胶结作用在深埋藏砂岩孔隙保存中的意义

在储层演化中 ,砂岩中很多胶结作用都是重要的保持性成岩作用 ,是深埋藏条件下砂岩孔 隙得以保持的重要机制。该文根据东海盆地古近系、 鄂尔多斯盆地上古生界和三叠系以及四川盆 地三叠系砂岩储层中(铁)白云石胶结物、 硅质胶结物和粘土矿物胶结物的产状、 胶结作用发生时间 和机制的研究 ,提出这些胶结作用很大一部分都发生在早成岩阶段有效压实作用发生之前 ,它们或 与埋藏早期的构造抬升有关 ,或与煤系地层早期酸性流体有关。这种分散的早期胶结作用可以提 高岩石机械强度 ,增加岩石的抗压实能力 ,改变以后浅埋藏 -深埋藏过程中岩石的孔隙度2深度曲 线 ,最终使砂岩孔隙在深埋藏条件下得以保存 ,这在储层质量预测中具有重要意义。

The significance of cementation in porosity preservation in deep-buried sandstones

Cementation in sandstone is very important retention processes in reservoir evolution , which enables porosity in deepburied sandstones to preserve. Based on the studies of occurrences of dolomite (ankerite) cement , quartz cement and clay cement and the timing and mechanism of cementation from Paleogene sandstone of East China Sea Basin , Upper Paleozoic and Triassic sandstone of Ordos Basin and Triassic sandstone of Sichuan Basin , a suggestion that large part of cementations occur at the early stage of diagenesis before effective compaction is presented here. Some of these cementations are related to tectonic uplift during earlier burial , and some to early acid fluid in coalbed. Partial and early cementation could enhance the mechanical strength of rocks and the resistance to porosity loss with depth and compaction by change of the porosity depth curve during shallow to deepburial diagenesis , which takes a significant part in reservoir quality prediction.