宝浪油田三工河组基准面旋回与储层宏观非均质性

Base level cycle and reservoir macroscopic heterogeneity of sangonghe formation in Baolang oilfield

新疆焉耆盆地宝浪油田侏罗系三工河组为浅水缓坡型辫状河三角洲沉积,储层非均质性强,有明显的旋回性和层次性。运用基准面旋回原理将含油层段划分为四个退积式叠置的短期旋回。分析结果认为,基准面旋回及其伴随的可容空间变化是引起储层宏观非均质特征的决定因素,受基准面旋回控制,河道类型、储层厚度、砂体规模、夹层分布、砂体拼接方式等层间非均质特征呈规律变化;随着可容空间的增加,河道特征逐渐由辫状河道向曲流河道转变,造成储层物性、层间非均质程度等的相应变化。

Sangonghe formation of Jurassic in Baolang oilfield of Yanqi basin is a braided river delta depositional system with shallow gentle slope,and it is characterized by strong reservoir heterogeneity,obvious cyclicity and well -bedded feature.By applying the base-level cycle theo- ry,oil-bearing intervals are classified as four short- term cycles with retrograding superposition feature.The research finds out that the base-level cycle and the corre- spondent containable space variation are key factors to af- fect the macroscopic heterogeneity.Controlled by base- level cycle,the characteristics of interlayer heterogeneity such as the channel pattern,reservoir thickness,sand- body scale,interbed distribution and connection manner of sandbody,are all changed regularly.With the increase of the containable space,channel character is converted from braided river course to meandering river course.As a re- sult,the reservoir properties and the degree of interlayer heterogeneity are also changed.