阜东斜坡齐古基准面旋回与储集层微观非均质性

Cyclic Sequences and Microscopic Heterogeneity of Reservoirs in the Qigu Formation of the Fudong Slope Area

为解决准噶尔盆地东部阜东斜坡区齐古组一段开发过程中由微观非均质性引起的油气采收率低下、剩余油难以开采等问题,探究不同级别基准面旋回内(水下)分流河道储集层微观非均质性的变化。运用基准面旋回沉积动力学的原理,在高分辨层序地层格架建立的基础上,主要应用区内钻井压汞数据对储集层颗粒、填隙物以及孔喉非均质性进行定量评价。研究认为,不同级别基准面旋回储集层微观非均质性表现具有差异性,短期基准面旋回中单一(水下)分流河道储集层微观非均质性表现为底强顶弱的特征,中期基准面旋回中叠置(水下)分流河道储集层微观非均质性表现为顶底强、中部弱的特征。基准面升降引起的可容纳空间与物源供给之间关系的改变是造成储集层微观非均质性差异的主要因素,原始颗粒非均质性决定储集层孔喉非均质性。

During the exploitation of Member 1 of the Qigu Formation in the Fudong slope area in the eastern part of the Jungar Basin,microscopic heterogeneity results in low oil and gas recovery and difficulties obtaining the residual oil.To solve these problems,this study investigated variations in the microscopic heterogeneity of(underwater)diversion channel reservoirs within cyclic sequences of different classes.Based on the sedimentary dynamics of the cyclic sequences and a stratigraphic framework with high-resolution sequences,quantitative evaluation of the heterogeneity of grains,filling materials,and reservoir pore and throat sizes was carried out mostly using mercury intrusion data of wells in the region.It is believed that the microscopic heterogeneity of the reservoirs with cyclic sequences of different classes differ.For short-term cycles,the microscopic heterogeneity of single(underwater)diversion channel reservoirs is strong at the bottom but weak at the top.For medium-term cycles,the microscopic heterogeneity of superimposed(underwater)diversion channel reservoirs is strong at the top but weak in the middle.Uplift or subsidence of cyclic sequences leads to changes in the relationships between available spaces and sediment sources.These are the main factors resulting in the differences microscopic heterogeneity of the reservoirs.And the heterogeneity of the original grains determines the heterogeneity of the reservoir pore and throat sizes.