前陆层序致密储层的单因素成岩相分析

Single factor diagenetic facies analysis of tight reservoir in western Sichuan foreland basin

对川西前陆盆地上三叠统的构造、沉积和成岩单因素进行了分析,并利用井资料对单因素成岩相进行了约束划分。在此基础上进行了平面叠加,确定了综合成岩相。在川西前陆盆地可以识别出前陆层序和非前陆层序,须二段是前陆层序中的油气储集体发育段,可划分出8种单因素成岩相,即压实压溶成岩相、碳酸盐胶结交代成岩相、石英次生加大成岩相、粘土矿物(伊利石)胶结交代成岩相、绿泥石衬边胶结成岩相、不稳定组分溶蚀成岩相、破碎裂缝成岩相和有机质充填成岩相。其中,冲断带发育的压实—破碎—溶蚀成岩相及近前渊三角洲相砂体中发育的强压实—溶蚀—绿泥石衬边胶结成岩相均可形成较好的储层。

The structure, sediment and diagenetic single factor of reservoirs in the western Sichuan foreland basin of the Upper Triassic were analyzed, and the single factor diagenetic facies of this area were divided under the restriction of well data. By superposing the single factor diagenetic facies, the comprehensive diagenetic facies were determined. The reservoir of Xu-2 Member of the Upper Triassic in the western Sichuan foreland basin can be divided into eight kinds of single factor diagenetic facies including compaction-pressolution facies, carbonate cementation facies, quartz secondary enlargement facies, lining chlorite facies, dissolution facies, fracture facies and organic matter filling facies. The compaction-fracture-dissolution facies of thrust belts and compactlon-dissolution-lining chlorite facies in sandstone of prodelta facies are favorable for reservoir formation.