CN115466605B

CN115466605B - Lignin-based high-heat-conductivity gel profile control agent and preparation method thereof

Info

Publication number: CN115466605B
Application number: CN202210993753.1A
Authority: CN
Inventors: 柏永青; 赵静; 张淮浩
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2022-08-18
Filing date: 2022-08-18
Publication date: 2023-11-03
Anticipated expiration: 2042-08-18
Also published as: CN115466605A

Abstract

The invention discloses a lignin-based high-heat-conductivity gel profile control agent and a preparation method thereof. The design thought of 'matrix network + functional network' is adopted, lignin or derivatives thereof are used as a matrix, chitosan or analogues thereof are used as a cross-linking agent, boron nitride is used as a high-heat-conductivity functional filler, and a reaction system is physically cross-linked by a one-pot method to form the functional double-network gel. The penetrating network formed by the boron nitride in the gel forms a three-dimensional heat conduction channel penetrating through the whole gel, and the gel is endowed with high heat conduction performance. And a biomass network formed by lignin and chitosan through supermolecular action and ionic bond provides a high-temperature-resistant and degradable carrier for a boron nitride functional network, and the gel has good environmental remediation performance. The lignin-based high-heat-conductivity gel profile control agent has good heat conductivity, biodegradability and environmental restoration performance, has extremely low phytotoxicity, and has wide application prospect in clean production of thickened oil as the profile control agent.

Description

Lignin-based high-heat-conductivity gel profile control agent and preparation method thereof

Technical Field

The invention belongs to the field of petroleum exploitation, and relates to a lignin-based gel profile control agent with high heat conductivity and a preparation method thereof.

Background

With the increasing demand for petroleum resources from global economy and the continuous consumption of traditional crude oil reserves, the importance of heavy oil to world energy supply is continuously increasing. Because cold recovery techniques have low recovery efficiency (only 3% -10%) and require additional viscosity reduction operation assistance, thermal recovery methods (including steam flooding, steam circulation throughput, steam assisted gravity drainage, etc.) remain the most effective recovery methods of thickened oil at present. The recovery of the thick oil is obviously improved by injecting high-temperature steam into the stratum and utilizing the thermal viscosity reduction, thermal expansion, distillation effect and the like brought by the steam. However, the consequent high energy consumption, low heat utilization and derived environmental pollution place an economic burden and environmental stress on the thermal recovery operations. At the same time, the high flow difference between the thick oil and the steamAnd the high heterogeneity of heavy oil reservoirs also limits the oil recovery capacity of thermal recovery. In order to effectively improve the displacement capacity of injected steam, researchers develop a series of macromolecule gel profile control agents, the temperature resistance and the mechanical property of the gel are effectively improved by compounding temperature-resistant soft materials (such as asphaltene, clay and the like), constructing a double network, adopting high-efficiency cross-linking agents (such as HMTA-HQ and the like) and adding temperature-resistant reinforcing agents (such as carbon black, activated carbon, nano silicon dioxide and the like), the injection performance of the gel is improved by synthesizing prefabricated particle gel, and good enhanced recovery effect is obtained. For example: amir et al prepared SiO by one pot method ₂ The nano particles are introduced into PAM/PEI double-network gel, so that the high-strength gel profile control and flooding agent is synthesized and is used for thermal recovery profile control and flooding of heavy oil. The gel can effectively improve steam injection profile and inhibit gravity delamination, thereby effectively improving oil recovery capacity of steam (Amir Z, saaid IM, jan BM, et al pam/PEI polymer gel for water control in high-temperature and high-pressure conditions: core flooding with crossflow effect.Korean Journal of Chemical Engineering,2022,39 (3): 605-615.). Hasankhani et al introduce asphalt particles into an HPAM/PEI interpenetrating network through physical crosslinking to prepare the temperature-resistant gel profile control agent for thick oil steam flooding. Experiments prove that the introduction of asphaltene obviously enhances the strength, shearing resistance and temperature resistance of the polymer gel, so that the gel maintains higher plugging strength at high temperature, thereby effectively improving the recovery ratio of thickened oil (Hasankhani GM, madani M, esmaeilzadeh F, et al, experimental investigation of asphaltene-augmented gel polymer performance for water shut-off and enhancing oil recovery in fractured oil reservoirs. Journal of Molecular Liquids,2019, 275:654-666.).

However, the gel material improves the fluidity ratio of the displacement fluid and the thick oil by adjusting the injection section so as to improve the oil extraction effect of the thermal recovery, and does not effectively control the ineffective heat dissipation and the environmental pollution in the thermal recovery. Specifically, 1) the traditional gel profile control agent has poor thermal conductivity, so that the thermal recovery efficiency of the thickened oil is low. In the profile control and flooding process, the low heat transfer rate of the traditional gel causes larger heat resistance hysteresis, so that the residence time of steam is overlong, the heat loss of the steam on the rock wall is increased, and the heat-induced viscosity reduction effect is poor. 2) Traditional gel flooding agents can exacerbate environmental pollution caused by thermal recovery. The high pH (easy to harden soil) and biological incompatibility of the traditional gel material make the traditional gel material incapable of effectively relieving environmental pollution caused by thermal recovery. Furthermore, the use of large amounts of synthetic polymers and chemical cross-linking agents in the gel results in serious soil and groundwater contamination. The recalcitrance of the polymer is more detrimental to this contamination. 3) Conventional gel flooding agents can cause severe formation damage. The traditional gel has high adhesiveness and is difficult to degrade, and a large amount of gel is easy to remain in the stratum after profile control and flooding, so that a plurality of permanent or semi-permanent stratum damages are caused, and subsequent thick oil exploitation is seriously hindered.

