基于相场方法的致密砂砾岩重力辅助气驱油微观机理  

Microscopic Mechanism of Gravity Assisted Gas Flooding in Glutenite Based on Phase Field Method

作　　者：杨柳[1] 蔡嘉伟 孔垂显[2] 刘岩[1] 姜晓宇 公飞 YANG Liu;CAI Jiawei;KONG Chuixian;LIU Yan;JIANG Xiaoyu;GONG Fei(State Key Laboratory for Tunnel Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;Research Institute of Exploration and Development,Xinjiang Oilfield Company,Karamay 834000,China)

机构地区：[1]中国矿业大学(北京)隧道工程灾变防控与智能建养全国重点实验室,北京100083 [2]中国石油新疆油田分公司勘探开发研究院,新疆克拉玛依834000

出　　处：《华南师范大学学报(自然科学版)》2025年第1期30-42,共13页Journal of South China Normal University(Natural Science Edition)

基　　金：国家自然科学基金面上项目(52374014);中央高校基本科研业务费专项资金项目(2024ZKPYSB03)。

摘　　要：重力辅助气驱(GAGD)是一种能够显著提升采收率的注气开采方式,但对于具有强非均质特征的砂砾岩储层微观重力辅助气驱机理尚不清楚。基于追踪两相界面动态变化相场方法建立砂砾岩2D渗流模型,开展了超临界CO_(2)-油两相流动数值模拟研究,对比分析了重力作用、非均质性、润湿性作用下的饱和度变化规律,建立了考虑非均质性的砂砾岩GAGD采收率预测经验公式。结果表明:重力的存在可以提高油气界面的稳定性,但在经过不同尺寸孔喉时会出现不稳定的压力波动,并在较小孔喉中出现前缘后移现象。砂砾岩非均质性会加剧GAGD指进现象,降低注入速度有利于增大波及范围。油湿性砾石的增加会有助于原油克服毛细管力参与流动,使得更多狭窄孔隙中的残余油得以排出。基于重力数、Bond数、黏度比、非均质系数与GAGD采收率相关关系,构建了适用于预测致密砂砾岩孔隙尺度GAGD采收率的新无量纲数N_(G),为更大尺度的致密砂砾岩油藏的开发及CO_(2)地质封存研究提供了理论指导和技术支撑。Gravity Assisted Gas Drive(GAGD)is a gas injection recovery method that can significantly improve oil recovery,but the micro gravity assisted gas drive mechanism for glutenite reservoirs with strong heterogeneity characteristics is still unclear.This article is based on the phase field method of tracking the dynamic changes of the two-phase interface,establishes a 2D seepage model of sand and gravel,conducts numerical simulation research on supercritical CO_(2)oil two-phase flow,compares and analyzes the saturation changes under gravity,heterogeneity,and wetting effects,and establishes an empirical formula for predicting the recovery rate of glutenite GAGD considering heterogeneity.The results indicate that the presence of gravity can improve the stability of the oil and gas interface,but unstable pressure fluctuations may occur when passing through different sizes of pore throats,and leading edge displacement may occur in smaller pore throats.The heterogeneity of glutenite can exacerbate the phenomenon of GAGD fingering,and reducing the injection rate is beneficial for increasing the coverage range.The increase of oil wet gravel will help crude oil overcome capillary forces and participate in flow,allowing more residual oil in narrow pores to be discharged.Based on the correlation between gravity number,Bond number,viscosity ratio,heterogeneity coefficient,and GAGD recovery rate,a new dimensionless number N_(G) suitable for predicting the pore scale GAGD recovery rate of glutenite reservoirs was constructed,providing theoretical guidance and technical support for the development of larger scale glutenite reservoirs and CO_(2)geological storage research.

关 键 词：砂砾岩 非均质性 GAGD CO_(2) 相场法 

分 类 号：O645.14[理学—物理化学]