松辽盆地彰武断陷九佛堂组碎屑岩储层特征研究

通过岩心观察、显微镜下常规及铸体薄片鉴定、扫描电镜、X-衍射等分析,对彰武断陷九佛堂组储层成岩作用、孔隙特征及其对储集物性的影响进行了研究。九佛堂组储层成岩作用类型主要有压实作用、胶结作用和溶蚀作用,其成岩作用主要为中成岩阶段A期;黏土矿物成岩作用顺序为黏土包壳—压实作用—早期溶蚀作用—绿泥石—伊利石—次生石英加大—微晶石英—钠长石—方解石—晚期溶蚀作用;孔隙类型主要包括原生孔隙和次生孔隙,次生孔隙包括溶蚀粒间孔隙、超大孔、溶蚀粒内孔隙、铸模孔、裂缝孔;储层主要为一套扇三角洲前缘沉积,岩石类型、黏土含量、成岩作用以及沉积微相是影响优质储层分布的主要因素。

Characteristics of clastic rock reservoirs in Jiufotang Formation,Zhangwu Depression,Songliao Basin

The diagenetic effect, porosity and its influence on physical properties of clastic reservoirs in the Jiufotang Formation in the Zhangwu Depression were analyzed by means of core observation, ordinary and casting thin section microscopic identification, SEM and X-ray diffraction. Compaction, cementation and erosion effects are common in the Jiufotang Formation, and are mainly in stage A of the middle diagenetic phase. The diagenetic process of clay minerals was described as clay rim, compaction, early dissolution, chlorite, illite, secondary quartz overgrowth, micro quartz, sodium feldspar, calcite and late dissolution. Both primary and secondary pores were found. The secondary pores include intergranular dissolution pores, giant pores, intragranular dissolution pores, mold pores and fracture pores. A set of fan delta front sediments provided reservoirs. Rock type, clay content, diagenetic effect and sedimentary micro-facies influenced the distribution of high-quality reservoirs.