阅读说明：本技术 一种超支化含氢硅氧烷超临界二氧化碳增稠剂的制备方法 (Preparation method of hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener ) 是由 王彦玲 刘斌 *** 梁雷 巩锦程 汤龙皓 于 2019-12-03 设计创作，主要内容包括：本发明涉及一种超支化含氢硅氧烷超临界二氧化碳增稠剂的制备方法。该方法包括：在催化剂存在下,使三乙二醇二甲基丙烯酸酯与1,3,5,7-四甲基环四硅氧烷经硅氢反应生成聚合物。本发明的超支化含氢硅氧烷聚合物超临界二氧化碳增稠剂具备较好的耐温耐压性能,可适用于不同温度和压力条件下实现增稠性能；与各种助溶剂的配伍性良好；无毒,使用安全,对地层伤害小；使用量少,增稠效果好。(The invention relates to a preparation method of a hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener. The method comprises the following steps: in the presence of a catalyst, triethylene glycol dimethacrylate and 1, 3, 5, 7-tetramethylcyclotetrasiloxane react through silicon hydrogen to generate a polymer. The hyperbranched hydrogen-containing siloxane polymer supercritical carbon dioxide thickener has good temperature resistance and pressure resistance, and can be suitable for realizing thickening performance under different temperature and pressure conditions; the compatibility with various cosolvents is good; the agent is nontoxic, safe to use and small in damage to the stratum; the use amount is small, and the thickening effect is good.)

1. A preparation method of a hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener (HBD-2) comprises the following steps:

in the presence of a catalyst, triethylene glycol dimethacrylate and 1, 3, 5, 7-tetramethylcyclotetrasiloxane react through silicon hydrogen to generate a polymer; wherein the catalyst is chloroplatinic acid and is activated before reaction.

2. The method for preparing the hyperbranched hydridosiloxane supercritical carbon dioxide thickener (HBD-2) according to claim 1, wherein the molar ratio of the triethylene glycol dimethacrylate to the 1, 3, 5, 7-tetramethylcyclotetrasiloxane is 1-5: 1.

3. The method for preparing the hyperbranched hydridosiloxane supercritical carbon dioxide thickener (HBD-2) according to claim 1, wherein the molar ratio of the triethylene glycol dimethacrylate to the 1, 3, 5, 7-tetramethylcyclotetrasiloxane is 2-3: 1.

4. The method of preparing the hyperbranched hydridosiloxane supercritical carbon dioxide thickener (HBD-2) according to claim 1, wherein the catalyst activation temperature is 60 ℃ to 120 ℃; preferably from 80 ℃ to 100 ℃.

5. The method for preparing hyperbranched hydridosiloxane supercritical carbon dioxide thickener (HBD-2) according to claim 1, wherein the amount of chloroplatinic acid used as the catalyst is 10ppm to 60 ppm; preferably 20ppm to 50 ppm.

6. The method of preparing the hyperbranched hydrosiloxane supercritical carbon dioxide thickener (HBD-2) of claim 1, wherein the hydrosilation reaction temperature and the catalyst activation temperature are the same.

7. The method for preparing hyperbranched hydridosiloxane supercritical carbon dioxide thickener (HBD-2) according to claim 1, wherein the silicon hydrogen reaction time is 2-24 h; preferably 4 to 8 hours.

8. The process for the preparation of the hyperbranched hydrosiloxane supercritical carbon dioxide thickener (HBD-2) according to any of claims 1 to 7, characterized by the following steps:

adding triethylene glycol dimethacrylate into a reaction vessel provided with a reflux device, stirring and heating, adding a catalyst chloroplatinic acid to activate for 1.5h-3h when the activation temperature is reached, and then dripping 1, 3, 5, 7-tetramethylcyclotetrasiloxane into the reaction vessel to react to obtain a colorless transparent product (HBD-2).

9. The preparation method of the hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener (HBD-2) as claimed in claims 1 to 7, wherein the prepared polymer (HBD-2) has a weight average molecular weight of 6000 to 11000.

10. Use of the hyperbranched hydrosiloxane polymer prepared by the method of claims 1-7 as a supercritical carbon dioxide thickener.

