歧南断阶带深层沙二段砂岩成岩演化特征与孔隙保存

歧南断阶带的成岩-孔隙演化模式表明,研究区内特定的成岩-孔隙演化史有利于深层沙河街组二段砂岩孔隙的保存.这一演化史的典型特征包括:储层深埋时间短;烃类流体侵入砂岩孔隙较早;快速埋藏期间的超压流体活动;碳酸盐胶结不普遍;石英的压溶作用受到抑制.各成岩动力学过程与孔隙演化之间的时空组合是导致研究区深部发育砂岩储层的直接原因.深层砂岩孔隙的发育程度及保存状况与各成岩动力学过程间的匹配关系极为密切.

DIAGENESIS EVOLUTION AND PRESERVATION OF POROSITY IN THE MEMBER 2, SHAHEJIE FORMATION, QI'NAN FAULT-STEP ZONE

The diagenesis-porosity evolution history is beneficial to porosity preservation of Shahejie Formation at great depths in the vicinity of Qi'nan fault-step zone, Bohai Bay. The most important of these characteristics include: short-term bury of Shahejie sandstones at present depths; overpressure fluid development during the quick bury; hydrocarbon fluid intrusion prior to distinctive reduction of sandstones porosity; sporadic carbonate cementation; and inhabitation of quartz pressure solution. The preservation and development of porosity in the deeply buried sandstones are closely related to the interactions between different diagenetic dynamic processes and porosity evolution.