中深层“甜点”储层地震预测方法探讨——以珠江口盆地西部文昌A凹陷为例

Seismic prediction method of “sweet” reservoir in middle-deep zone: A case study from Wenchang A sag, western Pearl River Mouth Basin

珠江口盆地西部文昌A凹陷古近系受埋藏深度及成岩压实作用的影响,普遍发育低孔、低渗储层,地震反射表现为连续性差、信噪比低的特征。面临"甜点"储层预测及烃类检测等难题,回避了依赖于测井岩石物理分析结果的常规地球物理技术,而是通过优势道分频属性技术对低孔、低渗储层进行定量预测,同时立足于测井岩石物理分析结果,并基于测井曲线重构的叠前反演技术对低孔、低渗储层进行半定量预测。实验表明,这2种技术在该区低孔、低渗储层预测中均有一定的效果,值得进一步推广。

Influenced by buried depth and diagenetic compaction, low porosity and low permeability reservoir developed in Paleogene in Wenchang A sag of the western Pearl River Mouth Basin. The seismic reflection characteristics were characterized by poor continuity and low signal-to-noise ratio, so it is difficult to carry out reservoir prediction and hydrocarbon detection. To solve this fundamental problem that conventional geophysical method is difficult to achieve an effective application due to the general overlay of rock physics parameters, the frequency dividing attribute technique of advantage trace was applied to qualitatively predict low porosity and low permeability reservoir by avoiding geophysical technology depending on logging petrophysical analysis results, which depends on totally seismic data. Meanwhile, based on logging petrophysical analysis results, prestack inversion based on curve reconstruction was used to semi- quantitatively predict low porosity and low permeability reservoir. Through test, both the two methods have a certain effect for predicting low porosity and low permeability reservoir, so they are worthy of further promotion.