阅读说明：本技术 一种适用于低渗透油藏的小分子粘土稳定剂及其制备方法 (Small-molecule clay stabilizer suitable for low-permeability oil reservoir and preparation method thereof ) 是由 张星 张全胜 李侠清 赵琳 肖驰俊 宋菲 宋志东 代兴益 冯雷雷 于 2019-10-30 设计创作，主要内容包括：本发明属于石油开采技术领域,具体涉及一种适用于低渗透油藏的小分子粘土稳定剂及其制备方法。所述方法包括以下步骤：(1)将装有N,N－二(2-氯乙基)－1－丙胺水溶液反应器进行水浴,回流冷凝,向反应器中滴加环氧氯丙烷并进行搅拌,滴加完成后维持原有温度反应30～120min；(2)提高搅拌速度并将水浴温度缓慢升高至30～100℃,加入引发剂,反应3-8h,得反应产物；(3)将反应产物使用有机溶剂充分溶解,丙酮提纯,真空干燥,配置成水溶液备用；(4)将步骤(3)配置成的水溶液与无机盐混合,即得。所得小分子季铵盐型阳离子聚合物类粘土稳定剂具有较好的稳定低渗透油藏粘土的效果。(The invention belongs to the technical field of oil exploitation, and particularly relates to a small-molecular clay stabilizer suitable for a low-permeability oil reservoir and a preparation method thereof. The method comprises the following steps: (1) carrying out water bath on a reactor filled with the N, N-bis (2-chloroethyl) -1-propylamine aqueous solution, refluxing and condensing, dropwise adding epoxy chloropropane into the reactor, stirring, and maintaining the original temperature after dropwise adding for reaction for 30-120 min; (2) increasing the stirring speed, slowly raising the temperature of the water bath to 30-100 ℃, adding an initiator, and reacting for 3-8 hours to obtain a reaction product; (3) fully dissolving a reaction product by using an organic solvent, purifying by using acetone, drying in vacuum, and preparing into an aqueous solution for later use; (4) and (4) mixing the aqueous solution prepared in the step (3) with inorganic salt to obtain the compound. The obtained micromolecule quaternary ammonium salt type cationic polymer clay stabilizer has a good effect of stabilizing low-permeability reservoir clay.)

1. A preparation method of a small molecular polyamine clay stabilizer is characterized by comprising the following steps:

(1) carrying out water bath on a reactor filled with the N, N-bis (2-chloroethyl) -1-propylamine aqueous solution, refluxing and condensing, dropwise adding epoxy chloropropane into the reactor, stirring, and maintaining the original temperature after dropwise adding for reaction for 30-120 min;

(2) increasing the stirring speed, slowly raising the temperature of the water bath to 30-100 ℃, adding an initiator, and reacting for 3-8 hours to obtain a reaction product;

(3) fully dissolving a reaction product by using an organic solvent, purifying by using acetone, drying in vacuum, and preparing into an aqueous solution for later use;

(4) and (4) mixing the aqueous solution prepared in the step (3) with inorganic salt to obtain the compound.

2. The method according to claim 1, wherein step (1) further comprises any one or more of the following conditions:

a1, wherein the mass concentration of the N, N-bis (2-chloroethyl) -1-propylamine aqueous solution is 70%;

a2, controlling the temperature of a water bath to be-10 to 10 ℃; preferably, the water bath temperature is-5-8 ℃;

a3, condensing water in the reflux condensation is not higher than 35 ℃, and preferably, the condensing water is not higher than 25 ℃;

a4: the molar ratio of the N, N-bis (2-chloroethyl) -1-propylamine to the epichlorohydrin is 0.8-2: 1, preferably 1-1.8: 1;

a5: the dripping speed of the epoxy chloropropane is controlled to be 5-20 mL/min, preferably 10-15 mL/min;

a6: keeping the original temperature and reacting for 50-90 min.

3. The method according to claim 1, wherein step (2) further comprises any one or more of the following conditions:

b1, slowly raising the temperature of the water bath to 40-90 ℃;

b2, the initiator is ammonium persulfate;

b3, reacting for 4-6 h.

