准噶尔盆地吉木萨尔页岩油不同温压CO吞吐下可动性实验研究

Experimental study on the mobility of Junggar Basin's Jimsar shale oil by CO huff and puff under different temperatures and pressures

王子强 葛洪魁 郭慧英 周浩 张远凯

WANG Ziqiang GE Hongkui GUO Huiying ZHOU Hao ZHANG Yuankai

中国石油大学(北京)，北京 102249 中国石油 新疆油田分公司 实验检测研究院，新疆 克拉玛依 834000 新疆页岩油勘探开发实验室，新疆 克拉玛依 834000

China University of Petroleum (Beijing), Beijing 102249, China Research Institute of Experiment and Detection, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China Xinjiang Laboratory of Shale Oil Exploration and Development, Karamay, Xinjiang 834000, China

准噶尔盆地吉木萨尔页岩油储集层主要发育微纳尺度孔喉裂隙系统，同时油质黏稠，动用难度大，注CO2吞吐是提高采收率的重要技术。为了认清吉木萨尔页岩油储层注CO2吞吐下的可动性规律，对该区芦草沟组45块岩心进行了研究。储层岩性为云屑砂岩、砂屑云岩和岩屑砂岩；储层覆压孔隙度介于2.0%~22.7%之间，平均为11%，覆压渗透率平均为0.01×10-3 μm2，小于0.1×10-3 μm2的样品占比达90%以上。根据岩心物性分类，选取20块岩样开展核磁实验，对页岩油低场核磁共振实验测量的6个关建参数进行了优化；通过将页岩油压汞实验数据和低场核磁共振实验数据对比，在对数坐标下建立了页岩岩心的T2值与孔隙半径之间的线性关系，通过T2谱定量获得了页岩的孔隙半径分布。在此基础上，在不同温压条件下开展9种CO2吞吐实验，结合采收率、动用程度等指标分析得知，半径小于300 nm的小孔隙中页岩油难以动用，300~1 000 nm的中孔隙和大于1 000 nm的大孔隙中页岩油动用程度相对较高，且随着温度和压力的提高而增大。

Micro- and nano-scale pore-throat fissure systems were mainly developed in the Jimsar shale oil reservoir of the Junggar Basin with the oil of viscous and difficult to be produced.CO2 huff-and-puff is an important technology to enhance the oil recovery. To understand the mobility law of Jimsar shale oil reservoir under CO2 huff and puff, 45 cores of the Lucaogou Formation in this area were studied in this study.The cores was classified into dolomitic sandstone, doloarenite and lithic sandstone. The overburden porosity of the reservoir is 2.0%-22.7%, and the average value is only 11.0%. The average overburden permeability is 0.01×10-3 μm2, and more than 90% of the samples have permeability lower than 0.1×10-3 μm2. According to physical property classification, 20 rock samples were further selected and 6 key parameters for low-field NMR measurement were optimized. By comparing the experimental data of shale oil mercury injection with those of low-field NMR, the linear relationship between T2 value and pore radius of shale core was established in logarithmic coordinates.The pore radius distribution of shale was obtained quantitatively according to the T2 spectrum. 9 kinds of CO2 huff and puff experiments were carried out under different temperatures and pressures. The analyses of recovery rate, utilization degree and other indicators show that shale oil in small pores(r < 300 nm) is difficult to produce, and the utilization degree of shale oil in medium pores (300 nm < r < 1 000 nm) and large pores(r>1 000 nm) is relatively higher, and increases with the increase of temperature and pressure.

新疆维吾尔自治区创新环境(人才、基地)建设专项 人才专项计划—天山青年计划2019Q110

https://doi.org/10.11781/sysydz2022061092