四川盆地川中地区须家河组气藏地震检测

The seismic detection of gas bearing for Xujiahe Formation in the middle of Sichuan Basin

四川盆地上三叠统须家河组蕴藏着巨大的天然气资源,是四川盆地重要的勘探开发层系。但勘探开发实践表明,须家河组储层厚度纵横向变化大、非均质性较强,气水分布关系非常复杂,严重影响了须家河气藏的勘探开发效益。准确进行气水识别,提高含气富集区预测精度,对须家河气藏规模效益开发至关重要。以岩石物理分析和模型正演为基础,分析了含不同流体储层的地震响应特征,建立了气、水层的AVO近、远道剖面识别模式,形成以AVO主振幅主频率为核心的地震气层检测技术系列,在川中地区安岳—高石梯等多个区块进行气水检测及含气富集区预测,预测成果的可靠性得到了大批新钻井的证实。

The tight sand reservoir in Xujiahe Formation of Upper Triassic in Sichuan Basin contains huge resources of natural gas,it is one of the most important exploration and development layer system.Practice shows that the Xujiahe Formation gas reservoir is very complex：Thin reservoirs,strong heterogeneity,complex distribution of gas and water,so it seriously affects the Xujiahe gas reservoir exploration and development benefits.How to accurately identification the gas and water and improve the prediction accuracy of gas enrichment zone is essential to the development of the gas reservoir.Based on the analysis of reservoir rock physics and forward modeling,this study summarizes the AVO response characteristics of gas and water layer,establishes a new method of near stack section and far stack section comparative analysis and forms the key method of Main amplitude and Main frequency technique.The methods are used to detect gas and water and forecast gas-rich region in many blocks at Anyue-Gaoshiti areas in the middle of Sichuan Basin,and the reliability of the prediction results has been confirmed by a large number of new drilling wells.