阅读说明：本技术 一种稠油开采用泡沫剂及其制备方法 (Foaming agent for thickened oil recovery and preparation method thereof ) 是由 郑万刚 钱钦 翟勇 吴国伟 徐涛 张仲平 张紫军 刘恒 赵云献 隋旭强 于 2019-10-14 设计创作，主要内容包括：本发明涉及一种稠油开采过程中使用的化学剂,具体是一种稠油开采用泡沫剂及其制备方法。该泡沫剂由邻烷基苯异氰酸酯和烷基苯酚聚氧乙烯醚通过聚合反应制得到。所述的邻烷基苯异氰酸酯与烷基苯酚聚氧乙烯醚的摩尔比为1：1.0～1.2,优选为1:1.1。与市售泡沫剂相比具有耐温耐盐性能强的特点,耐温达300℃,耐矿化度50000mg/L；同时该泡沫剂使用浓度低,在使用浓度0.5wt％时,可降低特超稠油粘度99.0％以上,泡沫阻力因子＞55。因此,本发明的泡沫剂可广泛地应用于稠油开采技术领域中。(The invention relates to a chemical agent used in a thickened oil recovery process, in particular to a foaming agent for thickened oil recovery and a preparation method thereof. The foaming agent is prepared from o-alkyl benzene isocyanate and alkylphenol polyoxyethylene ether through polymerization reaction. The molar ratio of the o-alkylbenzene isocyanate to the alkylphenol polyoxyethylene is 1:1.0 to 1.2, preferably 1: 1.1. Compared with the commercial foaming agent, the foaming agent has the characteristics of strong temperature resistance and salt tolerance, can resist the temperature of 300 ℃ and the mineralization degree of 50000 mg/L; meanwhile, the foaming agent is low in use concentration, the viscosity of the extra-super heavy oil can be reduced by over 99.0% when the use concentration is 0.5 wt%, and the foam resistance factor is larger than 55. Therefore, the foaming agent can be widely applied to the technical field of heavy oil recovery.)

1. The foaming agent for thickened oil recovery is characterized by being prepared from o-alkyl benzene isocyanate and alkylphenol polyoxyethylene ether through polymerization reaction, and the molecular formula of the foaming agent is as follows:

wherein: m is a natural number of 3-6;

R₁is C₁～C₅Linear or branched alkyl of (a);

R₂is C₂～C₇Linear or branched alkyl.

2. The preparation method of the foaming agent for thickened oil recovery according to claim 1, characterized by comprising the following steps:

(1) adding o-alkyl phenyl isocyanate, alkylphenol polyoxyethylene and solvent water into a four-neck flask with a thermometer, a reflux condenser and a stirrer, heating while stirring at the stirring speed of 200-400 rpm at the heating temperature of 30-60 ℃, introducing nitrogen, and introducing the nitrogen for 5-10 min;

(2) slowly adding the catalyst into the four-neck flask, continuously introducing nitrogen, heating the four-neck flask to 65-85 ℃, adjusting the stirring speed to 500-600 rpm, reacting for 4-7h, and cooling to room temperature to obtain a mixture;

(3) and removing solvent water from the mixture by using a rotary evaporator to obtain a crude product, washing the crude product for 3-5 times by using absolute ethyl alcohol to remove unreacted reactants, and then placing the crude product in an oven at the temperature of 80-100 ℃ for constant temperature for 24-48 hours to obtain brown viscous liquid, namely the foaming agent.

3. The method for preparing the foaming agent for thickened oil recovery as claimed in claim 2, wherein the molar ratio of the o-alkyl benzene isocyanate to the alkylphenol polyoxyethylene ether is 1:1.0 to 1.2.

4. The method for preparing the foaming agent for thickened oil recovery as claimed in claim 3, wherein the molar ratio of the ortho-alkylbenzene isocyanate to the alkylphenol ethoxylate is 1: 1.1.

5. The preparation method of the foaming agent for thickened oil recovery as claimed in claim 2, wherein the amount of the solvent water is 5-10 times of the mass of the o-alkyl benzene isocyanate.

6. The method for preparing the heavy oil recovery foaming agent according to claim 2, wherein the catalyst is dibutyltin dilaurate.

7. The method for preparing the foaming agent for thickened oil recovery as claimed in claim 6, wherein the amount of the dibutyltin dilaurate is 0.5-1% of the mass of the o-alkyl phenyl isocyanate.

8. The method for preparing the foaming agent for thickened oil recovery as claimed in claim 2, wherein the amount of the absolute ethyl alcohol is 0.5-3 times of the mass of the o-alkyl phenyl isocyanate.

Technical Field

The invention relates to a chemical agent used in a thickened oil recovery process, in particular to a foaming agent for thickened oil recovery and a preparation method thereof.

Background

In recent years, a large amount of research work and field tests are carried out on domestic oil fields such as Liaohe oil fields, Henan oil fields, Clarity oil fields and the like in the aspect of chemical method auxiliary steam production of thick oil, and the steam huff and puff development process is mainly applied from application condition analysis. The technology for improving the development effect of thermal recovery by using high-temperature nitrogen foam is applied for many years and is one of the main technologies for adjusting the steam absorption profile at present.

Researches show that the foam can effectively plug a high permeable layer and a dominant channel of a reservoir, improve the steam absorption profile of the reservoir, improve the swept area and the oil displacement efficiency of steam, and increase the periodic oil yield of the oil field. The principle is that a certain proportion of nitrogen and foaming agent is added during steam injection, the foaming agent is utilized to generate high-viscosity foam flow in a formation steam and water channeling pore channel, the flow resistance is increased, and the seepage capability of steam is reduced, so that the steam injection pressure is increased, the steam injected later is forced to turn to a low-permeability layer and high-oil-content saturation area, and the swept volume of the steam is enlarged; the high-water-content high-permeability layer is blocked by using the functions of large blocking without small blocking and water blocking without oil blocking of nitrogen foam, and the purpose of using the high-oil-content saturation layer for steam steering is realized, so that the effects of precipitation and oil increment and improvement of the development effect of marginal water invading into an oil reservoir are realized.