4. The method according to claim 1, wherein step (3) further comprises any one or more of the following conditions:

c1, the organic solvent is ethanol;

c2, vacuum drying at 50-75 ℃ for 3-10 h, preferably vacuum drying at 60 ℃ for 4-7 h;

c3, preparing the water solution with the mass concentration of 40-50%.

5. The method according to claim 1, wherein step (4) further comprises any one or more of the following conditions:

d1, the inorganic salt is potassium chloride or ammonium chloride;

d2, the mass ratio of the aqueous solution to the inorganic salt is 3-1: 1.

6. The small molecular polyamine clay stabilizer prepared by the preparation method of any one of claims 1 to 5.

Technical Field

The invention belongs to the technical field of oil exploitation, and particularly relates to a small-molecular clay stabilizer suitable for a low-permeability oil reservoir and a preparation method thereof.

Background

The drilling and completion aims to develop an oil-gas layer, form an oil-gas seepage channel and establish good production conditions of oil gas. Any additional factor that impedes the flow of hydrocarbons downhole is referred to as contamination or damage to the hydrocarbon reservoir. During each of the well completions and other stimulation procedures, damage to the hydrocarbon reservoir may occur, thereby greatly reducing the efficiency of hydrocarbon production.

Among the many factors that cause damage to hydrocarbon reservoirs, damage to clay minerals is one of its major factors. The stratum contains a certain amount of clay minerals, mainly comprising montmorillonite, kaolinite, illite (hydromica), chlorite, illite mixed layer, smectite mixed layer and the like. These clays swell during flooding, acidizing, fracturing when exposed to water or water-based materials and then disperse further (e.g., montmorillonite, chlorite) or directly (e.g., kaolinite, illite) into fine particles less than 10 microns in diameter. Thereby plugging the stratum seepage passage, reducing the permeability of the stratum and influencing the development effect of the oil and gas field. Therefore, in order to protect the permeability of oil and gas reservoirs, clay stabilizers are added to the working fluid used to prevent clay mineral swelling and particulate migration during stimulation.

Although the method has excellent effects in developing hydrocarbon reservoirs, particularly in medium and high permeability reservoirs, the method also has problems. Therefore, experts and scholars at home and abroad analyze and research the damage of the high molecular weight cationic organic polymer applied to the low permeability oil field, and the molecular weight of the general organic cationic polymer is 5 multiplied by 10⁵Belongs to macromolecular clay stabilizer, and the average size of the stabilizer can reach 1.1 mu m. Although the oil can pass through most pore passages, the oil reservoir is particularly weak when used for a low-permeability oil reservoir, and if the pore passages are blocked by larger molecules in the oil reservoir, other molecules can form bridge points, so that the stratum is damaged.

When the polymer is used for developing low-permeability oil-gas fields, the common macromolecular cationic polymer is adopted, so that the effect of stabilizing the stratum cannot be effectively achieved, and small pores of the stratum can be blocked, so that the migration of particles is prevented, the stratum permeability is reduced, and the oil well yield is influenced. Therefore, the research on small molecules or small molecular weight cationic polymers is very important.

Disclosure of Invention

The invention mainly aims to provide a preparation method of a clay stabilizer suitable for a low-permeability oil reservoir aiming at the defects of the prior art, and the obtained micromolecule quaternary ammonium salt type cationic polymer clay stabilizer has a good effect of stabilizing low-permeability oil reservoir clay.

In order to achieve the purpose, the invention adopts the following technical scheme:

one of the purposes of the invention is to provide a preparation method of a small molecular polyamine clay stabilizer, which comprises the following steps:

(1) carrying out water bath on a reactor filled with the N, N-bis (2-chloroethyl) -1-propylamine aqueous solution, refluxing and condensing, dropwise adding epoxy chloropropane into the reactor, stirring, and maintaining the original temperature after dropwise adding for reaction for 30-120 min;

(2) increasing the stirring speed, slowly raising the temperature of the water bath to 30-100 ℃, adding an initiator, and reacting for 3-8 hours to obtain a reaction product;

(3) fully dissolving a reaction product by using an organic solvent, purifying by using acetone, drying in vacuum, and preparing into an aqueous solution for later use;

(4) and (4) mixing the aqueous solution prepared in the step (3) with inorganic salt to obtain the compound.

