东海西湖凹陷砂岩硅质胶结物成因机制探讨

Discussion on the Formation Mechanism of Siliceous Cement in the Sandstone of Xihu Sag East China Sea

庄建建

ZHUANG Jianjian

中国石油化工股份有限公司上海海洋油气分公司研究院, 上海 200120

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

东海西湖凹陷古近系平湖组、花港组深部储层岩屑砂岩、长石砂岩中硅质胶结物普遍存在，硅质来源主要有长石、岩屑溶蚀、黏土转换以及碱性溶蚀，酸性溶蚀环境对石英次生生长最为有利，但构造活动对石英次生生长也有影响。研究表明：无论结晶还是溶蚀，自生石英的生长机制既动态地反映了成岩环境物理化学条件，也反映了成分成熟度、流体势、烃源岩成熟窗口以及黏土脱水等地质因素。因此，硅质胶结物的发育不仅影响深部储层物性，反映成岩事件影响，还记录了埋藏过程中重大地质变动的信息，对于深化成藏认识具有重要作用。

The siliceous cement is widespread in the lithic sandstone and arkose of the deep reservoir of Paleogene Huagang and Pinghu Formations in Xihu Sag, East China Sea. The silicon comes from the dissolution of feldspar and debris, clay conversion and corrosion in alkaline environment. The acidic corrosion environment is most favorable to the growth of secondary quartz,and the tectonic activities also have an impact on it. The study shows that the growth mechanism of authigenic quartz dynamically responses to the physical and chemistry condition of diagenesis environment, and also indicates the geological factors such as compositional maturity, fluid potential, hydrocarbon generation window of source rock and clay dehydration. Therefore, the development of siliceous cement not only affects the physical property of reservoir, reflects the influence of diagenetic event, but also records the signifcant information of geological movement occurred during the long burial process. It is of great importance in deepening the acknowledge of hydrocarbon accumulation.

https://doi.org/10.3969/j.issn.1008-2336.2018.01.009