砂质辫状河储集层隔夹层类型及其表征方法——以苏丹穆格莱特盆地Hegli油田为例

Classification and characterization of barrier-intercalation in sandy braided river reservoirs:Taking Hegli Oilfield of Muglad Basin in Sudan as an example

通过对岩心、测井和野外露头的综合分析，对苏丹穆格莱特盆地Hegli油田砂质辫状河储集层内隔夹层类型进行划分，并分析其成因。采用灰色理论进行单井隔夹层识别，在此基础上，结合辫状河现代沉积测量，建立不同类型隔夹层规模的定量计算关系式，对砂质辫状河隔夹层进行定量表征。研究区砂质辫状河储集层内发育3个层次隔夹层：单层间隔层、单砂体间夹层和心滩内夹层。隔层宽度为700～1500m，长度为1000-2000m，呈局部连片状分布；废弃河道夹层的宽度为170～350m；沟道夹层的宽度为60～100m，长度为900～1500m；心滩内夹层的宽度为100-400m，长度为300800m。以隔夹层定量规模为约束条件，采用相控与随机建模相结合的方法，建立了能够反映不同类型隔夹层空间分布特征的三维地质模型。

Based on comprehensive analysis of core data, well logs and outcrops, the barrier-intercalations in the sandy braided river of Hegli Oilfield, Muglad Basin, Sudan were classified and analyzed. The barrier-intercalations in single wells were identified using grey theory, which, in combination of the modem braided river deposit measurements, was used to establish the quantitative calculation formulas for different barrier-intercalations in different scale. Three hierarchies of the barrier-intercalations are developed in the sandy braided river reservoirs in the study area, including barriers between the two single layers, intercalations between the two single sandbodies and intercalations in a single braided river bar. The barriers are 700-1 500 m wide and 1 000-2 000 m long, in continuous sheet shape. The intercalations of abandoned channel are 170-350 m wide; the intercalations of chute are 60-100 m wide and 900-1 500 m long; and the intercalations of braided river bars are 100400 m wide and 300-800 m long. Based on the constraint of barrier- intercalation scale, 3-D geological models which accurately delineate different types of barrier-intercalations were built by facies-control and stochastic modeling.