Disclosure of Invention

The invention provides a lignin-based high-heat-conductivity gel profile control agent and a preparation method thereof. The lignin-based high-heat-conductivity gel profile control agent takes lignin or derivatives thereof as a matrix, has high heat conductivity, high biodegradability, low phytotoxicity and good environmental restoration performance, and can effectively solve the problems of poor steam heat transfer performance and high pollution in the thick oil steam flooding process when being used as a profile control agent in the high-temperature steam flooding of a thick oil reservoir.

According to the preparation method of the lignin-based high-heat-conductivity gel profile control agent, a boron nitride heat-conductivity filler network is introduced into a biomass matrix network through a one-pot method and a physical crosslinking reaction, so that a multi-level and multifunctional double-network gel with a matrix network and a functional network is formed. The boron nitride particles form a three-dimensional supermolecular network covering the whole gel through osmosis and Van der Waals force, so that a high-speed heat conduction channel is provided for the gel, and the gel is endowed with high heat conductivity. And lignin (or derivatives thereof) and chitosan (or analogues thereof) which contain a large amount of oxygen-containing functional groups and respectively have polyanion and polycation characteristics are combined through electrostatic attraction, hydrogen bond and hydrophobic effect, so that the gel is provided with a biodegradable matrix network with environment restoration effect. The method comprises the following specific steps:

(1) At 20-25 ℃, adding the biomass matrix and the cross-linking agent into water according to the mass content of the cross-linking agent of 1:1-3:1, wherein the concentration of the biomass matrix is 2-7wt% and the concentration of the cross-linking agent is 2-7wt%, and stirring to fully dissolve the biomass matrix and the cross-linking agent;

(2) Adding boron nitride into the solution under the stirring condition, and performing ultrasonic dispersion for a period of time to obtain uniform boron nitride dispersion liquid, wherein the mass content of the boron nitride in the boron nitride dispersion liquid is 1-5wt%;

(3) Dropwise adding a pH regulator into the boron nitride dispersion liquid under the gradually increased stirring rate until the pH value is more than 5.8 and more than 3.1, and continuously stirring at a high speed for 30-60 min to obtain biomass sol;

(4) Sealing the biomass sol, standing for 26-126 h at 60-120 ℃ to form gel and aging to obtain the lignin-based high-heat-conductivity gel profile control agent.

In the present invention, the concentration of each raw material is 100% by mass of the whole colloid-forming system, for example, the concentration of each of the biomass matrix and the crosslinking agent is 2 to 7% by weight, which means that the addition amounts of each of the biomass matrix and the crosslinking agent are 2 to 7% by mass of the biomass sol obtained in the step 3.

Preferably, in the step (1), the biomass matrix is lignin or a derivative thereof, and is selected from any one or more of lignin, alkali lignin, lignin sulfate, lignin hydrochloride, sodium lignin sulfonate, calcium lignin sulfonate and the like. In a specific embodiment of the invention, calcium lignosulfonate is used as a matrix.

Preferably, in the step (1), the cross-linking agent is chitosan or an analogue thereof, and is selected from any one or more of chitosan, chitosan hydrochloride, carboxymethyl chitosan, hydroxypropyl chitosan, chitosan oligosaccharide, chitosan tetraose, chitin and the like. In a specific embodiment of the invention, chitosan is used as a cross-linking agent.

Preferably, in step (1), the biomass matrix content is =1:1 by mass of the cross-linking agent.

Preferably, in the step (2), the boron nitride is used as a heat conducting functional filler and is selected from any one or more of hexagonal boron nitride, boron nitride micro-sheets, nano hexagonal boron nitride or boron nitride nano-sheets and the like. In the specific embodiment of the invention, hexagonal boron nitride is used as a heat conduction function filler.

Preferably, in the step (3), the pH regulator is an acid regulator commonly used in the art, and is selected from any one or more of hydrochloric acid, sulfuric acid, oxalic acid, formic acid, acetic acid and the like. In a specific embodiment of the present invention, the pH adjuster employed is hydrochloric acid.

Preferably, in both steps (1) and (2), the stirring speed is 600rpm.

Preferably, in the step (2), the ultrasonic dispersion is carried out for 15-45 min. Preferably, in the step (3), the stirring rate is increased from 600rpm to 1200rpm at a gradually increasing stirring rate.

Preferably, in step (3), the high speed stirring rate is 1200rpm.

The invention also provides the lignin-based high-heat-conductivity gel profile control agent prepared by the preparation method.

Furthermore, the invention provides application of the lignin-based high-thermal-conductivity gel profile control agent in clean production of thickened oil.

Compared with the prior art, the invention has the following advantages:

(1) The lignin-based high-heat-conductivity gel profile control agent prepared by the invention has good heat conductivity. In the composite gel, the high thermal conductivity of the boron nitride filler enables a supermolecular network to serve as a high thermal conductivity network to provide abundant high-efficiency thermal conductivity channels for the gel, so that the thermal conductivity of the gel is effectively enhanced. Therefore, in the profile control and displacement process, the high heat conduction gel can effectively relieve the thermal hysteresis of steam at the displacement front and reduce the ineffective heat loss of the steam on the rock wall.

(2) The lignin-based high-heat-conductivity gel profile control agent prepared by the invention has good environmental remediation performance. The lignin and chitosan in the gel can generate remarkable biological stimulation to petroleum degrading bacteria in soil, and provide rich nutrients and nitrogen sources for growth and propagation of the petroleum degrading bacteria, so that the bioavailability of petroleum pollutants is improved. Meanwhile, the lignin component in the gel can obviously improve the granularity of soil, improve the soil structure and improve the aeration capacity of the soil, so that the oxygen supply of microorganisms in petroleum polluted soil is obviously improved, and the metabolic activity of petroleum degrading bacteria is promoted.

(3) The lignin-based high-heat-conductivity gel profile control agent prepared by the invention has low phytotoxicity and biodegradability. The lignin-chitosan biopolymer network in the composite gel not only can provide a support skeleton with high thermal stability for the gel, but also is nontoxic, harmless and environment-friendly, and can be completely biodegraded into a nontoxic product humic acid, so that the gel has higher clean production potential, and the reversibility of stratum damage is obviously enhanced.

