水平井配汽三维物理模拟实验

水平井注汽物理模拟实验是模拟油田实际注汽过程的有效手段,国内外学者针对水平井配汽效果开展了许多实验研究,但现阶段缺少水平井配汽结构影响配汽效果的相关研究。通过构建三维实验模型,设计注汽井配汽结构,开展了不同配汽结构下的三维注汽实验。实验结果表明,不同配汽结构对配汽效果影响较大,其中割缝管柱实验配汽效果最差,注汽井附近储层发生汽窜的时间较早;均匀开孔管柱和趾端附近射孔加密管柱实验储层发生汽窜的时间较晚,储层动用范围更广;进行趾端附近配汽实验时,随着配汽量增大,会造成蒸汽回流;当配汽孔沿水平井方向均匀分布时,虽然在注汽前期可以较为均匀地分配蒸汽,但随着注汽量增大,蒸汽会优先从水平井跟端分配,跟端配汽量始终最多;当调整注汽井前、后配汽孔分布密度时,可有效改变水平井前、后的配汽量,并优化配汽效果。模拟实验可以为油田注汽井配汽结构优化设计提供理论支撑,以达到有效提高配汽效果和均匀动用储层的目的。

Three-dimensional physical model experiment of steam distribution in horizontal wells

The physical model experiment of steam distribution in horizontal wells is an effective means to simulate the actual steam injection process in the oilfield. Domestic and foreign scholars have carried out different experimental studies on the steam distribution effect of horizontal wells, but at this stage, few researches focus on the influence of the steam distribution structure of horizontal wells on the steam distribution effect. By constructing a three-dimensional experimental model, and designing the steam distribution structure of steam injection wells, the authors carried out three-dimensional steam injection experiments under different steam distribution structures. The experimental results show that different steam distribution structures have a great impact on the steam distribution effect. The steam distribution effect is the worst in the experiment using slotted tubing string, steam channeling occurred earlier in reservoirs near the steam injection well; and occurred later in experiments using the uniformly-perforated tubing strings, and the densely-perforated tubing strings near the toe end, the production range of reservoirs is wider. When performing the steam distribution experiment near the toe end, as the steam distribution volume increases, the steam will flow back. When the steam distribution hole is evenly distributed along the direction of horizontal well, although the steam can be distributed more evenly in the early stage of steam injection, with the increasing of steam injection volume, the steam will be preferentially distributed from the heel end of horizontal well, and the steam distribution volume at the heel end is always the largest. The steam distribution volume in front of and behind the horizontal well can be effectively changed and the steam distribution effect will be optimized by adjusting the distribution density of steam distribution holes in front of and behind the steam injection well. It will provide theoretical support for the optimization design of steam distribution structure of steam injection wells in oilfields, so as to achieve the goal of effectively improving the steam distribution effect and uniform reservoir production.