Further, step (1) further comprises any one or more of the following conditions:

a1, wherein the mass concentration of the N, N-bis (2-chloroethyl) -1-propylamine aqueous solution is 70%;

a2, controlling the temperature of a water bath to be-10 to 10 ℃; preferably, the water bath temperature is-5-8 ℃;

a3, condensing water in the reflux condensation is not higher than 35 ℃, and preferably, the condensing water is not higher than 25 ℃;

a4: the molar ratio of the N, N-bis (2-chloroethyl) -1-propylamine to the epichlorohydrin is 0.8-2: 1, preferably 1-1.8: 1;

a5: the dripping speed of the epoxy chloropropane is controlled to be 5-20 mL/min, preferably 10-15 mL/min;

a6: keeping the original temperature and reacting for 50-90 min.

Further, step (2) further comprises any one or more of the following conditions:

b1, slowly raising the temperature of the water bath to 40-90 ℃;

b2, the initiator is ammonium persulfate;

b3, reacting for 4-6 h.

Further, step (3) further comprises any one or more of the following conditions:

c1, the organic solvent is ethanol;

c2, vacuum drying at 50-75 ℃ for 3-10 h, preferably vacuum drying at 60 ℃ for 4-7 h;

c3, preparing the water solution with the mass concentration of 40-50%.

Further, step (4) further comprises any one or more of the following conditions:

d1, the inorganic salt is potassium chloride or ammonium chloride;

d2, the mass ratio of the aqueous solution to the inorganic salt is 3-1: 1.

The second object of the present invention is to provide a small molecule polyamine clay stabilizer prepared by the above preparation method.

The N, N-di (2-chloroethyl) -1-propylamine used in the invention has the molecular weight of 184, belongs to an amine substance, and the epichlorohydrin and the N, N-di (2-chloroethyl) -1-propylamine have a grafting reaction, wherein the grafting number is 1-5, and the obtained molecular weight is smaller and has the molecular weight of 222-806. The permeability of the core is obviously improved after the small-molecule clay stabilizer is injected, which proves that the small-molecule clay stabilizer not only can not cause damage to a reservoir, but also can show electronegativity and compress an electric double layer through neutralizing clay, so that the shrinkage and expansion of the clay are realized; the defect that the core is damaged when the low-permeability core is treated by the long-chain polyquaternium macromolecular clay is overcome. The micromolecule polyamine clay stabilizer is more suitable for the expansion prevention of the reservoir with smaller pore throat size of the low-permeability reservoir.

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

(1) the invention has the advantages of easily obtained raw materials, relatively low price and simple and convenient experimental operation during preparation.

(2) The monomer used in the invention has high synthesis efficiency, and the prepared polymer product has excellent tackifying performance and small using amount.

(3) The synthetic product of the invention has lower molecular weight and has more obvious clay stabilizing effect on low-permeability oil layers such as shale.

(4) The product of the invention has good compatibility with various cosolvents.

(5) The product of the invention has no toxicity, safe use and little damage to stratum.

Description of the drawings:

FIG. 1 is a reaction scheme of the present invention.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.

The instruments, reagents, materials and the like used in the following examples are conventional instruments, reagents, materials and the like in the prior art and are commercially available in a normal manner unless otherwise specified.

