CN114672294B

CN114672294B - Time-delay type composite plugging system and preparation method and application thereof

Info

Publication number: CN114672294B
Application number: CN202011552736.1A
Authority: CN
Inventors: 杨金彪; 方昭; 伊卓; 刘希; 祝纶宇; 胡晓娜; 李雅婧
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2023-05-30
Anticipated expiration: 2040-12-24
Also published as: CN114672294A

Abstract

The invention relates to the technical field of oilfield water shutoff and profile control, in particular to a time-delay type composite water shutoff and profile control system and a preparation method and application thereof. The preparation raw materials of the plugging system comprise: modified lignin, polyacrylamide, a cross-linking agent and a stabilizer; wherein the modified lignin is an amination and acylation product of lignin. The plugging system can be controlled to gel (3.5-9 d) in a delayed manner under the condition of higher oil reservoir temperature (55-100 ℃), and has higher strength; in addition, the production cost of the water shutoff profile control agent is effectively reduced.

Description

Time-delay type composite plugging system and preparation method and application thereof

Technical Field

The invention relates to the technical field of oilfield water shutoff and profile control, in particular to a time-delay type composite water shutoff and profile control system and a preparation method and application thereof.

Background

The profile control refers to the operation of plugging a high-permeability layer from a water injection well, and the water absorption profile of a water injection layer section can be adjusted. The water shutoff refers to the operation of plugging the high permeable layer from the oil well, and can reduce the water production of the oil well. After the plugging agent is solidified or expanded, the permeability of the high permeability layer is reduced, and the oil displacement effect of injected water at the low permeability layer is improved.

The water shutoff and profile control technology is an effective means for improving the heterogeneity of a reservoir under low oil price and realizing balanced displacement and stable production of an oil field. The existing plugging agent can be roughly divided into jelly, gel, sediment, particles, microspheres, foam, microorganisms and the like, wherein a jelly system is the most widely used plugging agent in the current domestic and foreign plugging technology, and the system takes polymer as a main agent and Cr as a main agent ³⁺ 、Al ³⁺ A space network structure formed by using phenolic resin, phenol, resorcinol and the like as cross-linking agents.

However, with the higher requirements on biodegradability, irritation and ecological toxicity of oilfield chemicals in the field application process of the oilfield, chromium gel, aluminum gel and the like face environmental protection problems such as pollution of high-valence metal ions in the application. Therefore, the gel system which has stable product performance and meets the environmental protection requirement is developed, and has important significance for the sustainable development of the water shutoff profile control technology.

Disclosure of Invention

The invention aims to further improve the stability of the plugging system and meet the environmental protection requirement, and provides a time-delay type composite plugging system, a preparation method and application thereof. The plugging system can be controlled to gel (3.5-9 d) in a delayed manner under the condition of higher oil reservoir temperature (55-100 ℃), and has higher strength; in addition, the production cost of the water shutoff profile control agent is effectively reduced.

In order to achieve the above object, the first aspect of the present invention provides a time-delay type composite plugging system, wherein the plugging system comprises the following preparation raw materials: modified lignin, polyacrylamide, a cross-linking agent and a stabilizer; wherein the modified lignin is an amination and acylation product of lignin.

The second aspect of the invention provides a preparation method of a time-delay type composite plugging system, which comprises the following steps: carrying out contact reaction on modified lignin, polyacrylamide, a cross-linking agent and a stabilizing agent in a solution to obtain the delayed type composite plugging system;

wherein the modified lignin is an amination and acylation product of lignin.

The third aspect of the invention provides a delayed type composite plugging system prepared by the preparation method.

The fourth aspect of the invention provides the application of the time-delay type composite plugging system in oil extraction in an oil field.

Through the technical scheme, the water shutoff and profile control agent provided by the invention realizes that the bio-based material replaces petrochemical raw materials, and the water shutoff and profile control system can be controlled to be gel (3.5-9 d) in a time delay manner under the condition of higher oil reservoir temperature (55-100 ℃), has higher strength, and effectively reduces the production cost of the water shutoff and profile control agent.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

In a first aspect, the present invention provides a delayed composite plugging system, wherein the plugging system comprises the following preparation raw materials: modified lignin, polyacrylamide, a cross-linking agent and a stabilizer; wherein the modified lignin is an amination and acylation product of lignin.

