, and its mass accounts for 1.0-4.0% of the total mass of the solution.

[0012] Among them, the surfactant is preferably dodecyl phosphate monoester. The surfactant can reduce the oil-water interfacial tension, thereby recovering the oil that is adhered to the rock surface and adsorbed in the core pore throat and is not easy to flow.

[0013] Furthermore,

[0014] The particle size of the nano silicon dioxide material is 40-80 nm, and the mass thereof accounts for 2.0-5.0% of the total mass of the solution.

[0015] Among them, nano-silica materials have strong hydrophobic and lipophilic properties as well as extremely large specific surface area and surface energy, which can reduce the oil-water interfacial tension and make crude oil easily displaced.

[0016] Furthermore,

[0017] The magnetic nanoparticle material is Fe 3 O 4 and / or γ-Fe 2 O 3 , its particle size is 30 to 80 nm, and its mass accounts for 0.5 to 2.5% of the total mass of the solution.

[0018] Among them, the magnetic nanoparticles are preferably Fe 3 O 4 The introduction of the magnetic nanoparticles can control the flow range of the oil displacement fluid through an external electric field, control the contact time between the nanofluid and the reservoir, and realize intelligent operation.

[0019] Furthermore,

[0020] The alkali is sodium hydroxide or sodium carbonate.

[0021] Furthermore,

[0022] The concentration of the alkali is 1.0-3.0%.

[0023] Furthermore,

[0024] The polymer is partially hydrolyzed polyacrylamide, and its mass accounts for 0.5-2.0% of the total mass of the solution.

[0025] Furthermore,

[0026] The thermosensitive polymer is poly (N-isopropylacrylamide) (PNIPAM)

[0027] Furthermore,

[0028] The mass of the temperature-sensitive polymer accounts for 0.5-1.0% of the total mass of the solution.

[0029] Among them, the temperature-sensitive substance is poly (N-isopropylacrylamide) (PNIPAM), which is lipophilic in high-temperature reservoir environments and can better stabilize the emulsion, allowing the displacement fluid to push the oil layer forward and achieve better displacement; it is hydrophilic at low temperatures and can break the emulsion more quickly, allowing the oil-water interface to separate quickly; at the same time, nanoparticles can achieve temporary blocking of large pores, displace crude oil in small pores that have not been affected, and expand the affected volume.

[0030] In a second aspect, the present invention provides a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent prepared by the method for preparing the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0031] Based on the above technical solutions, the technical effects that can be achieved by the present invention are:

[0032] The preparation method of the invention is simple, and in the oil displacement process, a controllable oil displacement process is realized by using a temperature-sensitive magnetic dual-response intelligent nanochemical oil displacement agent. The preparation conditions of the temperature-sensitive magnetic dual-response intelligent nanochemical oil displacement agent of the invention are mild, the oil displacement cost is low and the effect is good, and it is suitable for large-scale production. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0034] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the reagents, materials, etc. used in the following examples, unless otherwise specified, can be obtained from commercial channels.

[0036] Embodiment 1:

[0037] The preparation method of the nano oil displacement fluid of the present invention is:

[0038] 2.0% dodecyl phosphate monoester and 2.5% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe with a particle size of 80 nm. 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 0.5% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0039] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 85.1%, and the oil displacement efficiency was increased by 12.6% after water flooding.

[0040] Embodiment 2:

[0041] 2.0% dodecyl phosphate monoester and 2.5% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then mixed with 2.5% 80nm Fe 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 0.5% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0042] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 89.6%, and the oil displacement efficiency was increased by 15.3% after water flooding.

[0043] Embodiment 3:

[0044] 2.0% dodecyl phosphate monoester and 2.5% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe with a particle size of 80 nm. 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 1.0% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0045] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 91.2%, and the oil displacement efficiency was increased by 16.5% after water flooding.

[0046] Embodiment 4:

[0047] 2.0% dodecyl phosphate monoester and 2.5% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 1.0% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0048] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 91.5%, and the oil displacement efficiency was increased by 17.9% after water flooding.

