西湖凹陷KX构造平湖组储层特征及主控因素研究

Reservoir Characteristics and Main Controlling Factors of the Pinghu Formation of KX Structure of Xihu Depression

西湖凹陷KX构造始新统平湖组是重要产气层系。利用大量薄片、岩心和分析化验资料,对该平湖组储集层进行了详细的岩石学特征、储层物性分析以及影响储层发育的主控因素的研究。结果表明,该套储层的岩石类型以长石岩屑质石英砂岩主,填隙物丰富、分选中等一好、成分成熟度低、磨圆程度高;孔隙类型以次生孔隙为主;喉道类型以片状、弯曲片状喉道为主;孔喉组合类型为中孔小喉、小孔小喉组合;储层物性较差,为低孔低渗储层;平湖组储层主要受潮汐改造的分流河道微相控制,压实作用、胶结作用、溶蚀作用和破裂作用等成岩作用是研究区储集层物性的主要控制因素。

The study on KX structure in the Xihu depression is one of the key regions of the present offshore exploitation targets. The petrographical reservoir characteristics, the reservoir development characteristics and the main control factors on hydrocarbon accu- mulation have been studied by using large number of thin-sections and core data, and other analytical testing data. The study results indicate that the reservoir rocks are dominated by feldspar lithic quartzite sandstone, with rich pore-filling contents, being well-sorted, with low composition maturity, and high-rounded. The pore types are mainly secondary pores. The throat types are mainly laminated and curved lamellar throat. The pore structure feature is mainly mesoporous-small throats and small pores throats. The reservoirs are characterized by low porosity and permeability. The reservoir rocks were deposited under the control of distributary channel, and the main controlling factors on sandstone reservoirs in Pinghu formation are diagenetic compaction, cementation and dissolution.