Lignin is a complex natural polymer, and a three-dimensional network structure of hetero-branched chains is formed by bonding phenylpropyl groups through ether (C-O-C) or carbon-carbon bonds (C-C). Lignin is second only to cellulose in natural world, and is the second largest natural organic matter. The industrial lignin has rich sources and low cost, and can be used as a raw material for producing oilfield chemicals. The industrial lignin products have different structures due to different sources and separation methods, mainly contain active groups such as aryl, phenolic hydroxyl, alcoholic hydroxyl, carbonyl, methoxy, carboxyl and conjugated double bonds, and can carry out various chemical reactions such as oxidation, reduction, hydrolysis, alcoholysis, photolysis, acylation, sulfonation, alkylation, halogenation, nitration, condensation, graft copolymerization and the like.

The inventor of the invention unexpectedly discovers in research that by carrying out amination modification and acylation modification on lignin, modified lignin is obtained, and the modified lignin is matched with polyacrylamide, a cross-linking agent (polyethyleneimine) and a stabilizer to be used for preparing a gel system, so that the performance of a plugging agent is finally improved, namely, the time delay controllability of gel formation and the strength of gel are improved. Presumably, the reason for this is that lignin crosslinking sites are increased and lignin crosslinking activity is improved by subjecting lignin to amination and acylation modification. In addition, the modified lignin is matched with other components of the water shutoff profile control agent for use, and the rigid molecular structure of the modified lignin and the flexible molecular structure of the polymer are complementary to each other to form an interpenetrating network gel structure; the water shutoff and profile control agent is matched with other components for use, can be subjected to time delay controllable gel formation (3.5-9 d) at a higher gel formation temperature (55-100 ℃), has higher strength, and effectively reduces the production cost of the water shutoff and profile control agent.

Preferably, the modified lignin is prepared by the following method:

(1) Under a first alkaline condition, carrying out amination reaction on the lignin solution and organic amine to obtain lignin amine;

(2) And under the second alkaline condition, in the solution, carrying out acylation reaction on lignin amine and acyl chloride to obtain the modified lignin.

In the present invention, in step (1), the lignin, the organic amine and the acid chloride are all commercially available, and preferably the lignin is contained in an effective amount of 80 to 99.9%.

In the present invention, in the step (1), the lignin may be various lignin conventionally used, preferably, the lignin is at least one selected from alkali lignin, enzymatic lignin, chlorinated lignin, steam exploded lignin, lignin sulfonate and sulfur lignin, more preferably, enzymatic lignin, which is commercially available, for example, from Shandong Lignoto Biotechnology Co., ltd.

In the present invention, in the step (1), the organic amine may be various organic amines conventionally used, and preferably, the organic amine is at least one selected from dimethylamine, ethylenediamine, trimethylamine, triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, putrescine, cadaverine, spermidine and spermine.

In the present invention, in the step (1), the amount of the organic amine may be selected within a wide range, and in order to further improve the performance of the plugging system, it is preferable that the mass ratio of the organic amine to the lignin is 0.05-4.5:1, for example, 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.3:1, 2.4:1, 2.5:1, 3:1, 4:1.

In the present invention, in the step (1), preferably, the pH of the first alkaline condition is 10 to 11.5, for example, 10, 10.5, 11, 11.5 may be used.

In the present invention, the conditions of the amination reaction in the step (1) may be changed within a wide range as long as the amination modification of lignin can be effectively performed, and in order to further improve the performance of the plugging system, the temperature is preferably 60 to 75 ℃ (for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃) and the time is preferably 1.5 to 4 hours (for example, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours).

In a preferred embodiment of the present invention, in step (1), the amination reaction is carried out in the presence of an aldehyde; the aldehyde is preferably a C1-C5 aldehyde, for example, formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, more preferably formaldehyde. In this preferred embodiment, the properties of the prepared plugging system can be further improved.

Preferably, the mass ratio of aldehyde to lignin is 0.02-1.5:1, e.g. may be 0.02:1, 0.05:1, 0.1:1, 0.3:1, 0.5:1, 0.7:1, 0.9:1, 1.1:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1, 1.5:1.