[0049] Embodiment 5:

[0050] 2.0% dodecyl phosphate monoester and 2.5% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 1.0% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0051] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 91.7%, and the oil displacement efficiency was increased by 18.4% after water flooding.

[0052] Embodiment 6:

[0053] 2.0% dodecyl phosphate monoester and 5.0% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe 3 O 4The nanoparticle materials are compounded and stirred evenly to obtain a magnetic intelligent nanochemical oil-displacing agent; and then 1.0% poly (N-isopropylacrylamide) is coated on the surface of the magnetic intelligent nanochemical oil-displacing agent to obtain a temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent.

[0054] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 91.9%, and the oil displacement efficiency was increased by 18.1% after water flooding.

[0055] Comparative Example 1:

[0056] The preparation method of nano oil displacement fluid is:

[0057] 2.0% dodecyl phosphate monoester and 5.0% 50nm nano-SiO 2 After the materials are fully mixed, they are added to 2.0% sodium hydroxide solution, followed by 0.5% partially hydrolyzed polyacrylamide, and then 1.0% Fe 3 O 4 The nanoparticle materials are compounded and stirred evenly to obtain a finished magnetic intelligent nano oil displacement fluid.

[0058] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 82.5%, and the oil displacement efficiency was increased by 10.5% after water flooding.

[0059] Comparative Example 2:

[0060] The preparation method of nano oil displacement fluid is:

[0061] 2.0% dodecyl phosphate monoester and 5.0% 50nm nano-SiO 2 After the materials are fully mixed, they are added into a 2.0% sodium hydroxide solution, and then 0.5% partially hydrolyzed polyacrylamide is added and stirred evenly to obtain a finished product of a nano oil displacement liquid.

[0062] In an artificial core displacement experiment in the laboratory of the Engineering Technology Research Center of Tongji University, the oil displacement efficiency of the nano oil displacement fluid of this embodiment reached 77.8%, and the oil displacement efficiency was increased by 9.0% after water flooding.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a temperature-sensitive and magnetic dual-response intelligent nanochemical oil-displacing agent. It is characterized in that The following steps are involved: A surfactant, nano-silica, magnetic nanoparticles, alkaline solution and polymer are mixed to synthesize a magnetically responsive intelligent nano-chemical oil displacement agent; A thermosensitive polymer is coated on the surface of a magnetically responsive intelligent nanochemical oil-displacing agent to prepare a dual magnetically responsive thermosensitive composite intelligent nanochemical oil-displacing agent.

2. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The surfactant is an anionic surfactant dodecyl phosphate monoester, and its mass accounts for 1.0-4.0% of the total mass of the solution.

3. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The particle size of the nano silicon dioxide material is 40-80 nm, and the mass thereof accounts for 2.0-5.0% of the total mass of the solution.

4. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The magnetic nanoparticle material is Fe 3 O 4 and / or γ-Fe 2 O 3 , its particle size is 30 to 80 nm, and its mass accounts for 0.5 to 2.5% of the total mass of the solution.

5. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The alkali is sodium hydroxide or sodium carbonate.

6. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 5, It is characterized in that The concentration of the alkali is 1.0-3.0%.

7. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The polymer is partially hydrolyzed polyacrylamide, and its mass accounts for 0.5-2.0% of the total mass of the solution.

8. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 1, It is characterized in that The thermosensitive polymer is poly (N-isopropylacrylamide) (PNIPAM).

9. The preparation method of the temperature-sensitive magnetic dual-response intelligent nanochemical oil-displacing agent according to claim 8, It is characterized in that The mass of the temperature-sensitive polymer accounts for 0.5-1.0% of the total mass of the solution.

10. A temperature-sensitive magnetic dual-response intelligent nano-chemical oil-displacing agent prepared by the method for preparing a temperature-sensitive magnetic dual-response intelligent nano-chemical oil-displacing agent according to any one of claims 1 to 9.