石油与天然气地质 ›› 2011, Vol. 32 ›› Issue (1): 56-63.doi: 10.11743/ogg20110107

• 石油与天然气地质 • 上一篇    下一篇

四川盆地东北部长兴组-飞仙关组各沉积相带储层特征

  

  • 出版日期:2011-02-28 发布日期:2011-04-28

Reservoir characteristics of different sedimentary facies in the Changxing and Feixianguan Formations, northeast of the Sichuan Basin

  • Online:2011-02-28 Published:2011-04-28

摘要:

四川盆地东北部晚二叠世长兴组与早三叠世飞仙关组具有较大的天然气勘探潜力,储层主要发育在台地边缘礁滩相、局限台地相、开阔台地相及台缘斜坡-陆棚相中。利用测井解释资料以及样品实测资料,对达县宣汉、通南巴及元坝3个区块中长兴组-飞仙关组不同沉积相带的岩石物性特征进行了归纳统计与对比研究。结果表明,沉积相控制了沉积岩石类型,而不同岩石类型因内部结构差异及原生孔隙差异又导致不同相带的储层物性差异,沉积环境能量越高的相带越有利于优质储层的发育;台地边缘礁滩相储层岩石物性最好,主要构成孔隙型的Ⅱ类储层,台地相储层岩石物性次之,主要构成裂缝-孔隙复合型Ⅲ类储层,台地边缘斜坡-陆棚相储层岩石物性最差,只能形成裂缝型储层。综合研究认为,寻找优质储层,依然是优先寻找有利于形成优质储层的台地边缘礁滩相带。

关键词: 关键词:岩石物性;储层特征;沉积相, 长兴组;飞仙关组;四川盆地

Abstract:

Previous exploration activities indicate that the Changxing Formation of the Late Permian and the Feixianguan Formation of the Early Triassic in northeast of Sichuan Basin have great potential of gas discoveries. The reservoirs are mostly developed in platform margin reef & bank facies, restricted platform facies, open platform facies and platform margin rampcontinental shelf facies. In order to deepen the understanding of the reservoir characteristics,we studied the petrophysical characteristics of rock samples from different sedimentary facieses in the two formations from three blocks namely as Xuanhan, Tongnanba and Yuanba in Da County of Sichuan Province based on available log interpretations and sample test results. It turns out that the sedimentary facies controlled the rock types, which in turn result in varying reservoirs petrophysical characteristics due to differences in internal textures and primary porosity. It also points out that reservoirs are better developed in facies deposited in an environment with higher energy. Reservoirs in the platform margin reef & bank facies have the best petrophysical characteristics and are of porous types (type Ⅱ). The platform facies contains complex reservoirs of fractureporosity type (type Ⅲ) with second best petrophysical characteristics. The reservoirs in the platform margin rampcontinental shelf facies have poor petrophysical characteristics and are of fracture type. We therefore suggest that the platform margin reef & bank facies be the focus of exploration activities.