四川盆地上三叠统砂岩储层特征研究

根据134口井的岩石学、物性等资料，较系统地描述了四川盆地上三叠统须家河组砂岩储层特征及其主要影响因素：该组发育须二段、须四段和须六段3套厚层砂岩，岩石类型主要以长石岩屑砂岩、岩屑长石石英砂岩、长石石英砂岩为主，以岩屑长石砂岩、岩屑砂岩和石英砂岩为辅，其岩石组份随物源的变化而变化，从须二段到须六段岩石中岩屑含量逐渐增多，其中长石岩屑砂岩为富气岩石类型；砂岩剩余原生粒间孔、粒间及粒内溶孔为主要储集空间，杂基孔和微裂缝为次要储集空间，剩余原生孔隙的发育程度决定了储层的基本储集性质，次生孔隙的发育决定了优质储层的发育；储层致密主要是由早期压实和晚期胶结作用造成，而溶蚀作用和绿泥石衬边则起到增大和保护孔隙的作用，为有利的成岩作用。

Characteristics of Upper Triassic Sandstone Reservoirs in Sichuan Basin

Based on the petrologic data of 134 wells, the characteristics and the main controlling factors of the upper Triassic sandstone reservoirs in Sichuan Basin are systematically described．There developed three sets of thick sandstone sediments. The reservoir lithology is mainly feldspathic litharenite, feldspar lithic quartz and feldspar quartz sandstone, secondarily lithic arkose, lithic and quartz sandstone, and the components of rock change with matter source and the content of debris gradually increases from xu2 to xu4; the feldspathic litharenite sandstone is the rich gas sandstone. The main reservoir space includes primary intergranular pores, innergranular pores and intergranular pores (intergranular dissolved pores), the secondary reservoir space includes matrix pores and microcracks; the development degree of primary intergranular pores decide the basic properties of the reservoir. The secondary pores decide the development of excellent reservoirs．The main diagenetic events, causing the reservoir to become tight include early compaction and late cementation; dissolution and chlorite cementation are favorable diagenesis which protect and enlarge pores．