松辽盆地龙西地区泉四段砂岩成岩作用对储层物性的影响

Influence of Quan 4 Formation Sandstone Diagenesis on Reservoir Properties in Longxi Region,Songliao Basin

通过岩心观察、镜下薄片、扫描电镜和X衍射分析等资料,对松辽盆地龙西地区泉四段砂岩成岩强度、成岩作用类型及其对储层物性的影响进行了研究,根据自生矿物和古地温特征,认为:龙西地区泉四段砂岩为中成岩阶段A期,且细分为A1亚期和A2亚期;龙西地区泉四段的结构成熟度中等的长石岩屑砂岩和岩屑质长石砂岩,发生的主要成岩作用类型有压实作用、胶结作用、交代作用和溶蚀作用;压实作用和胶结作用使得原生孔隙减小,物性变差,而溶蚀作用使得储层孔隙结构得到改善,储层物性变好,在1 600～2 000 m形成次生孔隙发育带。

Based on the analysis of rock slides, casting slides, scan electron microscope and X ray diffraction etc, the characteristics of diagenetic evolution of clastic sandstone in Quan 4 Formation at Longxi region, Songliao basin are studied. The diagenesis in Quan 4 Formation is in the mesogenetic stage, and is subdivi- ded as A1 and A2 stages. Four types of diagenesis are recognized, including compaction, cementation, dis solution and metasomatism. The compaction and cementation destroy the primary pore structure intensively, and dissolution betters the pore structure effectively. Secondary porosity zones are developed in 1600- 2000 meters.