In the present invention, in the step (2), the acid chloride may be various acid chlorides conventionally used, and preferably, the acid chloride is at least one selected from acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride, trichloroacetyl chloride, fatty acid chloride, stearoyl chloride, linolenoyl chloride, oleic acid chloride and palmitoyl chloride.

In the present invention, in the step (2), the amount of the acid chloride may be selected within a wide range, and in order to further improve the performance of the plugging system, it is preferable that the mass ratio of the acid chloride to the lignin amine is 0.5-2.5:1 (for example, may be 0.5:1, 0.8:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1).

In the present invention, in the step (2), preferably, the pH of the second alkaline condition is 8 to 9.5, for example, may be 8, 8.5, 9, 9.5.

In the present invention, the condition of the acylation reaction in the step (2) may be changed within a wide range as long as the lignin can be effectively subjected to acylation modification to obtain lignin amide, and in order to further improve the performance of the plugging system, the temperature is preferably 55 to 65 ℃ (for example, may be 55 ℃, 60 ℃, 65 ℃) and the time is preferably 1 to 4 hours (for example, may be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours).

The inventors found in the study that better effect can be obtained when the modified lignin obtained under the acylation conditions of the temperature of 60-75 ℃, the time of 1.5-4h and the pH value of 10-11.5 is used in the water shutoff profile control agent, and the temperature of 55-65 ℃ and the time of 1-4h and the pH value of 8-9.5.

In the present invention, the lignin solution is preferably an aqueous lignin solution.

In the present invention, the method of adjusting the pH is a method commonly used in the art, and preferably, the pH adjustment is performed by adding an alkaline substance. The alkaline substance can be sodium hydroxide, potassium hydroxide, sodium carbonate solution and the like.

In a preferred embodiment of the invention: the preparation method of the modified lignin comprises the steps of preparing lignin into lignin aqueous solution, and then adding organic amine under stirring for amination reaction to obtain solid-phase lignin amine; preparing solid-phase lignin amine into lignin amine aqueous solution, and then adding acyl chloride under stirring to carry out acylation reaction to obtain the modified lignin.

Preferably, the concentration of lignin in the aqueous lignin solution is 3-50 wt%, for example, may be 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%.

Preferably, the organic amine is added to the aqueous lignin solution by means of dropwise addition.

Preferably, the concentration of lignin amine in the aqueous lignin amine solution is in the range of 3 to 30 wt%.

Preferably, the solid-phase lignin amine is obtained by the following steps: and after the amination reaction is finished, regulating the pH value to separate out a product, and then washing and drying to obtain an intermediate product lignin amine.

Preferably, the acid chloride is added dropwise to the aqueous lignin amine solution.

In a particularly preferred embodiment of the invention, the modified lignin is prepared by the following method:

(1) Dissolving lignin and alkali in water, and stirring to prepare lignin solution;

(2) Then adding organic amine, regulating pH, adding formaldehyde under stirring, heating and refluxing for reaction, regulating pH to be neutral after the reaction is finished, separating out a product, and washing and drying to obtain an intermediate lignin amine;

(3) Dissolving intermediate lignin amine in water, regulating pH, adding acyl chloride under stirring, continuing to react, and performing suction filtration, washing, drying and grinding to obtain a modified lignin product.

Preferably, the modified lignin is prepared by the following method:

(1) At room temperature, dissolving lignin and NaOH in water to prepare lignin solution; wherein the lignin concentration in the lignin solution is 3-50 wt%, and the NaOH concentration in the lignin solution is 0.001-8.0 wt%;

(2) Then dripping organic amine, regulating the pH to 10-11.5, dripping formaldehyde under stirring, heating and refluxing for reaction, regulating the pH to be nearly neutral after the reaction is finished, separating out a product, and washing and drying to obtain an intermediate lignin amine; wherein the mass ratio of the organic amine, formaldehyde and lignin is 0.05-4.5:0.02-1.5:1, the reaction temperature is 60-75 ℃ and the reaction time is 1.5-4h;

(3) Dissolving intermediate lignin amine in water, regulating and maintaining the pH value to 8-9.5, dripping acyl chloride under stirring, heating to 55-65 ℃ for continuous reaction for 1-4h, and carrying out suction filtration, washing, drying and grinding after the reaction to obtain a modified lignin product; wherein the mass ratio of the acyl chloride to the lignin amine is 0.5-2.5:1.

