气顶边水油藏中后期开发调整三维物理模拟研究

Three-Dimensional Physical Simulation Experiment on the Development Adjustment of Reservoirs with Gas Cap and Edge Water in Middle and Late Stage Reservoirs

  • 摘要: 气顶边水油藏天然能量开发中后期气窜、水锥加剧,地层压力加速下降,产量递减加快,生产形势急剧变差。为探索其后期开发调整方向,以海上气顶边水油藏为例,根据相似理论,设计了气顶边水油藏大型三维物理模型,研究了继续天然能量开发、转屏障注水和转老井侧钻等3种开发调整方式的生产特征及其挖潜效果。试验结果表明,天然能量开发以气顶能量为主,受高渗层气窜影响,水平井上部的中、低渗透率储层为后续挖潜的方向;屏障注水开发可以抑制高渗层气顶气窜,对低渗层增产和稳产效果明显;老井侧钻开发对中等渗透率储层占比大的油藏更为有效。现场优选了1口老井,实施了高部位侧钻,取得了良好的现场试验效果。研究结果可以为提升多种提高采收率方式的调整效果提供理论指导。

     

    Abstract: In the middle and late stages of natural energy development, reservoirs with gas cap and edge water are affected by gas channeling and intensified water coning, and the formation pressure drops rapidly. The production declines greatly, and production conditions deteriorate sharply. In order to explore the development adjustment direction of this type of reservoir in the middle and late stages, a large-scale three-dimensional physical model of the reservoir with a gas cap and edge water was designed based on the similarity theory by taking an offshore reservoir with large gas cap and middle edge water as the prototype. Three development adjustment methods and potential tapping effects were studied, namely, continued natural energy development, barrier water injection development, and sidetracking of old wells towards high locations. The experimental results show that the natural energy development of reservoirs with gas cap and edge water is dominated by gas cap energy and affected by gas channeling in the high-permeability layer. Oil enrichment occurs in the upper part of horizontal wells in reservoirs with medium and low permeability, which is the direction for subsequent potential investigation. The barrier water injection can effectively suppress the gas channeling of the gas cap in high-permeability layers and has a significant effect on increasing and stabilizing production in low-permeability layers. The sidetracking of old wells is more effective in improving oil recovery in reservoirs with a high proportion of medium-permeability layers. One old well underwent sidetracking towards higher locations, achieving good on-site application results. The research result can provide a reference for improving adjustment effect of multiple methods to enhance oil recovery.

     

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