下扬子地区五峰组—高家边组页岩气形成条件

 页岩气是一种清洁、高效的非常规能源。通过露头观测、钻井资料、有机地化与储集物性等资料，分析了下扬子地区上奥陶统五峰组—下志留统高家边组页岩的沉积环境、厚度、分布、埋深、有机质丰度、类型、热演化程度、孔缝特征及岩石矿物组成等。研究结果表明，该页岩主体为陆棚沉积，沉积厚度大，主要分布在300~400m之间、埋深适中；页岩有机碳含量主要分布在0.5%~1.0%之间，有机质类型为Ⅰ型和Ⅱ型，镜质组反射率主体分布在1.5%~2.5%之间，处于高成熟-过成熟阶段；页岩石英含量较高，普遍分布在34.2%～55.1%之间，微裂缝发育，有利于压裂改造。研究表明页岩气形成的有利区分布在苏北高邮—海安—句容、皖南泾县—宁国和浙西临安等地区。

Geological Conditions of Shale Gas in the Wufeng-Gaojiabian Formations in Lower Yangtze Area

In order to meet the need of further reservoir development it is essential to improve the cartographic accuracy of the microfacies map for clastic rock reservoirs, especially to enhance its prediction capability in the cross well area. In the second fault block of the Pubei oil field in Daqing placanticline, the reservoirs and the surrounding rocks of the Putaohua Formation can not be differentiated only according to the acoustic attributes; therefore, a cartographic method which combines the single well facies with the quasi-impedance results is proposed. Firstly, from all the logging attributes, the optimum logging attribute which can differentiate the reservoirs and the surrounding rocks is chosen. A spontaneous potential attribute is chosen in the Putaohua Formation. Secondly, the seismic inversion is processed by using the quasi-impedance logging curve and adding the information of the spontaneous potential curve. Thirdly, the cross well microfacied types can be predicted by the inverted sand thickness; the channel width in the map can be calculated based on the inversion information; and the whole pattern of the microfacies map can be determined on the basis of the quasi-impedance inversion slices. Finally, the microfacies map is completed after the calibration of the single well facies. The real application shows the high accuracy and the practicability of the new mapping method, for the reservoir development and adjustment.