四川盆地蜀南地区嘉二段低孔低渗储层特征及控制因素

Characteristics and controlling factors of low porosity and low permeability reservoir of the second member of Jialingjiang Formation in southern Sichuan Basin

针对四川盆地蜀南地区嘉二段储层薄、非均质性强的特点,利用岩心、岩石薄片、岩石物性和测井资料,对储层岩石特征、成岩作用、储集空间类型、储层物性及控制因素进行了研究。结果表明,研究区内优质储层基本发育在白云岩中,尤其是鲕粒白云岩和泥粉晶白云岩。其中鲕粒白云岩的形成与鲕粒灰岩早期白云石化有关,发育粒内溶孔;泥粉晶白云岩是泥晶灰岩经历准同生白云石化作用形成的,发育多种溶孔;鲕粒白云岩和泥粉晶白云岩均发生埋藏白云石化作用和埋藏溶蚀作用。储层总体具有低孔、低渗特征,储集性能受古隆起、沉积相和成岩作用的影响,分布在古隆起东南部局限台地的白云岩以及全区浅滩颗粒岩均为该区有利储集岩。

Based on core observation, casting thin sections, physical properties and logging data, this paper studied the petrologic characteristics, diagenesis, reservoir space types, physical properties and controlling factors of the reservoir of the second member of Jialingjiang Formation in southern Sichuan Basin. The results show that high-quality reservoir is mainly developed in dolomite, especially in oolitic dolomite and micritic dolomite. The formation of oolitic dolomite is related to early dolomitization, and that of mieritic dolomite is due to the dolomitization of micrite along with burial. Reservoir spaces of oolitic dolomite include intragranular dissolved pore, and the main pore types of micritic dolomite are dissolved pores and intracrystalline dissolved pores. The reservoir has the properties of low porosity and low permeability. Reservoir qualities are affected by palaeohigh, sedimentary facies and diagenesis. The restricted platform dolomite in the southeastern palaeohigh and grain beaches are favorable reservoirs.