川东北地区长兴组-飞仙关组礁滩相储层预测

Prediction of reef and shoal facies reservoirs in Changxing-Feixianuan Formations in northeastern Sichuan basin

普光气田有典型的台地边缘斜坡相沉积,在斜坡上沉积大型礁滩相储层,礁滩相储层出现比较明显的烟囱效应———地震剖面表现为波阻杂乱和中断,出现下拉。通过对已知气田分析建立起储层预测方法,在川东北地区进行全面的储层预测应用。研究发现,通南巴构造带上的马路背构造和苍溪九龙山构造存在典型的台地边缘相层序地层特征。预测的苍溪礁滩相具有典型的进积型层序地层特征,在地震剖面上并且具有可靠的波组下拉现象。预测苍溪一带有可能存在一个特大型长兴组-飞仙关组礁滩相气田。马路背礁滩相层序地层特征和普光气田基本上相同,为一个斜坡带,其上可能发育大型礁滩相储层,预测可能为一个大型气藏。

Puguang gas field has typical slope facies on platform margin. Large reef and shoal facies reservoirs have been deposited on the slope with relatively obvious chimney effect, i.e. chaotic and disrupted wave groups with push-down shape. The reservoir prediction method has been developed on the basis of analyzing the known gas fields. It is then used to make a comprehensive prediction of the reservoirs in northeastern Sichuan basin. It is found that the Malubei structure in Tongnanba structural zone and Jiulongshan structure in Cangxi County show the characteristics of typical sequence stratigraphy of platform margin facies. The predicted Cangxi reef and shoal facies show the characteristics of typical progradational sequence stratigraphy with reliable push-down. It is predicted that there would possibly be a super large reef and shaol facies gas field in Changxing-Feixianguan Formations in Cangxi area. The sequence stratigraphic characteristics of the Malubei reef and shoal facies are basically the same with that in Puguang gas field, i.e. would have been developed. It is, therefore, predicted a slope zone where large reef and shoal facies reservoirs that there would be a large gas reservoir.