基于核磁共振技术研究表面活性剂提高吉木萨尔页 岩油渗吸效率*

Surfactant-enhanced Imbibition Efficiency in Jimsar Shale Oil Reservoir Based on NMRI Experiment

罗 强 石国新 聂小斌 唐 可 刘红现 李 明 李织宏 刘佳幸

LUO Qiang SHI Guoxin NIE Xiaobin TANG Ke LIU Hongxian LI Ming LI Zhihong LIU Jiaxing

为评估表面活性剂提高吉木萨尔凹陷芦草沟组页岩油渗吸效率潜力，研究其微观动用特征，本文采用低场 核磁共振成像系统研究了阴离子表面活性剂Surf-L在不同润湿性天然页岩油岩心渗吸效率和不同孔隙中含油 饱和度随时间的变化。核磁共振T2谱结果表明，质量分数为0.1%的阴离子表面活性剂Surf-L能有效提高吉木萨 尔页岩油藏岩心的渗吸效率。对于中性润湿性的匀质粉砂岩岩心S52，胍胶溶液和含Surf-L的胍胶溶液主要动 用大、中孔隙内原油。其中，渗吸效率贡献率最大的是大孔隙，其次是中孔隙。含Surf-L的胍胶溶液可以有效动 用中、小孔隙内原油，最终渗吸效率比胍胶溶液提高6.95百分点。对于亲油的砂质云岩岩心S39，胍胶溶液主要 动用大孔隙内原油，而含Surf-L的胍胶溶液能有效动用中、小孔隙内原油，最终渗吸效率比胍胶溶液提高18.89 百分点。表面活性剂渗吸过程可分为前期、中期和后期3个阶段：渗吸初期，中孔隙的贡献率最大为61.7%；渗吸 中后期，大孔隙的贡献率逐渐上升。同时，胍胶溶液渗吸平衡时间约为51 h，而含表面活性剂的胍胶溶液渗吸平 衡时间约为100 h。无论是中性润湿岩心还是亲油性岩心，相对于胍胶溶液，含表面活性剂的胍胶溶液通过有效 动用中、小孔隙内原油，可进一步提高页岩油藏渗吸效率。

In order to estimate the potential of surfactant enhancing the imbibition efficiency of shale oil and to investigate its micro-mobilization characteristics in Lucaogou formation of Jimsar Sag，the imbibition efficiency of the anionic surfactant Surf-L in natural shale cores with different wettability and the change of oil saturation in different pores with time was studied by using the low-field nuclear magnetic resonance imaging（LF-NMRI）technique. The results from NMRI T2 spectrum showed that the 0.1% surfactant Surf-L could effectively improve the core’s imbibition efficiency. For neutral wetting and homogeneity sand core S52， guar gum solution and the Surf-L guar gum solution mainly mobilized the oil in large and middle pores. Among them，the contribution rate of large pores to imbibition efficiency was the highest. The 0.1% Surf-L guar gum solution could effectively mobilize crude oil in middle and small pores，and the final imbibition of 0.1% Surf-L guar gum solution was 6.95% higher than that of guar gum solution. For oil-wetting sandy dolomite core S39，guar gum solution mainly mobilized the crude oil in large pores， while the Surf-L guar gum solution enabled to mobilize the oil in middle and small pores. The imbibition efficiency of Surf-L guar gum solution was 18.89% higher than that of guar gum solution. The imbibition process of Surf-L guar gum solution can be divided into three stages，namely early，middle and late stage. In the early stage of imbibition，the maximum contribution rate supported by middle pores was 61.7% . In the middle and late stage of imbibition，the contribution of large pores gradually increased. The imbibition equilibrium time of guar gum solution was about 51 hours while the imbibition equilibrium time of Surf-L guar gum solution was about 100 hours. Regardless of neutral wetting or oil-wetting cores，surfactant can enhance imbibition oil recovery of shale reservoir by mobilizing the oil in the middle and small pores effectively compared with the guar gum solution.

10.19346/j.cnki.1000-4092.2021.04.019