Drawings

FIG. 1 is an infrared spectrum (FTIR) of lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4, calcium lignosulfonate and chitosan of example 1.

FIG. 2 shows a solid nuclear magnetic resonance carbon spectrum of lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4, calcium lignosulfonate and chitosan in example 1 ¹³ C-SSNMR) map.

FIG. 3 is an X-ray diffraction (XRD) pattern of lignin-based high thermal conductivity gel profile control agent, calS-CTS/h-BN-4, calcium lignosulfonate, chitosan, and hexagonal boron nitride in example 1.

FIG. 4 is a Differential Scanning Calorimeter (DSC) diagram of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate and chitosan in example 1.

FIG. 5 is a Scanning Electron Microscope (SEM) image of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 6 is a Scanning Electron Microscope (SEM) image of calcium lignosulfonate gel CalS in comparative example 1.

FIG. 7 is a Transmission Electron Microscope (TEM) image of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 8 is an element map of element C, N, B of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 in example 1.

FIG. 9 is a Zeta potential distribution diagram of calcium lignosulfonate-chitosan gel CalS-CTS, calcium lignosulfonate and chitosan in comparative example 2.

FIG. 10 is a graph of gellant pH versus gel time for the gel forming process of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 11 is a thermal conductivity-hexagonal boron nitride concentration curve of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN in an example.

FIG. 12 is a plot of the gel forming time contour plot of lignin-based high thermal conductivity gel profile control agent, calS-CTS/h-BN, at 80℃in the examples.

FIG. 13 is a graph of the gel strength contour plot of the lignin-based high thermal conductivity gel profile control agent, calS-CTS/h-BN, at 80℃in the examples.

FIG. 14 is a plot of gel viscosity contour plot of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN at 80℃in the examples.

FIG. 15 is a bar graph of crosslink density of lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 in example 1, calcium lignosulfonate gel CalS in comparative example 1, and calcium lignosulfonate-chitosan gel CalS-CTS in comparative example 2.

FIG. 16 is a low-field nuclear magnetic resonance spectrum (LF-NMR) of calcium lignosulfonate gel CalS of comparative example 1.

FIG. 17 is a low-field nuclear magnetic resonance spectrum (LF-NMR) of calcium lignosulfonate-chitosan gel CalS-CTS of comparative example 2.

FIG. 18 is a low field nuclear magnetic resonance spectrum (LF-NMR) of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 19 is a thermal conductivity versus ambient temperature curve for lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 in example 1 and calcium lignosulfonate-chitosan gel CalS-CTS in comparative example 2.

FIG. 20 is a graph of thermal diffusivity versus ambient temperature for lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 in example 1 and calcium lignosulfonate-chitosan gel CalS-CTS in comparative example 2.

FIG. 21 is a graph of gel surface temperature versus heating time in a heat dissipation test for lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 of example 1 and calcium lignosulfonate-chitosan gel CalS-CTS of comparative example 2.

FIG. 22 shows the gel surface temperature of the lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 of example 1 after being heated at 160℃for 10h in a heat dissipation test.

FIG. 23 shows the gel surface temperature of the calcium lignosulfonate-chitosan gel CalS-CTS of comparative example 2 after heating at 160℃for 10 hours in a heat dissipation test.

FIG. 24 is a Thermogravimetric (TGA) curve of the lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 of example 1 and the calcium lignosulfonate-chitosan gel CalS-CTS of comparative example 2.

FIG. 25 shows the temperature rise process of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 (b) in example 1 and the calcium lignosulfonate-chitosan gel CaLS-CTS (a) in comparative example 2 in a heat dissipation test at 160℃for 100 s.

FIG. 26 is a cumulative oil to gas ratio-injection volume curve of the core displacement experiment of the lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 of example 1.

FIG. 27 is a thermal efficiency-injection volume curve of core displacement experiments for lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 28 is a plot of sweep efficiency versus injection volume for core displacement experiments for lignin-based highly thermally conductive gel profile control agent CalS-CTS/h-BN-4 of example 1.

FIG. 29 is a plot of crude oil recovery versus injection volume for core displacement experiments with lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 30 is a visual core displacement experiment displacement effect of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 and water in example 1.

FIG. 31 is a temperature profile of the steam flooding before and after injection of the lignin-based highly thermally conductive gel profile control agent CalS-CTS/h-BN-4 of example 1.

FIG. 32 is a visual core displacement experiment displacement process of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 33 is a visual core displacement experiment displacement process of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1.

FIG. 34 is a plot of residual mass versus incubation time for lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 in example 1 in a natural degradation experiment.

FIG. 35 is a histogram of wheat germination percentage of lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4, comparative example 3 polyacrylamide and water in a phytotoxicity experiment in example 1

FIG. 36 is a graph of core permeability versus seal time for lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1 in a formation damage self-healing experiment.

FIG. 37 is a graph of core porosity versus seal time for lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1 in a formation damage self-healing experiment.

FIG. 38 is a graph of crude oil residue-degradation time in contaminated soil after application of lignin-based high thermal conductivity gel profile control agent CalS-CTS/h-BN-4 in a soil remediation experiment.

FIG. 39 shows the biodegradation rate of petroleum pollutants in soil at different amounts of the CaLS-CTS/h-BN-4 added after the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 is applied in a soil remediation experiment for one year.

FIG. 40 is a graph showing the gene abundance of bacteria-CaLS-CTS/h-BN-4 addition to contaminated soil after one year of culture with the application of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 in soil remediation experiments.

FIG. 41 is a graph showing the gene abundance of fungi-CaLS-CTS/h-BN-4 addition to contaminated soil after one year of culture with the application of lignin-based highly thermally conductive gel profile control agent CaLS-CTS/h-BN-4 in soil remediation experiments.

