CN-121975509-A - Intelligent nanocapsule oil displacement agent and preparation method and application thereof

CN121975509ACN 121975509 ACN121975509 ACN 121975509ACN-121975509-A

Abstract

The application discloses an intelligent nanocapsule oil displacement agent and a preparation method and application thereof, and belongs to the technical field of petroleum exploitation. The preparation method comprises the steps of (1) adding N-isopropyl acrylamide, methacryloyl ethyl sulfobetaine, unsaturated phosphate and an emulsifier into water to obtain a water phase, (2) adding modified nano particles into a first solvent to obtain an oil phase, (3) adding the oil phase into the water phase, stirring and mixing uniformly, and then adding an initiator under the condition of inert gas to react to obtain the intelligent nano capsule oil displacement agent. The intelligent nanocapsule oil displacement agent can be adjusted according to the actual temperature of an oil reservoir, and achieves the effects of low Wen Yibeng injection and high-temperature stable displacement, so that the petroleum recovery ratio is improved.

Inventors

CUI SHIZHANG
HUANG HAI
MA LI
Huang Qihuo
XIAO PAN
GUO XIN

Assignees

德仕能源科技集团股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260330

Claims (9)

1. The preparation method of the intelligent nano-capsule oil displacement agent is characterized by comprising the following steps of: (1) Adding N-isopropyl acrylamide, methacryloyl ethyl sulfobetaine and unsaturated phosphate and an emulsifier into water to obtain a water phase; (2) Adding the modified nano particles into a first solvent to obtain an oil phase; (3) Adding the oil phase into the water phase, stirring and mixing uniformly, and adding an initiator under the condition of inert gas to react to obtain the intelligent nanocapsule oil displacement agent; the preparation method of the modified nanoparticle comprises the following steps: s1, adding nano particles into a second solvent, uniformly mixing, and then adding a silane coupling agent containing double bonds to react to obtain an intermediate solution; S2, adding acrylic acid (N-methyl perfluorohexyl sulfonamide) ethyl ester into the intermediate solution, and adding an initiator under the protection of inert gas to react to obtain modified nano particles.
2. The method for preparing the intelligent nanocapsule oil-displacing agent according to claim 1, wherein the reaction condition in the step (3) is reacted for 2-4 hours at 25-35 ℃, and then the temperature is raised to 45-55 ℃ for 4-5 hours.
3. The method for preparing the intelligent nano-capsule oil displacement agent according to claim 1, wherein the addition amount of the modified nano-particles is 8-12wt% of the total weight of N-isopropyl acrylamide, methacryloyl ethyl sulfobetaine and unsaturated phosphate.
4. The preparation method of the intelligent nano-capsule oil displacement agent according to claim 1, wherein the molar ratio of the N-isopropyl acrylamide, the methacryloyl ethyl sulfobetaine and the unsaturated phosphate is 1 (0.4-0.5) (0.1-0.3).
5. The method for preparing an intelligent nanocapsule oil-displacing agent according to claim 4, wherein the unsaturated phosphate is one selected from diethyl vinyl phosphate, allyl diethyl phosphate, vinyl phosphate and oleyl phosphate.
6. The method for preparing an intelligent nanocapsule oil-displacing agent according to claim 1, wherein the reaction temperature in step S1 is 60-70 ℃ and the reaction time is 2-4h, and/or The reaction time in the step S2 is 70-80 ℃ and 3-5h.
7. The method for preparing the intelligent nano-capsule oil displacement agent according to claim 1, wherein the weight ratio of the nano-particles to the silane coupling agent containing double bonds to the (N-methyl perfluorohexyl sulfonamide) ethyl acrylate is 1 (0.3-0.6) to 0.2-0.3.
8. An intelligent nanocapsule oil-displacing agent, which is characterized by being prepared by adopting the preparation method of the intelligent nanocapsule oil-displacing agent according to any one of claims 1-7.
9. The use of the intelligent nanocapsule oil-displacing agent of claim 8 in oil recovery in an oilfield.

