| 凝析气藏循环注气三元开发机理与提高凝析油采收率新技术 |
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| 引用本文： | 江同文,孙龙德,谢伟,肖香姣,王勇,夏静. 凝析气藏循环注气三元开发机理与提高凝析油采收率新技术[J]. 石油学报, 2021, 42(12): 1654-1664. DOI: 10.7623/syxb202112010 |
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| 作者姓名： | 江同文 孙龙德 谢伟 肖香姣 王勇 夏静 |
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| 作者单位： | 1. 中国石油勘探与生产公司 北京 100007;2. 中国石油天然气股份有限公司 北京 100007;3. 中国石油塔里木油田公司 新疆库尔勒 841000;4. 中国石油勘探开发研究院 北京 100083 |
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| 基金项目： | 中国石油天然气股份有限公司科技重大专项（2018E-1804）资助。 |
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| 摘 要： | 塔里木盆地牙哈凝析气藏2000年开始采用循环注气开发技术提高凝析油采收率。但随着注气时间的延长，气油比受气窜的影响呈快速上升趋势。气藏历年的动态监测显示，注入的干气与地下凝析气并不能完全混相。室内多相流体PVT实验证实，干气与凝析气存在明显的界面，明确了驱替作用下干气和凝析气的非混相特征。基于瞬时平衡假设的相态和渗流理论无法准确描述其运动规律。熵增数学模型确定了不同储层物性特征对不同性质流体达到相平衡的影响；微元数学模型确定了重力作用对干气和凝析气渗流规律的显著作用；二维机理模型明确了3种作用力在注气井和采气井之间的作用范围。现场试验数据反映了气藏尺度的干气—凝析气运动规律，室内实验数据与数学模型分析反映了孔隙尺度和岩心尺度的开发机理，从而揭示了凝析气藏循环注气"扩散—驱替—重力分异"三元开发机理，明确了重力分异作用是影响循环注气效果的主要因素。基于循环注气三元开发机理，建立考虑扩散、重力分异与储层结构等多因素耦合的非平衡渗流数学模型，提高了循环注气开发过程中的流体分布预测精度，并建立了凝析气藏注气重力辅助立体驱替提高采收率新方法。该技术在塔里木盆地牙哈凝析气田得到了成功应用。
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| 关 键 词： | 深层 凝析气藏 重力分异 凝析油 提高采收率 牙哈 塔里木盆地 |
| 收稿时间： | 2021-04-30 |
| 修稿时间： | 2021-09-08 |
Three-element development mechanism of cyclic gas injection in condensate gas reservoirs and a new technique of enhancing condensate oil recovery |
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| Jiang Tongwen,Sun Longde,Xie Wei,Xiao Xiangjiao,Wang Yong,Xia Jing. Three-element development mechanism of cyclic gas injection in condensate gas reservoirs and a new technique of enhancing condensate oil recovery[J]. Acta Petrolei Sinica, 2021, 42(12): 1654-1664. DOI: 10.7623/syxb202112010 |
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| Authors: | Jiang Tongwen Sun Longde Xie Wei Xiao Xiangjiao Wang Yong Xia Jing |
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| Affiliation: | 1. PetroChina Exploration and Production Company, Beijing 100007, China;2. PetroChina Company Limited, Beijing 100007, China;3. PetroChina Tarim Oilfield Company, Xinjiang Korla 841000, China;4. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China |
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| Abstract: | Since 2000, cyclic gas injection development technique has been adopted to enhance condensate oil recovery in the Yaha condensate gas reservoir of Tarim Basin. However, as the gas injection time extends, gas-condesate ratio maintains an upward trend due to the impact of gas channeling. According to the dynamic monitoring of gas reservoir over the years, it is found that the injected dry gas and underground condensate gas cannot be completely miscible. The indoor multi-phase fluid PVT experiment has verified that there is an obvious interface between dry gas and condensate gas, and clarified the immiscible characteristics of dry gas and condensate gas during displacement, but the laws of gas flow cannot be accurately described by the theories of phase state and seepage based on transient equilibrium hypothesis. Therefore, the mathematical model of entropy increase is adopted to determine the impact of different physical reservoir properties on the phase equilibrium of fluids with different properties; the micro- element mathematical model is used to determine the significant impact of gravity action on the flow law of dry gas and condensate gas; the 2D mechanism model is employed to determine the action range of three acting forces between gas injection well and gas recovery well. The field test data reflect the laws of dry gas and condensate gas flow at the reservoir scale, and indoor experimental data and mathematical model analysis indicate the development mechanism at the pore and core scales, thus revealing the three-element development mechanism of "diffusion, displacement and gravitational differentiation" for cyclic injection in condensate gas reservoir, and clarifying that gravitational differentiation is the primary factor affecting the effect of cyclic gas injection. Based on the three-element development mechanismof cyclic gas injection, a mathematical model of non-equilibrium flow considering the coupling of multiple factors such as diffusion, gravitational differentiation and reservoir structure has been established, which improves the prediction accuracy of fluid distribution in the process of cyclic gas injection development. Then, a new technique of enhancing recovery by 3D displacement assisted by the gas injection gravity in condensate gas reservoir has been also established. Actually, this technique has also been successfully applied in Yaha condensate gas field, Tarim Basin. |
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| Keywords: | deep layer condensate gas reservoir gravitational differentiation condensate oil enhanced recovery (EOR) Yaha Tarim Basin |
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