用波形分析法预测滨浅湖滩坝砂岩储层:以东营凹陷西部地区沙-4上亚段为例

Prediction of Beach-bar Sand Reservoirs Using Waveform Analysis:A Case Study on Es4s in the West Area of the Dongying Sag

滩坝砂岩具有砂泥互层、单砂层厚度薄、并含有灰质白云质等高速夹层等特点,这些因素增大了滩坝砂岩储层的地震识别及预测难度.根据滩坝砂的实际岩性组合类型,用波形分析法对东营凹陷西部地区沙-4上亚段滩坝砂岩进行了储层预测.首先对滩坝砂岩常见的3类地震波形进行定义,建立了不同类型滩坝砂岩储层地震波形特征的实际正演模型;通过学习型地震波形预测技术,分析了不同岩性组合的地震波形特征,总结了波形模式与地层组合样式之间的关系;最后利用实际井资料作为约束对研究区地震波形进行了分类区划,明确了滩坝砂岩有利储层发育范围.

Beach-bar reservoirs are characterized by sand-mud interlayering, thin sand strata, and high seismic velocity of carbonate interbeds, which increases the difficulty of seismic interpretation and reservoir prediction. Based on the lithologic combination of the beach-bar sand of Es4s in the western Dongying sag, seismic ＂waveform＂ analysis was applied to its reservoir prediction. Firstly, we defined three dominate types of the waveform of the beach-bar sand and established the actual seismic forward models for different lithological combinations of beach bar reservoir. Then, by studying actual seismic for- ward model, the waveform characters of different lithologic combinations were analyzed. Relationships between the waveform modes and the different lithologic combinations were generalized as well. In the end, the seismic waveforms were classified by restriction of logging data, and the scope of beneficial beach-bar reservoir was defined.