Technical Field

The invention relates to a preparation method of a hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener, belonging to the technical field of oil exploitation.

Background

The exploration and development of unconventional oil and gas resources in China are in a starting stage, and the unconventional oil and gas resources face core technology attack and customs and are also subjected to complex geographic problems to be solved and ecological water resource ringsAnd (4) limitations of environmental problems. Along with the development of dense gas and shale gas in China, the situation of 'Wanfang liquid Qiafang sand' is more and more, the problems of water resource waste and environmental pollution are gradually revealed, and liquid CO₂The fracturing technology is produced as a clean, environment-friendly and low-harm environment-friendly fracturing technology. Liquid CO₂The fracturing technology can solve the problems of poor gel breaking performance, large formation damage, water resource waste, serious environmental pollution and the like of the traditional fracturing fluid and can also slow down CO₂The problem of global warming brought by the method has certain contribution. Supercritical CO₂The viscosity is only 0.02-0.05 mPa.s, which is difficult to reach the requirement of carrying the propping agent into the bottom layer, and the fluid loss is large, and the fracturing effect is not ideal.

At present, the supercritical carbon dioxide thickener most commonly uses fluorine-containing compounds or polymers, which have great harm to the stratum, pollute underground water resources, cause environmental pollution, have great biological toxicity and are expensive. The problems of price and environmental pollution, few available varieties and the like prevent the fluorine-containing substances from being widely used for fracturing yield increase of oil fields to a certain extent. The hydrocarbon polymer has low cost and little pollution, but has undesirable thickening effect. Therefore, there is a need to find a new class of supercritical carbon dioxide thickeners to address the above disadvantages.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener HBD-2, and the obtained polymer has a good thickening effect on supercritical carbon dioxide and good temperature resistance and pressure resistance.

The technical scheme of the invention is as follows:

a preparation method of a hyperbranched hydrogen-containing siloxane supercritical carbon dioxide thickener comprises the following steps:

in the presence of a catalyst, triethylene glycol dimethacrylate and 1, 3, 5, 7-tetramethylcyclotetrasiloxane react through silicon hydrogen to generate a polymer; wherein the catalyst is chloroplatinic acid and is activated before reaction.

According to the invention, the molar ratio of the triethylene glycol dimethacrylate to the 1, 3, 5, 7-tetramethylcyclotetrasiloxane is preferably 1-5: 1. More preferably, the molar ratio of the triethylene glycol dimethacrylate to the 1, 3, 5, 7-tetramethylcyclotetrasiloxane is 2-3: 1.

According to the invention, the activation temperature of the catalyst is preferably 60 ℃ to 120 ℃, and more preferably 80 ℃ to 100 ℃.

According to the invention, the chloroplatinic acid catalyst is preferably used in an amount of 10ppm to 60ppm, more preferably 20ppm to 50 ppm.

According to the invention, the hydrosilylation reaction temperature and the catalyst activation temperature are the same.

According to the invention, the reaction time of the silicon and hydrogen is preferably 2-24 h; further preferably 4 to 8 hours.

Further, a preferred embodiment according to the present invention is as follows:

adding triethylene glycol dimethacrylate into a reaction vessel provided with a reflux device, stirring and heating, adding a catalyst chloroplatinic acid to activate for 1.5h-3h when the activation temperature is reached, and then dripping 1, 3, 5, 7-tetramethylcyclotetrasiloxane into the reaction vessel to prepare a colorless transparent product (named as HBD-2). The raw material ratios and the process conditions used are as described above.

The weight average molecular weight of the polymer (HBD-2) prepared by the invention is 6000-11000. The polymer was a colorless transparent liquid.

The hyperbranched hydrogen-containing siloxane polymer (HBD-2) prepared by the invention is a polymer with a linear-chain interpenetrating network structure. The polymer (HBD-2) prepared by the invention is a mixed product of a chain structure polymerization form and a net structure polymerization form which are mutually interpenetrated and intertwined, and is particularly favorable for thickening supercritical carbon dioxide. Without purification.

