黏土矿物对三元复合体系驱油效果的影响

Effect of Clay Mineral on Oil Displacement Efficiency of Alkali-surfactant-polymer System

施雷庭 李尧 叶仲斌 张言亮 张晓芹 石京平

SHI Leiting LI Yao YE Zhongbin ZHANG Yanliang ZHANG Xiaoqin SHI Jingping

为研究黏土矿物含量对大庆三类油层油藏三元复合驱驱油效果的影响，采用孔隙度和渗透率相近、但黏土 矿物含量不同的天然岩心开展驱油实验，并对实验前后的岩心进行核磁共振、X射线衍射分析及产出液乳化粒 径测试。结果表明，随着黏土矿物含量逐渐增大，三元复合驱提高原油采收率幅度先增加后降低。在黏土矿物 含量为9.5%时，三元复合驱采收率增幅（15.7%）最大。产出液中存在明显的乳化现象，黏土矿物含量由2.3%增 至9.6%时，乳状液由油包水型转变为水包油型，粒径不断变小。黏土矿物含量越高，矿物中的高岭石越容易发生 运移，使岩心孔喉变大并形成特定渗流通道，导致水驱效果变差，总采收率降低。黏土矿物的含量对大庆油田三 元复合驱的驱油效果存在较大影响，主要通过改变产出液乳状液类型、粒径和矿物发生运移后岩心孔喉大小影 响水驱及三元复合驱原油采出程度，进而改变最终采收率。

In order to study the influence of clay mineral content on the oil displacement efficiency of ternary composite flooding in three types of reservoirs in Daqing，using natural cores with similar porosity and permeability but different content of clay，oil displacement experiment was developed. The core before and after the experiment was analyzed by X-ray diffraction and nuclear magnetic resonance. The emulsified particle size of the produced fluid was also tested. The results showed that with the increase of clay mineral content，the range of oil recovery improved by alkali-surfactant-polymer（ASP）flooding increased first and then decreased. When the clay mineral content was 9.5%，the recovery of ASP flooding had the largest growth rate（15.7%）. There was obvious emulsification in the produced solution. When the clay mineral content increased from 2.3% to 9.6%，the emulsion changed from water-in-oil type to oil-in-water type. The particle size kept decreasing. The higher the clay mineral content，the easier migration of kaolinite in mineral was. It made the pore throat of the core larger. A specific seepage channel formed，leading to the poor water flooding effect and the reduction of ultimate recovery factor. The content of clay mineral had a great influence on the oil displacement efficiency of ASP flooding in Daqing oilfield. The oil recovery degree of water flooding and ASP flooding was affected mainly through changing the type of emulsion in produced liquid，particle size and the size of core pore throat after mineral migration. As a result，the final recovery factor was changed.

10.19346/j.cnki.1000-4092.2022.04.020