In the present invention, the content of each component is not particularly limited, and in order to further obtain better effects, for example, to enable the profile control agent to achieve better time-delay controllable crosslinking, and the gel strength is better, preferably, the content of the modified lignin is 0.1-4.5 wt% (for example, may be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, and preferably 0.4-2 wt%), based on the total weight of the plugging profile control system; the polyacrylamide is contained in an amount of 0.1 to 3.5 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, preferably 0.1 to 1.5 wt%); the crosslinking agent is present in an amount of 0.05 to 1 wt% (e.g., may be 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, preferably 0.2 to 0.8 wt%); the stabilizer may be contained in an amount of 0.05 to 2.5 wt% (for example, 0.05 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.8 wt%, 1 wt%, 1.3 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.5 wt%, preferably 0.1 to 1 wt%).

In the present invention, the polyacrylamide may be various conventionally used polyacrylamides, and preferably, the polyacrylamide is at least one selected from the group consisting of anionic, cationic, nonionic and amphoteric polyacrylamides in order to further enhance the performance of the prepared system.

In the present invention, the weight average molecular weight of the polyacrylamide is preferably 600 to 3000 ten thousand, more preferably 1800 to 2200 ten thousand.

In the present invention, the solid content of the polyacrylamide is 80% by weight or more, preferably 85% by weight or more.

In the present invention, preferably, the environment-friendly crosslinking agent is polyethyleneimine, the weight average molecular weight of the polyethyleneimine is 3000-100000, and the effective content can be about 15-50 wt%; in the present invention, the polyethyleneimine is commercially available. For example, available from Shanghai Ala Biotechnology Co., ltd.

In the present invention, the stabilizer is commercially available; preferably, the stabilizer is selected from at least one of sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium dithionite, metaphenylene diamine, isoascorbic acid and thiourea.

It is clear to those skilled in the art that the preparation raw materials of the time-delay type composite plugging system of the invention further comprise a pH regulator and water. In a preferred embodiment of the invention, the plugging system is prepared from modified lignin, polyacrylamide, a cross-linking agent, a stabilizer, a pH regulator and water. It can be clear that due to the purity problem of the raw materials used, some impurities are inevitably present in each raw material, and therefore, it can be understood that the raw materials for preparing the plugging system consist of modified lignin, polyacrylamide, a cross-linking agent, a stabilizer, a pH regulator, water and impurities carried by each raw material itself.

In the present invention, the pH adjustor may be an acid or an alkali substance commonly used in the art for adjusting pH; preferably, the pH regulator is at least one selected from the group consisting of dilute hydrochloric acid, dilute sulfuric acid, sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium acetate and aqueous ammonia.

In the present invention, the water is not particularly limited, and may be river, lake, atmospheric water, sea water, groundwater, artificial water, oilfield produced water, etc., preferably has a mineralization degree of less than 20000mg/L.

In a second aspect, the invention provides a preparation method of a time-delay type composite plugging and regulating system, which comprises the steps of carrying out contact reaction on modified lignin, polyacrylamide, a cross-linking agent and a stabilizer in a solution to obtain the time-delay type composite plugging and regulating system;

wherein the modified lignin is an amination and acylation product of lignin.

In the present invention, the preparation, selection and amount of the modified lignin, polyacrylamide, crosslinking agent and stabilizer have been described in detail in the above first aspect, and in order to avoid unnecessary repetition, a detailed description is omitted herein.

According to a preferred embodiment of the invention, the preparation method of the time-delay type composite plugging system comprises the following steps:

(1) Adding modified lignin and polyacrylamide into water under stirring until the modified lignin and the polyacrylamide are uniformly dissolved;

(2) Adding a stabilizer, a pH regulator and a cross-linking agent to perform contact reaction to obtain the delayed type composite plugging system.

In the present invention, the order of adding the stabilizer, the crosslinking agent and the pH adjuster is not particularly limited, so as to achieve uniform mixing to obtain the water shutoff profile control agent.

In the present invention, the pH adjustor is preferably used in an amount such that the pH of the reaction system is 6 to 8.

In the present invention, preferably, the temperature and time of the contact reaction are not particularly required as long as the materials can be uniformly mixed.