Description

Intelligent nanocapsule oil displacement agent and preparation method and application thereof Technical Field The application relates to an intelligent nano-capsule oil displacement agent and a preparation method and application thereof, and belongs to the technical field of petroleum exploitation. Background With the reduction of easy-to-mine petroleum, the newly ascertained reserves are mostly low-grade resources, such as low-permeability, ultra-low-permeability and even dense oil reservoirs, and the development difficulty of the oil reservoirs is extremely high. The traditional water flooding technology (secondary oil recovery) and chemical flooding technology (tertiary oil recovery) can not well play roles in the oil reservoirs, and mainly have the following problems: (1) The water flooding technology cannot effectively displace crude oil in a hypotonic region, and a network structure formed by strong hydrogen bond association of water makes the crude oil difficult to enter a nano-scale throat, so that the crude oil cannot effectively play a role. (2) The chemical efficiency is low, most oil displacement agents are easy to absorb and lose on the surface of a reservoir medium, the effective concentration is reduced, and the severe challenges of temperature resistance and salt resistance are faced. (3) In the prior art, the oil displacement agent cannot adapt to the difference of the temperature gradient and the mineralization degree of the stratum, so that the oil displacement effect is improved, the injection amount is large, the oil displacement cost is increased, the medicament residue make it too hot for sb. is degraded, the environment is affected, and meanwhile, the existing oil displacement agent has good effect when being used in a near well, but is easy to degrade when penetrating into a deep well, and the recovery ratio is unstable in lifting range. The Chinese patent CN112080267B discloses an intelligent nano oil displacement agent and a preparation method and application thereof, wherein the intelligent nano oil displacement agent comprises montmorillonite silicate sheets and a cation displacement layer, the cation displacement layer is positioned between the montmorillonite silicate sheets, the cation displacement layer comprises a hydrophilic end and an oleophilic end, the hydrophilic end is close to the montmorillonite silicate sheets, the oleophilic end is far away from the montmorillonite silicate sheets, the cation displacement layer is from a quaternary ammonium salt surfactant, and the quaternary ammonium salt surfactant comprises betaine and long-chain alkyl ammonium halide, but the oil displacement agent acts when penetrating into a shallow well close to the ground in the oil well process, and cannot penetrate into the deep well to play a role, so that the recovery ratio of crude oil in the deep well is reduced. Therefore, it is now necessary to develop an intelligent nanocapsule oil displacement agent with high temperature resistance, salt tolerance, intelligent response and interface stability. Disclosure of Invention In order to solve the problems, the preparation method of the intelligent nano-capsule oil displacement agent is provided, N-isopropyl acrylamide, unsaturated phosphate and methacryloyl ethyl sulfobetaine are crosslinked to form a shell of a capsule, modified nano particles are used as an inner core of the capsule, and N-isopropyl acrylamide is added into the shell of the capsule, so that the temperature sensitivity of the intelligent nano-capsule oil displacement agent is improved, the temperature sensitivity of the intelligent nano-capsule oil displacement agent can be adjusted according to the actual temperature of an oil reservoir, the effects of low Wen Yibeng injection and high-temperature stable displacement are realized, and further the petroleum recovery rate is improved. The application provides a preparation method of an intelligent nanocapsule oil displacement agent, which comprises the following steps: (1) Adding N-isopropyl acrylamide, methacryloyl ethyl sulfobetaine and unsaturated phosphate and an emulsifier into water to obtain a water phase; (2) Adding the modified nano particles into a first solvent to obtain an oil phase; (3) And adding the oil phase into the water phase, stirring and mixing uniformly, and adding an initiator under the condition of inert gas to react to obtain the intelligent nano-capsule oil displacement agent. The polymer molecule chain contains active phosphate groups, can form hydrogen bonds with active groups on the surfaces of modified nanoparticles, and then the polymer molecule chain is gradually entangled and coated on the surfaces of the modified nanoparticles, so that the intelligent nano-capsule structure taking the modified nanoparticles as cores and the polymers as shells is finally formed. In addition, the addition of the N-isopropyl acrylamide enables the intelligent nanocapsule to have temperature-sensitive respon