Example 1

A preparation method of a quaternary ammonium salt cationic polymer with small molecular weight comprises the following steps:

(1) placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 37.6g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration of not less than 99% and 16.1g of deionized water are prepared, the water bath temperature is-3 ℃, introducing condensation water with the temperature of less than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration of more than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and maintaining the current temperature after the dropwise addition is finished and stirring for 90 min.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 50 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding with potassium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Example 2

(1) Placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 41.2g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration not lower than 99% and 17.7g of deionized water are prepared, the water bath temperature is 0 ℃, introducing condensation water with the temperature lower than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration higher than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and maintaining the current temperature after the dropwise addition is finished and stirring for 90 min.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 50 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding with potassium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Example 3

(1) Placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 56.4g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration of not less than 99% and 24.2g of deionized water are prepared, the water bath temperature is 3 ℃, introducing condensation water with the temperature of less than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration of more than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and maintaining the current temperature after the dropwise addition is finished and stirring for 90 min.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 50 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding with potassium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Example 4

(1) Placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 37.6g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration of not less than 99% and 16.1g of deionized water are prepared, the water bath temperature is 5 ℃, introducing condensation water with the temperature of less than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration of more than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and keeping the current temperature for stirring for 60min after the dropwise addition is finished.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 70 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding with potassium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Example 5

(1) Placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 37.6g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration of not less than 99% and 16.1g of deionized water are prepared, the water bath temperature is 5 ℃, introducing condensation water with the temperature of less than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration of more than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and maintaining the current temperature after the dropwise addition is finished and stirring for 90 min.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 90 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding with potassium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Example 6

(1) Placing a three-mouth reaction flask provided with a stirrer, a reflux condenser tube and a thermometer in a constant temperature water bath kettle, then adding an N, N-bis (2-chloroethyl) -1-propylamine aqueous solution into the three-mouth reaction flask, wherein 37.6g of N, N-bis (2-chloroethyl) -1-propylamine with the concentration of not less than 99% and 16.1g of deionized water are prepared, the water bath temperature is-3 ℃, introducing condensation water with the temperature of less than 25 ℃ into the reflux condenser tube, and then dropwise adding epoxy chloropropane with the concentration of more than 99% into the reaction flask at the speed of 15ml/min, wherein the dropwise adding mass is 20.5 g. Stirring at a constant speed of 800r/min, and maintaining the current temperature after the dropwise addition is finished and stirring for 90 min.

(2) After the stirring speed in the reaction flask was increased to 1000r/min and the temperature of the water bath was slowly raised to 50 ℃, 0.5g of ammonium persulfate initiator was added thereto and the current temperature was maintained for reaction for 5 hours.

(3) And (3) fully fusing a product obtained by reacting the reaction product obtained in the step (2) by using 50ml of ethanol with the mass concentration of not less than 99.7%, adding 100ml of acetone with the concentration of more than 99%, placing the mixture into a round-bottom flask, heating the mixture to 60 ℃, vacuumizing and drying, repeatedly purifying for not less than three times to obtain a purified product, and preparing the purified product into an aqueous solution with the mass concentration of 40% for later use.

(4) Diluting the prepared aqueous solution in the step (3) to 0.5 percent, and compounding the aqueous solution with ammonium chloride with the mass concentration of 1 percent to obtain a stabilizer mixed solution for use.

Comparative example 1

Only the synthesized product of step (3) in example 1 was used, and an aqueous stabilizer solution was prepared at a mass concentration of 1%.

Comparative example 2

Only 1% by mass aqueous potassium chloride solution was used.

Comparison of the Polymer products of the examples and the comparative example Properties:

the simulated formation was tested for swell prevention using a linear dilatometer using the reagent kerosene and deionized water, and the data is shown in table 1.

TABLE 1 results of evaluation of anti-swelling Properties

The core flow experiment effect of the small-molecule clay stabilizer prepared in example 5 of the invention is shown in table 2 below.

Table 2 core flow experiment effect of small molecule clay stabilizer in example 5 of the present invention

As can be seen from Table 2, the core permeability of the small-molecule clay stabilizer of the invention is obviously increased after injection, which proves that the small-molecule clay stabilizer not only can not cause damage to the reservoir, but also can show electronegativity and compress an electric double layer by neutralizing clay, thereby realizing the shrinkage and expansion of the clay.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.