Several polymeric forms of the invention are represented by the following formulae a, b, c, d:

a, b, c and d represent several different polymerization forms in the reaction of the method, wherein a reacts 1 Si-H site, b reacts 2 Si-H sites, c reacts 3 Si-H sites, and d reacts 4 Si-H sites. a. b and c are mainly linear chain structures, while the polymerization form d is mainly a net structure with a siloxane structure, and the cross between the linear structures and the interpenetration of the linear chain structures in the net structure have two functions of strengthening the thickening effect.

The hyperbranched hydrogen-containing siloxane polymer (HBD-2) prepared by the invention is used as a supercritical carbon dioxide thickener. To improve the tackifying effect.

The invention has the technical characteristics and excellent effects that:

the good tackifier is not only required to be fully dissolved in supercritical CO₂In addition, supercritical CO is also required₂Has better tackifying performance. The tackifier should contain a suitable proportion of the CO-philic component as viewed from the molecular level of the tackifier₂Radical and hydrophobic CO₂Groups which make the two components relatively soluble in supercritical CO in a proper proportion in the tackifier molecule₂And (5) thickening. The polymer prepared by the invention is made of CO-philic₂Group (-COO-) of (A) and (B) is a hydrophobic CO₂Siloxane-based radicals, per se in supercritical CO₂Has certain solubility, is beneficial to reducing the dosage of cosolvent, improves the economical efficiency and has excellent thickening effect.

The hyperbranched hydrogen-containing siloxane polymer HBD-2 is prepared by the method, so that the hyperbranched hydrogen-containing siloxane polymer HBD-2 has a good effect of thickening supercritical carbon dioxide. According to the invention, acrylate and cyclosiloxane compounds are used as reaction monomers, and a catenate-crossed and catenate-and-netlike interpenetrating network polymer HBD-2 is generated through a silicon-hydrogen reaction. Like the different polymerization forms a, b, c and d, the thickening effect of the polymerization product is enhanced by the two functions of the crossing of the linear chain structures a, b and c and the interpenetration of the linear chain structures in the net structure d, and the mutual crossing and winding way not only enables the polymer to have better solubility, but also improves the capability of thickening the supercritical carbon dioxide by siloxane.

The weaker the intra-or intermolecular chain-to-chain interactions of the tackifier, the more readily the tackifier is soluble in CO₂A homogeneous system is formed. Process for the preparation of polymersThe strength of the interaction is determined by cohesive energy density, and the lower the value in a certain range, the more beneficial the value is in CO₂Dissolving in water to increase viscosity. In addition, the number of shorter side chains attached to the main chain has a greater influence on solubility than the longer side chains. The existence of side chains on tackifier molecules can effectively weaken the stacking among chains, increase the free volume and favorable mixing entropy, and lead the tackifier to be applied to supercritical CO₂The solubility in water is increased to improve the thickening effect.

The invention has the advantages of easily obtained raw materials, relatively low price, simple and convenient experimental operation during preparation and high synthesis efficiency. The hyperbranched hydrogen-containing siloxane polymer supercritical carbon dioxide thickener (HBD-2) has good temperature resistance and pressure resistance, and can be suitable for realizing thickening performance under different temperature and pressure conditions; the compatibility with various cosolvents is good; the agent is nontoxic, safe to use and small in damage to the stratum; the use amount is small, the thickening effect is excellent, and the pollution to stratum underground water and surface water is reduced.

The invention is suitable for industrial batch production and has better application in oilfield exploitation.

Drawings

FIG. 1 is an infrared spectrum of a sample of polymer HBD-2 synthesized in example 1.

FIG. 2 is an infrared spectrum of 1, 3, 5, 7-tetramethylcyclotetrasiloxane, a starting monomer for the synthesis of example 1;

FIG. 3 is a photograph of chembio3D of the polymer HBD-2 synthesized in example 1, with H atoms for the white spheres, C atoms for the light gray spheres, Si atoms for the dark gray, and an R group for the near black. Showing the network structure of the polymer.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the present invention is not limited thereto, and the reactants described in the examples are all obtained from Mecang Biochemical technology Co., Ltd, Shanghai, and subjected to reflux for impurity removal before use.