多孔介质中预交联凝胶颗粒渗滤规律及动力学模型研究

Performed Particle Gel(PPG) is a type of polymer microspheres with well water swelling characteristic. Comparing with traditional rigid particles, it possesses a very good property of "amoeba". Therefore, a series of behaviors are performed when it flows in porous media, such as migration, deposition or plugging, entrainment or deformation, remigration or restarting, thus, dynamic profile control is realized. In this study, first, static experiments are carried out to study the swollen properties of PPG and rheology of PPG suspension; then,microscopic visual experiments are performed to study the influencing factors and controlled conditions of surface deposition, pore throat plugging, remigration and restarting in porous media; On this basis, coreflooding and NMR imaging technique are used to study the mechanisms of particle migration, deposition and plugging processes, the variation of porosity and permeability due to PPG retention,and the EOR mechanisms of PPG flooding, according to these results, the kenitic model of PPG filtration will be estabilished. Finnally, a novel mathematical model of PPG flooding for EOR will be also estabilished, and used to optimize some programs and parameters for PPG flooding in oilfield. The significances involve that, on one hand, it makes great attribution and fills the gap in the field of PPG filtration and numerical simulation in porous media; on the other hand, it provides theoretical basis and key parameters for carrying out PPG flooding to improve oil recovery in high water-cut resercoirs.

预交联凝胶颗粒（PPG）是一种可以吸水溶胀的高分子微球，它不同于刚性颗粒，具有良好的"变形虫"特性，可以在多孔介质中发生运移->沉积或堵塞->携带或变形->再运移或重启动等一系列行为，从而实现动态调剖功能。本研究首先通过静态实验研究PPG吸水溶胀性能、悬浮体系流变性；然后，开展微观可视化实验研究PPG发生表面沉积、孔喉堵塞、沉积颗粒再运移、堵塞颗粒重启动控制条件和影响因素；在此基础上，通过岩心驱替实验和核磁共振成像技术研究多孔介质中颗粒运移、封堵机理以及颗粒滞留导致多孔介质孔隙度、渗透率变化规律，据此建立描述PPG渗滤机理的动力学模型；最后，建立PPG驱提高采收率数学模型系统并采用数值模拟方法优化设计矿场PPG驱实施方案。本研究一方面可填补国内外关于粘弹性可变形颗粒多孔介质中渗滤规律及数学模型方面研究的空白，另一方面可为迫切需要提高原油采收率的高含水油藏开展PPG驱提高理论依据和关键参数。

目前，我国大部分油田已经进入高含水期，注水长期冲刷作用导致油藏非均质性加剧，层间矛盾异常突出，后续水驱无效循环现象严重，生产井含水率急剧升高，必须采取有效的控水增油措施。近年来，预交联凝胶颗粒（PPG）深部调剖液流转向调驱技术在中东部大部分油田开展应用，并取得了较好的效果。预交联凝胶颗粒不同于刚性颗粒，它具有良好的"变形虫"特性，可以在多孔介质中发生运移->沉积或堵塞->携带或变形->再运移或重启动等一系列复杂行为，实现动态调剖的效果，但是其复杂的运移、调驱行为给模拟仿真、方案优化带来较大困难。本研究首先开展静态实验研究了PPG吸水溶胀、悬浮特性和力学流变性；然后，开展微观可视化实验研究了PPG孔喉堵塞、堵塞颗粒重启动、变形通过行为、颗粒破裂行为，得到了不同类型颗粒堵塞重启动和破裂条件，建立了预交联凝胶颗粒堵塞重启动临界条件模型；为了从理论角度实现可变形凝胶颗粒堵塞-重启动规律定量化，基于弹塑性力学理论，推导得到了孔喉单元中预交联凝胶颗粒运移机理模型，与实验结果具有较好的一致性。在此基础上，通过填砂驱替实验和颗粒特性在线分析技术揭示了颗粒沉积、堵塞时物性变化规律和PPG封堵强度影响因素，创建了考虑颗粒-孔喉匹配的凝胶颗粒渗滤动力学模型，据此提出了半随机半经验凝胶颗粒渗滤数学模型并开发了数值模拟软件，填补了可变形凝胶颗粒调驱数值模拟技术空白；最后，对数值模拟方法进行验证和应用，近一步揭示了凝胶颗粒在多孔介质中的运移特征及其影响因素和非均质油藏注采井间PPG调驱特征及其提高采收率效果和影响因素。本研究一方面填补了国内外关于可变形颗粒多孔介质中渗滤规律及数学模型方面研究的空白，另一方面为迫切需要提高原油采收率的高含水及稠油油藏开展PPG调驱技术提供了理论依据和关键参数。研究成果应用于胜利油田、河南油田高含水及稠油油藏非均相体系调驱方案优化、调驱效果预测，实现了降本增效和高含水期高效开发。