FIG. 42 is a graph comparing soil particle sizes before and after CaLS-CTS/h-BN-4 gel addition in soil remediation experiments.

FIG. 43 shows the remediation effect of different concentrations of the CaLS-CTS/h-BN-4 gel on heavy metal pollution of soil after the application of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 gel for one year in a soil remediation experiment.

FIG. 44 shows the adsorption and solidification effects of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 on different heavy metal elements in soil remediation experiments.

FIG. 45 shows the chemical morphology of heavy metals in soil before and after CaLS-CTS/h-BN-4 gel addition in soil remediation experiments.

FIG. 46 is an element map of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 of example 1 for adsorbing different heavy metal elements.

FIG. 47 is a schematic flow chart of a method for synthesizing lignin-based high thermal conductivity gel profile control agent according to the present invention.

Table 1 shows the infrared spectrum absorption peak changes of each component of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN gel in example 1 during the gelling process.

Table 2 shows the variation of the absorbance peak of the nuclear magnetic resonance carbon spectrum of each component of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN gel in example 1 during the gelling process.

Detailed Description

The present invention will be described in detail below with reference to examples and drawings with respect to the objects, technical solutions and advantages of the present invention.

According to the invention, a heat conduction function network is introduced into a biomass matrix network through a physical crosslinking reaction by a one-pot method, so that the multifunctional gel profile control agent with high heat conductivity, biodegradability and environmental remediation performance is prepared. Specifically, according to the permeation principle, a three-dimensional permeation network of boron nitride covering the whole gel is constructed by utilizing Van der Waals force, so that a high-speed heat conduction channel is provided for the gel. Simultaneously, under the acidic condition, lignin and chitosan in the gel are coupled and crosslinked through electrostatic attraction, hydrogen bond and hydrophobic effect, so that a biodegradable matrix network with good environmental remediation performance is formed. The profile control agent has good heat conductivity, biodegradability and environment restoration capability, so that the problems of poor heat transfer and high pollution of steam in the thick oil steam flooding process are solved.

The following is an experiment using calcium lignosulfonate as a biomass matrix, chitosan as a cross-linking agent, and boron nitride as a heat-conducting functional filler, and a lignin-based high heat-conducting gel profile control agent synthesized by a one-pot method as a representative example, and the structure of the lignin-based high heat-conducting gel profile control agent and the synthesis method thereof are described, and the specific flow process is shown in fig. 47.

Example 1

The preparation of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4 comprises the following specific steps:

(1) At 25 ℃, adding calcium lignosulfonate and chitosan into water according to the concentration of the calcium lignosulfonate being 4 weight percent and the concentration of the chitosan being 4 weight percent, and stirring at 600rpm for 30min to fully dissolve the calcium lignosulfonate and the chitosan;

(2) Adding 1wt% of hexagonal boron nitride into the solution under the stirring condition of 600rpm, and performing ultrasonic dispersion for 30min to obtain uniform filler dispersion;

(3) Hydrochloric acid was added dropwise to the above filler dispersion to a pH of 4 under gradually accelerated electromagnetic stirring (stirring rate increased from 600rpm to 1200 rpm), and stirring was continued at a high speed of 1200rpm for 45min to obtain a biomass sol.

(4) And (3) sealing the biomass sol, standing for 72 hours at 80 ℃ to enable the biomass sol to be glued and aged, and obtaining the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4.

Example 2

The preparation of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-2 comprises the following specific steps:

(1) At 25 ℃, adding calcium lignosulfonate and chitosan into water according to the concentration of 2 weight percent of calcium lignosulfonate and the concentration of 2 weight percent of chitosan, and stirring at 600rpm for 30min to fully dissolve the calcium lignosulfonate and the chitosan;

(3) Hydrochloric acid was added dropwise to the above filler dispersion to a pH of 4 under gradually accelerated electromagnetic stirring (stirring rate increased from 600rpm to 1200 rpm), and stirring was continued at a high speed of 1200rpm for 30min to obtain a biomass sol.

(4) And (3) sealing the biomass sol, standing for 36h at 80 ℃ to enable the biomass sol to be glued and aged, and obtaining the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-2.

Example 3

The preparation of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-7 comprises the following specific steps:

(1) Adding calcium lignosulfonate and chitosan into water at 25deg.C according to the concentration of calcium lignosulfonate of 7wt% and chitosan concentration of 7wt%, stirring at 600rpm for 45min to dissolve completely;

(3) Hydrochloric acid was added dropwise to the above filler dispersion to a pH of 4 under gradually accelerated electromagnetic stirring (stirring rate increased from 600rpm to 1200 rpm), and stirring was continued at a high speed of 1200rpm for 60min to obtain a biomass sol.

(4) And (3) sealing the biomass sol, standing for 126 hours at 80 ℃ to enable the biomass sol to be glued and aged, and obtaining the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-7.

Example 4

The preparation of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4/3 comprises the following specific steps:

(2) Adding 3wt% of hexagonal boron nitride into the solution under the stirring condition of 600rpm, and performing ultrasonic dispersion for 40min to obtain uniform filler dispersion;

(4) And (3) sealing the biomass sol, standing for 72 hours at 80 ℃ to enable the biomass sol to be glued and aged, and obtaining the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4/3.

Example 5

The preparation of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4/5 comprises the following specific steps:

(2) Adding 5wt% of hexagonal boron nitride into the solution under the stirring condition of 600rpm, and performing ultrasonic dispersion for 45min to obtain uniform filler dispersion;

(4) And (3) sealing the biomass sol, standing for 72 hours at 80 ℃ to enable the biomass sol to be glued and aged, and obtaining the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4/5.

