中高渗油藏水驱后富气混相驱小井距先导试验

Small-space Well Pilot Test for Enriched-gas Flooding in the Medium-high Permeability Reservoir After Water Flooding

世界范围内大多数注气混相驱项目具有井距大、项目实施周期长的特点。为尽早获得该类油藏富气混相驱替规律,提供推广依据,用小井距井组开展先导试验。结合Eclipse组分模拟器,用灰色关联多目标决策模型对井距方案进行了优化,并对日注量、段塞大小、注入方式以及注入层位等注入参数进行了敏感性分析,给出了推荐方案。矿场实施表明,富气驱替效果明显,小井距注采井组可加快试验周期,能充分揭示矿场驱替规律。但油藏渗透性好、剩余油分散,气窜等问题严重,建议采取有利于扩大富气波及体积的非连续性注气技术加以预防和控制。

Most gas flooding projects in the world are characteristics of big-space wells and long-term cycle, The pilot tests have been operated with small-space wells to get a general conclusion of enriched-gas flooding reservoir and providing generalization proof for popularizing. Based on the software of Eclipse＇s compositional simulation model, the well space was optimized by Multi-Criteria decision grey relation model and the injection parameters was analyzed, such as daily injection rate, slug size, injection method, injection-production interval and so on. The pilot tests results showed that enriched-gas flooding operation effect is obvious and the small-space well can accelerate the project cycle, and reveal the principals of enriched-gas flooding in a sufficient way. When it comes to reservoir with medium permeability, dispersal remain oil distribute and small well spacing, it is difficult to control gas breakthrough and pressure pulse. In such cases, we suggest discontinuity injection be applied for increasing swept volume in the field.