吉木萨尔页岩油藏泡沫辅助注气吞吐试验研究

Experimental Study on Foam-Assisted Gas Huff-and-Puff in the Jimsar Shale Oil Reservoir

熊晓菲 盛家平

XIONG Xiaofei SHENG Jiaping

中国石油大学（北京）非常规油气科学技术研究院, 北京 102249 德克萨斯理工大学Bob L. Herd 石油工程系, 拉伯克 43111

Unconventional Oil and Gas Research Institute, China University of Petroleum (Beijing), Beijing, 102249, China Bob L. Herd Department of Petroleum Engineering, Texas Tech University, Lubbock, Texas, 43111, United States

吉木萨尔页岩油藏储层渗透率极低，改造后存在大量人工裂缝和天然裂缝，采用注氮气吞吐方式开采易发生气窜，造成氮气波及范围小，页岩油采收率低。为了增大氮气波及范围、提高吉木萨尔页岩油藏的采收率，在评价泡沫封堵页岩裂缝能力的基础上，利用吉木萨尔页岩岩样进行了泡沫辅助注气吞吐试验，分析了泡沫辅助注气吞吐提高采收率的机理，研究了吞吐轮次和裂缝页岩岩样基质渗透率对泡沫辅助注气吞吐采收率的影响。研究发现：泡沫可以封堵裂缝，有效抑制气窜；当泡沫体积分数为50%、注气速率为2 mL/min时，突破压力最大，封堵效果最好；与氮气吞吐相比，泡沫辅助注气吞吐之所以能够提高采收率，是因为其不仅能够采出大孔隙和中孔隙中的原油，还能够采出微孔隙中的原油；在最优泡沫注入参数下，裂缝岩样的采收率随吞吐轮次增多而升高，但升高幅度逐渐减小；对于基质渗透率较高的裂缝岩样，泡沫辅助氮气吞吐的采收率也较高。研究结果为吉木萨尔页岩油藏采用泡沫辅助注气吞吐开发提供了理论依据。

Due to the fact that the Jimsar shale oil reservoir has low permeability and massive artificial and natural fractures, and gas channeling easily happens when N2 huff-and-puff is adopted for development, there is a problem of limited sweep range of N2 and low shale oil recovery. For a greater sweep range of N2 and enhanced oil recovery (EOR) in the Jimsar shale oil reservoir, the Jimsar shale samples were used for foam-assisted gas huff-and-puff experiments based on the evaluation of plugging capacity of foam for shale fractures. Besides, the team analyzed the EOR mechanism of foam-assisted gas huff-and-puff, and studied the influence of the huff-and-puff rounds and matrix permeability of fractured shale samples on the oil recovery by foam-assisted gas huff-and-puff. The experimental results showed that foam could seal fractures and effectively inhibit gas channeling, and when the foam volume fraction was 50% and the gas injection rate was 2 mL/min, the breakthrough pressure could reach the maximum value, with the best effect of plugging. Compared with N2 huff-and-puff, the foam-assisted gas huff-and-puff can improve the recovery of crude oil not only from the large and medium pores, but also from micropores. With optimal foam injection parameters, the recovery of fractured samples increase with the rounds of huff-and-puff, but the increasing extent will gradually fall. For fractured samples with high matrix permeability, the recovery of foam-assisted N2 huff-and-puff are also high. The results can provide the guidance for the development of the Jimsar shale oil by foam-assisted gas huff-and-puff.

国家自然科学基金项目“页岩油藏空气氧化热破裂机制研究”（编号：51974334）、中国石油战略合作科技专项“页岩油储层改造与提采一体化机理与技术研究”（编号：ZLZX2020）和中国石油大学（北京）科研基金（编号：2462018YJRC001）资助

https://doi.org/10.11911/syztjs.2022017