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

the water shutoff profile control agent can realize controllable delay gel formation in 3.5-9 days at a higher gel formation temperature (55-100 ℃), has higher strength, effectively reduces the production cost of the water shutoff profile control agent, and can be applied to water shutoff profile control in the oil extraction process of an oil field.

The present invention will be described in detail by examples. In the following examples and comparative examples,

the complex viscosity was tested using a rotational rheometer (available from sameidie technologies, inc. RS 6000).

Gel strength was measured using a breakthrough vacuum method (GL-802A minitable vacuum pump available from Haimen, inc. of Chemie Bell instruments, inc.).

The enzymatic lignin was purchased from Shandong Longli Biotechnology Co., ltd, and the lignin content was more than 80% by weight.

Polyacrylamide A was purchased from Shandong Bao Mole Biochemical Co., ltd, and had a solid content of 90% and a weight average molecular weight of 1550 ten thousand.

Polyacrylamide B was prepared as in example 1 of CN108017754A, with a solids content of 89% and a weight average molecular weight of 2100 ten thousand.

Polyacrylamide C was prepared as described in example 2 of CN108017754A, with a solids content of 91% and a weight average molecular weight of 1980 ten thousand.

Diethylenetriamine, tetraethylenepentamine, oleic acid chloride and palmitoyl chloride were purchased from carbofuran technologies.

Preparation example 1

This preparation example is used to illustrate the preparation of modified lignin L1

(1) At room temperature, 10g lignin and 1.6g NaOH were dissolved in water to prepare a 15 wt% lignin solution.

(2) Then 12g of diethylenetriamine is dripped into the mixture, the pH value is regulated to 10.5, 13.3g of formaldehyde is dripped into the mixture under stirring, the mixture is heated and refluxed for 2.5 hours, the pH value is regulated to be nearly neutral after the reaction is finished, the product is separated out, and the intermediate lignin amine is obtained through washing and drying.

(3) 6g of lignin amine is taken and dissolved in water, the pH value is regulated and kept to 8.5, 7.33g of oleic acid acyl chloride is dripped under stirring, then the temperature is raised to 60 ℃ for continuous reaction for 3 hours, and after the reaction, the modified lignin L1 is obtained through suction filtration, washing, drying and grinding.

Preparation example 2

This preparation example is used to illustrate the preparation of modified lignin L2

The procedure of preparation example 1 was followed except that 12g of diethylenetriamine was replaced with 23.1g of tetraethylenepentamine and 7.33g of oleic acid chloride was replaced with 6.93g of palmitoyl chloride, to obtain modified lignin L2.

Preparation example 3

This preparation example is used to illustrate the preparation of modified lignin L3

The procedure of preparation example 1 was followed, except that formaldehyde was not added in step (2), to obtain a modified lignin product L3.

Example 1

The embodiment is used for explaining the plugging system provided by the invention

8.9g of modified lignin L2 and 3g of polyacrylamide B are dissolved in the prepared water with the mineralization degree of 7000mg/L, and stirred at the rotating speed of 500r/min until the modified lignin L2 and the polyacrylamide B are uniformly dissolved; then adding 1.82g of sodium bisulphite and 5.5g of polyethyleneimine, regulating the pH value of the system to 6.5, and uniformly mixing to obtain the water shutoff profile control agent with the total mass of the system of 1 kg. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 2

Dissolving 4g of modified lignin L2 and 15g of polyacrylamide B in the preparation water with the mineralization degree of 12000mg/L, and stirring at the rotating speed of 500r/min until the modified lignin L2 and the polyacrylamide B are uniformly dissolved; then 5g of sodium bisulphite and 8g of polyethyleneimine are added, the pH value of the system is regulated to 7, the total mass of the system is 1kg, and the water shutoff profile control agent is obtained after uniform mixing. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 3

Dissolving 20g of modified lignin L2 and 1g of polyacrylamide B in water with the mineralization degree of 10000mg/L, and stirring at the rotating speed of 500r/min until the modified lignin L2 and the polyacrylamide B are uniformly dissolved; then 10g of sodium bisulphite and 2g of polyethyleneimine are added, the pH value of the system is regulated to 7.5, the total mass of the system is 1kg, and the water shutoff profile control agent is obtained after uniform mixing. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 4

