两亲磷酸锆纳米材料驱油机理及改善低渗透油田驱油效果研究

To resolve the problems of high water pressure and low water flooding recovery in low permeability reservoir due to the low permeability and high capillary pressure, the amphiphilic zirconium phosphate nano-displacing agent will be studied in this project. At first, the method of controlling the scale of single sheet zirconium phosphate nanomaterials will be studied, and its periphery will be modified, then amphiphilic nano-displacing agent will be prepared, finally the ideas of molecular design of nano-displacing agent corresponding to chemical flooding of low permeability reservoir will be obtained. The physical-chemical performance of zirconium phosphate nano-displacing agent will be carried out. The experimental techniques and means of preparation of nano oil-displacing agent will be improved, and the modification, characterization and evaluation methods of nano-displacing agent will be established. The oil displacement performance of zirconium phosphate nanomaterials will be studied. Simulation by adding nano-displacing agent in low permeability reservoir water injection process, the adsorption of zirconium phosphate nanomaterials on surface of rock in low permeability reservoir and the interaction with the formation fluids will be performed. The fluid flow of zirconium phosphate nanomaterial in the core of low permeability reservoir will be studied. By microfluidic chip, the mechanism of microscopic oil displacement of amphiphilic zirconium phosphate nanomaterial will be studied to solve the problem of low injection and improve microscopic oil displacement efficiency in low permeability reservoir. The results will promote the enrichment and the development of nano-displacing agent theory and will offer the theory and technology supporting for the synthesis and application of nano-displacing agent.

针对低渗透油藏由于渗透率低、毛管压力高导致注水压力高、水驱采收率很低的问题，本项目拟以两亲磷酸锆纳米驱油剂为研究对象。研究单层片状磷酸锆纳米材料的尺度的控制方法，并对其外围进行一定的修饰，制备出两亲纳米驱油剂，获得与低渗透油藏化学驱相适应的纳米驱油剂分子设计思路；开展磷酸锆纳米驱油剂的理化性能研究，发展纳米驱油剂研制的实验技术和手段，建立驱油纳米材料的表面修饰方法和表征评价方法；对磷酸锆纳米驱油剂的驱油性能进行研究，模拟在低渗透油藏的注水开采过程中加入纳米驱油剂，研究磷酸锆纳米材料在低渗透油藏岩石表面的吸附作用以及与地层流体的相互作用；探索磷酸锆纳米材料在低渗透油藏岩石中流动的渗流规律，利用微流芯片模型研究两亲磷酸锆纳米驱油剂在低渗透油藏中的微观驱替机理，解决低渗透的注入性问题和提高低渗透微观驱油效率。从而促进纳米驱油剂理论的丰富和发展，为纳米驱油剂合成及应用提供理论和技术指导。

本项目基于α-磷酸锆纳米材料，制备了三种改性α-磷酸锆用于低渗透油藏注水开发过程中的降压、增注，并对合成过程、理化性能以及降压增注效果的影响因素进行了研究。.首先通过回流法、草酸法、最小溶剂法制备了α-磷酸锆(α-ZrP)，并通过一系列的表征手段对α-ZrP进行分析测试，证实成功合成了片层状α-ZrP，单分散的α-ZrP颗粒粒径为70 nm左右，属于纳米级别范畴。然后选用十八烷基异氰酸酯对α-ZrP进行表面疏水改性。通过室内岩心流动实验研究了疏水改性α-ZrP用于低渗透油藏注水开发的降压增注的效果。结果表明疏水改性的α-ZrP能够起到降低注水压力的效果，最佳质量浓度为50 mg/L，注入量为1～2 PV，吸附时间为24h。在最佳的实验参数条件下，后续水驱压力降低47.23%，水测渗透率为注入纳米材料之前的1.89倍。.通过四丁基氢氧化铵（TBAOH）对磷酸锆纳米颗粒进行剥层，然后加入盐酸，使剥层后的磷酸锆纳米薄片恢复表面活性。使用十八烷基三氯硅烷对磷酸锆纳米薄片进行疏水改性，将改性后的疏水磷酸锆纳米薄片（ZrP-OTS）用于提高石油采收率实验。注入ZrP-OTS溶液后，注入压力明显降低。注入浓度为50mg/L时，驱油压力降至1.56MPa，注入浓度为500mg/L时，驱油压力降至1.41MPa。这表明没有发生堵塞现象。结果表明，ZrP-OTS纳米片具有良好的注入性能。.在十八烷基异氰酸酯疏水改性α-ZrP的基础上，将亲水性四丁基氢氧化铵基团插入到疏水α-ZrP层间，使其发生剥层反应，制得双亲性的α-ZrP。利用动态光散射与环境扫描电镜测试研究了纳米颗粒的分散情况，双亲α-ZrP在低浓度时能够均匀分散，平均粒径均小于100 nm，但随浓度的增加，纳米颗粒出现不同程度的团聚现象。双亲α-ZrP能够稳定分散在水中，具有一定的表面活性。