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胜利油田东营凹陷主要储层砂岩自始新世形成以来经历了至少四期流体的活动,这四期流体与砂岩的相互作用通过矿物溶解、胶结及脉体充填等成岩事件而表现出来。作用过程中溶解作用使砂岩孔隙度增加,改善储层质量;而胶结作用通常使孔隙度减少,伤害储层或破坏储层,但早期胶结作用形成的粗晶碳酸盐矿物可以支撑格架颗粒,阻止后期的压实而导致孔隙“坍塌”。通过东营凹陷坨胜永断裂带和中央背斜及凹陷带沙三段(Es3)和沙四段(Es4)段储层砂岩薄片镜下观察,胶结物电子探针成分分析,综合其它资料得出:第一期流体与砂岩相互作用发生在孔店晚—沙四晚期,以方解石+石膏胶结为标志;第二期发生在沙三—东营(Ed)末,以粗晶“马鞍状”白云石为标志;第三期发生在馆陶(Ng)沉积时期,以微晶含铁白云石为标志;第四期发生在馆陶沉积之后,以铁白云石脉为标志。
The main reservoir sandstone in the Dongying Sag of Shengli Oilfield has undergone at least four stages of fluid activity since the Eocene. The interaction between the four fluids and sandstones is manifested by diagenetic events such as mineral dissolution, cementation and vein filling. During the dissolution process, the porosity of sandstone is increased and the quality of the reservoir is improved. However, the cementation generally reduces the porosity and damages the reservoir or destroys the reservoir. However, coarsely-grained carbonate minerals formed by early cementation can support the framework particles , To prevent the latter compaction and lead to porosity “collapse ”. Through the observation of the thin sandstones in the Tuosheng-Yongzhai fault zone, central anticline and sag zone Es3 and Es4 of Dongying Sag and the electronic probe composition analysis of the cement, the other data shows that: The first phase of interaction between fluid and sandstone occurred in the later period of Kongdian-Shadian, with calcite and gypsum cementation as the markers. The second occurred in the end of Sha 3-Dongying (Ed) with coarse grains, “saddle-shaped” white clouds The third period occurred in the sedimentary period of Ng and was marked by microcrystalline iron-bearing dolomite. The fourth occurred after the deposition of Guantao and was marked by an iron dolomite vein.