苏北盆地高邮凹陷阜宁组储层次生孔隙成因机制探讨

The Mechanism of Secondary Pores in the Reservoir of Funing Formation in Gaoyou Depression of Subei Basin

高邮凹陷阜宁组储层为低渗透储层,次生孔隙是储集空间的主要组成部分。研究认为,大气等淡水淋滤水、有机质演化形成的有机酸、粘土矿物转化形成的层间酸性水等产生的溶蚀作用是次生孔隙形成的主要原因,各种因素在时间和空间上的有机配置及相互作用对次生孔隙的形成具有重要的影响。在分析次生孔隙成因机制的基础上,利用声波、密度及中子测井对次生孔隙进行建模,编制程序进行了预测。综合分析表明,纵向上阜三段储集层次生孔隙的发育最佳,横向上沙埝南—富民北一带是油气勘探的有利区带,据此进行勘探施工证实了次生孔隙预测的准确性。

The secondary pores that account for a great proportion of the Funing Formation in Gaoyou Depression is the main part of reservoir spaces. The development mechanism of secondary pores may have three types： the first is the leakage of water from ground ; the second is dissolution from the thermal evolution of organic matter in mudstones ; the third is dissolution related to the clays. The interactions of all factors have important effect on secondary pores. Based on the analysis of mechanism of secondary pore, the method used to calculate secondary pore is got from the datum of AC,EDN, and CNL. Above of all, the formation of Fu 3 Member is the best in Funing Formation and the secondary porosity is the highest, so the area to be explored should be located in the region from the south of Shanian to the north of Fumin.