The preparation of the plugging profile control system was performed as in example 1, except that sodium bisulphite was replaced with an equal amount of sodium thiosulfate to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 5

Preparation of a plugging system was performed as in example 1, except that polyacrylamide B was replaced with an equal amount of polyacrylamide a to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 6

Preparation of a plugging system was performed as in example 1, except that polyacrylamide B was replaced with an equal amount of polyacrylamide C to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 7

Preparation of the plugging system was performed as in example 1, except that modified lignin L2 was replaced with modified lignin L1. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 8

Preparation of the plugging system was performed as in example 1, except that modified lignin L2 was replaced with modified lignin L3. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Example 9

Dissolving 7g of modified lignin L1 and 4.4g of polyacrylamide B in 12000mg/L of formulated water, and stirring at 500r/min until the components are uniformly dissolved; then adding 1.46g of sodium dithionite and 4.2g of polyethyleneimine, regulating the pH value of the system to 7.5 and the total mass of the system to 1kg to obtain the water shutoff profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Comparative example 1

Comparative example for reference

The preparation of the plugging system was carried out in the same manner as in example 1, except that the same mass of polyacrylamide B was used in place of the modified lignin L2 to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Comparative example 2

Comparative example for reference

Preparation of a plugging system was performed as in example 9, except that the same mass of polyacrylamide B was used instead of the modified lignin L1 to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Comparative example 3

Comparative example for reference

The preparation of the plugging system was carried out in the same manner as in example 6, except that polyacrylamide C of the same quality was used instead of modified lignin L2, to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

Comparative example 4

Comparative example for reference

Preparation of a plugging system was performed according to the method of example 1, except that modified lignin L2 was replaced with lignin amine prepared in step (2) to obtain a plugging profile control agent. The gel forming temperature, gel forming start time and compound viscosity and gel strength of the water shutoff profile control agent after the crosslinking reaction are shown in table 1.

TABLE 1

As can be seen from the comparison examples and the comparison examples, the invention provides a novel lignin modified product and a preparation method thereof, and creatively applies the lignin modified product to the water shutoff and profile control process of an oil field, and increases lignin crosslinking sites through lignin amination and acylation modification, improves lignin crosslinking activity, and finally improves the performance of the plugging agent. The water shutoff profile control agent provided by the invention can realize delayed controllable crosslinking at a higher gel forming temperature (55-100 ℃) and a longer gel forming time (3.5-9 d), and the gel has higher strength, and in addition, the production cost of the water shutoff profile control agent is effectively reduced.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. The time-delay type composite plugging agent is characterized by comprising the following raw materials: modified lignin, polyacrylamide, a cross-linking agent and a stabilizer; wherein the modified lignin is an amination and acylation product of lignin; the lignin is at least one selected from alkali lignin, enzymolysis lignin, chlorination lignin, steam explosion lignin and sulfur lignin.

2. The plugging agent of claim 1, wherein the modified lignin is prepared by a process comprising:

3. The plugging agent according to claim 2, wherein in the step (1), the organic amine is at least one selected from dimethylamine, ethylenediamine, trimethylamine, triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, putrescine, cadaverine, spermidine and spermine; and/or the pH value of the first alkaline condition is 10-11.5; the mass ratio of the organic amine to the lignin is 0.05-4.5:1; and/or, the amination reaction conditions include: the temperature is 60-75 oC, and the time is 1.5-4 hours;

and/or, in step (1), the amination reaction is carried out in the presence of an aldehyde;

and/or in the step (2), the acyl chloride is at least one selected from acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride, trichloroacetyl chloride, fatty acyl chloride, stearoyl chloride, linolenoyl chloride, oleic acid acyl chloride and palmitoyl chloride; and/or the pH value of the second alkaline condition is 8-9.5; the mass ratio of the acyl chloride to the lignin amine is 0.5-2.5:1; and/or, the conditions of the acylation reaction include: the temperature is 55-65 oC, and the time is 1-4h.

4. The plugging agent of claim 3, wherein the aldehyde is a C1-C5 aldehyde.

5. The plugging agent according to claim 1 or 2, wherein the polyacrylamide is at least one selected from the group consisting of anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide and amphoteric polyacrylamide; the weight average molecular weight of the polyacrylamide is 600-3000 ten thousand.

