尕斯油田N2^1油藏南区储层非均质性研究

Study on the heterogeneity of the south area of N21 reservoir in Gasi Oilfield

针对尕斯油田N21油藏南区储层非均质性严重的特点,从层间、层内及平面非均质性3个方面进行了系统研究.层间非均质性相对较弱,层间隔层分布较为稳定,各油组砂层发育情况差别不大.层内非均质性较强,并且与沉积微相密切相关.单砂层垂向上渗透率的变化以正韵律和复合韵律模式为主,局部发育反韵律模式.按照非均质性的强弱,沉积微相依次为:分流河道、河口砂坝、分流间湾、远砂坝.统计了平面上不同微相砂体的几何形状,并且采用流动单元法综合评价储层的平面展布特征.

The intraformational, interlayer and plane heterogeneities of the south area of N 2 1 reservoir in Gasi Oilfield are systematically studied. It is shown that the interlayer heterogeneity is weaker than intraformational and plane heterogeneities, and the distribution of interbeds is stable and there is little difference in the development of sandbodies. The intraformational heterogeneity is serious, and it is relative to the depositional microfacies. The positive rhythm and compound rhythm are main heterogeneous models of single sandbody in vertical direction. The sequence of heterogeneity of various microfacies from stronger to weaker is: distributary channel, mouth bar, interfluve and distant bar microfacies. The geometric characters of various microfacies are discussed and the reservoir plane distribution characters are evaluated by the method of flow units.