基于悬浮聚合构筑超低密度支撑剂及其结构与性能关系研究

Proppant is the key material for the exploitation of petroleum and natural gas. However, conventional proppant showed drawbacks of high density, low flow conductivity and high cost for the exploitation, and complex preparation process, bad mechanical property was found in existing ultra-low density proppant. Therefore, polymer-fly ash hybrid proppant with ultra-low density and good mechanical property will be prepared via facile suspension polymerization in this project. Firstly, functionalized fly ash will be synthesized based on molecular design, and the effect of modification procedure on the surface property of fly ash will be investigated systematically. Then, ultra-low density proppant will be made directly through suspension polymerization with functionalized fly ash, styrene, and methyl methacrylate. The effect of feed ration and polymerization parameters on the structure and property of obtained proppant will be investigated deeply, especially for the density, mechanical and thermal property. On the basis of the above research, the relationship between molecular structure and property will be constructed, and which will provide guidance for the property optimizing of proppant. Key scientific issues such as molecular design and relationship between structure and property were taken into account, the implementation of this project will accelerate the development of design theory for the ultra-low density proppant, which have significant meaning in both academic research and industrial production.

支撑剂是石油、天然气开采中的关键材料，但是传统支撑剂存在密度高、导流能力差、开采成本高的问题，而现有超低密度支撑剂又存在制备工艺复杂、强度差的缺点。因此，本项目拟通过简单的悬浮聚合制备超低密度、高强度的聚合物-粉煤灰复合支撑剂。首先通过分子设计合成亲油改性的粉煤灰，揭示改性工艺对粉煤灰表面性能影响的本质规律；然后以功能化的粉煤灰、苯乙烯、甲基丙烯酸甲酯等为原料通过悬浮聚合一步制备超低密度支撑剂，深入探讨投料比、聚合工艺对支撑剂结构和性能影响的本质规律，特别是对密度、强度和耐热性的影响；在此基础上，构建支撑剂分子结构与宏观性能的关系，进而指导支撑剂分子设计的优化。项目涉及支撑剂分子设计及结构与性能关系的关键科学问题，项目的开展将推动超低密度支撑剂设计理论的发展，具有重要的科学研究意义和工业生产价值。

油气水力压裂开采过程中超低密度支撑剂的使用可提高开采效率、降低成本并减少地层伤害和环境污染。针对当前应用的超低密度支撑剂存在抗压强度低、耐温性差、成本高等问题。提出了以工业废弃物粉煤灰为填料，通过分子设计及实验探究，优选KH-550硅烷偶联剂、硬脂酸对粉煤灰进行改性，制备出疏水亲油型功能化粉煤灰。以功能化粉煤灰为填料，优选苯乙烯(St)、甲基丙烯酸甲酯(MMA)为单体、二乙烯基苯(DVB)为交联剂，通过简单的悬浮聚合工艺制备了低密度(＜1.3 g/cm3)、高强度(52MPa压力下破碎率＜1%)的Poly(St-co-MMA)/FA复合微球，可作为超低密度支撑剂。研究了投料比及聚合工艺对支撑剂密度、耐热性、酸蚀率，特别是抗压强度影响的本质规律，阐明了支撑剂微观结构与宏观性能关系的基础科学问题，解决了超低密度、高强度支撑剂设计与合成的技术难题，实现新型超低密度支撑剂的可控制备。在此基础上以硅藻土（Dia）、高岭土（Kaolin）、埃洛石（HNTs）、硅灰（SF）等无机非金属矿物为填料，制备出Poly(St-co-MMA)/Dia、Poly(St-co-MMA)/Kaolin、Poly(St-co-MMA)/HNTs、Poly(St-co-MMA)/SF系列超低密度支撑剂。该项技术如能推广应用，有望促进我国压裂支撑剂产业的创新驱动发展。