密井网约束的复杂断块油田地质建模方法——以扶余油田中区泉四段为例

我国大庆、大港、辽河、胜利、吉林等油田部分老油区井网密度已达到密井网级别,这些位于东部裂谷带拉张型盆地的油气田具有油层多、断层多、断块小的特点,建立精细地质模型难度较大。针对这类油气田,以扶余油田中区泉四段储集层为例,提出了一套地质建模方法:1以密井网资料为基础,在三维地震解释数据约束下,进行小层划分与对比、低级序断层识别及微构造研究;2分级次建立断层模型,采用"骨架网格+关键层面+小层层面"三步建立层面模型,该构造模型较好地反映了复杂断块内部地层与断层的配置关系;3采用相控下的多次迭代随机模拟方法提高砂体模型精度,采取了"砂控+相控"随机模拟建模方法建立储层参数模型,运用砂模型体控制物性边界,分不同微相进行变差函数分析;4最后,通过概率分布一致性检验及交叉验证证明该方法是可靠的。

Geological modeling method of complex fault block fields based on dense well pattern condition: an example from the Quan4 Member in central Fuyu oilfied

The well density within several old sections of Daqing, Dagang, Liaohe, Shengli and Jilin has reached densely-spaced class. These fields locate in the extensional basin of eastern rift belt bearing such features as multi-pays, multi-faults and small-scale fault blocks, which leads to difficulty for building fine geological model. This paper, focusing on this type of fields and taking the case of Quan4 Member in central Fuyu oil field as an example, proposes a scheme of geological modelling methodology. 1) Based on the densely-spaced well data and constrained by 3D seismic interpretation, first conducting layer division and correlation, small-scale fault identification and micro-tectonics study. 2) Then constructing fault models in order of scale, and establishing horizon model by 3 steps of "frame grid key surface single layer surface". So the structural model reflects an accurate contact relationship between layers and faults. 3) Then adopting the multi-iteration under facies-control stochastic methodology to improve the sandbody model accuracy, and applying stochastic modelling methodology of "sand and facies control" especially to reservoir parameters, controlling the boundary by sandbody model and taking variogram analysis in different microfacies. 4) Finally, verifying the reliability of the proposed methodology by means of probability distribution accordance and cross-validation.