6. The plugging agent of claim 1, wherein the cross-linking agent is polyethylenimine; and/or

The stabilizer is at least one selected from sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium dithionite, m-phenylenediamine, isoascorbic acid and thiourea.

7. The plugging agent according to claim 6, wherein the weight average molecular weight of the polyethyleneimine is 3000 to 100000.

8. The plugging agent of claim 1, wherein the modified lignin is used in an amount of 0.1 to 4.5% by weight based on the total weight of the plugging agent; the dosage of the polyacrylamide is 0.1 to 3.5 weight percent; the amount of the crosslinking agent is 0.05 to 1 wt%; the stabilizer is used in an amount of 0.05 to 2.5% by weight.

9. The plugging agent of claim 8, wherein the modified lignin is used in an amount of 0.4-2 wt%, based on the total weight of the plugging agent's raw materials; the dosage of the polyacrylamide is 0.1 to 1.5 weight percent; the amount of the crosslinking agent is 0.2 to 0.8 wt%; the stabilizer is used in an amount of 0.1 to 1% by weight.

10. A preparation method of a time-delay type composite plugging agent is characterized by comprising the following steps: carrying out contact reaction on modified lignin, polyacrylamide, a cross-linking agent and a stabilizing agent in a solution to obtain the time-delay type composite plugging agent;

the modified lignin is an amination and acylation product of lignin, and the lignin is at least one of alkali lignin, enzymolysis lignin, chlorination lignin, steam explosion lignin and sulfur lignin.

11. The method of preparation of claim 10, wherein the method of preparation of modified lignin comprises:

12. The production method according to claim 11, wherein in the step (1), the organic amine is selected from at least one of dimethylamine, ethylenediamine, trimethylamine, triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, putrescine, cadaverine, spermidine and spermine; and/or the pH value of the first alkaline condition is 10-11.5; the mass ratio of the organic amine to the lignin is 0.05-4.5:1; and/or, the amination reaction conditions include: the temperature is 60-75 oC, and the time is 1.5-4 hours;

and/or in step (2), the acyl chloride is selected from at least one of acetyl chloride, benzoyl chloride, oxalyl chloride, chloroacetyl chloride, trichloroacetyl chloride, fatty acyl chloride, stearoyl chloride, linolenoyl chloride, oleic acid acyl chloride and palmitoyl chloride; and/or the pH value of the second alkaline condition is 8-9.5; the mass ratio of the acyl chloride to the lignin amine is 0.5-2.5:1; and/or, the conditions of the acylation reaction include: the temperature is 55-65 oC, and the time is 1-4h.

13. The method of claim 12, wherein the aldehyde is a C1-C5 aldehyde.

14. The production method according to any one of claims 10 to 11, wherein the polyacrylamide is at least one selected from the group consisting of anionic polyacrylamide, cationic polyacrylamide, nonionic polyacrylamide and amphoteric polyacrylamide.

15. The preparation method of claim 14, wherein the polyacrylamide has a weight average molecular weight of 600 to 3000 ten thousand.

16. The method of claim 10, wherein the cross-linking agent is polyethylenimine; and/or

17. The process according to claim 16, wherein the weight average molecular weight of the polyethyleneimine is 3000 to 100000.

18. The production method according to claim 10, wherein the modified lignin is used in an amount of 0.1 to 4.5% by weight based on the total weight of the raw materials of the plugging agent; the dosage of the polyacrylamide is 0.1 to 3.5 weight percent; the amount of the crosslinking agent is 0.05 to 1 wt%; the stabilizer is used in an amount of 0.05 to 2.5% by weight.

19. The production method according to claim 18, wherein the modified lignin is used in an amount of 0.4 to 2% by weight based on the total weight of the raw materials of the plugging agent; the dosage of the polyacrylamide is 0.1 to 1.5 weight percent; the amount of the crosslinking agent is 0.2 to 0.8 wt%; the stabilizer is used in an amount of 0.1 to 1% by weight.

20. The time-lapse composite plugging agent prepared by the preparation method of any one of claims 10 to 19.

21. Use of the time-lapse composite plugging agent of any one of claims 1-9 and 20 in oil recovery in an oilfield.