Comparative example 1

The preparation method of the calcium lignosulfonate gel CalS comprises the following specific steps:

(1) Adding 4wt% of calcium lignosulfonate into water at 25 ℃, stirring at 600rpm for 20min to fully dissolve the calcium lignosulfonate, and obtaining a calcium lignosulfonate solution;

(2) Hydrochloric acid was added dropwise to the above calcium lignosulfonate solution to a pH of 2 under gradually accelerated electromagnetic stirring (stirring rate increased from 600rpm to 1200 rpm), and stirring was continued at a high speed of 1200rpm for 30min to obtain a calcium lignosulfonate sol.

(4) Sealing the calcium lignosulfonate sol, standing at 80 ℃ for 72 hours, and performing gelling and aging to obtain calcium lignosulfonate gel CalS.

Comparative example 2

The preparation of the calcium lignosulfonate-chitosan gel CalS-CTS comprises the following specific steps:

(3) Hydrochloric acid was added dropwise to the above filler dispersion to a pH of 4 under gradually accelerated electromagnetic stirring (stirring rate increased from 600rpm to 1200 rpm), and high-speed stirring was continued for 45min at 1200rpm, to obtain a biomass sol.

(4) Sealing the biomass sol, standing at 80 ℃ for 72 hours, and gelling and aging the biomass sol to obtain the calcium lignosulfonate-chitosan gel CalS-CTS.

Comparative example 3

The preparation of the reference polyacrylamide plant culture solution comprises the following specific steps:

(1) At 50℃3wt% polyacrylamide was slowly added to water with stirring at 600rpm and stirred at 1200rpm for 45min to obtain an aqueous polyacrylamide solution.

(2) Cooling the polyacrylamide aqueous solution to room temperature, and sealing and storing in a shade and dry place for later use.

Infrared spectroscopy (FTIR) analysis of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate and chitosan is shown in figure 1. As shown in FIG. 1, characteristic peaks of CaLS and CTS exist in the FTIR spectrogram of the CaLS-CTS/h-BN-4 gel, and meanwhile, certain characteristic peaks of the gelling agent also have peak position shift and peak intensity change (specific data are shown in tables 1 and 2), so that strong supermolecular effect exists between the two components in the gel. Specifically: after gelling, in the infrared spectrum of the CalS-CTS/h-BN-4 gel, 1) calcium lignosulfonate phenol-based infrared beta _O-H Characteristic peak-to-peak and infrared beta of chitosan secondary amino group _N-H The characteristic peak disappears, and the strong electrostatic attraction between the phenolic hydroxyl group of the calcium lignosulfonate and the amino group of the chitosan is proved. 2) Infrared beta of chitosan primary amino group _N-H Characteristic peak and infrared V of amino _(C-N) The characteristic peaks red shifted, and these information indicate that extensive and varied hydrogen bonds are formed between calcium lignosulfonate and chitosan in the gel. 3) The characteristic infrared gamma (benzene ring) peak of calcium lignosulfonate phenyl is red shifted, which indicates that certain hydrophobic interaction exists between CalS in the gel.

Solid nuclear magnetic resonance carbon spectrum of lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate and chitosan ¹³ C-SSNMR) analysis, see FIG. 2. As shown in FIG. 2, calS-CTS/h-BN-4 gel ¹³ The characteristic peaks of CalS and CTS exist in the C-SSNMR spectrum, and simultaneously, some characteristic peaks of the gelatinizer also have peak position shift and peak intensity change (specific data are shown in Table 2), which indicates that strong supermolecular effect exists between the two components in the gel. Specifically: 1) The C2 nuclear magnetic resonance characteristic peak of the chitosan disappears, and the electrostatic attraction between the phenolic hydroxyl group of the calcium lignosulfonate and the chitosan amino group is proved again. 2) Lignin calcium sulfonateThe disappearance of the-COO-nuclear magnetic characteristic peak and the C4 nuclear magnetic peak of the chitosan and the change of the peak position of the C1 nuclear magnetic peak prove that a large amount of hydrogen bonds are formed between calcium lignosulfonate and chitosan in the gel.

TABLE 1 Infrared Spectroscopy absorption peak Change of CalS-CTS/h-BN gel Components during gel formation

TABLE 2 Nuclear magnetic resonance carbon Spectrometry Change of CalS-CTS/h-BN gel Components during gel formation

X-ray diffraction (XRD) analysis of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate, chitosan and hexagonal boron nitride is shown in figure 3. As shown in fig. 3, chitosan is in a semi-crystalline state, and calcium lignosulfonate is in an amorphous state. After the gel is formed, the CaLS-CTS/h-BN-4 is in an amorphous state, and the characteristic peak of the (020) crystal face of the chitosan is shifted from 12.14 degrees to 15.73 degrees, and the characteristic peak of the (110) crystal face of the chitosan disappears, which shows that in the gel forming process, the calcium lignosulfonate generates stronger plasticizing effect on the chitosan through the supermolecule combination, so that the chitosan is converted into an amorphous structure from a semi-crystalline state. Meanwhile, the characteristic peak of the hexagonal boron nitride (002) crystal face is completely reserved in the CaLS-CTS/h-BN-4 gel, which proves that the cross-linking reaction between chitosan and calcium lignosulfonate in the gelling process does not damage the crystal structure of the hexagonal boron nitride so as to influence the heat conducting property of the hexagonal boron nitride.

Differential Scanning Calorimeter (DSC) analysis of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate and chitosan is shown in figure 4. As shown in FIG. 4, in the DSC spectrum of the CaLS-CTS/h-BN-4 gel, the heat drop Jie Feng (310 ℃) of chitosan disappears, and the glass transition temperature of calcium lignosulfonateDegree (T) _g ) The temperature is reduced from 87 ℃ to 62 ℃, and the strong supramolecular combination between calcium lignosulfonate and chitosan in the gel is again demonstrated.

