西湖凹陷北部花港组深部储层次生溶蚀带分析

Analysis of Secondary Dissolution Zone in the Deep Reservoir of Huagang Formation in the North Area of Xihu Sag

陈琳琳 巩兴会 李昆

CHEN Linlin GONG Xinghui LI Kun

中国石油化工股份有限公司上海海洋油气分公司勘探开发研究院, 上海 200120

Institute of Exploration and Development, SINOPEC Shanghai Offshore Oil & Gas Company, Shanghai 200120, China

西湖凹陷北部花港组深部储层成岩作用研究是深部有利储层预测的基础工作。西湖凹陷北部GZZ构造四口钻井取样分析揭示了深部储层次生溶蚀带分布特征，分析指出其主控因素有两点：（1）砂岩成分构成提供了后期改造溶蚀空间，自生石英增强了抗压实能力；（2）成岩环境酸碱性转换控制了溶蚀与胶结两个成岩过程。酸性溶蚀环境下长石、岩屑溶蚀以及伊蒙混层黏土转换极大地改善了储层孔渗条件，而碱性成岩环境下的碳酸盐重结晶、连晶胶结作用，以及绿泥石、伊利石自生黏土析出堵塞孔喉，致使储层物性变差。

The study of diagenesis in the deep reservoir of Huagang Formation in the north area of Xihu Sag is the base for the prediction of deep favorable reservoir. Based on the analysis data of samples from four wells drilled at structure GZZ, the distribution characteristics of secondary dissolution zones in the deep reservoir were concluded. It shows that there are two controlling factors controlling the petrophysical properties of the deep reservoirs:(1) the unstable components of sandstone provided the dissolution space in later stage, and authigenic quartz enhanced the compaction resistance of sandstone to some extent; (2) the alternation of acidic and alkaline digenesis environment controlled the corrosion and cementation. In acidic environment, the dissolution of feldspar and debris and the mineral transition of mixed-layer illite/smectite significantly improved the petrophysical properties of the deep reservoirs; In alkaline environment, however, the recrystallization and interlocking cementation of carbonate, pore throat plugging caused by precipitation of authigenic clay (chlorite and illite) deteriorated the petrophysical properties of the deep reservoirs.

https://doi.org/10.3969/j.issn.1008-2336.2016.02.012