Research shows that the nitrogen foam profile control effect is better in the first three periods of steam huffing and puff, but the nitrogen foam profile control effect is gradually reduced along with the increase of the steam huffing and puff, and the main reason is that the residual oil in a high-saturation oil reservoir area is reduced after the steam huffing and puff, and the residual oil in the profile control area cannot be used. At present, researchers use nitrogen foam and surfactant together to improve the oil reservoir mobility. Although this technique improves the oil wash rate in high saturation (low permeability reservoir) reservoir regions, it still does not provide for the remaining oil in the profile control region.

Disclosure of Invention

The invention provides a foaming agent for thickened oil exploitation and a preparation method thereof aiming at the defects of the prior art, and solves the problems of poor channeling sealing effect, low exploitation degree and the like of a conventional foaming system after multiple steam huff and puff of a thickened oil reservoir. The foaming agent has the functions of defoaming and viscosity reduction when meeting oil and foaming and profile control when meeting water; compared with the commercial foaming agent, the foaming agent has the characteristics of strong temperature resistance and salt tolerance, can resist the temperature of 300 ℃ and the mineralization degree of 50000 mg/L; meanwhile, the foaming agent is low in use concentration, the viscosity of the extra-super heavy oil can be reduced by over 99.0% when the use concentration is 0.5 wt%, and the foam resistance factor is larger than 55.

One of the purposes of the invention is to disclose a foaming agent for thickened oil recovery, which is prepared by the polymerization reaction of ortho-alkyl phenyl isocyanate and alkylphenol polyoxyethylene ether, and the molecular formula of the foaming agent is as follows:

wherein: m is a natural number of 3-6;

R₁is C₁～C₅Linear or branched alkyl of (a);

R₂is C₂～C₇Linear or branched alkyl.

The molar ratio of the o-alkyl benzene isocyanate to the alkylphenol polyoxyethylene is 1: 1.0-1.2, and 1:1.1 is preferred.

The invention also discloses a preparation method of the foaming agent, which specifically comprises the following steps:

(1) adding o-alkyl phenyl isocyanate, alkylphenol polyoxyethylene and solvent water into a four-neck flask with a thermometer, a reflux condenser and a stirrer, heating while stirring at the stirring speed of 200-400 rpm at the heating temperature of 30-60 ℃, introducing nitrogen, and introducing the nitrogen for 5-10 min;

(2) slowly adding the catalyst into the four-neck flask, continuously introducing nitrogen, heating the four-neck flask to 65-85 ℃, adjusting the stirring speed to 500-600 rpm, reacting for 4-7h, and cooling to room temperature to obtain a mixture;

(3) and removing solvent water from the mixture by using a rotary evaporator to obtain a crude product, washing the crude product for 3-5 times by using absolute ethyl alcohol to remove unreacted reactants, and then placing the crude product in an oven at the temperature of 80-100 ℃ for constant temperature for 24-48 hours to obtain brown viscous liquid, namely the foaming agent.

The amount of the solvent water is 5-10 times of the mass of the o-alkyl phenyl isocyanate; the catalyst is dibutyltin dilaurate, and the using amount of the catalyst is 0.5-1% of the mass of the o-alkyl phenyl isocyanate; the amount of the absolute ethyl alcohol is 0.5-3 times of the mass of the o-alkyl phenyl isocyanate.

The preparation equation of the foaming agent of the invention is as follows:

the structural formula of the foaming agent disclosed by the invention has double benzene rings, the benzene rings belong to a rigid structure, the temperature resistance of molecules is improved, the thermal recovery development requirements are completely met, and meanwhile, the molecules have no anions and cations and have the advantage of strong resistance to hypersalinity; a plurality of oxygen atoms on the molecules can form strong hydrogen bonds with the water phase, so that a film between gas and liquid is more stable, and the formed foam has higher strength; the long carbon chain polyether introduced into the structure has higher flexibility, is easier to be enriched at an oil-water interface after defoaming, and the benzene ring and the introduced alkyl are more compatible with thick oil, so that molecules are also stable at the oil-water interface, thereby forming a more stable oil-in-water emulsion. Therefore, when the foaming agent is injected along with steam, the foaming agent is mainly at a gas-liquid interface, and the formed foam has high strength; in the process of thickened oil recovery, after foam is defoamed by oil, lipophilic groups of the foaming agent react with thickened oil, hydrophilic groups react with water, and molecules of the foaming agent can be stripped to emulsify thickened oil under the action of external force, so that the oil washing efficiency of a high-permeability strip is improved.

Compared with the prior art, the invention has the following beneficial effects and advantages:

(1) the defoaming agent has the advantages of wide raw material source, simple synthesis process, clean and pollution-free process, and easily obtained, transported and stored products;

(2) the foaming agent has the dual functions of profile control and viscosity reduction and oil washing, and saves the cost;

(3) the foaming agent has strong temperature resistance and salt tolerance, can resist the temperature of 300 ℃ and the mineralization degree of 50000 mg/L;

(4) the foaming agent has low use concentration, and when the concentration is 0.5 wt%, the foam resistance factor is more than 55, and the viscosity reduction rate on ultra-thick oil is more than 99%.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The present invention is described in further detail below with reference to specific examples and with reference to the data. It will be understood that these examples are intended to illustrate the invention and are not intended to limit the scope of the invention in any way.