Scanning Electron Microscope (SEM) analysis of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 and calcium lignosulfonate gel is shown in fig. 5 and 6. As shown in fig. 5 and 6, the chitosan successfully crosslinked the lignin network in the CaLS-CTS/h-BN-4 gel and significantly enhanced the crosslinking degree of the lignin network, which is advantageous for improving the mechanical properties and temperature resistance of the gel, compared to the sodium lignin sulfonate gel.

Transmission Electron Microscope (TEM) analysis of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 is shown in figure 7. As shown in FIG. 7, the introduction of chitosan and hexagonal boron nitride does not destroy the three-dimensional network structure of lignin in the gelling process of CaLS-CTS/h-BN-4, and the lignin network still has higher integrity in the gelling process.

Elemental mapping analysis of element C, N, B of lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 is shown in FIG. 8. As shown in FIG. 8, the C, N and B elements are densely distributed in the whole gel network of the same sampling point of the CalS-CTS/h-BN-4 gel, and the following is explained: 1) Hexagonal boron nitride forms a three-dimensional penetrating network in the CalS-CTS/h-BN-4 gel through the action of supermolecules such as Van der Waals force, thereby providing a heat conduction channel throughout the gel. 2) The hexagonal boron nitride network and the calcium lignosulfonate-chitosan network are effectively compounded to form a good interpenetrating double-network structure.

And (3) analyzing Zeta potential of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate and chitosan, and a pH-gel forming time curve of a gelling agent in the gelling process of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4, wherein the pH-gel forming time curve is shown in fig. 9 and 10. As shown in FIG. 9, the Zeta potentials of the calcium lignosulfonate and the chitosan are-38.9 mV and 43.6mV respectively, strong electronegativity and electropositivity are respectively presented, the lacing electric quantity of the CaLS-CTS/h-BN-4 gel after gel formation is obviously reduced, and the potential of the lacing electric quantity approaches to electroneutrality (8.4 mV). Meanwhile, as shown in FIG. 10, the CaLS-CTS/h-BN-4 gelling process is carried out in an environment with the pH of approximately 4 and is not in the pH range of sedimentation of calcium lignosulfonate (pH less than or equal to 3.1) and chitosan (pH less than or equal to 5.8). The experimental phenomena described above illustrate: the CaLS-CTS/h-BN-4 gel is mainly crosslinked and glued by virtue of strong electrostatic attraction between calcium lignosulfonate and chitosan, but not sedimentation of the calcium lignosulfonate and the chitosan in an acidic environment.

The thermal conductivity-hexagonal boron nitride concentration curve of the lignin-based high thermal conductivity gel profile control agent CaLS-CTS/h-BN is shown in figure 11. As shown in fig. 11, according to the percolation theory, hexagonal boron nitride particles at low concentrations (insulating regions) are dispersed in a gel system in isolation, and no effective connection is established between them, resulting in a slow increase in gel thermal conductivity. As the concentration of hexagonal boron nitride increases, the probability of contact between hexagonal boron nitride particles in the gel increases, and when the penetration threshold (percolation region) is reached, a hexagonal boron nitride three-dimensional heat conduction network is formed throughout the gel, resulting in a sharp increase in thermal conductivity. Then, the increase in hexagonal boron nitride concentration only increases the heat conduction network (network growth zone), and the gel thermal conductivity tends to stabilize (increase slowly). Therefore, to maintain a high gel thermal conductivity, hexagonal boron nitride is suitably used in a concentration range of 1wt% to 5wt%.

The gel forming time contour diagram, the gel strength contour diagram and the gel viscosity contour diagram of the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN at 80 ℃ are shown in figures 12, 13 and 14. As shown in FIGS. 12 to 14, at 80℃C _CaLS 、C _CTS When the weight percentage is less than 2%, the gel has low temperature resistance and strength, and is not suitable for a thermal recovery high-temperature environment. And when C _CaLS 、C _CTS When the weight percentage is higher than 7%, the gel forming time is too short, so that the profile control depth is too shallow, and a good profile control effect is difficult to realize. Thus, C is suitable for steam flooding _CaLS 、C _CTS The concentration range is 2 to 7 weight percent, and the corresponding gel forming time, gel strength and gel viscosity are respectively 26 to 126 hours, 39 to 311Pa and 0.42 to 2.31 Pa.s. In the range, the strength, viscosity and gel forming time of the gel can be adjusted by changing the concentration of the gelling agent, so that the thermal recovery device is suitable for different profile control and flooding requirements.

Cross-linking density histogram of lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4, calcium lignosulfonate gel CaLS, calcium lignosulfonate-chitosan gel CaLS-CTS and low-field nuclear magnetic resonance spectrumLF-NMR) analysis is shown in FIG. 15, FIG. 16, FIG. 17, and FIG. 18. As shown in FIGS. 16, 17 and 18, the addition of chitosan provides the CalS-CTS/h-BN-4 gel with a higher crosslink density and smaller transverse relaxation time (T) ₂ ) The electrostatic attraction and hydrogen bonding between chitosan and calcium lignosulfonate are shown to produce a remarkable crosslinking effect. Meanwhile, as shown in fig. 15, compared with the crosslinking data of calcium lignosulfonate-chitosan gel and CaLS-CTS/h-BN-4 gel, the addition of hexagonal boron nitride did not significantly change the crosslinking density and crosslinking morphology of the gel, indicating that there is no strong interaction between hexagonal boron nitride and calcium lignosulfonate and chitosan, less interference to the crosslinking reaction, and the calcium lignosulfonate-chitosan network has good compatibility to hexagonal boron nitride network.

