张静, 郑彬, 李红英, 刘玉娟, 闫志明. 厚油层注采井间注入水纵向波及程度定量研究[J]. 石油钻探技术, 2022, 50(2): 118-125. DOI: 10.11911/syztjs.2021124
引用本文: 张静, 郑彬, 李红英, 刘玉娟, 闫志明. 厚油层注采井间注入水纵向波及程度定量研究[J]. 石油钻探技术, 2022, 50(2): 118-125. DOI: 10.11911/syztjs.2021124
ZHANG Jing, ZHENG Bin, LI Hongying, LIU Yujuan, YAN Zhiming. Quantitative Study of Vertical Sweep Degree Between Injection andProduction Wells in Thick Oil Layers[J]. Petroleum Drilling Techniques, 2022, 50(2): 118-125. DOI: 10.11911/syztjs.2021124
Citation: ZHANG Jing, ZHENG Bin, LI Hongying, LIU Yujuan, YAN Zhiming. Quantitative Study of Vertical Sweep Degree Between Injection andProduction Wells in Thick Oil Layers[J]. Petroleum Drilling Techniques, 2022, 50(2): 118-125. DOI: 10.11911/syztjs.2021124

厚油层注采井间注入水纵向波及程度定量研究

Quantitative Study of Vertical Sweep Degree Between Injection andProduction Wells in Thick Oil Layers

  • 摘要: 注水开发油藏经过注入水的长期冲刷,在进入高含水、高采出程度阶段后,剩余油分布零散,纵向水淹异常复杂。这种问题在厚油层油藏尤为突出。为了定量研究厚油层注采井间注入水纵向波及程度,以渗流理论为基础,考虑油水两相流动、有效渗透率和密度随饱和度的变化,建立了水滴质点在平面和纵向的运动方程,形成了完整描述厚油层注采井间注入水纵向波及的数学模型。以L油田为例进行了计算分析,结果表明:注采量越大,原油黏度越大,注采井距越小,渗透率越小,含水率越低,渗透率变化程度越高,注入水纵向波及程度越高;油层厚度仅对水滴质点运移路径产生影响,不会影响波及程度;厚油层注采量界限为180 m3/d,原油黏度界限为200 mPa·s,定油层厚度时注采强度界限为3.00 m3/(d·m),定注采强度时油层厚度界限为30 m。研究结果表明,厚油层注水开发时,注入水受重力作用向下渗流,纵向波及程度随之降低,影响采收率。定量研究厚油层注采井间注入水的纵向波及程度,可以为认识剩余油分布和提高纵向波及程度提供理论指导。

     

    Abstract: After a long-term scouring by injected water, the remaining oil distribution is scattered and vertical water flooding is extremely complex in reservoirs developed by water flooding, especially in the reservoirs with thick oil layers. For quantitative study of vertical sweep degree between injection and production wells in thick oil layers, motion equations of water droplets in planar and vertical directions were built based on seepage theory and giving due consideration to the oil-water two-phase flow, effective permeability, and density variation with saturation. A complete set of mathematical models describing the vertical sweep between injection and production wells in thick oil layers was developed. Taking L Oilfield as an example, according to the analysis results, the following findings could be found: a greater injection-production rate, a greater viscosity of crude oil, tighter injection-production well spacing, a lower permeability, a lower water cut, and a higher permeability change degree meant a higher vertical sweep degree of the injected water. Most affected by the thickness of the oil layers was the migration path of the water droplets instead of the sweep degree. Moreover, the injection-production rate limit in thick oil layers was 180 m3/d, and the viscosity limit of crude oil was 200 mPa·s.The limit of injection-production intensity was 3.00 m3/(d·m) when the oil layer thickness was fixed, and the limit of oil layer thickness was 30 m when the injection-production intensity was fixed. The results show that for the thick oil layers developed by water flooding, the injected water infiltrates downward due to gravity, which reduces the vertical sweep degree and recovery. In a nutshell, quantitatively evaluating the vertical sweep degree between injection and production wells in thick oil layers can provide theoretical guidance for understanding the remaining oil distribution and improving the vertical sweep degree.

     

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