基于三角洲复合砂体构型的流动单元划分及剩余油分布模式

以涠西南凹陷W油田为例，为加深对储层非均质性的认识，开展了基于复合砂体构型的流动单元研究，总结了剩余油分布模式。基于油田稀井网资料，通过井震结合、动静结合，并参考类似储层地质知识库特点，开展了复合砂体构型解剖；利用筛选的孔隙度、渗透率和流动带指数（FZI）把研究区储层分为四类流动单元，并在复合砂体内部刻画了流动单元的分布，总结了其分布规律。研究认为:研究区三角洲前缘复合砂体内部结构复杂，复合砂体构型、流动单元、断层等地质因素对油田水淹特征及剩余油分布影响较大，并深入分析了调整井水淹层的水淹特征，总结出了受流动单元主控的“差异驱替控油模式”、受流动单元与隔夹层共控的“复合遮挡控油模式”和受流动单元与断层共控的“断储联合控油模式”3种主要剩余油分布模式。研究成果为油田挖潜提供了重要参考。

Flow-unit Classification Based on Compound Sand-Body Architecture of Delta and Distribution Pattern of Remaining Oil

Flow-unit classification in an example of compound sand-body architecture was carried out in a delta in the W oilfield， Weixinan Sag， Beibuwan Basin to further describe reservoir heterogeneity and also to summarize the remaining oil distribution pattern. Combining well logging， seismic， production dynamics and a geological knowledge database with similar sedimentary characteristics， the compound sand-body architecture was analyzed using sparse well network data in W oilfield. The porosity， permeability and flow-zone index were adopted to divide the reservoir into four types of flow units. Their distribution was well described within compound sand-body architecture constraints， and their distribution pattern was summarized. The study revealed a complex internal architecture for the delta front compound sand-body for W oilfield in the third member of the Weizhou Formation. Geological factors （compound sand-body architecture， flow units and faults） had significant influence on the flooding characteristics and the distribution of remaining oil. In-depth analysis of the waterlogged properties of the water-flooded zone of the adjustment wells revealed three main distribution patterns of the remaining oil: （i） differential displacement patterns due mainly to flow units only； （ii） complex blocking patterns controlled by flow units combined with mud interlayers； and （iii） fault?flow unit patterns controlled by flow units and faults. These results provide an important reference for tapping the full potential of the oilfield.