The thermal conductivity-environmental temperature curve and the thermal diffusivity-environmental temperature curve of the lignin-based high-thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 and the calcium lignosulfonate-chitosan gel CaLS-CTS are shown in fig. 19 and 20. As shown in fig. 19 and 20, after the hexagonal boron nitride network is introduced, the thermal conductivity and the thermal diffusivity of the sodium lignin sulfonate-chitosan gel are respectively increased by about 280 percent and 290 percent, which indicates that the construction of the hexagonal boron nitride three-dimensional heat conduction network and the structural design of the double networks obviously improve the heat conduction performance of the CaLS-CTS/h-BN-4 gel. Interestingly, thanks to the high thermal stability of the CaLS-CTS/h-BN-4 gel matrix lignin (the TGA analysis results of which are shown in fig. 24), the increase in temperature does not significantly impair the thermal conductivity of the CaLS-CTS/h-BN-4 gel, its thermal conductivity and thermal diffusivity at 300 ℃ respectively reach 1.02w·m ^-1 ·K ^-1 And 0.30mm ² ·s ^-1 The CaLS-CTS/h-BN-4 gel has good heat conduction performance, which is beneficial to improving the thermal recovery efficiency of thick oil and realizing clean production.

The lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4 and the calcium lignosulfonate-chitosan gel CaLS-CTS have gel surface temperature-heating time curves in heat dissipation tests, gel surface temperature after constant temperature heating at 160 ℃ for 10h and temperature heating process at 160 ℃ for 100s, and are shown in figures 21, 22, 23 and 25. As shown in FIG. 21, FIG. 22, FIG. 23 and FIG. 25, under the heating of 160℃constant temperature planar heat source, andcompared with calcium lignosulfonate-chitosan gel, the heating rate of CaLS-CTS/h-BN-4 is improved by 62.0 percent and reaches 0.379 ℃ s ^-1 . Meanwhile, in the atmosphere, calS-CTS/h-BN-4 has a significantly lower equilibrium temperature (constant temperature of 160 ℃ for 10 hours) than calcium lignosulfonate-chitosan gel, reaching 81.5 ℃. The experimental results show that the CaLS-CTS/h-BN-4 gel with high heat conductivity has good heat transfer effect and heat dissipation efficiency, and is beneficial to improving the thermal management capability of the profile control agent on thick oil thermal recovery.

Cumulative oil-gas ratio-injection volume curve, thermal efficiency-injection volume curve and temperature profile of steam flooding before and after injection of lignin-based high-thermal conductivity gel flooding agent CaLS-CTS/h-BN-4 are obtained in core displacement experiment of lignin-based high-thermal conductivity gel flooding agent CaLS-CTS/h-BN-4, and see fig. 26, 27 and 31. According to FIGS. 26, 27 and 31, the thermal efficiency and the oil to gas ratio (COSR) of the steam flooding are improved by 260% and 293%, respectively, after the CaLS-CTS/h-BN-4 gel is injected. Meanwhile, the effective heating area (290-140 ℃ temperature zone) of the steam flooding is obviously improved, which shows that the CaLS-CTS/h-BN-4 gel profile control flooding can greatly improve the heat efficiency and the energy efficiency of the steam flooding, and has higher clean production capacity. This is because the good heat conducting property of the CaLS-CTS/h-BN-4 gel makes it possible to effectively improve the steam heating profile, prolong the heating time, reduce the ineffective heat dissipation, thereby enhancing the thermally induced viscosity reduction, thermal expansion and distillation effects of the steam flooding and further improving the thermal efficiency.

Core displacement experiment sweep efficiency-injection volume curve, crude oil recovery-injection volume curve and visualized core displacement experiment displacement effect and displacement process of lignin-based high-heat-conductivity gel profile control flooding agent CaLS-CTS/h-BN-4 are shown in fig. 28, 29, 30 and 32. As shown in fig. 28, 29, 30 and 32, injection of CaLS-CTS/h-BN-4 gel increased steam sweep efficiency and thickened oil recovery by 76% and 40%, respectively. The CaLS-CTS/h-BN-4 gel shows a displacement effect which is comparable to that of water and good oil displacement capacity in a visual displacement experiment (figure 33), and shows that the CaLS-CTS/h-BN-4 has higher profile control and displacement performance.

The residual mass-culture time curve of the lignin-based high-thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 in the natural degradation experiment is shown in figure 34. As shown in FIG. 34, the degradation amount of the CaLS-CTS/h-BN in the soil in one year is 76.9wt percent, and degradation products of the CaLS-CTS/h-BN mainly comprise humic acid and humic acid derivatives, and the degradation products are good in biodegradability and non-toxicity.

Wheat germination percentage bar graph of lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4, polyacrylamide and water in phytotoxicity experiment is shown in figure 35. As shown in FIG. 35, polyacrylamide can limit germination and root growth of wheat seeds, and has high phytotoxicity. In comparison, wheat seeds have high germination rate and fully grown root systems in distilled water and CaLS-CTS/h-BN-4 gel environments, and the germination indexes are 100%, which indicates that the CaLS-CTS/h-BN-4 gel has no phytotoxicity to wheat. The low phytotoxicity of CalS-CTS/h-BN-4 gel is mainly due to: 1) The CaLS and CTS which form the gel skeleton can be used as fertilizer and plant growth regulator, and has no toxicity, no harm and easy degradation. 2) The degradation products of the CalS and the CTS are mainly humus, which is beneficial to the growth of plants and microorganisms.

Core permeability-sealing time curve and core porosity-sealing time curve of lignin-based high-thermal conductivity gel profile control agent CaLS-CTS/h-BN-4 in formation damage self-repairing experiment are shown in fig. 36 and 37. As shown in fig. 36 and 37, due to the good biodegradability of the CaLS-CTS/h-BN-4 gel, the stratum damage caused by gel profile control and flooding is gradually recovered along with the extension of time, after 12 months of sealing, the core permeability recovery rate reaches 68.6%, the porosity recovery rate reaches 73.9%, and the higher stratum damage self-repairing capability is presented, so that the subsequent oil production capability of an oil reservoir is protected, and the productivity sustainability is improved.

