低品石油资源开发利用中界面分子相互作用与聚集的物理化学基础

Understanding the association and dessociation of amphiphilic (surface active) molecules at oil-water interface is of great scientific and techonological importance in exploration and utilization of low grade petroleum resources. Molecular association and dessociation are alos one of key phenomena in a number of scientific disciplines such as chemistry, physics, materials science and life science. The main purpose of this project is to determine molecular structure of indigenous amphiphilic molecules in complex crude; design and synthesize model compounds of similar structure to natural amphiphilic molecules; study relationship between molecular structure and its association at oil-water interfaces and aggregation in bulk heavy oil by both molecular dynamics simulation and direct measurement of interfacial properties such as interfacial tension, pressure-area isotherms, rheology and molecular imaging as well as dynamic light scattering; control molecular agregation at oil-water interface and hence interfacial properties by design of PH (or CO2) and temperature responsive amphiphilic surfactant molecules and polymers; and achieve desired control of emulsification and demulsification by fine-tuning interfacial properties with responsive molecules for enhanced oil production and utilization from low grade petroleum resources.. The ultimate goal of this project is to provide a scientific basis for maximizing petroleum production from low grade petroleum resources at minimal energy consumption and reduced environemtnal impact. This will be accomplished by using PH or temperature responsive amphiphilic molecules to control interfacial properties. The success of the project will play a crucial role in securing ever-increasing demand of petroluem products from limited resources.

两亲性分子的界面自组装与解组装是低品石油资源开发的重要科学问题，也是涉及化学、物理、材料以及生命科学等诸多领域的基本问题之一。本项目的主要研究内容包括：揭示原油复杂体系中表面活性分子的结构；设计与原油中天然活性分子结构类似的模型分子，通过分子动力学模拟和界面物理化学实验考察活性分子体相聚集于油水界面聚集的关系；设计并合成对酸碱、温度或C02敏感的开关型表面活性剂或聚合物，调控原油乳状液的界面行为，最终实现储层中原油乳化与地面破乳脱水之间的统筹兼顾. 项目的研究结果将为低品石油资源开发利用提供理论指导，酸碱、温度等环境敏感型表面活性剂可望用于低品石油资源有效清洁开采与利用，对缓解我国日益严峻的石油紧缺局面具有重要意义。

随着常规油气资源的不断开发，非常规油气资源的开发利用越来越重要，由于非常规油粘度大，密度大，出砂严重，其采平均收率不足20%。原油中沥青质作为主要的界面活性物质，所涉及的界面自组装与解组装是解决低品石油资源开发的关键所在。本项目通过深度研究原油沥青质的界面性质，拓展了传统原油自组分分离法，获得具有高界面活性的沥青质组分，以此提出并合成了新的沥青质模型分子，该系列模型分子以苝为稠环核心，烷基和可调节的极性基团为侧链，通过溶解度，界面活性，表面力等测试验证了其作为模型分子的合理性。然后通过分子动力学模拟研究模型分子体相自组装和界面相吸附，发现分子间主要通过π-π重叠以及活性基团之间的相互作用形成聚集体或吸附于界面上。在此基础上，设计并合成对酸碱、温度或CO2敏感的开关型表面活性剂和聚合物，也可以通过CO2调控自组装实现开关过程。由于CO2的加入使得氨基，胍基，脒基等弱碱性基团质子化而亲水，N2的加入排出CO2，分子结构回到初始状态，从而实现开关过程。利用该开关过程调控原油乳状液的界面行为，最终实现储层中原油乳化与地面破乳脱水之间的统筹兼顾。本项目的研究结果为低品石油资源开发利用提供理论指导，开关型表面活性剂的开发为石油资源有效清洁开采利用提供了新思路，对缓解我国日益严峻的石油紧缺局面具有重要意义。