The natural degradation rate of petroleum pollutants in soil under different addition amounts of the CaLS-CTS/h-BN-4 is shown in figures 38 and 39. As shown in fig. 38 and 39, the natural degradation rate of petroleum pollutants in soil is low, and only 13wt% of the petroleum pollutants are degraded in one year. After the CaLS-CTS/h-BN-4 gel (3 wt%) is added, the natural degradation rate of petroleum in the soil is improved by 254%, and the natural degradation rate reaches 46wt%. Moreover, as the addition amount of the gel is increased, the natural degradation rate of petroleum is gradually increased, which proves that the CaLS-CTS/h-BN-4 gel can effectively promote the natural degradation of petroleum and obviously enhance the bioremediation capability of petroleum polluted soil.

The gene abundance-CaLS-CTS/h-BN-4 addition curve of bacteria and the fungus gene abundance-CaLS-CTS/h-BN-4 addition curve of bacteria in contaminated soil after the lignin-based high-heat-conductivity gel profile control agent CaLS-CTS/h-BN-4 is applied for one year, and the graph is shown in fig. 40 and 41. With the increase of the addition amount of the CaLS-CTS/h-BN-4, the gene abundance of bacteria and fungi in the soil is respectively improved by 260 percent and 750 percent, which shows that the CaLS-CTS/h-BN-4 gel has good biological stimulation effect and can effectively promote the biodegradation of petroleum pollutants in the soil. This is because calcium lignosulfonate and chitosan in the CaLS-CTS/h-BN-4 gel can significantly promote the growth and improvement of bacterial and fungal communities in petroleum contaminated soil, thereby greatly enhancing the bioremediation of the contaminated soil. Specifically, the calcium lignosulfonate serving as a slow-release fertilizer and a biosurfactant provides nutrients for petroleum degrading bacteria and improves the bioavailability of crude oil, and the chitosan provides an N source for soil microorganisms.

A comparison of soil particle sizes before and after CaLS-CTS/h-BN-4 gel addition is shown in FIG. 42. As shown in FIG. 42, after 3wt% of CaLS-CTS/h-BN-4 gel is added, the granularity of soil particles is increased by 46.11 percent and reaches 2.82mm, which indicates that the calcium lignosulfonate component in the CaLS-CTS/h-BN-4 gel can increase the granularity of soil, improve the structure of soil, be beneficial to increasing the air permeability and oxygen content of polluted soil and promote the growth and metabolic activity of microorganisms in soil.

The repair effect of the lignin-based high-heat-conductivity gel flooding agent CaLS-CTS/h-BN-4 gel with different concentrations on the heavy metal pollution of soil and the adsorption and solidification effects of the gel on different heavy metal elements after one year of culture are applied, and are shown in figures 43 and 44. As shown in FIG. 43 and FIG. 44, the addition of the CaLS-CTS/h-BN-4 gel can effectively reduce the heavy metal content in soil (the addition amount of 3wt% is reduced by 35.8%), and the gel has remarkable adsorption and removal effects on Cr, fe, mn, pb (FIG. 46).

The chemical morphology of heavy metals in the soil before and after the addition of CalS-CTS/h-BN-4 gel is shown in FIG. 45. The existence forms of heavy metals in soil are divided into exchangeable states, carbonate states, fe-Mn oxide states, organic states and residual states according to the extraction difficulty. The exchangeable and carbonate heavy metals have strong toxicity and high mobility, and have great harm to human beings, animals and plants, and the organic and residual states have extremely low harm to organisms. As shown in FIG. 45, after the CaLS-CTS/h-BN-4 gel is added, the content of exchangeable and carbonate heavy metals in the soil is obviously reduced (decreasing amplitude: 44%), the content of organic states is obviously increased, which indicates that the CaLS-CTS/h-BN gel can effectively solidify heavy metals, improve the existence form of the heavy metals and reduce the bioavailability and the danger of the heavy metals.

Claims

1. The preparation method of the lignin-based high-thermal-conductivity gel profile control agent is characterized by comprising the following specific steps:

(1) Adding the biomass matrix and the cross-linking agent into water according to the mass content of the cross-linking agent of 1:1-3:1 at 20-25 ℃ and stirring to fully dissolve the biomass matrix and the cross-linking agent;

(2) Adding boron nitride into the solution under the stirring condition, and performing ultrasonic dispersion for a period of time to obtain uniform boron nitride dispersion liquid, wherein the mass content of the boron nitride in the boron nitride dispersion liquid is 1wt% -5 wt%;

(3) Dropwise adding a pH regulator into the boron nitride dispersion liquid to a value of 5.8 > pH > 3.1 at a gradually increased stirring rate, and continuously stirring at a high speed for 30-60 min to obtain biomass sol, wherein the mass of a biomass matrix and the mass of a crosslinking agent are 2wt% -7 wt% of the mass of the biomass sol;

(4) Sealing the biomass sol, standing for 26-126 hours at 60-120 ℃ to form glue and age the biomass sol, and obtaining the lignin-based high-heat-conductivity gel profile control agent;

wherein the biomass matrix is any one or more of sodium lignin sulfonate and calcium lignin sulfonate;

the cross-linking agent is chitosan or analogues thereof, and is selected from one or more of chitosan, chitosan hydrochloride, carboxymethyl chitosan, hydroxypropyl chitosan, chitosan oligosaccharide, chitosan tetraose or chitin.

2. The method of claim 1, wherein in steps (1) and (2), the stirring speed is 600rpm.

3. The method of claim 1, wherein in step (2), the ultrasonic dispersion is performed for 15 to 45 minutes.

4. The method of claim 1, wherein in step (3), the stirring rate is increased from 600rpm to 1200rpm at a gradually increasing stirring rate.

5. The lignin-based high thermal conductivity gel profile control agent prepared according to the method of any one of claims 1-4.

6. The use of the lignin-based high thermal conductivity gel profile control agent prepared by the method of any one of claims 1-4 in the clean production of heavy oil.